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Current treatment strategy for managing Weber B ankle fractures is mainly governed by mortise congruency, malleolar alignment, deltoid ligament competence and fracture stability. While nonoperative treatment has yielded good functional outcomes in satisfactorily aligned stable injuries, a biomechanical rationale is not firmly established. Furthermore, current radiographic analysis is obscured by observer inaccuracy and beam rotation. This study aimed to utilize weightbearing CT and computational biomechanics to analyse 3D mortise displacement and contact mechanics in Weber-B ankle fractures and compare them with the uninjured contralateral side. 32 patients were included who sustained a Weber-B ankle fracture and underwent bilateral weightbearing CT imaging at injury. Segmentation into 3D models of bone was performed semi-automatically, and individualized cartilage layers were modeled based on a previously validated methodology. The 3D mortise congruency was evaluated by use of following parameters: alpha angle, fibular length, talocrural angle, medial gutter- and tibiofibular clear space- distance mapping. Contact mechanics were evaluated by the mean and maximum contact stress of the tibiotalar articulation. Statistical analysis revealed that there were no significant differences for all anatomical parameters. There was also no significant difference between the mean contact stress of the injured (2.10 ± 0.42 MPa) and uninjured side (2.10 ± 0.41 MPa), nor the maximum contact stress of the injured (7.67 ± 1.55 MPa) and uninjured (7.47 ± 1.67), respectively. Contact mechanics were unaffected in congruent Weber-B fractures. These findings support consideration of nonoperative management in such cases, given their presumably low risk for posttraumatic arthritic development in the long term. Level of Evidence: Level III; retrospective case-control study. [ABSTRACT FROM AUTHOR]

The stability of coal pillars in fault areas is crucial for ensuring the safe passage of working faces. Based on field observations, frequent coal pillar spalling and substantial tectonic coal crumbs leakage, as well as tilting of hydraulic supports, are observed when working faces transition from primary coal to tectonic coal. To analyze the instability mechanisms behind these phenomena, this paper establishes a mechanical model of coal pillars in fault areas and analyzes the distribution of tectonic stresses and factors affecting the stability of coal pillars. The results indicate that horizontal tectonic stress adheres to an exponential function dependent on the angle factor, where (k0) is a parameter associated with the friction angle of the coal body, the dip angle of the fault, and the friction angle of the fault plane. The stability of coal pillars is influenced by factors such as roof and floor pressures, coal pillar integrity, mining height, and shield support force, with coal pillar integrity being the most critical. To ensure the smooth passage of working faces through faults, this study proposes a combined control technique of "inclined mining" and "grouting," including reducing mining heights, adjusting the slope of working face advancement, and pre-grouting of coal pillars. Industrial experiments conducted on-site have shown improved integrity of tectonic coal, enabling the working face to pass through faults smoothly and significantly increasing production efficiency. [ABSTRACT FROM AUTHOR]

This study analyzed the enhancement effects and mechanisms of steel, glass, and polypropylene fibers on the mechanical properties of concrete, aiming to guide the selection of suitable fiber types and dosages for shotcrete projects. Through laboratory tests, numerical simulations, and field experiments, it investigated the enhancement laws of flexural and compressive strengths of concrete with different dosages of these three fibers. Results showed: (1) After 28 days of curing, flexural strength peaked with 2.0% steel, 1.5% glass, and 2.0% polypropylene fibers, increasing by 118.6%, 42.86%, and 138.6%, respectively, over plain concrete. Compressive strength increased by 2.13%, 10%, and 18.3% at optimal dosages of 0.5%, 1.0%, and 2.0% for steel, glass, and polypropylene fibers. Fiber effects on compressive strength were less significant than on flexural strength, with polypropylene fibers outperforming the others. (2) Based on ABAQUS numerical simulations, microscopic analysis indicates that fibers, due to their high yield capacity, enhance the connections between concrete elements, reduce stress concentration, and improve the mechanical properties of concrete. (3) For shotcrete, 2.0% polypropylene fibers were preferred due to high flexural strength and reduced agglomeration. (4) The optimal dosage was applied to a mine's wet shotcrete support, effectively controlling tunnel deformation. These findings provide practical guidance for shotcrete applications. [ABSTRACT FROM AUTHOR]

