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Inspired by the cross-laminated hierarchical structure and flexible interface of high toughness Strombus gigas shell, the "fiber-metal-polymer" laminated composites with different laying modes including cross-laminated structure and interfacial properties were designed, and the corresponding damage and toughening mechanisms were investigated. It shows that the cross-laminated structure, accompanying soft interface modification by metal ultra-thin strip and polymer can optimize the full-field stress distribution and failure behavior, then achieve maximize energy absorption and ensure good strength (ultimate strain and toughness increased to 352% and 127.5%, respectively compared to unidirectional laminated material), which may provide optimization strategies for the design of lightweight composites. [ABSTRACT FROM AUTHOR]

AbstractOptimal dental health significantly contributes to an individual’s physical and psychological well-being, with an increasing focus on esthetics and functionality in dental restoration procedures. This research explores the use of zirconia ceramic materials combined with calcium silicate and silver compositions as an alternative for dental crown applications. The study employs 3D finite element analysis to assess stress distribution on full crowns with composites under axial and oblique loads, aiming to understand biomechanical aspects and identify fracture resistance and failure modes. The materials include zirconia-calcium silicate-silver composites with varying volume fractions (Zr 74 to 29%, Ca2SiO4 68 to 25%, and Ag 3 to1%). Results show stress concentration at the crown intaglio surface, influenced by the material’s elastic modulus. Specifically, the C14 composite crown with Young’s modulus 90.82 GPa exhibits lower stress levels for crown 10.9 MPa at axial load and 12.77 MPa at oblique load, making it a potentially recommended choice. These findings suggest the potential of designed biomaterials, emphasizing the importance of material selection in enhancing the longevity and resilience of dental crowns. Also, the study enhances understanding of biomechanical aspects in dental crown restorations, contributing valuable insights for clinical applications. [ABSTRACT FROM AUTHOR]

The pullout capacity of horizontal anchor plates plays a crucial role in ensuring the stability and performance of various structures subjected to uplift or lateral loading. This paper presents an investigation into the pullout capacity of horizontal anchor plates using the method of stress characteristics. The method offers a simplified analytical approach that allows for quick estimations and insights into the stress distribution and failure mechanism of anchor plates. The study focuses on circular anchor plates with varying embedment ratios, considering different soil friction angles. Through computational analyses and the generation of characteristic grids, the behavior and stress distribution of anchor plates are examined. The results are compared with several experimental data from the literature to validate the applicability of the method. The findings provide valuable insights into the influence of embedment ratios and soil friction angles on the pullout capacity of horizontal anchor plates. This research contributes to the understanding of anchor plate behavior and offers a practical tool for assessing their performance in geotechnical engineering applications. [ABSTRACT FROM AUTHOR]

The life of compressor impeller is very short under extreme working conditions, so it is necessary to explore the life extension method and mechanism. Since the crack initiation location cannot be accurately predicted in advance, the hole drilling strategy of prefabricated hole will determine the remaining life of impeller after cracks appear. This article presents a strategy of prefabricated hole to extend the fatigue crack propagation life (FCPL) of compressor impeller. The stress distribution of impeller during operation is simulated by finite element method, and the crack initiation location is determined. The Forman-Newman-de Koning model is used to investigate the effects of hole drilling strategy and rotational speed on FCPL, and the three-dimensional crack propagation process is simulated. In addition, this paper investigates the main phenomena and influencing mechanism for the extension of FCPL due to prefabricated hole. It is found that the prefabricated hole can attract the crack propagation path, and make the crack pass through the hole more easily. At this time, the crack propagation driving force will decrease sharply, and the crack propagation rate will decrease accordingly, thus extends the FCPL. Even if it cannot pass through the hole, the optimal hole drilling strategy can extend life by 104.23%. The life extension effect of prefabricated hole increases with the increase of speed. The design in this paper can reduce the economic cost to a great extent, and provides a new idea for the life extension problem of complex models. [ABSTRACT FROM AUTHOR]

The steering tool combined bearing is a mechanical component that can support forces, guide movement, and bear vibrations at the same time. In the process of analyzing the contact and load distribution inside the combined bearing, there are several contact points, and the static equilibrium equation is statically indeterminate. Based on dynamics theory and Hertz elastic contact theory, the concept of a load integral and the displacement estimation formula for roller bearings are introduced, and a numerical solution to the statically indeterminate problem of the steering tool combined bearing is given. According to the statically indeterminate equation matrix of the combined bearing, the relationship between the load and displacement of the combined bearing is studied to improve the statically indeterminate equation matrix. Moreover, the simulation results of the maximum stress and displacement distribution results of the inner and outer ring eccentricity from 1 to 6mm are compared with the algorithm prediction results. The error between the numerical solution of the statically indeterminate problem of the steering tool combined bearing and the simulation result is small, improving the calculation efficiency. This provides theoretical support for the design and reasonable application of the steering tool combined bearing. [ABSTRACT FROM AUTHOR]

The Miocene Galatian Volcanic Province (GVP) is one of the largest volcanic provinces in central-western Anatolia, with an extent of ~ 8,900 km2. The volcanic activity is extended from 22.5 to 7.5 Ma. The volcanic compositions straddle the alkaline-subalkaline fields, from basic to acid compositions and mostly transitional to sodic affinity. Major oxides show good correlation with SiO2 indicating prolonged effects of fractional crystallization. Primitive mantle-normalized multi-element patterns indicate overall similarities among the different samples of the three geographic sectors, sharing strong negative anomalies in Nb–Ta–Ti, strong positive peaks at Cs and K, coupled with a common, albeit not always present, positive anomaly at Pb. Mineral-melt geothermobarometric estimates indicates ~1070–1235°C and ~7–19 kbar for melting conditions of basaltic compositions and ~1000–1150°C and ~3–12 kbar for andesitic-dacitic rocks. The absence of correlation between radiogenic isotopes and SiO2 and MgO is here interpreted as consequence of assimilation-fractional-crystalization processes involving lower continental crust as contaminant. The GVP parental magmas are generated from ~2% to 10% partial melting of a lherzolitic mantle with high spinel/garnet ratio based on intra-REE fractionation constraints. The subduction-related metasomatism inferred for the GVP mantle sources based on their chemistry is interpreted to be linked to the northward subduction of the northern branch of the Neo-Tethys slab. Successive slab retreat resulted in extension for the critical stress distribution through the Cyprus slab, favouring magma propagation for the GVP volcanic region. The eventual break-off of the slab after the continent-continent collision of Arabian and Eurasian plates could have caused a toroidal mantle flow, favouring the widely distributed 15–16 Ma alkaline magmatism in the eastern GVP, associated with passive hot asthenospheric upwelling imaged by teleseismic P-wave tomography. [ABSTRACT FROM AUTHOR]

