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A pile group under lateral loading is a complex pile‒soil-pile interaction problem. In this study, numerical analysis was used to investigate the lateral behavior of pile groups arranged in a 3 × 3 configuration with varying piles spacings. The hypoplastic constitutive model embedded into ABAQUS software through the UMAT subroutine was used to characterize the stress‒strain relationship of Toyoura sand. The effects of the pile spacing on the load‒displacement relationship of the pile group, the bending moment-depth relationship of each pile in the pile group, the deflection-depth relationship, and the soil resistance distribution were investigated. The results indicate that the lateral bearing capacity of the pile group decreases by more than 50% when the pile spacing is reduced from 7D to 3D. When the pile spacing is greater than 5D, the "edge effect" of the laterally loaded pile group gradually decreases, and when the pile spacing is greater than 7D, the "shadowing effect" can be negligible, and the wedge-shaped failure zone of the pile group occurs within a depth of 5D below the mud surface. [ABSTRACT FROM AUTHOR]

This study builds on existing researches to further investigates cyclic responses of the steel tube-confined reinforced concrete (RC) columns, with a primary focus on those subjected to high-axial load. A total of eleven column specimens were tested under lateral displacement reversal and axial load of either 0.3Ag fcm,c or 0.5Ag fcm,c , where Ag and fcm,c refers to concrete cross section area and tested concrete strength of the column, respectively. Three specimens represented the conventional reinforced concrete (RC) columns while the rest were the steel tube-confined circular RC columns. The key test parameters included (1) amount of longitudinal reinforcement, (2) axial load level, (3) continuity of the confining steel tube, and (4) clear cover of the longitudinal reinforcement. Test results showed that all the steel tube-confined RC specimens sustained the target axial load and maximum lateral strength up to around 10% drift ratio. A simple strength model was proposed to reasonably estimate the maximum strength of the steel tube-confined RC columns. The flexural rigidity ratio, (EI)test/Ecm,cIg , for RC specimens and specimens confined by continuous steel tube ranged between 0.6 and 0.8, approximately. Specimens confined by the cutoff steel tube showed lower (EI)test/Ecm,cIg ratio between approximately 0.3 and 0.6. [ABSTRACT FROM AUTHOR]

Self-centering columns (SC), while attracting interest for their high recoverability, do not dissipate seismic energy as efficiently as conventional reinforced concrete or steel columns, potentially leading to a more significant seismic response. This study proposes a concept aimed at enhancing both energy dissipation during earthquakes and postearthquake restoration performance. This is achieved by exhibiting an SC capacity only during restoration. The proposed aseismic column consists of a central component, the SC core constructed from steel tubes filled with high-strength mortar, and energy-dissipation (ED) components made from steel plates. This SC core generates a moderate SC force sufficient to counteract the P-Δ effect. Given the minimal SC force from the SC core, the plasticization effect of the ED components becomes more conspicuous during large earthquakes, resulting in the emergence of a spindle-shaped lateral load capacity, leading to residual displacement in the columns. During restoration after earthquakes, the SC force emerges when the ED components are removed. The residual displacements of the columns can be gradually reduced during this process. Cyclic loading tests are conducted on the proposed column prototype followed by removal tests of the ED components with vertical axial forces acting on the column with residual displacement. In the cyclic loading tests, we confirmed the superior ED performance of the proposed column prototype, although residual displacement occurred in the column. In the ED component removal tests, a substantial reduction in the residual displacement of the column was observed when the ED components were removed. Specifically, the residual displacements were reduced by up to 96.2%, to a value of only 0.13% of the column height. In conclusion, the proposed concept can achieve superior energy absorption during earthquakes and high restoration performance afterward. [ABSTRACT FROM AUTHOR]

Braced timber frames (BTFs) are an efficient lateral force resisting system that can effectively resist wind and earthquake loads. It is well-known that the performance of BTFs is strongly dependent on connection behavior, but clear design guidelines are not available for detailing ductile BTFs. Furthermore, conventional connections with steel fasteners can exhibit significant stiffness and strength degradation under earthquake loads and result in large residual deformations. There is a need for more resilient energy-dissipating connections for BTFs and other mass timber systems. This study investigates the behavior of dowel-type and bolted wood-steel-wood connections with superelastic nickel-titanium (NiTi) shape memory alloy (SMA) fasteners. Under bending, the SMA fasteners are able to effectively recover their original shape with negligible residual deformation, even after undergoing large deflections. The SMA connections tested in this research showed significant potential for self-centering. Post-test autopsies of the connection test specimens showed ductile deformation mechanisms and similar levels of wood crushing between the steel and SMA fasteners under cyclic loading. However, the connection displacement ductility ratios of 4.6 and 6.2 observed with SMA fasteners is not sufficient to meet the requirement for moderately ductile frames. Additional research is required to better understand and characterize the behavior of SMA connections at the component and connection levels. [ABSTRACT FROM AUTHOR]

To investigate how the curve radius parameter affects the safety of high-speed train operation in a wind–sand environment, researchers used the wind–sand section of the Lanzhou–Urumqi high-speed railway as their research backdrop. The Euler‒Lagrange method was used to discretize the sand particles based on train aerodynamics theory, and the wind–sand flow model of the head–middle– tail three-member formation was established. The accuracy of the model was verified by comparing the data from published papers, and then the train's wind– sand load was calculated and extracted. Subsequently, a dynamic model of a CRH2 train was created, and the dynamic response of the train was estimated by choosing various curve radii and adding wind–sand loads. The results demonstrated that as wind speed increases, the forces acting on the train due to wind rise. Due to the different shapes and positions of the carriages, the wind– sand load on each car differs; the middle car is subjected to greater lift, lateral force, and overturning moment, as well as lower resistance, nodding moment, and head shaking moment, while the head and tail cars move in the opposite direction and, as a whole, are exposed more adverse forces. The study found that when the curve radius increased from 7000 to 9000 m, the derailment coefficient and wheel-rail lateral force are reduced by approximately 29%~32%, along with an approximately 20%~23% decrease in the wheel load reduction rate. When the radius reaches 10000 m, there is a decrease in the derailment coefficient and wheel-rail lateral force of approximately 5%~8%, as well as a reduction in the wheel weight load reduction rate of approximately 3%~6%.It has been concluded that increasing the curve radius can significantly reduce the safety indices in the wind-blown sand environment, thus improving operational safety. However, it should be noted that a radius of 8000~9000 m is appropriate, and the effect of further increase is not obvious. The results of this study can provide certain guidance for the selection of curve radius and the evaluation of the operational safety of high-speed trains in windy–sandy areas. [ABSTRACT FROM AUTHOR]

Flying cars, or vertical takeoff and landing (VTOL) aircraft, are revolutionary devices that can address traffic congestion and help build a three-dimensional transportation system in the future. Flight safety could deteriorate in actual flight because ducted fans may suffer from significant thrust fluctuations induced by crosswinds. In this article, we propose a variable-speed control method to reduce thrust fluctuations by applying a speed waveform opposite to the fluctuation waveform. We choose a typical condition of a 5 m/s crosswind for validation. The results of unsteady Reynolds averaged Navier‒Stokes (URANS) calculations show that crosswinds lead to fluctuations in all thrusts with the frequency of the blade passing frequency. The total thrust fluctuation amplitude accounts for 6.2% of the total thrust. By applying the variable-speed control where the frequency is identical to the thrust fluctuation frequency, the phase difference is 180 degrees, and the amplitude is approximately the square root of the fluctuation amplitude, the standard deviation of the thrust fluctuation is reduced by 92% without affecting the mean total thrust. Fluctuations in other performance parameters, such as lateral force and pitching moment, are improved as well. This active control method can achieve accurate control without any auxiliary equipment and has good application prospects. It provides a promising idea for solving the problem of performance fluctuations in turbomachinery. [ABSTRACT FROM AUTHOR]

