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Negative Poisson's ratio in auxetic structures plays a crucial role in energy absorption and impact mitigation. Origami-based lattices within the realm of auxetic structures offer the advantage of facile fabrication and design. Nevertheless, the utilization of periodic lattices in origami-based auxetic structures constrains the available design space for achieving diverse mechanical properties. Addressing this limitation, our study introduces origami-based auxetic structures with functionally graded thickness, utilizing origami-based lattices known as Tachi–Miura polyhedra. We investigated the impact of functionally graded thickness on buckling behavior and force responses through dynamic loading experiments employing 3D-printed test pieces. The experimental results indicate that functionally graded thickness induces partial auxetic deformation in lattices, and the resulting nonsymmetric deformation prevents global buckling, thereby averting bounded forces observed in structures with uniform thickness. These findings extend the applicability of auxetic structures, spanning from energy absorption to the design of cushioning structures. [ABSTRACT FROM AUTHOR]

We make the source network load storage access power wireless private network, this paper proposes a source network load storage access power wireless private network technology based on 5G ultra dense network. The multiple rotation scheduling and self-organizing learning methods are used to establish the deployment model of the source network load storage access node of the power wireless private network under the 5G communication mode. According to the routing control algorithm design of the 5G ultra dense networking node, combined with the integration analysis of the access load parameters, the source network load storage access model of the 5G ultra dense networking under the dynamic load distributed control mode is established. Through the method of optimal control of reactive power and voltage of distribution network, the transmission link equilibrium structure model of 5G source network load storage access to power wireless private network is constructed. Combined with the coverage analysis of link topology structure and the benefit maximization constraint analysis of production and consumption users, the active and reactive capacity analysis of transaction between production and consumption user groups and multiple production and consumption users is adopted. Combined with the energy storage characteristics analysis and power flow parameter calculation of the source network load storage access power, the 5G ultra dense networking and private network access to the source network load storage access power are realized. The test shows that this method has better power balance dispatching ability and larger output power gain when it is applied to the design of source network load storage access power wireless private network. [ABSTRACT FROM AUTHOR]

The structural integrity of steel trusses and I-beams is of vital importance for preventing the potential collapse of steel bridges when subjected to extraordinary forces. Thus, identifying damage to I-beams, which cannot be noticed in typical inspections, based on their measured response, would enable early damage detection, and would trigger the necessary mitigation measures to restore the structural integrity of the bridge. This investigation built a vast database of structurally damaged cantilever I-beams, in which openings of various degrees and locations were placed along the beams to emulate reductions in stiffness. Both damaged and undamaged I-beams were modeled using Abaqus software, facilitated by Python scripting. Three deep-learning algorithms were trained, validated and tested with the healthy and damaged I-beam cases: long short-term memory (LSTM), a LSTM-based autoencoder, and multivariate time-series transformers (MTTs), for which the input data consisted of acceleration responses recorded at specific points on the top flange of both undamaged and damaged I-beams subjected to harmonic dynamic loads. To enhance adaptation for field monitoring data, random normal noise was introduced into the acceleration responses before running the machine learning (ML) damage identification algorithms. The three algorithms demonstrated exceptional ability to accurately distinguish between the damaged and the undamaged I-beams. Furthermore, the location of the damage on the beam was identified by the LSTM and MTT algorithms, which had the best accuracy for damage localization. Finally, a comparative analysis of the three algorithms was conducted to clarify the optimal quantity of data points required to attain reliable results. [ABSTRACT FROM AUTHOR]

Wide-base tires (WBTs) have been gradually adopted for trucks to improve fuel economy and driving comfort. This study aims to investigate the impact of WBTs on flexible pavement responses as compared to dual tires (DTs) coupling the effects of multiaxle and dynamic loading. A semi-analytical finite element model (SAFEM) was developed to simulate pavement responses under dynamic moving loads with high efficiency and good accuracy. The model was validated by comparing simulation results with field measurements from the instrumented section in the Long-Term Pavement Performance (LTPP) database. The influence of tire type, axle configuration, and pavement roughness was analyzed in terms of four critical pavement responses: longitudinal tensile strain at the bottom of asphalt layer, transverse tensile strain on pavement surface, near-surface shear strain, and compressive strain at the top of subgrade. The analysis results show that pavement responses induced by dynamic loads conform to normal distribution, and the variation of pavement responses increases linearly with that of dynamic loads. WBTs cause greater pavement damage than DTs in general. Among four pavement distresses, the highest damage ratio is observed for top-down cracking and the least one is for near-surface rutting. The damage ratios vary with axle configuration or speed rather than pavement surface roughness, especially for top-down cracking. The study emphasizes the impact of pavement roughness, tire type, and axle configuration on pavement responses. [ABSTRACT FROM AUTHOR]

In this state of art, efforts had been devoted to critically review the progressive research on connected and disconnected pile raft foundation (CPRF and DPRF) subjected to lateral and vertical dynamic loads embedded in different soils. DPRF was employed to bring down the large shear forces and bending moments generated at the pile head in CPRF. Design aspects of CPRF and DCPF were discussed such as load sharing mechanism, differential settlements, peak acceleration, period lengthening, bending moment etc. It was also explained the importance of considering soil structure interaction in design of both CPRF and DCPF subjected to dynamic loads. [ABSTRACT FROM AUTHOR]