Dynamic analysis of underground structures, such as tunnels, is crucial to ensure their safety and stability during seismic loading. This paper proposes a more general method of large elliptic arc assumption-based wave function expansion, which is attributed to the important role of the large circular arc assumption-based wave function expansion method in the elastic wave scattering problem. The study is conducted within elliptic coordinate systems, employing the Mathieu function and Mathieu function addition theorem. The applicability and limitations of this method are analysed by comparing it with the existing exact analytical solutions obtained through the mirror-based wave function expansion method. [ABSTRACT FROM AUTHOR]

This study conducts quasi-static tests and finite element (FE) analysis by using ABAQUS software to examine the effects of floor combination effect (FCE) on the seismic behavior of a novel type of prefabricated steel-concrete composite (PSCC) exterior joints. This analysis assesses PSCC exterior joints featuring bolted-welded hybrid connections, focusing on their seismic performance under the influence of FCE. The variables in this research include floor construction parameters, axial compression ratio (n), and core area concrete (CAC). The results indicated that these variables, particularly the floor construction parameters, n, and CAC, significantly influence stress distribution and magnitude within the joint core area (JCA) and the floor slab. Although the floor construction parameters exert a minor effect on seismic performance, increasing n markedly enhances the joints' load-bearing and energy dissipation capacities. However, it also makes the joints more susceptible to brittle failure. Optimal bearing capacity and ductility for energy dissipation are achieved when n equals 0.3. In addition, CAC substantially increases the initial stiffness (IS) and bearing capacity, with a peak increase in bearing capacity of approximately 18% and an IS enhancement of around 25%. However, rising CAC strength has a relatively minor impact on seismic performance. [ABSTRACT FROM AUTHOR]

Metatarsalgia occurring in individuals with pes cavus is typically associated with abnormal loading patterns in the forefoot resulting from structural alterations. Simultaneously, the frequent overstress of the plantar fascia (PF) caused by the persistence of this foot deformity may further exacerbate the chronic pain induced by metatarsal overload. We aimed to investigate and quantify the effects of PF stiffness on the internal biomechanics of pes cavus using a computational modelling approach. A patient-specific finite element model of the foot-ankle complex using the actual three-dimensional geometry of idiopathic pes cavus bones and soft tissues was reconstructed. A sensitivity study was conducted to evaluate the effects of varying elastic modulus (0–700 MPa) of the PF on the metatarsal stress distribution, and force transmission through the metatarsophalangeal (MTP) and tarsometatarsal (TMT) joints in the pes cavus. The results indicated that variations in PF stiffness led to stress redistribution in the metatarsal region. Peak stress gradually reduced with decreasing stiffness until the PF was released, eventually resulting in a reduction of 22.39% compared to the reference value of 350 MPa. Furthermore, adjusting the PF stiffness to twice the reference value (700 MPa) increased the contact forces through the TMT and MTP joints by up to 23% and 116%, respectively. The reduction of PF stiffness alleviated focal metatarsal loading, and therefore, surgical fascia release can be considered to alleviate metatarsalgia in patients with pes cavus. [ABSTRACT FROM AUTHOR]

To solve the congestion of reinforcement and the difficulty of concrete pouring in concrete-encased steel (CES) structure, steel fiber-reinforced concrete-encased steel (SFRCES) structure was proposed. Push-out tests of 34 SFRCES specimens were carried out in this paper to study the interfacial bond stress distribution, and load-displacement curves were obtained. The interfacial ultimate bond strength calculated based on load-displacement curve is much greater than 0.2 MPa which is the interfacial design shear strength of composite steel and concrete structure in Eurocode 4. This illustrates that the design of SFRCES structure is partial to safety. Furthermore, different from the previous method using the assumption of uniform distribution of interfacial bond stress, the interfacial local bond stress was obtained based on strain data and mechanical derivation in this paper. Moreover, the influence of steel fiber volume rate, embedded length of steel, and thickness of concrete on the distribution of interfacial bond stress was analyzed by defining the uneven coefficient of interfacial bond stress distribution. Analysis results provide a theoretical basis for the design of SFRCES structure and lay a foundation for the application of SFRCES structure in practical engineering. [ABSTRACT FROM AUTHOR]

This study analyses the bending of helicoidal laminated composite plates, inspired by biological helicoids. The analysis employed Navier solution-based shear deformation theory. Five helicoidal schemes—recursive, exponential, semi-circular, linear, and Fibonacci—were studied. Plate thickness stress distribution investigations have been done. The helicoidal distribution parameter greatly affects stress variation. Helicoidal designs have homogeneous stress distribution across the thickness of the plate, unlike quasi-isotropic schemes. Helicoidal lamination designs also eliminate stress channeling caused by cross-ply and quasi-isotropic systems. Also, the helicoidal schemes exhibited the lowest value for the transverse shear stresses ( σ ¯ yz ). HIGHLIGHTS: Bending analysis of bio-inspired helicoidal laminated composite (BILC) plates. Kinematics in framework of parabolic shear deformation theory. Stress distribution across thickness of BILC plates for first time are analyzed. BILC plates are effective compared to quasi-isotropic laminates. The study can be used to construct pressure vessels, domes, automobiles, and aerospace structures. [ABSTRACT FROM AUTHOR]

We develop finite element models to describe the progressive damage behaviors of two types of carbon fiber reinforced epoxy (CF/EP) composite tubes triggered by three types of initiators, i.e. a flat surface plate, an outward-triggering plug and an inward-triggering cap, using a continuum damage mechanics-based approach. First, the quasi-static compression experiments were conducted to capture the load–displacement relation, failure mode, and microscopic damage of CF/EP composite tubes. These experimental results were utilized to validate the proposed finite element models. The numerical crushing response agreed well with the experimental data. Then, a comparative study on the progressive damage behaviors of two types of CF/EP composite tubes subjected to three typical initiators was performed. The failure mechanisms were systematically articulated, showing that the fiber breakages were significant due to the concentration of compressive stress caused by external loads, while the matrix and interlaminar damage behaviors were predominant under any of these initiators. [ABSTRACT FROM AUTHOR]