Ultra-low friction is crucial for the anti-friction, anti-wear, and long-life operation of nanodevices. However, very few two-dimensional materials can achieve ultra-low friction, and they have some limitations in their applications. Therefore, exploring novel materials with ultra-low friction properties is greatly significant. The emergence of ternary two-dimensional materials has opened new opportunities for nanoscale ultra-low friction. This study introduced nickel phosphorous trisulfide (NiPS3, referred to as NPS), a novel two-dimensional ternary material capable of achieving ultralow friction in a vacuum, into the large nanotribology family. Large-size and high-quality NPS crystals with up to 14 mm × 6 mm × 0.3 mm dimensions were grown using the chemical vapor transport method. The NPS nanosheets were obtained using mechanical exfoliation. The dependence of the NPS nanotribology on layer, velocity, and angle was systematically investigated using lateral force microscopy. Interestingly, the coefficient of friction (COF) of NPS with multilayers was decreased to about 0.0045 under 0.005 Pa vacuum condition (with load up to 767.8 nN), achieving the ultra-low friction state. The analysis of the frictional dissipation energy and adhesive forces showed that NPS with multilayers had minimum frictional dissipation energy and adhesive forces since the interlayer interactions were weak and the meniscus force was excluded under vacuum conditions. This study on the nanoscale friction of a ternary two-dimensional material lays a foundation for exploring the nanoscale friction and friction origin of other two-dimensional materials in the future. [ABSTRACT FROM AUTHOR]

The surging demand for sustainable and efficacious approaches of enhancing the ground has resulted in the investigation of novel waste materials. This study investigates the utilization of Polyoxymethylene (POM) as a granular column to ameliorate the ability of soft clay soil to resist horizontal loads. The study introduces a new implementation of polyoxymethylene columns as ground improvement approach to tackle the complexities related to soft clay soils. The capability of polyoxymethylene columns was analyzed through a sequence of laboratory experiments, containing engineering characteristic tests, unconfined compressive strength (UCS) tests, and consolidated isotropic undrained (CIU) triaxial tests. The effects of the number of columns, column diameter, column depth, substitute area ratio, depth penetration ratio, column aspect ratio, volume infusion ratio, and confining pressures, were evaluated to analyze the behavior of individual and clustered encapsulated polyoxymethylene columns. The findings verified a notable development in the ability of soft clay soil, when strengthened with polyoxymethylene columns, to oppose the lateral loads and maintain overall stability. Additionally, a regression analysis was implemented to establish a prediction model that estimates the increase in shear strength of POM columns based on different column dimensions. This model is a practical tool for evaluating the performance of reinforced soft clay soils in large-scale projects. This study not only accentuates the mechanical benefits of polyoxymethylene but also accentuates its environmental benefits, prescribing for the implementation of recyclable materials in ground renovation. [ABSTRACT FROM AUTHOR]

A seismic vibration control system, consisting of a swing story substructure, a lateral force resisting substructure and connecting dampers, is recently proposed. The analytical model and optimization method based on the stability maximization and H2 criteria have been established. In this paper, excellent vibration control effects of the proposed system are verified through the small-scale shaking table tests on a two-story model. Experimental results demonstrate the accuracy of the analytical model and the validity of the vibration control strategy. Through numerical analyses of benchmark structures, the input energy of the optimally designed system is remarkably mitigated, and favorable vibration control effects for reducing both inter-story drifts and absolute floor accelerations under earthquake ground motions are verified by comparing with conventional moment-resisting frame structures. In addition, significant control effects can be achieved when the optimal stiffness is greater than the critical buckling stiffness. A seismic design flow chart of the intensity-reduced design method is proposed based on the numerical analyses and the Chinese Seismic Design Code of Buildings. The results indicate that the seismic intensity-reduced design for the proposed system is feasible. [ABSTRACT FROM AUTHOR]

This article conducts experimental research on the influencing factors of the anti-skid performance testing system SCRIM for asphalt pavement. Studied the distribution pattern of anti-skid performance test results of the testing system under different testing speeds, test tires, temperature, water film thickness, test wheel position, tire wear degree, and other factors. Revealed the influence law of various influencing factors on the anti-skid performance of asphalt pavement. The test results indicate that the SFC test value decreases with the increase of vehicle speed. The test results of tires made of different materials vary greatly, and tires with wear exceeding 3 mm cannot be used for testing. The influence of water film thickness on the measured values varies depending on the SFC level. The SFC measurement value of the normal trajectory of the vehicle's driving wheel track is the smallest, and the measurement value of the left trajectory is greater than that of the right trajectory. The SFC measurement decreases as the tire wear increases. [ABSTRACT FROM AUTHOR]

Methane (CH 4) cycling in the Baltic Sea is studied through model simulations that incorporate the stable isotopes of CH 4 (12 C–CH 4 and 13 C–CH 4) in a physical–biogeochemical model. A major uncertainty is that spatial and temporal variations in the sediment source are not well known. Furthermore, the coarse spatial resolution prevents the model from resolving shallow-water near-shore areas for which measurements indicate occurrences of considerably higher CH 4 concentrations and emissions compared with the open Baltic Sea. A preliminary CH 4 budget for the central Baltic Sea (the Baltic Proper) identifies benthic release as the dominant CH 4 source, which is largely balanced by oxidation in the water column and to a smaller degree by outgassing. The contributions from river loads and lateral exchange with adjacent areas are of marginal importance. Simulated total CH 4 emissions from the Baltic Proper correspond to an average ∼1.5 mmol CH 4 m -2 yr -1 , which can be compared to a fitted sediment source of ∼18 mmol CH 4 m -2 yr -1. A large-scale approach is used in this study, but the parameterizations and parameters presented here could also be implemented in models of near-shore areas where CH 4 concentrations and fluxes are typically substantially larger and more variable. Currently, it is not known how important local shallow-water CH 4 hotspots are compared with the open water outgassing in the Baltic Sea. [ABSTRACT FROM AUTHOR]

Nanoparticle adhesion to polymer and similar substrates may be prone to low nano-Newton forces, disrupting the surface bonds and patterning, potentially reducing the functionality of complex surface patterns. Testing this, a functionalised surface reported for biological and medical applications, consisting of a thin plasma-derived oxazoline-based film with 68 nm diameter covalently bound colloidal gold nanoparticles attached within an aqueous solution, underwent nanomechanical analysis. Atomic Force Microscopy nanomechanical analysis was used to quantify the limits of various adaptations to these nanoparticle-featured substrates. Regular and laterally applied forces in the nano-Newton range were shown to de-adhere surface-bound gold nanoparticles. Applying a nanometre-thick overcoating anchored the nanoparticles to the surface and protected the underlying base substrate in a one-step process to improve the overall stability of the functionalised substrate against lower-range forces. The thickness of the oxazoline-based overcoating displayed protection from forces at different rates. Testing overcoating thickness ranging from 5 to 20 nm in 5 nm increments revealed a significant improvement in stability using a 20 nm-thick overcoating. This approach underscores the importance of optimising overcoating thickness to enhance nanoparticle-based surface modifications' durability and functional integrity. [ABSTRACT FROM AUTHOR]