Traditional methods for analyzing the P–Δ effect in tall structures often fail to fully account for time-varying axial forces, potentially underestimating the impact of the P–Δ effect on structural safety. To address this limitation, this paper introduces a high-precision method based on the Differential Quadrature Method (DQM) for advanced analysis of the P–Δ effect, applicable to both distributed mass, and concentrated mass structural systems. This method discretizes the partial differential equations governing the motion of structures subjected to arbitrary lateral and axial dynamic loads using Differential Quadrature (DQ) principles, applying DQ weighting matrix corrections method to handle boundary conditions. Additionally, it incorporates the unconditionally stable Newmark average acceleration method to solve for dynamic responses inclusive of the P–Δ effect. The method is validated through case studies of high-rise buildings and tall bridge piers, demonstrating strong agreement with results from general finite element software. Results indicate that the proposed method not only effectively captures the influence of time-invariant and time-varying axial forces on lateral vibration characteristics but also provides high-precision dynamic response analysis, offering a highly efficient, and practical tool for analyzing dynamic responses in tall structures. [ABSTRACT FROM AUTHOR]

The impact of high-pressure inflow on water pump performance is crucial in determining whether the gravitational potential energy effectively synergizes with the mechanical energy of the pump. Using an independently developed Wankel pump and test platform, we conducted a preliminary demonstration of the gravity-pump pressure collaborative dynamic loading method. The Wankel pump demonstrates excellent performance under self-priming conditions with high-pressure and high-flow rates. The power decreases linearly with increasing inlet pressure during high-pressure inflow, while maintaining acceptable flow fluctuations. This demonstrates the feasibility of the driving method. The trend of total efficiency with inlet pressure is primarily determined by mechanical efficiency, while volatility is influenced by both volumetric efficiency and hydraulic efficiency. The descent stage's slow fluctuation range plays a critical role in determining the range of utilization of gravitational potential energy, and it is influenced by the target flow rate. [ABSTRACT FROM AUTHOR]

Background: The porous structure in bone tissue is essential for maintaining the physiological functions and overall health of intraosseous cells. The lacunar-canalicular net (LCN), a microscopic porous structure within osteons, facilitates the transport of nutrients and signaling molecules through interstitial fluid flow. However, the transient behavior of fluid flow within these micro-pores under dynamic loading conditions remains insufficiently studied. Methods: The study constructs a fluid-solid coupling model including the Haversian canal, canaliculi, lacunae, and interstitial fluid, to examine interstitial fluid flow behavior within the LCN under dynamic loading with varying frequencies and amplitudes. The relationship between changes of LCN pore volume and fluid velocity, and pressure is researched. Results: The results demonstrate that increasing strain amplitude leads to significant changes of LCN pore volume within osteons. In a complete loading cycle, with the increase of compressive strain, the pore volume in the osteon gradually shrinks, and the pressure gradient in the LCN increases, which promotes the increase of interstitial fluid velocity. When the compressive strain reaches the peak value, the flow velocity also reaches the maximum. In the subsequent unloading process, the pore volume began to recover, the pressure gradient gradually decreased, the flow rate decreased accordingly, and finally returned to the steady state level. At a loading amplitude of 1000 µε, the pore volume within LCN decreases by 1.1‰. At load amplitudes of 1500 µε, 2000 µε, and 2500 µε, the pore volume decreases by 1.6‰, 2.2‰ and 2.7‰ respectively, and the average flow velocity at the center of the superficial lacuna is 1.36 times, 1.77 times, and 2.14 times that at 1000 µε, respectively. Additionally, at a loading amplitude of 1000 µε under three different loading frequencies, the average flow velocities at the center of the superficial bone lacuna are 0.60 μm/s, 1.04 μm/s, and 1.54 μm/s, respectively. This indicates that high-frequency and high-amplitude dynamic loading can promote more vigorous fluid flow and pressure fluctuations with changes in LCN pore volume. Conclusions: Dynamic mechanical loading can significantly enhance the interstitial fluid flow in LCN by the changes of LCN pore volume. and dynamic loading promoted fluid flow in shallow lacunae significantly higher than that in deep lacunae. The relationship between changes of LCN pore volume and interstitial fluid flow behavior has implications for drug delivery and bone tissue engineering research. [ABSTRACT FROM AUTHOR]

The ability to forecast system conditions is integral to the definition and functionality of digital twins. While forecasting methods have been explored for use in digital twin systems, the integration of feedback mechanisms for real-time forecasting and in-situ decision-making in DC microgrids has not been extensively investigated. This research develops a modular forecasting framework tailored for digital twins in DC microgrids to enable real-time monitoring, online forecasting, and decision-making. DC microgrids, characterized by dynamic load variations, benefit from advanced predictive capabilities to maintain stability and operational efficiency. The proposed digital twin-based forecasting framework addresses these challenges by providing real-time predictive insights based on dynamic system conditions and a forecasting window defined by a decision-maker, facilitating proactive management strategies. Leveraging real-time sensor data, the digital twin forecasts system behavior under varying load conditions, enabling proactive management through real-time decision-making within operational constraints. As a proof of concept, the framework incorporates an electro-thermal digital twin designed to manage power flow based on thermal constraints in power distribution cables. Experimental validation using a simplified three-bus DC microgrid testbed demonstrates the effectiveness of the framework in enabling timely adjustments to power flows and preventing thermal overloads. [ABSTRACT FROM AUTHOR]