During the swivel construction of a large-tonnage cable-stayed bridge, a single spherical hinge is susceptible to be damaged from excessive force. Consequently, this paper suggests a multi-point support swivel method of gear rails. The paper introduces a multi-point support swivel system of large-tonnage gear-tooth-rail, along with the swivel construction and monitoring technology. Models of the spherical hinge are established. Results indicate that the force applied to the spherical hinge is reasonable, exhibiting a gradual increase in contact stress from the center to the outer edges. The distribution of Mises stress differs from the distribution of contact stress. The force applied by the driving device is reasonable, ensuring the safety and feasibility of the proposed approach. The findings have guiding significance for future engineering. [ABSTRACT FROM AUTHOR]

The sensitivity of grain boundary (GB) cracks often limits the high-temperature plasticity of superalloys. The 750 ℃ tensile deformation of fine-grained Ni-Co based wrought superalloys was observed in situ using a scanning electron microscope (SEM) equipped with an electron backscatter diffraction (EBSD) probe to clarify the texture formation and GB response. The GB stress concentration depends on the grain orientation and slip system alignment on both sides. This reflects the ability of GBs to cope with deformation incompatibility. This study provides valuable insights for predicting the failure of polycrystalline superalloys and offers new ideas for microstructure evaluation and GB design. IMPACT STATEMENT: The lattice rotation and GB response of Ni-Co based fine-grained wrought superalloys under 750 ℃ deformation were explained through in-situ observation, which helps predict the superalloys' service behavior. [ABSTRACT FROM AUTHOR]

AbstractHorizontal bone loss (HBL) and dehiscence are common supportive tissue defects. This study evaluated the stress distribution in the presence of HBL or dehiscence and two types of fiber posts. Twelve premolars that were endodontically treated (Model-E), restored with conventional (Model-C), and bundle (Model-B) post were modeled. Bone defects were created as control (Model-1), with 4 mm (Model-4) and 8 mm (Model-8) HBL, and dehiscence involving two-thirds of the root (Model-D). HBL was included in all aspects of the models, while dehiscence was confined to the buccal aspect. The models were subjected to a 200 N force, and von Mises stress was analyzed. Model-B1 showed higher stress than Model-C1 but was more homogeneous. In Model-D, the stress was limited to the area without bone and only occurred at the buccal aspect. The highest stress was observed in Model-B8. The presence of a post caused a 2–5.8 times increase in stress. When the crown–root ratio was 1:0.8, stress was in the coronal two-thirds of the root, while at a ratio of 1:0.3, stress was distributed throughout the entire root. Bundle post with 8 mm HBL increased the stress 5.8 times. HBL resulted in stress extending beyond the marginal bone, while dehiscence did not. [ABSTRACT FROM AUTHOR]

AbstractThis paper introduces an innovative approach to soil parameter estimation using deep artificial neural networks (ANN) tailored to estimate a wide range of soil types. Previous research in this field has relied on limited datasets and oversimplified assumptions in semi-empirical models. In this work, the sensitivity of stress distribution is analyzed with respect to soil parameters, revealing significant errors resulting from the simplifications in semi-empirical models and emphasizing the need for more accurate estimation methods with minimal reliance on simplifying assumptions. Training an ANN requires a comprehensive dataset, which has been a challenge due to limited access to diverse soil samples. Addressing this issue, the paper conducts simulations of a single wheel’s movement across a wide range of soil parameter combinations to generate the required dataset. These simulations are done using a dynamic motion-compliant semi-empirical model detailed in the article. Subsequently, the network’s hyperparameters are fine-tuned through a grid search, followed by extensive training of the optimized ANN model. In the end, the ANN demonstrates promising performance in accurately estimating soil parameters, validated through simulation results of both single wheel and Mars rover motion. [ABSTRACT FROM AUTHOR]

AbstractThe contact pressure at the socket–residual limb interface is the most critical parameter for evaluating the comfort of a leg prosthesis. Experimental studies have analyzed this parameter for typical postures and during walking on a flat surface of an amputee; however, experimental tests require a real socket prototype equipped with transducers. To optimize socket design, this work presents a virtual approach based on a digital avatar of a patient wearing a lower limb prosthesis. Our study integrates two different types of simulations: the first concerns the femur with an implant, the second without an implant, and includes the evaluation of pressure at the socket–residual limb interface using finite element analyses (FEA). The objective of this study is to understand the distribution of loads and stresses at the interface between the residual limb and the prosthesis. The lower contact pressure is represented by CPRESS, while CSHEAR1 is the frictional shear stress component in the first local tangent direction, and CSHEAR2 is the frictional shear stress component in the second local tangent direction. [ABSTRACT FROM AUTHOR]

Abstract\nHIGHLIGHTSThis work implements a 3D finite element to analyze wear in borided AISI 316 L stainless steel. The 3D model was validated through sliding wear test under a ball-on-flat configuration, following the ASTM G133 standard procedures. ABAQUS software was used with an Arbitrary Lagrangian-Eulerian (ALE) remeshing technique alongside the UMESHMOTION subroutine to apply an elemental level Archard’s equation. The artificial roughening of the worn surfaces due to discretization in finite element sizes was controlled by relating the maximum increment time on each wear step to the element size and the stroke. The study also described the evolution of the stress field and the behavior of the contact area. The maximum stress was estimated after the first indentation, decreasing as the contact area increased, reaching a minimum at the last wear step. The results revealed a good correlation between the experimental and modeled data, with a maximum error of 8.34% in the contact stress and a maximum error of 22% in the wear depth.Implementation of a 3D finite element analysis to model wear under ball-on-flat configuration in borided AISI 316 stainless steel.The finite element analysis provides a better understanding about the stress distribution in the selected configuration.Correlation between numerical modeling and experimental data of wear in a borided material. [ABSTRACT FROM AUTHOR]