Bulk high-temperature superconductors (HTSs) such as REBa2Cu3O7−x (REBCO, RE = Y, Gd) are commonly used in rotationally symmetric superconducting magnetic bearings. However, such bulks have several disadvantages such as brittleness, limited availability and high costs due to the time-consuming and energy-intensive fabrication process. Alternatively, tape stacks of HTS-coated conductors might be used for these devices promising an improved bearing efficiency due to a simplification of manufacturing processes for the required shapes, higher mechanical strength, improved thermal performance, higher availability and therefore potentially reduced costs. Hence, tape stacks with a base area of (12 × 12) mm2 and a height of up to 12 mm were prepared and compared to commercial bulks of the same size. The trapped field measurements at 77 K showed slightly higher values for the tape stacks if compared to bulks with the same size. Afterwards, the maximum levitation forces in zero field (ZFC) and field cooling (FC) modes were measured while approaching a permanent magnet, which allows the stiffness in the vertical and lateral directions to be determined. Similar levitation forces were measured in the vertical direction for bulk samples and tape stacks in ZFC and FC modes, whereas the lateral forces were almost zero for stacks with the REBCO films parallel to the magnet. A 90° rotation of the tape stacks with respect to the magnet results in the opposite behavior, i.e., a high lateral but negligible vertical stiffness. This anisotropy originates from the arrangement of decoupled superconducting layers in the tape stacks. Therefore, a combination of stacks with vertical and lateral alignment is required for stable levitation in a bearing. [ABSTRACT FROM AUTHOR]

The accurate prediction of the nonlinear flutter response is one of the important prerequisites for accurately evaluating the post-flutter performance of long-span bridges. In fact, as the vibration amplitude increases, the participation of lateral degree-of-freedom (DOF) will become more and more obvious and thus ignoring self-excited forces related to lateral vibration may no longer be applicable. To this end, based on 18 amplitude-dependent flutter derivatives (FDs), a 3-DOFs coupled nonlinear flutter analysis method was proposed in this study. Then, 18 amplitude-dependent FDs of two typical bridge decks were identified, and they were used to calculate the 3-DOF coupled nonlinear flutter responses based on the proposed flutter analysis method. Meanwhile, the correctness of the above flutter analysis method was also verified by compared with the numerical simulation results. Finally, the influence and mechanism of the lateral DOF, structural modal parameters and amplitude-dependent FDs on the nonlinear flutter of these typical bridge decks were investigated. The results show that when the torsional amplitude of the nonlinear flutter is large, the participation of lateral DOF will significantly increase the steady-state amplitude of the nonlinear flutter, and the larger the torsional amplitude, the more significant this increase is. The main reason is the participation of the lateral DOF introduces the negative coupled aerodynamic damping to the system, which then reduces the stability of the system. Besides, for the twin-box section, the influence of the lateral DOF on the nonlinear flutter is relatively smaller compared with the single-box section since the proportion of negative aerodynamic damping by the lateral DOF is smaller. Compared with the single-box section, the mass of the twin-box section has a smaller effect on the critical wind speed, and the torsional structural damping ratio of the twin-box section has a greater effect on the nonlinear flutter. [ABSTRACT FROM AUTHOR]

This paper investigates the seismic performance of thin-walled stiffened steel square box columns, modeling bridge piers subjected to unidirectional cyclic lateral loading with a constant axial load, focusing on local, global, and local-global interactive buckling phenomena. Initially, the finite element model was validated against existing experimental results. The study further explored the degradation in strength and ductility of both thin-walled and compact columns under cyclic loading. Thin-walled, stiffened steel square box columns exhibited buckling near the base, forming a half-sine wave shape. The research also addresses discrepancies from different material models used to analyze steel tubular bridge piers. Analysis using a modified two-surface plasticity model (2SM) yielded results closer to experimental data than a multi-linear kinematic hardening model, particularly for compact sections. The 2SM, which accounts for cycling within the yield plateau and strain hardening regime, demonstrated enhanced accuracy over the multi-linear kinematic hardening model. Additionally, a parametric study was conducted to assess the impact of key design parameters—such as width-to-thickness ratio (Rf), column slenderness ratio (λ), and magnitude of axial load (P/Py)—on the performance of thin-walled stiffened steel square box columns. Design equations were then developed to predict the strength and ductility of bridge piers. These equations closely matched experimental results, achieving an accuracy of 95% for ultimate strength and 97% for ductility. [ABSTRACT FROM AUTHOR]

To meet growing energy demands, offshore wind turbines (OWTs) with higher energy outputs are being developed, presenting increased challenges for their foundation design. Over the past decade, extensive research on the design optimization of OWT support structures has significantly reduced the anticipated costs of offshore wind farm development. Various design methods have been developed and applied in practice, each with its own advantages and limitations. In this study, 3D finite element (FE) modeling, validated against the measured response of a large-scale test monopile, is used to investigate the lateral load response of monopiles with different geometries and slenderness ratios in smaall and large displacements. The results are compared to the standard p–y method, and specific behavioral and design aspects of large-diameter monopiles, such as the moment contribution ratio from different resisting components and the minimum embedment length criteria, are evaluated and discussed. The results showed that the maximum and minimum differences between the 3D FE modeling and one-dimensional (1D) DNV p–y method are 41% and 11% for large displacements, and 32.5% and 13.3% for small displacements, respectively. As the slenderness ratio increases, the discrepancy between the finite element (FE) modeling results and the 1D DNV p–y method decreases, with an average difference of about 13% across all monopile diameters at an L/D ratio of 10, in both small and large displacements, indicating the reasonable accuracy of the 1D method for slenderness ratios of 10 and above. Among the three minimum embedment length criteria examined, the DNV recommended and vertical-tangent criteria offered shorter embedment lengths. The primary resisting moment across all slenderness ratios comes from the distributed lateral load along the monopile shaft ( M C R p − y ), which increases as the L/D ratio increases. [ABSTRACT FROM AUTHOR]

It has been difficult to detach abrasive particles smaller than 50 nm from polished surfaces in post-CMP cleaning. During the cleaning process, the residual nano-particles exert shear force in the inevitable shear flow. In order to understand the cleaning mechanism, it is indispensable to investigate not only the force but also the energy acting on different-sized nano-particles. In this article, we proposed the evaluation of detachment energy (the energy required to detach nano-particles) by using Lateral Force Microscopy. As an example, the dominant detachment energy of the silica nano-particle between the oxide film is the potential energy of the hydrogen bond. It suggested that the silica nano-particle detachment involves the breaking of hydrogen bonds. [ABSTRACT FROM AUTHOR]

Traditional wheelchairs are pushed from behind the occupant, which hinders eye contact and communication. It was proposed that the wheelchair be pushed from the side using a push bar to place the caregiver beside the occupant. However, this method requires the caregiver to exert continuous effort to maintain a straight trajectory because the force at the lateral push location generates a moment. This study explores simple modifications to the front castor wheel of the wheelchair that allow pushing it from the side without additional effort. We used a three-dimensional dynamic model of the castor wheel to predict the effects of altering its dimensions and rake, cant, and bank angle and present a simplified steady-state solution. Experimental results support the model's predictions, and a proof-of-concept experiment with a wheelchair showed that it is possible to push a wheelchair from the side without increasing forces or moments. The results also confirmed that the lateral ground reaction force generated on the castor wheel is proportional to the normal force and the cant angle, which can counter the moment caused by the lateral push location. The implications of this model extend beyond wheelchair design and can be applied to other applications that use castor wheels, such as robotics, trolleys, and walkers. [ABSTRACT FROM AUTHOR]