The rapid development of Blockchain Internet of Things (IoT) has intensified the need for efficient and secure cross-chain transmission across heterogeneous systems. However, traditional cross-chain methods, such as hash time-locked contracts and relay chains, focus primarily on security and correctness while neglecting performance optimization. This limitation is particularly pronounced in high-dynamic environments like port areas, where network congestion, high latency, and uneven resource utilization are prevalent challenges. To address these gaps, this study proposes a novel load-adaptive cross-chain control method tailored for Blockchain IoT systems in port areas. The proposed method integrates multi-feature joint learning with adaptive multi-channel joint bus control, enabling dynamic resource allocation and interference suppression for enhanced transmission efficiency. Furthermore, a distributed intelligent scheduling mechanism is introduced to improve scalability and stability under high-concurrency conditions by decentralizing task coordination across blockchain nodes. Additionally, federated learning is employed to optimize cross-chain communication while preserving data privacy, ensuring secure and collaborative optimization in multi-party environments. Extensive simulations validate the effectiveness of the proposed approach, demonstrating significant improvements in throughput, latency, and packet loss rate compared to traditional centralized methods. The results highlight the method's ability to balance dynamic network loads, minimize interference, and adapt to real-time conditions. This work bridges the gap between performance-oriented optimizations and privacy-preserving mechanisms, offering a scalable and secure solution for Blockchain IoT systems in complex and dynamic environments. [ABSTRACT FROM AUTHOR]

AbstractDespite many favorable properties of sandwich panels, moisture penetration into the core of these panels has been known to cause catastrophic failures. To address these issues, developing an alternative panel with equivalent mechanical behavior can be a viable solution. Exploring the mechanical behavior equivalency between stiffened composite plates and existing sandwich panels is advantageous due to their potential for similar applications. This study employed explicit finite element modeling using LS-DYNA package to simulate the behavior of these panels. Also, experimental investigations were conducted on stiffened composite plates to examine the effect of stiffener arrangements and impact location on their static and dynamic behaviors. The experiments highlighted the significance of stiffener arrangements in influencing the static and impact behavior of the plates. Additionally, as a case study, an optimization procedure for designing an optimal stiffened plate under ice impact was studied, utilizing the Taguchi method and analysis of variance, to identify the optimal design point. The results indicated that the stiffened plate exhibited a maximum deflection similar to that of a sandwich panel under low-velocity impact, while having a 19.3% lower von Mises stress. This means that the equivalent stiffened plate demonstrated comparable deflection while providing enhanced strength during dynamic loading. Furthermore, the analysis of the parametric study showed that the thickness of stiffeners had the most pronounced influence on the behavior of stiffened plates subjected to hail impact. [ABSTRACT FROM AUTHOR]

AbstractCaisson composite–pile foundation (CCPF) is a major type of deep–water foundation. It is composed of gravity caissons and a pile foundation. It is widely used in bridge piers, wharf platforms, breakwaters, offshore platforms, and offshore wind–power foundations. Herein, the geotechnical characteristics and deformation of CCPFs are examined. Further, Emphasis is placed on theoretical, experimental, and numerical studies of the loading mechanism, transfer law, and deformation distribution of blended foundations under static and dynamic loading. Based on these studies, suggestions for future research and development are provided. [ABSTRACT FROM AUTHOR]

This study addresses the pressing need for optimized solar power systems in the context of climate change concerns. Focusing on Maximum Power Point Tracking (MPPT) techniques, the research evaluates various models to enhance energy generation in solar systems under fluctuating solar irradiation conditions. The Adaptive Neural-Fuzzy Inference System (ANFIS) is chosen for its responsiveness, but designing an efficient ANFIS-MPPT system requires precise training data. The study introduces a novel approach, combining ANFIS with Gene Expression Programming (GEP), aimed at optimizing the reference maximum power output using solar irradiance and temperature as input parameters. The integration was tested on a boost converter via Matlab/Simulink simulations, which reveals the GEP-ANFIS double diode model's exceptional 99.84% efficiency under high solar irradiation. This underscores the substantial potential of GEP-ANFIS for improving solar power efficiency and MPPT performance in diverse environments, contributing to the advancement of solar energy utilization. [ABSTRACT FROM AUTHOR]

With the continuous increase in bridge lifespans, the rapid check and evaluation of the vertical bearing capacity for the pile foundations of existing bridges have been in greater demand. The usual practice is to carry out compression bearing tests under static loads in order to obtain the accurate ratio of the dynamic to static stiffness. However, it is difficult and costly to conduct in situ experiments for each pile foundation. Herein, a rapid evaluation method to measure the vertical bearing capacity of bridge pile foundations is proposed. Firstly, a 3D-bearing cap–pile group–soil interaction model was established to simulate a bearing test of a pile foundation that was subject to static loads and dynamic loads, and then the numerical results were validated by in situ dynamic and static loading tests on an abandoned bridge pier with the same pile group foundation; the dataset for machine learning was constructed using the numerical results, and finally, the bearing capacity of the pile foundation could be predicted rapidly. The results show the following outcomes: the established numerical model can effectively simulate dynamic and static loading tests of pile foundations; the intelligent prediction model based on machine learning can predict the ratio of static stiffness to dynamic stiffness and can thus rapidly evaluate the vertical residual bearing capacity and the designed ultimate loading capacity, allowing for the nondestructive testing and evaluation of the pile foundations of existing bridges. [ABSTRACT FROM AUTHOR]

AbstractThe filling medium in joints has a significant influence on the impact fracture behavior of rock masses. Three-point bending impact fracture experiments were conducted on specimens with prefabricated cracks containing filling materials using a dynamic caustics experimental method combined with a high-speed camera to investigate the effect of joint filling materials on crack propagation under dynamic loading. Additionally, numerical simulations were performed to analyze the effect of filling materials on crack propagation under dynamic loading. The results indicate that the propagation of Crack A is primarily controlled by the Mode I stress intensity factor at the tip of the vertical prefabricated crack. The filling medium within the horizontal prefabricated crack has no significant effect on the initiation or propagation of the vertical prefabricated crack. However, the filling medium has a profound impact on the initiation time and propagation trajectory of the secondary Crack B. The stronger the filling medium, the greater the energy required for the initiation of Crack B, and the longer the time needed for Crack B to penetrate the specimen. Furthermore, the fracture point of Crack B deviates further from the hammer impact point as the strength of the filling medium increases, exhibiting characteristics of a typical mixed-mode I-II crack. The numerical simulation results also confirm that the type of filling medium primarily affects the propagation trajectory of the secondary Crack B, aligning closely with the experimental findings. [ABSTRACT FROM AUTHOR]