AbstractThe mechanical behavior of monopile support systems for offshore wind turbines under current-induced loads was investigated through numerical simulations. Using the Large Eddy turbulence model, the fluid-structure coupling was analyzed in both unidirectional and bidirectional directions. In the unidirectional coupling, the pressure and velocity profiles of the fluid around the pile were determined. While in the bidirectional coupling, the force distribution, pile displacement, and moment distribution were obtained, along with the current-induced load transmitted from the pile to the soil. The coupling analysis revealed that the fluid flow around the pile exhibited cyclic loading behavior due to the interaction between the fluid and the pile, effectively resulting in an oscillating pile within a steady flow. Additionally, the pile’s stress distribution remained within the tensile yield limit of the steel, indicating a stable state in the fluid-pile model within the given flow conditions. Furthermore, the soil reaction forces obtained from the fluid-pile-soil coupling model validated the accuracy of the current-induced load calculations. This study introduces a novel approach that considers the fluid-pile-soil coupling, offering valuable insights for pile foundation design. The findings of this research have significant engineering implications and practical value, providing a robust foundation for future offshore wind turbine installations. [ABSTRACT FROM AUTHOR]

Determining adhesive failure in adhesively bonded joints is still challenging in the field. While the three-point bending test (3PBT) (ISO 14679:1997) has been helpful in identifying critical forces and displacements related to bond strength, it only allows for a qualitative assessment of the bond line. Recently, a new quantitative methodology has been developed to determine critical stress and fracture toughness using the coupled stress–energy criterion and the 3PBT. However, these assessments require a significant effort using semi-analytical or finite element (FE) analysis. Therefore, the present study proposes a reliable set of analytical equations to determine peel and shear stress distributions using a weak interface formulation and 1D Euler–Bernoulli approach. More precisely, a particular numerical method computes the integration constants from these equations. A new method has been proposed for calculating the interfacial stiffness in peel and shear mode, based on the material and geometrical parameters of the geometry. This method differs from the previous approach, where the interfacial stiffness was calibrated from the experimental behavior of the test. The whole approach has been validated through experimental and numerical analysis, including the costly 3D FE analysis. An analytical expression for interfacial energy release is suggested, developed following the works of Fraisse and Schmit on J-integral assessment of sandwich-type overlaps and depending on the applied force and a rotation, which could be experimentally measured. Therefore, this work is significant progress in determining bond strength using a simple mechanical test and equations applicable to various industries. [ABSTRACT FROM AUTHOR]

In the present research work, a comprehensive study on the stress analysis in the two composite pipes bonded by a layer of DP 410 adhesive and a socket buried in the soil has been performed. The pipe material was considered as a four layers of epoxy-fiber glass with different fiber orientations (cross-ply, angle-ply and quasi-isotropic). The soil dimensions and properties as well as the traffic load (H-20) were based on AASHTO. The simulation of the stress analysis was performed using ANSYS software. In the present study, the influences of bed distance, temperature change, internal pressure, traffic load, fiber orientation angle and layups, and gap distance on stress distribution in the buried composite pipe have been investigated. The findings revealed that the annual temperature change in the soil and the pipe enhances the stresses in the joint components to a maximum value of 5.5 MPa at a pipe temperature of −22 °C. Moreover, the outcomes indicated that the adhesive layer is the most sensitive component to any rise in the load prism, as well as other loads, for a buried pipe at a depth of 120 cm. The maximum and minimum state for von Mises stress component were related to, in turn, quasi-isotropic and angle-ply laminations. [ABSTRACT FROM AUTHOR]

AbstractThe application of balloon dilation catheters in the management of intracranial arterial stenosis has been gradually increasing. However, studies on the feasibility and effectiveness of different types of balloons remain relatively scarce. In this study, catheter models of three different materials were designed to simulate balloon crimping,splitting, and dilatation processes. A compliant balloon produces large deformations with poor dilatation and a stress concentration phenomenon. During dilatation, the shear stress generated in the intima and lesion area by the semi-compliant balloon was smaller than that generated by the non-compliant balloon. These results demonstrate the feasibility of using semi-compatible balloons. [ABSTRACT FROM AUTHOR]

AbstractIncreased drought and salinity is a threat to agriculture in arid and semiarid zone worldwide. Almond is nutritious, rich in minerals protein and fiber with increasing world demand and production. The objective was to determine the effect of drought and salinity stress on nutrient concentrations in almond trees. Almond is known as sensitive to salt stress compared to other trees. There are limited studies on almond nutrition uptake under salt and drought stress conditions. This study had three drought and four salinity levels, and combined applications for a total of 12 treatments each with three replications. Drought increased K, Mg, Ca, Na and Cl concentrations in leaves, yet, decreased B concentrations. Similarly under salinity, almond leaves increased in K, Mg and Ca concentrations (as well as in Na and Cl). This study showed that the nutrient uptake varies under drought and salt stress conditions. Mineral nutrition should be taken into consideration, fertilization needs to account for stress factors. [ABSTRACT FROM AUTHOR]

The grinding process is the primary process in mineral processing, which not only liberates target minerals from ore, but also provides the desired size interval for subsequent sorting processes. Since the feed of each sorting method and equipment has an optimal particle size range, particles outside this range are difficult to be separated effectively. While going through literatures, it has been found that very few works have been done in terms of comprehensive reviewing the evolution behavior and the optimization of particle size distribution during the grinding process. This comprehensive review delves into six crucial facets, offering a systematic appraisal: (1) the statistical framework and evaluation methodologies for characterizing particle size distribution, which includes the intricacy of model analysis and interpretation; (2) the property of grinding products, which emphasizes the physicochemical attribute that influences the sorting efficiency and the product quality; (3) grinding kinetics models, which emphasizes the integration of advanced algorithms and experimental validations; (4) the intricate relationship between characteristic particle size and energy consumption, which elucidates the mechanistic underpinning of particle size reduction and energy consumption; (5) stress intensity theory, which elucidates the role of mechanical forces in particle breakage and size reduction; and (6) optimization techniques tailored toward achieving the desired particle size interval, which highlights the grinding technical efficiency and the attainable region method inherent in optimizing the operation parameter of mills. Furthermore, this review critically assesses current applications in this domain and highlights their successes and limitations. It underscores the imperative for meticulous optimization of operational parameters, such as mill speed, grinding media size and so on, to maximize the yield of the desired size interval in the grinding product, thus enhancing energy efficiency and overall process performance. By aligning with the forefront of mineral processing technology, this review serves as a well-referenced source and fosters the development of innovative strategies for optimizing grinding processes. [ABSTRACT FROM AUTHOR]