Background: The thresholds of mechanical inputs for bruising caused by blunt impact are important in the fields of machine safety and forensics. However, reliable data on these thresholds remain inadequate owing to a lack of in vivo experiments, which are crucial for investigating the occurrence of bruising. Since experiments involving live human participants are limited owing to ethical concerns, finite-element method (FEM) simulations of the bruising mechanism should be used to compensate for the lack of experimental data by estimating the thresholds under various conditions, which requires clarifying the mechanism of formation of actual bruises. Therefore, this study aimed to visualize the mechanism underlying the formation of bruises caused by blunt impact to enable FEM simulations to estimate the thresholds of mechanical inputs for bruising. Methods: In vivo microscopy of a transparent glass catfish subjected to blunt contact with an indenter was performed. The fish were anesthetized by immersing them in buffered MS-222 (75–100 mg/L) and then fixed on a subject tray. The indenter, made of transparent acrylic and having a rectangular contact area with dimensions of 1.0 mm × 1.5 mm, was loaded onto the lateral side of the caudal region of the fish. Blood vessels and surrounding tissues were examined through the transparent indenter using a microscope equipped with a video camera. The contact force was measured using a force-sensing table. Results: One of the processes of rupturing thin blood vessels, which are an essential component of the bruising mechanism, was observed and recorded as a movie. The soft tissue surrounding the thin blood vessel extended in a plane perpendicular to the compressive contact force. Subsequently, the thin blood vessel was pulled into a straight configuration. Next, it was stretched in the axial direction and finally ruptured. Conclusion: The results obtained indicate that the extension of the surrounding tissue in the direction perpendicular to the contact force as well as the extension of the thin blood vessels are important factors in the bruising mechanism, which must be reproduced by FEM simulation to estimate the thresholds. [ABSTRACT FROM AUTHOR]

Decoupling dynamic touch signals in the optical tactile sensors is highly desired for behavioral tactile applications yet challenging because typical optical sensors mostly measure only static normal force and use imprecise multi-image averaging for dynamic force sensing. Here, we report a highly sensitive upconversion nanocrystals-based behavioral biometric optical tactile sensor that instantaneously and quantitatively decomposes dynamic touch signals into individual components of vertical normal and lateral shear force from a single image in real-time. By mimicking the sensory architecture of human skin, the unique luminescence signal obtained is axisymmetric for static normal forces and non-axisymmetric for dynamic shear forces. Our sensor demonstrates high spatio-temporal screening of small objects and recognizes fingerprints for authentication with high spatial-temporal resolution. Using a dynamic force discrimination machine learning framework, we realized a Braille-to-Speech translation system and a next-generation dynamic biometric recognition system for handwriting. A sensitive upconversion nanocrystal-based biometric optical tactile sensor instantaneously and quantitatively decomposes dynamic touch signals into individual components of vertical normal and lateral shear force from a single image in real-time. [ABSTRACT FROM AUTHOR]

The performance of joint connections in composite slabs is crucial for ensuring their bidirectional load-bearing capacity and overall structural integrity. To effectively address the challenge of protruding rebar in precast components, a new structural form of a tightly connected hollow concrete composite slab without protruding rebar on the slab side is proposed. To investigate the mechanical performance and failure modes of this slab-side tight-joint connected hollow concrete composite slab, bending performance tests under monotonic load were conducted on three tightly connected hollow composite slabs and one seamless hollow composite slab. The analysis focused on the failure modes, crack distribution, bending capacity, and bending stiffness of additional steel bars at the joints of the slabs. The results indicate that, under normal operating conditions, the flexural performance development of concrete hollow composite slabs with tightly connected slab sides is generally consistent with that of the non-spliced cast hollow composite slab. Under ultimate conditions, tearing or brittle fracture failure at the joint interface is likely to occur in the composite slabs, leading to a reduction in flexural bearing capacity. With an increase in joints, the bending capacity of the hollow composite slab decreases by 17.1%, Conversely, when joints are positioned away from the most stressed section, the flexural stiffness of the section increases by 13.5%. A comparison of experimental data and theoretical calculations indicates that the additional rebar at the joints effectively contributes to the lateral load transfer in the hollow composite slab, achieving bidirectional load-bearing capacity. This further validates that the design of the single-joint, tight-joint connected hollow concrete composite slab without protruding rebar meets the requirements for bidirectional load-bearing performance. [ABSTRACT FROM AUTHOR]

In this study, to investigate the factors affecting container semitrailer rollovers while driving on interchange loop ramps, a simulation model was established in TruckSim on the basis of data collected from an in-depth investigation of the vehicle, road, and driving behaviors in a real accident. The established model was validated by reproducing the accident in a simulation. The effects of vehicle speed, the height of the cargo's center of gravity, tractor-semitrailer interactions, and the radius of the circular curve on container semitrailer rollover were investigated using the established model. The results reveal that if the height of the container semitrailer is within the limits in Chinese standards and the container semitrailer is moving at a speed of less than 45.3 km/h, it can safely travel through a loop ramp with a circular curve radius of 60 m. The height of the cargo's center of gravity and the lateral load transfer ratio have a negative relationship, and a higher center of gravity reduces the safe speed for a container semitrailer traveling through a loop ramp. During rollover, the rear axle of the semitrailer first begins to roll over and then drives the tractor to overturn. [ABSTRACT FROM AUTHOR]

The building industry requires the development of a ductile lateral force resisting system made of mass timber to help mass timber to continue to grow in popularity as the primary structural building material. The OpenSees framework was used to develop a numerical model of a single-story timber frame with a timber buckling-restrained brace, which was validated by the results of a previously completed series of quasistatic cyclic timber buckling-restrained brace (TBRB) component and subassembly tests. The experimental validation included a model developed for the hysteretic behavior of the TBRB and the rotational capacity of beam–column joints made with mass ply lam (MPL) panels, two slotted-in steel plates, and a number of steel dowels. The single-story model TBRB braced frame was then expanded to a numerical model of an eight-story mass timber buckling-restrained braced frame. The TBRB frame was analyzed with static pushover, quasistatic cyclic loads, and earthquake simulations. During the simulation of eleven design-level earthquake ground motions, the building experienced a peak interstory drift at of 2.54% at the first-floor level and a peak floor acceleration of 1.7g at the roof. The numerical model developed in this research of a timber buckling-restrained braced frame with TBRBs is novel and could be used to design timber buckling-restrained braced frames as a ductile lateral force resisting solution for mass timber buildings in seismic regions. [ABSTRACT FROM AUTHOR]

Two methods to predict the pushover response of a hybrid steel braced frame that features concentric and eccentric connections are presented. The proposed hybrid frame configuration is intended for cold-formed steel (CFS) building structures and plays a dual role by providing gravity and lateral load resistance. The hybrid system features CFS columns for resisting gravity loads, tension only CFS straps connected concentrically to hollow structural steel (HSS) chords for resisting lateral loads, and prestressing strands connected eccentrically to the same HSS chords for further enhancing lateral load capacity. The first pushover response prediction method employs a nonlinear finite element modeling protocol that features only beam and truss elements. This method is presented as an alternative to three-dimensional (3D) nonlinear finite element models, which require considerable modeling effort due to the multitude of the components included in the hybrid system, and the variety of interactions that would need to be defined. The second method includes closed form equations that allow the definition of the pushover curves using manual calculations and is appropriate for preliminary analysis. Formulations for predicting the initial in-plane system stiffness, and secondary stiffness are presented. Similarly, formulations for predicting the load to cause the first and second yield as well as ultimate lateral load capacity are provided. A closed form equation is presented to obtain the ultimate lateral displacement, which completes the definition of the pushover curve. The validation of the proposed pushover response prediction methods is conducted by first comparing responses from 3D nonlinear FEA to those obtained from the simplified FEA model. Similarly, predictions from the simplified FEA model are compared to those obtained from the closed form equations. Good agreements are noted in both cases. The influence of hybrid steel braced frame aspect ratio on system push over response is quantified. The contribution of each lateral load resisting element to lateral load capacity is presented as a function of aspect ratio. Finally, improvements in behavior and enhancements in lateral load capacity offered by the hybrid frame-wall compared to the traditional strapped wall system are demonstrated through monotonic pushover, cyclic pushover, and response history analysis. [ABSTRACT FROM AUTHOR]