Evaluating complicated stress across the elbow under joint motion remains difficult. Here, we aimed to evaluate the distribution of the subchondral bone density in the normal elbow bones and further characterize their spatial relationships during elbow motion to estimate the loading stress across the articular surface using three-dimensional computed tomography bone models. The normal elbow joint exhibited a consistent distribution pattern of subchondral bone density. High-density regions were distributed in the capitellum and posterior humeral trochlea, sagittal ridge of the ulnar trochlear notch and ulnar-volar side of the radial head. Motion analyses revealed that the high-density regions proximate with elbow flexion with forearm pronation in the radiocapitellar joint and in the fully extended position in the ulnohumeral joint. This reasonably reflects the stress acting on the joint surface under actual loading conditions. These findings suggest that daily activities involving lifting or carrying objects in these positions are stress-prone activities. [ABSTRACT FROM AUTHOR]

ABSTRACT Background/Aim Materials and Methods Results Conclusion The fiber splint represents an advanced treatment for traumatized dental injuries. The complete understanding of the localization of a splint on traumatized teeth remains elusive. The aim of this study was to assess the impact of the incisal/cervical positions of the fiber splint on the stress distribution of traumatized dental roots in various occlusal relationships.Three‐dimensional finite element models were generated based on a cone beam computer tomogram of a patient. The incisal and cervical splints were simulated by strips that were bonded close to the incisal/cervical labial surface of traumatic teeth. Force was loaded on the incisal ridge, incisal and cervical positions on the palatal surface of each tooth to simulate the conditions of traumatized teeth during mastication. The equivalent stress (von Mises) on the traumatic teeth and abutment teeth was calculated by Ansys software (version 2021, R1).The incisal splint effectively transferred the stress from the traumatized tooth roots to the abutment teeth when force was loaded on the incisal ridge and incisal and cervical positions on the palatal surface. Nevertheless, the reduction effect was notably diminished when the cervical splint was used. Notably, in cases of cervical splints, with a loading force on the incisal ridge, there is an increase in stress on the roots of traumatized teeth, which poses a disadvantage in the management of traumatic dental injuries.The incisal splint demonstrated a more effective transfer of stress from the roots of the traumatic teeth to the abutment teeth than the cervical splint and the raw. [ABSTRACT FROM AUTHOR]

Highlights Carbon fiber reinforced resin matrix composites, when subjected to multi‐angle delamination during vacuum hot pressing, suffered from defects such as uneven fiber distribution, resin‐rich zones, and voids. These defects caused varied damage and failure behaviors in the composites, seriously affecting their mechanical properties. In this paper, the defect distribution, tensile and flexural properties, and damage behaviors of multi‐angle lay‐up specimens prepared in an autoclave were studied. The results indicated that irregularly shaped voids in laminates with a 0° angle difference primarily led to local stress concentration. Elliptical and elongated voids in laminates with a 90° angle difference were mainly susceptible to delamination. The [0/90]8 layer exhibited the best overall mechanical properties. The proportion of 0° laminates had a direct impact on the mechanical properties, with 0° contact laminates on the bending‐compression side capable of withstanding higher bending loads. The [+45/−45]8 plyer demonstrated pseudo‐delayed behavior, enabling the laminate to show better toughness under load. Variations in damage due to the proportions and positions of the laminates influenced the mechanical properties and damages behavior of multi‐angle laminates. Angular differences were observed to affect void and resin distribution. The best overall mechanical properties were attributed to [0/90]8 laminates. Pseudo‐delay behavior was exhibited by [+45/−45]8 laminates. Proportion of 0° layers impacted mechanical properties. Greater bending loads were withstood by the 0° contact layer. [ABSTRACT FROM AUTHOR]