AbstractThis work proposes topology optimization for steel I-beams, including consideration of bolted beam-column connections with geometric and material nonlinear analysis. The aim is to assess and compare the topological configurations influenced by different connections, examining their stress distribution and rotational stiffness to illustrate the potential of structural optimization. The bi-directional evolutionary structural optimization (BESO) approach is implemented. Furthermore, several bolted steel beam-column configurations were validated based on experimental tests. Subsequently, a series of finite element models were developed, contributing to a comprehensive understanding of the plastic-limit behavior of I-beams under different loading conditions. The proposed method could potentially use a lesser quantity of material while maintaining the same level of structural performance. The results indicate that the implementation of structural topology optimization on I-beams while considering various beam-column connections, yields structural performance similar to that of solid web configurations, achieved through material reduction. [ABSTRACT FROM AUTHOR]

AbstractHybrid anchorage technique can effectively prevent end debonding and impede intermediate debonding of CFRP sheet in strengthened reinforced concrete (RC) beams. However, its effectiveness in the presence of bond defects at the CFRP-concrete interface is unclear. Therefore, this study conducted four-point bending tests on CFRP-strengthened RC beams, considering two factors: bond defects (with and without) and strengthening methods (externally bonded and hybrid anchorage). The results showed that bond defects can lead to premature intermediate debonding of the CFRP sheet, resulting in a 22.49% decrease in debonding load due to local stress concentration around them. Owing to the effectiveness of the hybrid anchorage method, the propagation of the intermediate debonding is significantly impeded, leading to a 4.32% and 21.61% higher in ultimate load and deflection, respectively. This is because the hybrid anchorage can control the distribution of local cracks and improve the overall stress distribution of CFRP. A finite element analysis was performed and compared against the experimental results which shows good agreement. Then, parametric analyses were conducted to further analyze the flexural behavior of the strengthened beams with bond defects. Finally, an analytical model was proposed to predict the flexural capacity of the hybrid strengthened beams with bond defects. [ABSTRACT FROM AUTHOR]

Detecting the anchoring length is an integral part of the quality inspection of the bolt anchoring, which is crucial to the safety of the roadway support. This paper studies the influence of the anchoring length on the propagation characteristics of the exciting stress wave of the bolt. The research finds that the change in the anchoring length affects the attenuation rate and frequency distribution of the stress wave signal amplitude. Under the same test conditions, the anchoring length negatively correlates with the consolidation wave velocity. The VMD analysis and processing method decomposes the original detection signal once or the characteristic mode function twice. The bottom reflection time is obtained from the bottom reflection signal identified according to the decomposed mode function. Based on the propagation characteristics of the exciting stress wave in the anchor rod, a method of calculating the anchoring length using the bottom reflection time is proposed. Experimental verification of anchoring models for different anchoring lengths is carried out. The calculated results are consistent with the actual anchoring length; the longer the length, the smaller the relative error. The error rate meets the accuracy requirements of on-site engineering tests and guarantees safe production. [ABSTRACT FROM AUTHOR]

In this study, high loadings of boron nitride (BN) nanoplatelets were added to silica fiber-reinforced phenolic composites to study the multifunctional impact of BN loading and manufacturing processing on the subsequent mechanical, thermal, and thermomechanical properties. A series of high-quality laminates were made with various loadings of BN using compression-molded out-of-autoclave processing. Three-point bend and short beam shear testing determined the relationship between BN loading and mechanical performance. The fracture properties were analyzed using optical and scanning electron microscopy. The thermal conductivity performance was increased up to a 93% improvement, indicating the thermal management multifunctionality of the modified composites without changing the crosslinking ability or glass transition temperature significantly. The modified performance of hybrid silica/phenolic/BN composites is demonstrated through micromechanical multiscale modeling, where BN loading and particle stress concentrations impact the modulus and strength of the composite. [ABSTRACT FROM AUTHOR]

This research article presents a methodology for estimating the multicomponent reliability based on progressively first-failure censored samples, where the underlying distribution of stress and strength is modelled using the power Lindley distribution. The classical and Bayesian estimation methods are utilized for estimating the multicomponent reliability. In the Bayesian estimation, the Markov Chain Monte Carlo approximation method is employed to obtain the posterior mean under a generalized entropy loss function. Various intervals including asymptotic confidence, bootstrap-p confidence, bootstrap-t confidence, Bayesian credible, and highest posterior density credible intervals are computed. A simulation study is conducted to evaluate the performance of the proposed methodology. Also, two different real data applications are presented to illustrate the practicality of the approach. [ABSTRACT FROM AUTHOR]

This study addresses the need for cement-based materials with high mechanical properties and reduced autogenous shrinkage by investigating the effectiveness of incorporating superabsorbent polymers (SAP) and basalt fibers (BF) to enhance the volumetric stability of cement mortar. The effects of individual and combined additions of SAP and BF on mortar were systematically evaluated through autogenous shrinkage tests, mechanical properties tests, and workability assessments, culminating in an optimized mixture. The synergy between SAP and BF was further examined by using Scanning Electron Microscopy (SEM) to observe changes in the surface microstructure of the cement matrix. The findings demonstrate that (1) the optimal proportions of SAP and BF are 0.25% each, leading to cement mortar with superior mechanical properties and improved volumetric stability; (2) SAP significantly reduces shrinkage strain by water absorption and subsequent water release, promoting hydration, while BF contributes to the stress distribution capacity of the matrix, particularly increasing tensile and flexural strength and reducing crack propagation; and (3) the synergistic interaction between SAP and BF enhances the interfacial microstructure and bonding, as well as reduces porosity following SAP-induced water release, thereby improving the mechanical properties and crack resistance of the cement mortar. [ABSTRACT FROM AUTHOR]

AbstractConcrete-filled CFRP steel tube structures are presently employed on extensively in various engineering practices. This study examines the mechanical performance of concrete-filled square CFRP steel tubes under compressive-torsional hysteresis loads. Through the analysis of nine specimens, the research focuses on failure modes, torque–angle (T–θ) behavior, triaxial strain, and the synergistic effects of the steel tube and CFRP during cyclic loading. A numerical simulation method is initially introduced based on the test data to predict the actions of concrete-filled CFRP steel tube compressive-torsional specimens under hysteresis loading. This method is subsequently verified by contrasting it with the outcomes from representative experiments. In addition, the stress distribution of each material during the entire loading process of the sample is examined. Finally, using data from experiments and finite elements, combined with the trilinear model, a hysteretic model under compressive-torsional hysteresis stresses has been established for square CFRP steel tube filled with concrete. The calculated outcomes of the developed finite element model closely align with those of the hysteretic model. [ABSTRACT FROM AUTHOR]