Seasonal freeze–thaw (F–T) cycles significantly affect the mechanical properties of soils and the behavior of pile foundations in soils subjected to F–T cycles under different loading conditions. Soils exposed to F–T cycles can impact the performance of pile foundations. Consequently, the effects of F–T cycles should be taken into account when designing piles, particularly in cold regions such as Canada. In recent years, climatic conditions in Canada have changed due to global warming, increasing the number of F–T cycles in many regions each year. This study aimed to investigate the influence of different numbers of F–T cycles on the behavior of piles in sandy soils. Laboratory experiments were conducted on physical models of piles subjected to axial (uplift) and lateral loads combined with F–T cycles. The model was scaled using standard scaling principles, and the test apparatus was equipped with various sensors to measure temperatures, forces, and displacements. The results showed that as the number of F–T cycles increased, the lateral capacities of the piles under individual and combined loads increased steadily. The lateral load capacity increased from 350 to 430 N after five F–T cycles under individual loading and from 225 to 455 N after five F–T cycles under combined loading. However, the pile's uplift load capacity remained constant under individual and combined loads and there was no change due to F–T cycles. The results of this experimental study will be useful for understanding the behavior of piles subjected to seasonal F–T cycles and for improving the design of pile foundations in cold regions. [ABSTRACT FROM AUTHOR]

In general, pile foundations are utilized to support structures like tall buildings, bridges, and transmission towers, which are frequently subjected to lateral stresses initiated by wind, action of waves, earthquakes, or traffic loads. Several high-rise structures, highway and railroad overpasses, as well as transmission towers, are constructed near slopes and rely on pile foundations for support. Due to the effects of wind and waves, pile foundations are continuously subjected to cyclic loads. For piles supporting tall buildings, transmission towers, offshore structures, or infrastructure in seismic zones, 1-way or 2-way cyclic lateral loads are commonly applied. Therefore, while designing pile foundations, it is essential to understand how piles behave laterally when they are located near a sloping crest. One of the primary challenges in ensuring the efficient functioning of the superstructure is analyzing how the soil and foundations respond when exposed to long-term lateral loads, such as wind, over an extended period on the piles of offshore platforms. Because of the presence of slope, the pile's lateral load capacity decreased due to the reduced ability of the soil to provide passive resistance. This paper presents small-scale 1-g model tests conducted on the sand to assess the loss of pile's lateral capacity when subjected to 100 cycles under 1 and 2-way cyclic loading. The Relative Density (60%) and varying slopes (Horizontal ground, 1V:3H) with varying spacing (5D and 7D) and aspect ratios (L/D) of 25 and 40 were implemented in this study. Cyclic lateral load tests were performed for sloping as well as horizontal ground. A major reduction in lateral capacity, exceeding 60%, was observed due to the application of cyclic loading. Moreover, the transition from horizontal ground (HG) to sloping ground (SG) decreased the maximum bending moment by 25–40%. This study exemplifies the piles' behaviour when subjected to cyclic lateral loading while resting on a sloping crest, which represents a critical scenario in pile foundation design. [ABSTRACT FROM AUTHOR]

This study aims to investigate the effects of manure and vermicompost in terms of soil elasticity modulus changes in loam soil. The uniaxial compression test measures the compressive strength of a soil cylinder without any lateral load. The modulus of elasticity was determined by plotting the strain-stress diagrams and calculating the slope of these diagrams. The increase in moisture and organic matter content significantly improved soil flexibility and decreased its elasticity modulus. It was found that adding animal manure had a greater effect on the flexibility of the soil as compared to vermicompost, while the elasticity modulus of the samples containing animal manure was lower. The interaction effect of moisture and the organic matter content indicated that the increase in humidity was more effective in the soil containing vermicompost as compared to the soil containing manure, such that when the manure rate was around 19%, the moisture increase had no significant impact on the elasticity modulus. It was found that adding organic matter was more effective at the low moisture level of 15.5% than at higher moistures where the effect of adding organic matter did not affect the soil elasticity modulus decrement as strongly. [ABSTRACT FROM AUTHOR]

In recent decades, reinforced concrete (RC) shear walls have been one of the best structural solutions to resist lateral load in high-rise buildings. Shear wall openings are essential for preparations and architectural requirements, which weaken the wall, reducing bearing capacity, energy absorption, and stiffness while also causing stress concentrations. This paper presents a comprehensive finite element (FE) investigation of the behavior and performance of RC shear walls with openings and subjected to lateral loads. The study aims to evaluate the influence of various parameters, such as opening location, size, wall aspect ratio, axial load, and concrete strength, which affect the performance of shear walls. FE models were developed to simulate the seismic response of RC shear walls under the combined effect of constant axial and lateral loads. The obtained results from the FE model showed a successful validation using the experimental data available in the literature. The FE analysis results demonstrate that the inclusion of lower openings leads to a 25% decrease in the bearing capacity of the wall when compared to the upper openings. Moreover, it was observed that augmenting the sizes of the openings and the aspect ratios of the wall resulted in declines in the strength, stiffness, and energy absorption capacity of the wall while simultaneously enhancing the ductility and displacement of the RC shear walls. [ABSTRACT FROM AUTHOR]

Modern masonry systems are generally built with hollow clay bricks with high thermal insulating properties, fulfilling the latest sustainability and environmental criteria for constructions. Despite the growing use of sustainable masonries in seismic-prone countries, there is a notable lack of experimental and numerical data on their structural behavior under lateral in-plane loads. The present study investigates the in-plane shear behavior of load-bearing masonry walls with thin bed joints and thermal insulating hollow clay blocks. Shear-compression tests were performed on three specimens to obtain information about their shear strength, displacement capacity and failure modes. The experimental characterization was supplemented by three shear tests on triplets, along with flexural and compression tests on the mortar for the thin joints. Furthermore, two Finite Element (FE) models were built to simulate the shear-compression tests, considering different constitutive laws and brick-to-brick contact types. The numerical simulations were able to describe both the shear failure modes and the shear strength values. The results showed that the experimental shear strength was 53% higher than the one obtained through Eurocode 6. The maximum shear load was found to be up to 75% greater compared to similar masonry specimens from the literature. These findings contribute to a better understanding of the potential structural applications of sustainable hollow clay block masonry in earthquake-prone areas. [ABSTRACT FROM AUTHOR]

Micropile groups (MPGs) are typical landslide resistant structures. To investigate the effects of these two factors on the micropile–soil interaction mechanism, seven sets of transparent soil model experiments were conducted on miniature cluster piles. The soil was scanned and photographed, and the particle image velocimetry (PIV) technique was used to obtain the deformation characteristics of the pile and soil during lateral loading. The spatial distribution information of the soil behind the pile was obtained by a 3D reconstruction program. The results showed that a sufficient roughness of the pile surface was a necessary condition for the formation of a soil arch. If the surface of the pile was smooth, stable arch foundation formation was difficult. When the roughness of the pile surface increases, the soil arch range behind the pile and the load-sharing ratio of the pile and soil will increase. After the roughness reaches a certain level, the above indicators hardly change. Pile spacing within the range of 5–7 d (pile diameters) was suitable. The support effect was poor when the pile spacing was too large. No stable soil arch can be formed, and the soil slips out from between the piles. [ABSTRACT FROM AUTHOR]