AbstractThis work investigated the quasi-static and dynamic behavior under dynamic loads of viscoelastic shells reinforced using functionally graded carbon nanotube-reinforced composite material (FG-CNTRC). The dynamic analysis of CNTRC shells by single-walled CNTs (SWCNTs) is the subject of this study. SWCNTs were thought to have a homogenous pattern and to be straight and aligned. Three different FG-CNT distributions of carbon nanotubes over thickness were studied, as well as homogenous CNT topologies. With the use of Hamilton’s principle, the equation of motion for composite shells was achieved. The time-dependent equations were obtained by using the Navier solution method to solve the equation of motion. The truncated series approach was applied while formulating the system’s equations to improve numerical stability. A viscoelastic damped movement for dynamic loaded FG-CNTRC shells has been obtained for the first time by applying the approach of truncated equations as proposed here. Laplace domain was used to transform these equations. The subsequent computations were performed using the modified-Durbin technique, which changed the Laplace area to the time-area. The conclusions indicate that using the Laplace approach, there is no need to employ modes or vibration to solve the issue exactly, efficiently, and simply. The composites reinforced by FG-CNT have demonstrated great potential in developing high-performance, smart materials and structures. The numerical investigation is envisaged to provide guidelines for the design of developing smart engineering structures. A suitable change in damping ratios, curvature ratio, FG configurations, volume fractions can enable the manufacture of smart products that intelligently respond to dynamic problems. [ABSTRACT FROM AUTHOR]

Electric vehicle (EV) production is pivotal in achieving environmental sustainability by reducing greenhouse gas emissions and air pollution. Since the weight of electric vehicles directly influences the energy consumption and driving range of the vehicle, innovative engineers face a significant challenge in designing an optimized vehicle chassis that remains robust under complex loading conditions. This paper focuses on the dynamic analysis of an EV chassis subjected to transient suspension forces due to hitting speed bumps and proposes a load factor between static and dynamic loads. A quarter vehicle model was adopted and solved using MATLAB Simulink to simulate the transient force transmitted to the chassis under different bump dimensions and vehicle speeds. The load was implemented into three different dynamic analysis studies: Front Loading, Rear Loading, and Torsional Loading. Subsequently, static and dynamic analyses were performed using Finite Element Analysis (FEA) with SimSolid software. The results obtained from the dynamic analysis studies showed that the maximum stress was 288 MPa with a safety factor of 1.12, while the maximum stress in the static analysis was 64 MPa with a safety factor of 5.69. Additionally, a load factor of 4.44 between static and dynamic loads was revealed. Based on these findings, the chassis experiences only elastic deformation and is considered safe for practical use. [ABSTRACT FROM AUTHOR]

Predicting rockburst disasters is one of the most critical issues in deep rock mechanics. This paper introduces an innovative method for predicting rockburst. The localization and energy level recording of seismic events generated by coal and rock rupture were achieved using numerical simulation methods. The dynamic and static loading characteristics of deep mining in steeply inclined double coal seams were investigated, and rockburst hazards were predicted. The experimental and engineering field investigation results verify the accuracy of the numerical simulation. The energy of seismic events generated by coal-rock rupture is approximately 0.6% of the released strain energy monitored by numerical simulation. After entering deep mining in steeply inclined double coal seams, seismic events gradually spread to the central area of the inclined axis. The frequency and energy of seismic events on roof #B3 + 6 and the concentration of static loading stress gradually exceeded those on the rock pillar, indicating a shift in the main controlling factor of rockburst from the rock pillar to roof #B3 + 6. The rate of increase in rockburst hazard in the northern area was more significant than in the southern area as the mining depth increased. The research results provide a new approach for predicting rockbursts. Highlights: The recording of rockburst seismic events in coal and rock was achieved using numerical simulation methods. The correlation between seismic energy released during coal and rock rupture and the strain energy released was determined. The positions, frequencies, and energy of microseismic events during the mining of steeply inclined coal seams were documented. The rockburst hazards and zoning differences of deep mining in steeply inclined coal seams were predicted. [ABSTRACT FROM AUTHOR]

This paper puts forward the dynamic load prediction of charging piles of energy storage electric vehicles based on time and space constraints in the Internet of Things environment, which can improve the load prediction effect of charging piles of electric vehicles and solve the problems of difficult power grid control and low power quality caused by the randomness of charging loads in time and space. After constructing a traffic road network model based on the Internet of Things, a travel chain model with different complexity and an electric vehicle charging model, the travel chain is randomly extracted. With the shortest travel time as a constraint, combined with the traffic road network model based on the Internet of Things, the travel route and travel time are determined. According to the State of Charge (SOC) and the travel destination, the location and charging time of the energy storage electric vehicle charging pile are determined. After obtaining the time-space distribution information of the energy storage electric vehicle charging pile at different times and in different regions, it is used as the input of the deep multi-step time-space dynamic neural network, and the network output is the dynamic electric vehicle charging pile. The experimental results show that this method can realize the dynamic load prediction of electric vehicle charging piles. When the number of stacking units is 11, the indexes of Mean Absolute Percentage Error (MAPE) and Root Mean Square Error (RMSE) are the lowest and the index of R2 is the largest. The load of charging piles in residential areas and work areas exists in the morning and evening peak hours, while the load fluctuation of charging piles in other areas presents a decentralized change law; The higher the complexity of regional traffic network, the greater the load of electric vehicle charging piles in the morning rush hour. [ABSTRACT FROM AUTHOR]