To analyze the fixation strength of cannulated screws fixation in the treatment of femoral neck fracture with posterior tilt due to insufficient reduction. Two sets of digital models of anatomical reduction and 15° tilting reduction were established by CT data. Each group of models was modeled with two different fixation methods. One fixation method was fixed according to the standard cannulated screws recommended by AO. Another fixation method is to tilt the screw posterior tilt 15°. The final four groups of models were obtained: AO principle nailing posterior tilt model (Group A), posterior direction nailing posterior tilt model (Group B), AO principle nailing anatomic reduction model (Group C) and posterior direction nailing anatomic reduction model (Group D). The maximum displacement of the fracture end, the maximum Von-Mises stress and the stress distribution of the internal fixation were compared among the four groups. Four groups of models were established on artificial bone by 3D printing guide plate technology. The 600 N pressure test and yield test were performed on a biomechanical machine. The finite element and biomechanical models showed that groups B and C were more stable than groups A and D. The stability of group B was not worse than that of group C. When the femoral neck fracture produces a posterior tilt, a posterior reduction is allowed. The change of AO screw to posterior tilting screw fixation has more powerful advantages. No posterior tilt or posterior reduction, AO screw placement is still required. [ABSTRACT FROM AUTHOR]

In this work, we presented a model which consists of three layers with different materials; the second layer was taken to be viscous-elastic material, while the first and third layers are made of elastic material. This model is solved in the context of the generalized thermoelasticity theory with one relaxation time. The first layer's upper surface is taken to be traction-free and is subjected to a constant thermal shock. Nobody forces or heat sources affecting the layer. Laplace transform techniques are used. The solution in the transformed domain is obtained by using a direct approach. The inverse Laplace transforms are obtained using a numerical method based on the Fourier expansion technique. The effect of thermal shock is discussed and studied of the three layers on the behavior of the solutions, in the presence of viscoelastic effects and its absence. Numerical results are computed and represented graphically for the temperature, displacement, and stress distributions. [ABSTRACT FROM AUTHOR]

Dynamic incident anti-plane shearing (SH guided wave) is considered to calculate dynamic stress and electric intensity in an infinite piezoelectric strip that contains an elliptic inclusion. By the means of the conformal mapping method, the field of an ellipse can be transformed into a unit circle. With the aid of series expansion method, the expression of SH guided wave is established, which satisfies the stress-free and electric insulation conditions on the upper and lower horizontal boundaries of the strip. The expression of scattering waves is conducted based on repeated image superposition. Boundary conditions are solved by applying the orthogonal function expansion technique. Results clarified the influence on the dynamic stress concentration factor and electric field intensity concentration factor under proper conditions. [ABSTRACT FROM AUTHOR]

The problem of scattering in seismic waves caused by underground tunnels is an important factor in the study of earthquake engineering. Since the medium of the lined tunnel was generally simplified to be isotropic by scholars in past research, the phenomenon of scattering of SH-waves caused by an orthotropic cylindrical tunnel in a homogeneous isotropic half-space is studied in this paper. Then, an analytical solution is obtained in a two-dimensional wave propagation problem by a separation of variables and a multipolar coordinate method. The results show that the reference wave number, buried depth, and modulus ratio have obvious effects on the dynamic stress concentration factors around the tunnel and displacement amplitudes of the ground surface. [ABSTRACT FROM AUTHOR]

A combination of chirality, anti-chirality, and re-entrant lattice pattern is proposed to form a new two-dimensional meta-structure, and a comprehensive parametric study is conducted by using experimental and numerical analysis. The proposed structure can undergo larger deformations without significant stress concentrations. Based on the verified finite element model, the effects of various geometrical parameters on the in-plane mechanical response of the structure are investigated. Results show that the thickness of the structure is the most dominant factor in affecting the Young modulus while other parameters can alter Poisson's ratio. In addition, the proposed structure exhibits tunable negative/near-zero Poisson's ratios. [ABSTRACT FROM AUTHOR]

The heat dissipation needs of high-power devices cannot now be met by traditional packing solders due to the fast development of microelectronics interconnect technology. In addition to having outstanding thermal and electrical conductivity, nano-silver-tin paste better satisfies the needs of electronic devices. Studying the thermal reliability of solder joints is extremely important, this article investigates the fatigue life of the nano-silver-tin solder joints in temperature cycling experiments. Based on the life test results, the thermal cycling fatigue life of the nano-silver-tin solder joint is determined to be 2880 cycles. Finite element software was used to replicate the chip's bonding process and assess the solder joint stress and strain distribution. The stress and strain of nano-silver-tin solder connections under thermal cycling load are accurately modeled using the Anand viscoplastic model and elastic model. The findings indicate that the contact region between the solder connections and copper columns is where the chip generates the most stress and strain. The fatigue life of the solder joint is estimated by using the Coffin–Manson modified equation, and this prediction aligns closely with the experimental results. [ABSTRACT FROM AUTHOR]

In this article, the dynamic characteristics of bimaterial composite spheres under spherical waves induced by cyclic pressure are studied. First, on the basis of the Lamb Decomposition and Variable Separation method, the analytical expression of spherical wave is conducted, which satisfies the stress equilibrium on the outer and inner surfaces of the sphere. Next, algebraic equations with respective boundary conditions are composed and solved by Legendre Polynomial expansion and effective truncation techniques. Obtained results enable to reveal the influence on the dynamic stress concentration factor intensity under proper conditions. The conclusions of this article are verified by comparing the analytical solutions to the ones obtained by the finite element method. This article can provide a theoretical method for the analysis of mechanical properties of multilayered spherical structure under dynamic loading. [ABSTRACT FROM AUTHOR]