The construction of buildings and infrastructure on marine deposits is challenging. The impact of the horizontal behavior of structures on reclaimed areas is critical. This study investigated the behavior of laterally loaded drilled shafts in marine deposits through a comprehensive analysis and full-scale lateral load test conducted in Songdo, South Korea. It identified various critical pile characteristics for designing and constructing architectural and civil structures in marine environments, focusing on a 2.5 m diameter, 40 m long drilled shaft. At a 900 kN design load, the test pile experienced a maximum moment of 3520.2 kN·m and a lateral deflection of 2.32 mm, with anticipated failure at a load of 1710 kN and 11.30 mm displacement. Fiber Bragg Grating (FBG) sensors enabled precise displacement and strain measurements, essential for constructing accurate load–displacement curves and understanding lateral load responses. Inverse analysis with validated data from a commercial software (LPILE) showed good alignment of maximum moment and displacement but highlighted challenges at failure loads. The study developed depth-dependent p-y curves for marine deposits, crucial for predicting soil–pile interaction and optimizing shaft design. Practical implications include using derived p-y curves and an empirical equation using Standard Penetration Test (SPT) results to predict the coefficient of horizontal subgrade reaction (kh) with high accuracy. Overall, this research emphasizes the importance of advanced instrumentation and analytical techniques for optimizing drilled shaft design and ensuring structural stability in challenging marine geological conditions. [ABSTRACT FROM AUTHOR]

Using the potential function method, a theoretical model of the interaction was presented, and the interaction force between atoms/ions and (doped) graphene was obtained. Based on the interaction force, the dynamical control equation of atom/ion migration was derived. The dynamical behavior of atom/ion migrating on finite-size graphene surfaces along a specific direction and the regulation of boron nitride (BN) doping on the migration behavior were studied. The results show that the atoms/ions exhibit different migration mechanical behaviors due to different lateral forces inside and at the edges of the graphene surface. In addition, near the normal equilibrium height, atoms/ions are mainly affected by the lateral force, and their migration behavior is also influenced by the initial position, initial height, initial lateral velocity, etc. Furthermore, BN doping can affect the energy barrier of atom/ion migration on the graphene surface and effectively regulate the migration behavior of atoms/ions at the edge of the graphene surface. The research results can provide a theoretical reference for graphene surface localization modification and graphene-based atom/ion screening and detection. [ABSTRACT FROM AUTHOR]

The global population rise has fostered the need for high buildings, which differ from traditional buildings of limited height in their resistance to lateral loads. So now, it's critical to think about lateral loads. To prevent possible collapse, compared to wind loads, which are only 1:3 percent of the structure's weight, and earthquake loads can reach 30:40 percent [1]. This necessitated us to use reinforced concrete walls. on the other hand, the existing structures frequently need to be modified to meet modern living standards, so cutting out openings in RC shear walls is one of the most widely used improvements. This study reviews some of the most recent experimental and finite element research that has been published in the literature and lists the major contributions until 2023. Also, this paper presents a summary of some studies available in the literature concerning the mode of failure commonly observed in RC shear walls and analyzes the impact of opening attributes such as size, position, and shape on shear wall behavior. Moreover, it investigates how variables like steel reinforcement ratio and opening arrangement affect the shear wall's response to lateral loads. The influence of aspect ratio on overall performance is also explored. Additionally, the research highlights design provisions and guidelines available for cases involving RC shear walls with openings. From this study, it is clear that the width of openings plays a more significant role than the height. Also, the small openings do not affect the flexural behavior of slender walls, and the creation of openings greatly reduces cumulative energy dissipation and increases the ductility of the RC shear walls. [ABSTRACT FROM AUTHOR]

The threat of rockfall impacting bridges in mountainous areas poses a great risk to the safety of passing trains. This study delves into the dynamics of rockfall impact and its implications on the interaction between train vehicles and bridges. Leveraging LS-DYNA, this study first captured the force–time history of rockfall impact on bridge structures. Subsequently, there was a comparison with the impact forces generated at various speeds with those predicted by established formulas, validating the accuracy of simulations. Employing BANSYS software, the dynamic responses of both bridge structures and the vehicle–bridge coupling system to falling rocks were analyzed. The investigation encompassed parameters such as impact speed, position, and train location. The findings reveal that escalating impact speeds correlate with increased average and maximum impact forces from falling rocks. Notably, the average impact force does not linearly correspond with rock speed and often exceeds values calculated by conventional formulas. Impact position minimally affects maximum impact force, yet alterations in position prolong impact duration, consequently reducing average impact force. Rockfall-induced impacts precipitate notable spikes in train lateral acceleration, lateral wheelset force, wheel unloading rate, and derailment coefficient, albeit with a comparatively lesser impact on vertical acceleration. Increasing impact speed and altering position intensifies the vehicle’s response, particularly when the train is in close proximity to the impact site. [ABSTRACT FROM AUTHOR]

The use of a micropile group is an effective method for small and medium-sized slope management. However, there is limited research on the pile–soil interaction mechanism of micropile groups. Based on transparent soil and PIV technology, a test platform for the lateral load testing of slopes was constructed, and eight groups of transparent soil slope model experiments were performed. The changes in soil pressure and pile top displacement at the top of the piles during lateral loading were obtained. We scanned and photographed the slope, and obtained the deformation characteristics of the soil interior based on particle image velocimetry. A three-dimensional reconstruction program was developed to generate the displacement isosurface behind the pile. The impacts of various arrangement patterns and connecting beams on the deformation attributes and pile–soil interaction mechanism were explored, and the pile–soil interaction model of group piles was summarized. The results show that the front piles in a staggered arrangement bore more lateral thrust, and the distribution of soil pressure on each row of piles was more uniform. The connecting beams enhanced the overall stiffness of the pile group, reduced pile displacement, facilitated coordinated deformation of the pile group, and enhanced the anti-sliding effect of the pile–soil composite structure. [ABSTRACT FROM AUTHOR]

Aiming at the problems of the poor trajectory-tracking performance and low control accuracy of unmanned vehicles under complex working conditions, we first estimate the lateral force of tires using the square root cubature Kalman filter (SRCKF) in order to correct the lateral stiffness of the tires online, which reduces the model bias caused by constant lateral stiffness, and then adopt a Gaussian function-based adaptive time-domain model predictive control method to improve the trajectory-tracking control accuracy of unmanned vehicles under complex working conditions. Finally, the proposed control algorithm is validated via Carsim and MATLAB/Simulink joint simulation. The results show that compared with the classical model predictive control (MPC) algorithm, the proposed control algorithm reduces the average lateral tracking error by 73.07% and the peak beta and the peak yaw rate by 50.89% and 47.51%, respectively, so that the unmanned vehicle is able to maintain good tracking performance and control accuracy. [ABSTRACT FROM AUTHOR]