A proper and reliable fracture fixation is important for fracture healing. The proximal femoral intramedullary nail (IN), such as proximal femoral nail anti-rotation (PFNA) or Gamma nail, is widely used for intertrochanteric fracture fixation. However, it still suffers considerable stress concentrations, especially at the junction between the nail and the blade or lag screw. In this study, we propose a novel intramedullary nail design to enhance the intramedullary nail integrity by introducing a bolt screw to form a stable triangular structure composed of the nail, the lag screw, and the bolt screw (PFTN, Proximal femoral triangle nail). Systematic finite element numerical simulations were carried out to compare the biomechanical performances of PFTN and PFNA under both static and dynamic loads during the postures of ascending and descending stairs. The simulation results highlight the advantages of the proposed PFTN design with lower stresses, less stress concentration, and higher structure stability. [ABSTRACT FROM AUTHOR]

Hanging sleepers, which result from the differential settlement of the ballast layer, are a prevalent issue that leads to the rapid degradation of track components that include the ballast, sleeper, fastener, and rail. A novel type of sleeper, the wedge-shaped self-leveling sleeper (WSS), was proposed as a solution to the hanging sleeper problem. The WSS leverages the train's dynamic loading and the gravity of the ballast to naturally allow the ballast particles to fill the gap between the ballast and the sleeper. This paper focuses on the dynamic performance of the WSS from different aspects, which include wedge angles (30°, 45°, and 60°), sleeper materials (concrete and plastic), and the number of WSS to replace regular sleepers in the transition zone. A series of numerical modeling [which coupled multibody simulation (MBS) and discrete-element methods (DEM)] were conducted to design, optimize, and test the WSS. The results reveal that a concrete WSS is well-suited to address the problem of hanging sleepers in transition zones. The WSS with a 45° angle demonstrated superior performance compared with other types of WSS. Importantly, the WSS could reduce vibrations in the vehicle and track, even when dealing with hanging sleepers. Due to the self-leveling function, the WSS shows significant promise for applications in transition zones, which could reduce the frequent need for track geometry maintenance. [ABSTRACT FROM AUTHOR]

Mechanically stabilized earth (MSE) retaining walls have been successfully implemented in numerous applications, particularly where dynamic loads such as earthquake and traffic loading are prevalent. However, using MSE walls as foundations for high-speed train track systems remains uncertain, and their performance under high-speed train loading is inconclusive. This paper extensively investigates the behavior of MSE walls under various high-speed train loading conditions, addressing key considerations, challenges, and findings. The study focuses on evaluating wall performance in terms of horizontal displacement, settlement behind the facing, tensile load and displacement of reinforcement elements, and wall amplification characteristics. The performance of the wall is also assessed by examining the influence of the cement asphalt mortar layer. The total axle load and loading duration are identified as critical design parameters for high-speed train loading, and an empirical equation is developed to estimate horizontal wall displacement based on these parameters. [ABSTRACT FROM AUTHOR]

IEC 61400-2 establishes the Simplified Load Method for designing low-power wind turbine blades without considering dynamic loads in the simplified load methodology. This paper analyzes the load hypotheses established by the standard, also considering the natural frequencies in a 900 W blade. The research methodology begins with the design parameters, the application of the BEM Method, and the use of the QBlade software. Then, the load hypotheses of the standard are defined. Finally, the structural design and the modal and structural analysis of the blade were conducted using FEM-based software. The results show that the minimum participation factors are found on the z-axis and the maximum on the x- and y-axis, and their magnitudes decrease when the natural frequency increases. In general, the principal maximum stresses are located in the middle section of the blade, in the external fiberglass layer, both on the intrados and extrados sides. In conclusion, structural scenarios were established to relate the participation factors of the modal analyses with the load hypotheses. The critical scenarios are at natural frequencies below 280 Hz. [ABSTRACT FROM AUTHOR]

A taphonomic study, followed by the biometrical analysis and mortality profile of 490 bone remains from the Neolithic to Bronze Age levels at El Portalón (Atapuerca, Burgos, Spain) is presented in this work. The pig is the third most represented taxon in the Neolithic, Pre-Bell Beaker Chalcolithic, Bell-Beaker Chalcolithic, and Late Bronze Age levels, and the fourth taxon in the Early and Middle Bronze Age levels, when it was replaced by horses. There was a slight decrease in pig size from the Bell-Beaker to the Middle Bronze Age, coinciding with a change in suid management. The possible causes of these changes are analyzed and discussed in this work. Taphonomic alterations, as well as anthropic evidence, such as cut marks, human tooth marks, dynamic loading, and fire modifications, suggest consumption of domestic suids throughout the El Portalón site's entire chronocultural sequence. [ABSTRACT FROM AUTHOR]

Finite element analysis (FEA) has been used as a successful supplement to experimental testing in various studies for simulation of anchorage behaviour. Throughout the years, researchers have employed different modelling techniques in various FEA packages to capture the behaviour of post-installed anchors. However, the vast amount of knowledge accrued is yet to be reviewed. This article critically reviews all aspects of FEA from pre-processing to post-processing and provides a comprehensive review of published literature on FEA studies for predicting the behaviour of post-installed anchorage systems. Most current efforts focus on investigating failure mechanism of anchors in uncracked concrete under tensile loading. Findings show that developing finite element model for post-installed anchorage in concrete is very challenging due to complex geometrical configuration of anchors, difficulty in modelling concrete–anchor interface and lack of reliable information on selecting material properties and parameters. The analysis identified key gaps in research related to the effect of geometrical simplification, anchor subjected to dynamic loading and anchor performance in cracked concrete which needs attention in future research. This review article is a valuable resource in facilitating future research on assessing the performance of post-installed anchorage in concrete with FEA. [ABSTRACT FROM AUTHOR]