AbstractThis study aimed to evaluate the material properties of four dental cements, analyze the stress distribution on the cement layer under various loading conditions, and perform failure analysis on the fractured specimens retrieved from mechanical tests. Microhardness indentation testing is used to measure material hardness microscopically with a diamond indenter. The hardness and elastic moduli of three self-adhesive resin cements (SARC), namely, DEN CEM (DENTEX, Changchun, China), Denali (Glidewell Laboratories, CA, USA), and Glidewell Experimental SARC (GES—Glidewell Laboratories, CA, USA), and a resin-modified glass ionomer (RMGI—Glidewell Laboratories, CA, USA) cement, were measured using microhardness indentation. These values were used in the subsequent Finite Element Analysis (FEA) to analyze the von Mises stress distribution on the cement layer of a 3D implant model constructed in SOLIDWORKS under different mechanical forces. Failure analysis was performed on the fractured specimens retrieved from prior mechanical tests. All the cements, except Denali, had elastic moduli comparable to dentin (8–15 GPa). RMGI with primer and GES cements exhibited the lowest von Mises stresses under tensile and compressive loads. Stress distribution under tensile and compressive loads correlated well with experimental tests, unlike oblique loads. Failure analysis revealed that damages on the abutment and screw vary significantly with loading direction. GES and RMGI cement with primer (Glidewell Laboratories, CA, USA) may be suitable options for cement-retained zirconia crowns on titanium abutments. Adding fillets to the screw thread crests can potentially reduce the extent of the damage under load. [ABSTRACT FROM AUTHOR]

AbstractThe surge in popularity of running has led to a multitude of designs in running shoe technology, notably, there is an increasing trend in toe spring elevation. However, the impact of this design on foot structures during running remains an essential exploration. To investigate the effects of toe spring on the foot during forefoot running, we employed finite element simulation to create two sole models with different toe spring heights (6.5 cm and 8 cm) and ground contact angles (5°, 10°, and 15°). We established and validated two foot-shoe coupling models and compared stress variations in metatarsal bones and the big toe under identical loading and environmental conditions. Higher toe spring resulted in lower peak stress and reduced stress concentration in metatarsal bones. The fourth and fifth metatarsals exhibited increasing stress trends with ground contact angle, with the fifth metatarsal experiencing the most significant stress concentration. In the case of low toe spring, stress on the fifth metatarsal increased from 15.917 MPa (5°) to 27.791 MPa (15°), indicating a rise of 11.874 MPa. Conversely, the first metatarsal showed lower stress, indicating relative safety but reduced functional significance. Moreover, higher toe spring running shoes exerted less pressure on the big toe, with an increasing trend in stress on the big toe with an increase in ground contact angle. Shoes with a higher toe spring design result in reduced pressure on the big toe. Therefore, it is advisable to avoid landing angles greater than 15° to prevent stress fractures resulting from repetitive loading. [ABSTRACT FROM AUTHOR]

AbstractIn this article, the problem of a semi-infinite piezoelectric strip with irregular boundaries is studied by boundary element method, and SH guided wave and line source loads are considered as external loads acting on piezoelectric strip. The superiority of the boundary element method is induced by two different arithmetic examples. Firstly, when the irregular boundary is not subjected to line source loads, the dynamic characteristics are analyzed in the first example, employing the image method and Graf addition theorem. Then, the Green’s identities are introduced and the Green’s function in infinite three-dimensional space is solved. When irregular boundaries are subjected to line source loads, the dynamic characteristics are investigated using the boundary element method in the second example. Finally, results clarified the influence on the dynamic stress concentration factor and electric field intensity concentration factor under proper conditions. Besides, the analytical solutions are compared with the finite element solutions to verify the accuracy of the conclusions in this article. [ABSTRACT FROM AUTHOR]

AbstractUltra-large container ships face challenges in structural strength under complex sea conditions. The traditional equivalent design wave method inadequately considers nonlinear wave effects, leading to inaccuracies in strength assessments. This article improves the method by incorporating nonlinear wave effects and optimizing wave spectrum parameters to better simulate structural responses. A study on a container ship, using refined wave load calculations and finite element analysis, focusing on stress distribution in critical hull areas. The findings show that the enhanced method more accurately reflects real loading conditions, confirming the ship’s structural soundness and offering optimization suggestions for improved safety and longevity. [ABSTRACT FROM AUTHOR]

Soft pneumatic robotic grippers have found extensive applications across various engineering domains, which prompts active research due to their splendid compliance, high flexibility, and safe human-robot interaction over conventional stiff counterparts. Previously simplified rod-based models principally focused on clarifying overall large deformation and bending postures of soft grippers from static or quasi-static perspectives, whereas it is challenging to elaborate grasping characteristics of soft grippers without considering contact interaction and nonlinear large deformation behaviors. To address this, based on absolute nodal coordinate formulation (ANCF), comprehensively allowing for structural complexity, geometric, material and boundary nonlinearities, and incorporating Coulomb' friction law with a multiple-point contact method, we put forward an effective nonlinear dynamic modeling approach for exploring grasping capability of soft gripper. Moreover, we solved the established dynamic equations using Generalized-α scheme, and conducted thorough numerical simulation analysis on a three-jaw soft pneumatic gripper (SPG) in terms of grasping configurations, displacements and contact forces. The proposed dynamic approach can accurately both describe complicated deformed configurations along with stress distribution and provide a feasible solution to simulate grasping targets, whose effectiveness and precision were analyzed theoretically and verified experimentally, which may shed new light on devising and optimizing other multifunctional SPGs. [ABSTRACT FROM AUTHOR]

In order to prevent the body from overheating, a corresponding thermal protection device is usually designed on the inner wall of the combustion chamber. The working environment of this thermal protection device is very harsh, and it needs to withstand internal and external pressure loads and thermal radiation loads of the combustion chamber, especially at the connection between the cylinder and the support parts, the force is harsher. In order to avoid engine damage, causing unnecessary losses. In this article, the thermal–mechanical coupling analysis of the heat shield is carried out by finite element method to analyze the thermal stress and mechanical stress. According to the finite element simulation results, the initial cracks are inserted, respectively, at the stress concentration. Using linear elastic fracture mechanics and Forman–Newman–de Koning models, the crack growth lifetimes of cracks at different locations were calculated. The results of the study show that comparing the initial cracks at different locations, the cracks on the side near the edge of the heat shield have the largest reduction in crack growth life of 64.4% and the critical crack length of 52.0%. The linear superposition of thermal and mechanical stresses under different working conditions has different degrees of nonlinear effects on the crack growth life and critical crack length. The research work in this article can provide a basis for the evaluation of fatigue crack growth life of heat shield and can also provide a reference for engine maintenance. [ABSTRACT FROM AUTHOR]