Featured Application: Featured Application: Seismic design of steel moment-resisting frames equipped with viscoelastic dampers in the framework of the Eurocode 8 provisions. The effectiveness of viscoelastic dampers as passive control devices has been demonstrated in the past through both experimental and numerical investigations. Based on the Modal Strain Energy Method, some authors have also proposed design procedures to size the viscoelastic dampers assuming a fist-mode behavior of the structure. However, even if the damped structure is governed by the first mode of vibration, viscoelastic dampers are sensitive to the frequencies of the upper modes and transmit unexpected internal forces to braces. This paper aims to develop a simple design procedure for steel moment-resisting frames equipped with viscoelastic dampers considering the effects of the higher modes of vibrations on the internal forces transmitted from the dampers to the braces. In the perspective of a designer-oriented study, the seismic demand is evaluated through simple analytical tools, such as the lateral force method or the response spectrum analysis. The design procedure is applied to a set of steel moment-resisting frames considering two levels of seismic hazard and two types of soil. Finally, the effectiveness of the proposed procedure is verified through nonlinear dynamic analysis. Based on the results, it is found that the proposed design procedure ensures the control of the story drift below prefixed limits and to predict accurately the internal forces that arise in the braces. [ABSTRACT FROM AUTHOR]

Corrugated wear on the metro curved track was studied. Dynamic analysis was implemented to analyze the effects of the vehicle speed and the curve radius on the wheel-rail creep forces. A mixed Lagrangian/Eulerian description-based finite element model of a wheel/rail system was set up. The wheel inertia can be considered in this model. Moreover, the steady rolling of the wheel under different creepage for braking or traction can be simulated. The complex eigenvalue analysis is used to investigate the frequency-domain characteristics of the friction-induced vibration of the wheel/rail system under the steady-state curving of the wheel. The initiation of the corrugation under the friction-induced vibration of the wheel/rail system was studied. The effects of the creep forces in the longitudinal and lateral directions on the friction-induced vibration of the wheel/rail system were revealed. The results show the dominant cause of the corrugation on the low rail surface is the friction-induced vibration of the wheel/rail system at about 320 Hz. The friction-induced vibration on the side of the high rail is not easy to occur. Therefore, the corrugated wear hardly happens to the high rail. The corrugated wear caused by the friction-induced vibration is frequency-fixed. It is necessary to consider the wheel inertia in the study of the friction-induced vibration of the wheel/rail system. Without considering wheel inertia, missing prediction of the friction-induced vibration and overestimation of the occurrence probability and development speed of the corrugation may occur. The lateral creep force plays a leading role in the friction-induced vibration of the wheel/rail system, while the longitudinal creep force has little effect on the friction-induced vibration. The corrugated wear will become more serious as the curve radius becomes smaller. [ABSTRACT FROM AUTHOR]

Various masonry wall organization techniques were used in ancient Anatolian buildings depending on the local characteristics and the kind of stone used in the region. Traces of iron clamps or dowels can be seen on numerous ancient walls. This study's main goals are to ascertain the impact of iron clamps and dowels on the vulnerability of various ancient wall organizations in Anatolia and investigate potential relationships between wall organization types and clamp or dowel usage. Another study objective is to gather information about using metal connectors for restoration or anastylosis studies in archaeological sites. First, a site analysis was performed on ancient cities to document various types of masonry. Four types of walls, namely isodomic, isodomic with header and stretcher, pseudo isodomic, and isodomic in alternation header and stretcher row were determined. Quasi-static tilt analysis was performed on 3D models of walls without clamps and dowels, with clamps, and with dowels to compare the failure mechanisms of the wall types. As a result, the wall type with the highest strength gain when metal connectors were utilized in the analysis was isodomic organization, which also includes numerous traces of clamps and dowels in ancient cities. This indicates that knowledge was gained because of experiences against lateral loads at that time. This information is not only significant in terms of understanding the history of architecture but also provides data to reinforce ancient walls during conservation work. [ABSTRACT FROM AUTHOR]

This paper presents experimental results of combined cyclic load testing on a reinforced concrete (RC) column that was retrofitted with newly designed steel rods. The steel rods were installed around the column longitudinally and then anchored. The proposed steel rods utilize simple components and installation to enhance both the strength and ductility of RC columns. Cyclic lateral load tests were conducted on three specimens: one unreinforced specimen as reference, one specimen with the entire length of the column retrofitted, and one specimen with only the plastic hinge region of the column retrofitted. All specimens were tested under eccentric constant axial load and incrementally increasing lateral loading cycles with eccentricity. The implementation of steel rods resulted in significant improvement in ductility and an up to 60% increase in ultimate loading capacity. [ABSTRACT FROM AUTHOR]

(1) Background: The kinematic characteristics of disc prosthesis undergoing complex motion are not well understood. Therefore, examining complex motion may provide an improved understanding of the post-operative behavior of spinal implants. (2) Methods: The aim of this study was to develop kinematic tests that simulate multiplanar motion and combined rotational–translational motion in a disc prosthesis. In this context, five generic zirconia-toughened alumina (BIOLOX®delta, CeramTec, Germany) ball and socket samples were tested in a 6 DOF spine simulator under displacement control with an axial compressive force of 100 N in five motion modes: (1) flexion–extension (FE = ± 7.5°), (2) lateral bending (LB = ± 6°), (3) combined FE-LB (4) combined FE and anteroposterior translation (AP = 3 mm), and (5) combined LB and lateral motion (3 mm). For combined rotational–translational motion, two scenarios were analyzed: excessive translational movement after sample rotation (scenario 1) and excessive translational movement during rotation (scenario 2). (3) Results: For combined FE-LB, the resultant forces and moments were higher compared to the unidirectional motion modes. For combined rotational–translational motion (scenario 1), subluxation occurred at FE = 7.5° with an incremental increase in AP translation = 1.49 ± 0.18 mm, and LB = 6° with an incremental increase of lateral translation = 2.22 ± 0.16 mm. At the subluxation point, the incremental increase in AP force and lateral force were 30.4 ± 3.14 N and 40.8 ± 2.56 N in FE and LB, respectively, compared to the forces at the same angles during unidirectional motion. For scenario 2, subluxation occurred at FE = 4.93° with an incremental increase in AP translation = 1.75 mm, and LB = 4.52° with an incremental increase in lateral translation = 1.99 mm. At the subluxation point, the incremental increase in AP force and lateral force were 39.17 N and 38.94 N in FE and LB, respectively, compared to the forces in the same angles during the unidirectional motion. (4) Conclusions: The new test protocols improved the understanding of in vivo-like behavior from in vitro testing. Simultaneous translation–rotation motion was shown to provoke subluxation at lower motion extents. Following further validation of the proposed complex motion testing, these new methods can be applied future development and characterization of spinal motion-preserving implants. [ABSTRACT FROM AUTHOR]

The critical lateral buckling load of cantilever beams with IPE cross-section was calculated using analytical closed-form equations and numerical finite element analyses within the scope of the research. The equations suggested in the specifications for simply supported beams were used to calculate the buckling load of cantilever beams. The rationality of the values calculated due to this is not fully known. In the research, a single loading was made to the shear center at the free end of the cantilever beam. Cantilever length and section height were kept variable. As a result, it has been determined that there are partial differences in the analysis result obtained from the elastic stability theory and finite element method. Accordingly, the results obtained from ANSYS and SAP2000 analyses confirm each other. On the other hand, the results obtained using the formulation of Timoshenko and Gere, the calculation results made according to the AISC and DCCPSS regulations, and the results obtained from the LTBeam program confirm each other. However, it differs from the FEA analysis due to the cantilever beam length’s shortening and the section height increase. Thus, to obtain accurate and reliable results in the buckling load calculation of cantilever beams, the equations used in analytical calculations were optimized according to finite element analysis (FEA) results. As a result of the study conducted according to the error criteria, it was determined that the updated equation results gave similar results to the FEA results. [ABSTRACT FROM AUTHOR]