Aiming at resolving trajectory tracking control challenges during high‐speed lane changes in intelligent driving vehicles, an innovative fractional‐order sliding mode control approach is introduced in the present study. The control strategy comprises upper and lower‐level controls. First, the upper‐level control designs the vehicle trajectory tracking controller, integrating a non‐singular terminal sliding mode (NTSM) surface with a fractional‐order fast super‐twisted sliding mode control (FOF‐STSMC) algorithm. The NTSM surface properties ensure rapid convergence of the system tracking error to zero within a finite time, while the fractional‐order control extends the control system's regulation range and enhances algorithm flexibility. Additionally, the integration with the super‐twisting algorithm effectively mitigates oscillation issues in the control input, achieving a smooth input. Second, the lower‐level control aims to enhance vehicle driving stability. Utilizing the reference yaw rate, and sideslip angle and accounting for tire force saturation, a fractional‐order sliding mode control (FOSMC) algorithm is developed to compute the external yaw moment. Through dynamic load allocation, considering the vertical load for each tire, intelligent external yaw moment distribution significantly improves vehicle stability. Finally, the results of the Carsim–Simulink co‐simulation demonstrate that, compared to the STSMC strategy, the FOSMC strategy with front‐wheel‐only steering, and the linear quadratic regulator (LQR) control strategy, the proposed control strategy in this paper reduces the tracking error by 77%, 61%, and 58%, respectively, achieving more precise and stable trajectory tracking under high‐speed conditions. [ABSTRACT FROM AUTHOR]

Forced vibrations resulting from moving loads, along with efficient vibration control, are essential in transportation engineering, earthquake engineering, and aerospace engineering. In this study, the vibrational response of an axially functionally graded (AFG) beam subjected to a moving harmonic load within a thermal environment was investigated. The primary aim was to explore the potential of controlling this vibration by incorporating a nonlinear energy sink (NES). A model for the AFG beam, with clamped–clamped boundary conditions, was developed using Euler–Bernoulli beam theory and the Lagrange method, accounting for the effects of the thermal environment and the moving load. The numerical simulations were performed using the Newmark method to solve the governing equations. The results demonstrated the effectiveness of the NES in mitigating the vibrational response of the beam under thermal and dynamic loading conditions. The effective reduction of maximum deflection caused by moving loads was set as the optimization objective to identify the most optimal parameters of the NES. The results were presented through a series of parameter analyses, revealing that the nonlinear damper can quickly dissipate the beam's energy when the loads exit the structure. Furthermore, a properly designed NES can result in a 2.4-fold increase in suppression efficiency. [ABSTRACT FROM AUTHOR]

The aim is to investigate the impact of retention type, implant/abutment angulation, and the presence of sealant/antimicrobial agents on screw loosening of implant-supported restorations. Fifty dental implants along with their respective abutments and screws were allocated to five groups (n = 10). The groups were categorized based on type of crown retention (screw-/cement-retained), implant/abutment angulation (0°/20°), and type of disinfectant/sealant as follows: Cem_control (cemented/0°/none), Cem_GP (cemented/0°/gutta-percha), Cem_CHX (cemented/0°/chlorhexidine), Cem_Ang (cemented/20°/none), and Screw (screwed/0°/ none). Abutment screws were tightened (20 Ncm), and CAD/CAM zirconia crowns were fabricated. Glass ionomer cement was used for crown cementation in the cemented groups. Samples were subjected to dynamic loading in a chewing simulator (1,200,000 cycles/98 N). After loading, the reverse torque values (RTVs) of the abutment screws were determined (Ncm) using an electronic screwdriver, and the reverse torque difference (RTD) was subsequently calculated. The lowest RTD was reported in group Cem_GP (−2.22 ± 1.03), whereas the highest RTD was seen in group Screw (−4.65 ± 1.79). Group Screw showed a statistically significant difference from all other groups (p < 0.05). No statistically significant difference between the cemented test groups Cem_GP, Cem_CHX, and Cem_Ang and the control group was found. Screw-retained restorations exhibited significantly greater RTD values compared to cement-retained ones. Implant/abutment angulation and the sealant/disinfectant appeared to have no notable effect on the screw stability of single-implant restorations. [ABSTRACT FROM AUTHOR]

The deterioration of the US transportation highway network and the onset of new technologies in the freight industry are expected to cause changes in the axle load magnitude and distribution, further exacerbating the reduction in the service life of flexible pavements. In this study, a reviewed framework to incorporate roughness-induced dynamic wheel loading into tire–pavement contact stress prediction is presented. The response to nonfree-rolling conditions, usually overlooked, was considered. State-of-the-art numerical models were used to account for pavement unevenness, vehicle dynamics, and 3D and nonuniform contact stresses. In this framework, for a given target international roughness index, an artificial multitrack roughness profile was converted into a dynamic loading profile based on the mechanical properties of a Class 9 vehicle. Upon discretization of the dynamic loading profile into a finite number of loads based on percentile distributions, a 3D finite element model of a dual-tire assembly was used to predict the contact stress distribution over a rigid surface. The performed numerical simulations allowed us to analytically quantify the variation of vertical and in-plane contact stress distribution. Hence, changes in the stress/strain field distribution and peak values under various axle loading scenarios were determined. The findings reveal that disregarding the effect of road roughness and vehicle maneuvering could result in considerable underestimation of the net forces and contact stress distribution developed at the tire–pavement interface. These considerations are particularly impactful on in-plane contact stresses, which, in turn, are associated with near-surface distresses. Practical Applications: The distribution of contact stresses at the tire–pavement interface influences the likelihood of failure near the surface and is greatly affected by driving behavior (braking, cornering, and acceleration). Truck electrification is likely to modify driving behavior due to the instant torque availability provided by electric powertrains, and the incorporation of battery packs is likely to alter the distribution of axle loading. The impact of these variables on the applied load to a pavement system could be further exacerbated by road conditions. In that regard, this paper aims to quantify the changes in the contact stress distribution when roughness, driving behavior, and axle loading are compounded. Because these considerations are not taken into account by current pavement analysis procedures, pavement engineers can use the results to assess the importance of each parameter on load characterization, a controlling variable on the prediction of pavement responses. [ABSTRACT FROM AUTHOR]