The behavior of a coned disk spring can be significantly affected by friction or restraint, yet the existing theoretical solutions cannot fully capture these influences. The limitation is particularly problematic for analyzing the behavior of coned disk springs with bi-stability. This paper proposes an explicit solution that can predict the behavior of the coned disk spring under these boundary conditions. The solution considers detailed influences of friction and restraint at the edges of the coned disk spring on its moment equilibrium and location of the neutral fiber. The theoretical results are validated using existing literature, FE analysis, and a series of tests. The theoretical solution confirms that the friction force at the edge of the coned spring significantly affects the axial response of the spring but not its bending moment or distribution of tangential stress. The bending moment and overall behavior of the coned disk spring are, on the other hand, very sensitive to restraints in radial directions. The proposed explicit solution shows good accuracy for coned disk springs with restrained radial stretching and rotation. The solution is particularly useful for coned disk springs in multistable structures and metamaterials. [ABSTRACT FROM AUTHOR]

A friction coefficient of tire model for cornering simulation is generally set inductively to be consistent with experimental results. However, the inductively set friction coefficients have no clear relationship with the viscoelasticity of the rubber, so they cannot be used in the design of rubber formulations to obtain the desired friction coefficient. In this study, we propose a new tire mechanical model for cornering simulation that includes a friction coefficient deductively derived from the viscoelasticity of rubber based on the Persson's multiscale friction theory. In this model, the contact pressure, sliding velocity, and lateral stress distributions are calculated based on an elliptical contact patch. Because the proposed model analytically connects the lateral force with the viscoelasticity of rubber, it is applicable to rubber design for achieving the targeted cornering properties. The validity of the model was experimentally verified using an internal drum machine with quartz piezoelectric sensors on an aluminium road segment. With appropriate parameter settings, the friction coefficient distribution in the length direction calculated by the proposed model agreed well with the experimental results compared to the elliptical contact patch tire model. [ABSTRACT FROM AUTHOR]

A novel analytical model is proposed to improve the accuracy of predicting the mechanical response of a strand with asymmetrically broken wires. This model incorporates a new approach to compute the contact force between the broken wire and the duct. When there is more than one asymmetrically broken wire, the previous method cannot handle this situation due to the large deflection of the center wire near the breaking end. This deflection results in a significant contact force between the center and broken wires. The omission of this force in the previous method leads to unrealistic solutions for two or three asymmetrically broken wires. This paper addresses the issue appropriately. The calculated results have been compared with those from a previous experiment, demonstrating satisfactory agreement. Furthermore, the proposed analytical model has been adopted to predict the mechanical behavior of the broken wire in multi-strand scenarios relevant to a prestressed concrete bridge. The contact force between strands is accurately calculated. The findings indicate that the axial force of the asymmetrically broken wire in multi-strands can recover after a short distance from the broken end. This recovery is attributed to the confinement effect of the other strands. [ABSTRACT FROM AUTHOR]

This paper describes California bearing ratio (CBR) tests carried out to investigate the suitability of waste polyethylene terephthalate (PET) bottles for ground improvement. For the studies, quarry dust is used as an infill, and it is prepared at a relative density of 57.6% within the CBR mould with a diameter of 150 mm. Experiments are carried out by embedding cut PET bottles with a diameter of 5.6 cm within the infill to provide cellular confinement in three different configurations, i.e. three-bottle, four-bottle and five-bottle configurations. The effect of bottle height on the performance of the systems is investigated by considering three cell (bottle) heights, viz., 6.6 cm, 9.3 cm and 11.6 cm. To analyse the performance of the cellular confinement, vertical stress distribution below the applied load is determined. It is observed that the performance of the PET bottle embedded system is better when it is placed within the isobar (σz/q) of 0.3. Based on the CBR values and improvement factor, it is observed that a four-bottle configuration with a height of 6.6 cm is effective in sustaining higher loads. The proposed study provides guidelines for using these bottles for stabilising blocked pavements. [ABSTRACT FROM AUTHOR]

In the process of lightweight design, there will be problems such as stress concentration and structural weakening. In order to improve the design defect of serious insufficient life caused by the bending failure of worm gear, the bending stress of worm gear tooth root was analyzed by solution method and finite element simulation method. The main research contents include: firstly, the bending stress of worm gear is calculated by analytical solution method; Secondly, CAD is used to reconstruct the model; Finally, HyperMesh is used for analysis of the structure. The maximum bending stress obtained from theoretical calculation is 34.56Mpa, and the maximum stress from simulation is 39.3Mpa, 29.6Mpa and 26.3Mpa respectively in the three areas of gear root A, B and C (figure 7). Compared with the finite element, the maximum stress difference between them is 4.74Mpa. The stress concentration point is determined, and the structure optimization is carried out; CAE analysis of the optimized model shows that stresses in A, B and C regions of the worm gear root are 33.4 MPa, 22.5 MPa and 5.9 MPa, respectively. After optimization, the maximum stress difference between the two is 1.16Mpa.The above analysis results provide theoretical support for the design of worm gear reducer. [ABSTRACT FROM AUTHOR]

For the seismic risk of utility tunnel in trapezoidal backfilled soil and its possible amplification effect of ground motion, the seismic response of utility tunnel in trapezoidal backfilled soil under P wave is studied by a high-precision indirect boundary element method (IBEM) with the idea of "partition fit." The results show that the peak surface displacement appears on the backfill surface, and the softer the backfilled soil, the greater the peak surface displacement; the peak vertical displacement at oblique incidence is generally smaller than that at vertical incidence; the existence of utility tunnel can restrain the incidence wave to a certain extent, especially for the low-frequency wave; the peak displacement and stress of utility tunnel in the soft backfilled soil are all greater than that in stiff backfilled soil; the peak stress of utility tunnel at oblique incidence is greater than that at vertical incidence; the stress concentration occurs at the axillary corner; and the stress in the inner wall of utility tunnel is greater than that in the outer wall. The similar conclusions could be further confirmed from the time history analysis. The research results can provide some reference for the seismic design of utility tunnel in the backfill site and the evaluation of seismic performance of near surface pipeline, etc. [ABSTRACT FROM AUTHOR]