Full-scale axial load tests were performed on five screw injection piles founded in medium-dense to dense sand at a site in Delft, the Netherlands. Each pile was instrumented with distributed fiber-optic sensors along its full length, giving detailed insights into the shaft and base response under compression loading. The paper focuses on the pile base response and combines the test results with a newly compiled database of instrumented load tests on screw displacement piles in sand. Given the range of screw displacement piles on the market, the influence of different installation methods and pile geometries on the base resistance can be assessed through the database. In summary, the analysis showed that all screw displacement pile types tended to mobilize base capacities similar to bored or nondisplacement piles. Despite high variability in the database, no significant trend with pile geometry, such as length or diameter, was evident. [ABSTRACT FROM AUTHOR]

Pile response in unsaturated soils is an area of interest due to its prevalence in real-world scenarios. Significant differences exist in the lateral behavior of single piles in partially saturated soils due to increased soil stiffness. In this study, a single pile was monotonically loaded laterally to investigate the performance of piles in soils with variable water table levels. Pile head lateral response showed that a mix of unsaturated-saturated soil led to an increase in lateral loads on the pile at a similar displacement compared with the fully saturated or dry soil conditions. The lateral response of the pile was obtained based on the curvature data from the strain gauges. A derivative method was used to generate the shear force and lateral resistance along the pile length based on finite differences at the seven strain gauge locations, thereby eliminating errors associated with curve fitting. Various lateral response plots, such as the normalized p-y curves, M-y curves, and maximum bending moment response plots, were used to assess the response to lateral load. Further, the effect of two different loading rates were assessed on the fully saturated and unsaturated-saturated soil, and the range of loading rates evaluated had minimal influence on the pile lateral response. Results indicated that considering the influence of the unsaturated soil could increase lateral resistance under similar lateral displacements. However, there is a risk of inducing large pile bending moments, potentially leading to pile flexural failure if the pile plastic moment is reached. [ABSTRACT FROM AUTHOR]

Nanomechanical testing plays a crucial role in evaluating surfaces containing nanoparticles. Testing verifies surface performance concerning their intended function and detects any potential shortcomings in operational standards. Recognising that nanostructured surfaces are not always straightforward or uniform is essential. The chemical composition and morphology of these surfaces determine the end-point functionality. This can entail a layered surface using materials in contrast to each other that may require further modification after nanomechanical testing to pass performance and quality standards. Nanomechanical analysis of a structured surface consisting of a poly-methyl oxazoline film base functionalised with colloidal gold nanoparticles was demonstrated using an atomic force microscope (AFM). AFM nanomechanical testing investigated the overall substrate architecture's topographical, friction, adhesion, and wear parameters. Limitations towards its potential operation as a biomaterial were also addressed. This was demonstrated by using the AFM cantilever to apply various forces and break the bonds between the polymer film and gold nanoparticles. The AFM instrument offers an insight to the behaviour of low-modulus surface against a higher-modulus nanoparticle. This paper details the bonding and reaction limitations between these materials on the application of an externally applied force. The application of this interaction is highly scrutinised to highlight the potential limitations of a functionalised surface. These findings highlight the importance of conducting comprehensive nanomechanical testing to address concerns related to fabricating intricate biomaterial surfaces featuring nanostructures. [ABSTRACT FROM AUTHOR]

While numerous experimental tests have been conducted on single-story cross-laminated timber (CLT) shear walls, research addressing the drift performance of multistory CLT structures remains limited. This paper presents an experimental parameter study of the lateral performance of two-story platform-type CLT shear wall structures utilizing self-tapping screw connections. The test program consisted of six reversed cyclic tests investigating the impact of: (1) additional floor mass; (2) different angle bracket connections between floors; (3) different tension strap connections between floors; and (4) acoustic insulation layers on both sides of the first-level floor. The results showed that additional dead load increased the lateral resistance and that designing angle brackets to remain elastic limited the sliding contribution to total lateral deformations to less than 10%. The results also showed that the acoustic layer had minimal effect on the performance of the shear walls under the tested conditions. The tension straps significantly influenced the rocking performance, underscoring their importance to achieve similar story drifts in multistory CLT shear wall structures. Finally, while preceding single-story shear wall tests allowed designing the structures, hold-down uplifts on single-story tests were shown not to be representative for tension strap uplifts in multistory tests. [ABSTRACT FROM AUTHOR]

In this study, the authors conducted five low-cycle reciprocating loading tests on hexagonal ultrahigh-performance concrete (UHPC)-filled steel tubular (UHPCFST) and UHPC-filled double-skin steel tubular (UHPCFDST) columns. The main parameters investigated in this research program are the hollow ratio, axial load ratio, and column type. Based on the experimental results, the failure modes, lateral load-story drift ratio curves, lateral load-strain curves, ultimate lateral load and corresponding base moment, and ultimate story drift ratios are obtained and discussed. The results show that hexagonal UHPCFST and UHPCFDST satisfy the requirements of ductility in GB 50936-2014. Moreover, the authors developed a fiber beam model (FBM) to predict the hysteretic behavior and strength under combined compression and bending. Subsequently, a parametric study was conducted, based on the validated FBM, to investigate the effect of material strength, outer steel tube thickness, and hollow ratio on the strength of hexagonal columns under combined loadings. Comparisons of the predictions from T/CESS 7, AISC 360, and EC4 and numerical results suggest the necessity of a design method with higher accuracy. Finally, the authors proposed a calculation formula for hexagonal UHPCFST and UHPCFDST columns, which effectively predicts the strength of these two types of columns under combined compression and bending. [ABSTRACT FROM AUTHOR]

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In this article, a nonlinear static analysis model of a bridge pile foundation is established using numerical simulation, and the correctness of the model is verified via experiments. Then, the damage characteristics and mechanical behaviors of bridge pile foundations in cold regions under lateral loads are investigated based on the validated analysis model. The results showed that the impact of soil freeze–thaw cycles on the lateral performance of the pile–soil system is more pronounced in seasonally frozen regions compared with permafrost regions. Specifically, as the number of soil freeze–thaw cycles increases, there is a tendency for the lateral load capacity of the pile–soil system to decrease initially and then stabilize. It is worth noting that soil freeze–thaw cycles significantly influence both the stiffness and deformation capacity of the pile–soil system, with these parameters exhibiting a decreasing trend followed by stabilization as the number of freeze–thaw cycles increases. However, it has little effect on the shear force and bending moment of the pile foundation. [ABSTRACT FROM AUTHOR]

Because fixed-wing unmanned aerial vehicles (UAVs) require high-speed taxiing for takeoff and landing, the aircraft's stability during taxiing is critical. However, despite research on the taxiing stability of fixed-wing UAVs conducted in taxiing motion simulations employing various tire models, the applicability of the models to fixed-wing UAV taxiing simulations remains unclear, as does the rationale behind the parameter settings in the models. Therefore, in our study, we measured the forces acting on the tires of a fixed-wing UAV under various conditions, including tire loads of 1.6–3.6 kg and tire slip angles of 0–40 deg. Based on the results, we modified conventional tire models and assessed their applicability in taxiing simulations. Among our findings, the parameter values of the models significantly differed from those used in crewed aircraft taxiing simulations, and the presence or absence of load parameters in the lateral force tire models significantly affected the dynamics. Furthermore, the aerodynamics acting on the aircraft enhanced the straight-line stability during taxiing, resulting in reduced forces on the tires. [ABSTRACT FROM AUTHOR]