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This paper introduces a dynamic context-aware load balancing mechanism called EdgeUP, which leverages dynamic contexts of both edge nodes and IoT devices to balance tasks on edge nodes optimally. To perform this, we devised a lightweight load balancer to allocate tasks optimally based on CPU utilization across edge nodes while satisfying the task priority of IoT devices. We implemented EdgeUP on real edge devices (i.e., Raspberry Pi 400) and evaluated it in terms of the average CPU utilization of edge nodes, idle CPU distance, and execution time. The experimental results show that EdgeUP outperforms three conventional load balancing algorithms, including round-robin, hill climbing, and K-Means, by 5.6×, 2.1×, and 3.6×, respectively. [ABSTRACT FROM AUTHOR]

In alternating current (AC) microgrids, the prevalent approach for controlling the power distribution between generators and loads is droop control. This decentralized technique ensures accurate power sharing; however, its utility is restricted by significant drawbacks. Notably, in scenarios involving dissimilar power sources, mismatched impedance lines, or meshed microgrids, conventional droop control fails to ensure effective reactive power sharing among inverters, often leading to notable circulating currents. Hence, the primary objective of this paper is twofold: firstly, to examine limitations inherent to conventional droop control; secondly, to introduce a robust power-sharing methodology for AC microgrids. This novel approach is specifically designed to achieve consistent sharing of active and reactive power across meshed topology microgrids. The technique considers the presence of distributed power loads and the dynamic nature of the topology. Despite the attainment of satisfactory active and reactive power sharing, deviations in voltage and frequency occasionally manifest. To address this issue, a supplementary control mechanism is proposed as a third phase. This secondary control method focuses on reinstating the microgrid's voltage and frequency to rated values, all while upholding the precision of power sharing. The efficacy of this multi-stage methodology is rigorously validated through simulations using MATLAB/Simulink and practical experimentations. [ABSTRACT FROM AUTHOR]

The wind-induced response of structures is typically studied in wind tunnels either on scaled models or using numerical approaches under similar transient load conditions. In early design phases—where the potential for impactful change is most significant—information is often limited. As a result, studies are frequently conducted on simplified or reduced-resolution structural models. Typical applications for dimensionally reduced engineering models include early design phases, deciding on the need for high-fidelity analyses, and verifying wind tunnel models, which are often constructed using beams with lumped masses. In this contribution, the validity of these approaches is tested. Various limitations intrinsically arising from such modeling assumptions, showcased on a generic high-rise under dynamic wind load conditions, are highlighted. The systematic parametric analysis focuses on the variations in transient structural responses, particularly displacement and accelerations at the top of a building. Various wind loading cases are studied, with the reduction of the resolution taking place either in the original or in modal space. Results indicate that a considerable reduction is possible, but characteristic design values tend to deteriorate in cases of a high reduction, particularly when higher mode contributions are truncated. It is observed that the top-floor acceleration and displacement can be captured with considerable accuracy with three lumped masses for tall buildings. It is critical to study the impact of simplifying models starting at the highest level of detail possible. Here, a three-DoF model was able to capture the displacement up to a deviation of 11% and accelerations up to 20%. These approximate models are useful for initial design stages, optimization, uncertainty quantification, etc., where fast, cheap, and moderately accurate model evaluations are necessary. [ABSTRACT FROM AUTHOR]

AbstractTo investigate the impact of traffic loading on the deformation characteristics of soft dredger fill, a series of dynamic triaxial tests of soft dredger fill were carried out. The deformation characteristics of the soft dredger fill under varying confining pressures and dynamic stress ratios were analyzed comparatively. The test results indicate that the cumulative plastic strain curve of the soft dredger fill exhibits three distinct patterns: destructive, critical, and stable; Based on the cumulative plastic strain development law of the dredger fill, an empirical formula of critical dynamic stress and the prediction model of cumulative plastic strain development were established, considering the influence of confining pressure. Under continuous loading, the hysteresis curve of soft dredger fill showed pronounced non-linearity, and hysteresis. Initially, the curve exhibited an “ellipse” shape, transitioning to a “crescent” shape in the middle and late stages. The higher the dynamic stress ratio, the greater the height and width of the hysteresis loop. These findings provide valuable insights into the dynamic behavior of dredger fill under traffic loading. [ABSTRACT FROM AUTHOR]

AbstractThis study systematically investigated the dynamic mechanical properties and penetration-damage behavior of high-density VNbTa medium-entropy alloys under dynamic loading. The split Hopkinson bar, impact energy release, and spaced-target plate tests were carried out. Results from the impact energy release test indicated that a significant chemical reaction and substantial energy release occurred when the alloy hit a rigid target plate at high speed. The spaced-target plate penetration test verified the combined destructive effect of the alloy’s kinetic and chemical energies during penetration, leading to large perforations and severe deformation of the rear target plate. Moreover, a shock-induced energy release model and a fragment cloud diffusion model were established, uncovering the energy release mechanism and fragment-cloud expansion law. These findings provide a theoretical and experimental basis for the design and application of high-density, high-energy structural materials. [ABSTRACT FROM AUTHOR]

AbstractThis study introduces a novel hybrid tetra-chiral honeycomb (NHTCH) structure achieved by combining a tetra-chiral honeycomb and its inverse configuration. The honeycomb prototype was created through 3D printing, and a quasi-static compression experiment was conducted in the opposite direction. Utilizing Abaqus/Explicit, we developed a finite element numerical model and verified its accuracy. The mechanical properties of the proposed structure, denoted as NHTCH, were compared with those of traditional tetra-chiral honeycombs (TCH). Results indicated that NHTCH exhibits superior mechanical properties compared to TCH, and its plastic deformation displays a noticeable negative Poisson’s ratio effect. Furthermore, we analyzed the in-plane mechanical response of NHTCH under varying impact velocities and conducted parametric studies on the angle between chiral elements and the radius of the node circle. Our findings reveal that, under high-speed impacts, NHTCH demonstrates higher energy-absorbing and load-carrying capacities compared to the other two configurations. Simultaneously, optimizing the clamping angle and nodal circle radius of NHTCH efficiently enhances the mechanical properties within a specific range, without causing significant changes to the plastic deformation of the structure. [ABSTRACT FROM AUTHOR]

This study examines the vibration characteristics of static drill-rooted nodular (SDRN) piles in elastic soils under time-harmonic torsional loads via an analytical approach. SDRN piles, which are characterized by uniformly distributed nodes and enhanced surrounding cemented soil, are able to increase the vertical bearing capacity of piles in soft soils. Piles are modelled using elastic rod theory, while surrounding soils are separated into two sublayers along radial direction: a core zone made up of cemented soil and an outer semi-infinite natural soil layer. An analytical method is proposed to solve the problem after formulating the wave equations for pile and radial soil layer. This methodology rigorously considers the continuity of twist angle and shear stress across the interface of the pile and radial soil layers. The simulation of nodes in the SDRN pile involves discretizing the pile-soil system and applying the principle of impedance function recursion to accurately compute the torsional stiffness at the top of the pile. Developed results are validated against the existing benchmarks for a cylindrical pile in elastic soil. Detailed numerical examples are carried out to assess the effect of major factors on the torsional impedance of the pile. For improved comprehension in engineering applications, the impedance function is applied to derive the twist angle of the rigid foundation, with the amplitude-frequency response expressed in a closed form. Results indicate that the vibration behavior of the piles is significantly influenced by the inner radius, outer radius, the dimension of the node, the radial width of the cemented soil and the damping ratio of the radial soil layer. The developed solution offers valuable insights for the optimization design of SDRN piles under dynamic torsional loads. [ABSTRACT FROM AUTHOR]

AbstractCoral reef limestone (CRL) is found only in ocean reef islands. Deepening the investigation of the dynamic performances of CRL helps expand its utilization in reef engineering. This study studied the dynamic response of shallow weakly-cemented CRL (WCRL) using experimental and numerical methods. First, the impact performance of the WCRL was tested using the Split Hopkinson Pressure Bar apparatus. The dynamic peak stress and peak strain of WCRL exhibited rate-sensitivity. Subsequently, the impact process of the WCRL was calculated in the numerical software LS_DYNA, with key dynamic parameters of WCRL calibrated based on the Holmquist-Johnson-Cook (HJC) model for the first time. The accuracy of the numerical results was verified with the experimental results. Thereafter, the dynamic failure process and energy dissipation mechanism of the WCRL were numerically investigated. As the strain rate increased, the failure of the WCRL specimens intensified. The energy analysis demonstrated that the destruction of WCRL specimens consumed more energy at high strain rates, though the distribution proportion of energy was rate-independent. Finally, the sensitivity analysis revealed that the certain parameters (A, B, C, N, pc, and μc) of the HJC model played a crucial role in describing the material’s dynamic response. [ABSTRACT FROM AUTHOR]

Structural fatigue can lead to catastrophic failures in various engineering applications and must be properly monitored and effectively managed. This paper provides a state-of-the-art review of recent developments in structural fatigue monitoring using piezoelectric-based sensors. Compared to alternative sensing technologies, piezoelectric sensors offer distinct advantages, including compact size, lightweight design, low cost, flexible formats, and high sensitivity to dynamic loads. The paper reviews the working principles and recent advancements in passive piezoelectric-based sensors, such as acoustic emission wave and strain measurements, and active piezoelectric-based sensors, including ultrasonic wave and dynamic characteristic measurements. These measurements, captured under in-service dynamic strain, can be correlated to the remaining structural fatigue life. Case studies are presented, highlighting applications of fatigue life monitoring in metals, polymeric composites, and reinforced concrete structures. The paper concludes by identifying challenges and opportunities for advancing piezoelectric-based sensors for fatigue life monitoring in engineering structures. [ABSTRACT FROM AUTHOR]

This paper presents a field pile load test program conducted on four 0.36 m closed-end steel pipe piles with lengths ranging between 11 and 13 m installed in fine-grained soils. Subsurface investigations with standard penetration tests and cone penetration tests with pore pressure measurements were performed at the site. Three pushed-in piezometers at incremental offsets from the piles were also installed to monitor pore water pressure changes during and after the installation of piles. Several dynamic load tests were performed at different times to observe the change in pile resistance. A static load test was also performed on one of the piles. Some load test results showed an unexpected decrease in the resistances of some piles with time. The study showed that construction activities, e.g., installation of other piles, disturbs the soil and groundwater conditions which can significantly affect the pile resistance measured during load tests. This investigation revealed that pile driving and restrikes should be scheduled such that the effect of construction activities on load tests results will be avoided or minimized. [ABSTRACT FROM AUTHOR]