In this work, the A 18 B 4 O 33 w (ABOw) was in-situ generated on the surface of Al 2 O 3 through the reaction of B 2 O 3 and Al 2 O 3 , resulting in the thorn structure. Then, the ABOw@Al 2 O 3 /AZ91 composites were fabricated through a combination of freeze casting and pressure casting. The influence of the initial content of B 2 O 3 on the microstructure and mechanical properties of ABOw@Al 2 O 3 /AZ91 composites was investigated. The results show that the lamellar structure of ABOw@Al 2 O 3 /AZ91 composites were weakened, which gradually changed to dendritic structure with the increasing B 2 O 3 content. The in-situ formation of ABOw on the surface of Al 2 O 3 was favorable to improve the compressive strength of both ABOw@Al 2 O 3 ceramic scaffold and ABOw@Al 2 O 3 /AZ91 composites, while also reducing the anisotropy of the composites. Furthermore, the in-situ generated ABOw within the ceramic layer could effectively relieve stress concentration and delay crack initiation and propagation, which led to the enhancement of the load-bearing capacity of ABOw@Al 2 O 3 /AZ91 composites. The ABOw@Al 2 O 3 /AZ91 composite exhibited the outstanding mechanical properties with the compressive strength of ∼685 MPa, when the B 2 O 3 's content is 5 wt%. [ABSTRACT FROM AUTHOR]

Based on the shear flow theory for thin‐walled sections, a method for calculating the shear stress nonuniformity coefficient (µ) of a thin‐walled section is proposed according to the energy principle, and the formulas for calculating the µ values of several common sections are derived. The obtained µ value of a box section increases as the aspect ratio increases. Compared with commonly used calculation methods, the proposed method gives more reasonable results and shows that the effect of shear stress in the flange of the flat box section should not be ignored. The effects of the web and flange thicknesses on µ are analyzed and discussed. Based on these effects, a simplified method for calculating the µ value of complex box sections is presented, and this method is demonstrated to considerably reduce the calculation error and meet engineering needs. [ABSTRACT FROM AUTHOR]

The ultrasonic surface rolling process (USRP) can effectively reduce surface roughness, reduce the stress concentration and extend the service life of a workpiece. Surface roughness prediction by finite element simulation has been a hot research topic of late. Most of the previous studies are based on plane models, but the influence of initial surface roughness on the prediction results of shaft parts has not been considered. In this paper, wavelet transform is used to reconstruct the measured cylindrical sample surface data, and the shaft model with initial surface roughness is established. Then the finite element simulation model of USRP is established to predict the surface roughness. The results show that compared with the experimental results, the maximum error of the proposed method is 9 %, which is better than that of the finite element simulation model without considering the initial surface roughness, which verifies the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Ultrasonic vibration as a novel and advanced auxiliary lithotripsy technology possesses great potential in the fields of deep mine drilling. This paper carries out a finite element (FE) analysis to investigate the coupling effects of weight on bit (WOB) and ultrasonic vibration amplitude on the ultrasonic vibration assisted drilling (UVAD) of hard rock. The critical model of WOB and amplitude for hard rock breaking is established to explore the coupling effects quantitatively. The results show that the ultrasonic-frequency axial percussive motion significantly enhances the drilling rate. During the UVAD process, the principle stress undergoes severe fluctuation, constituting more than 50 % of the maximum principal stress, and larger ultrasonic amplitudes correspond to more pronounced stress fluctuations. There are critical coupling values of WOB and ultrasonic amplitude for the rock breaking, with the amplitude increases from 0 µm to 15 µm, the critical WOB for rock breaking reduces by 25 %. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the viscoelastic performance and energy dissipation of conditioned dentin infiltrated with polymeric nanoparticles (NPs) doped with tideglusib (TDg) (TDg-NPs). Dentin conditioned surfaces were infiltrated with NPs and TDg-NPs. Bonded interfaces were created, stored for 24 h and submitted to mechanical and thermal challenging. Resin-dentin interfaces were evaluated through nano-DMA/complex-loss-storage moduli-tan delta assessment and atomic force microscopy (AFM) analysis. Dentin infiltrated with NPs and load cycled attained the highest complex modulus at hybrid layer and bottom of hybrid layer. Intertubular dentin treated with undoped NPs showed higher complex modulus than peritubular dentin, after load cycling, provoking energy concentration and breakdown at the interface. After infiltrating with TDg-NPs, complex modulus was similar between peri-intertubular dentin and energy dissipated homogeneously. Tan delta at intertubular dentin was higher than at peritubular dentin, after using TDg-NPs and load cycling. This generated the widest bandwidth of the collagen fibrils and bridge-like mineral structures that, as sight of energy dissipation, fastened active dentin remodeling. TDg-NPs inducted scarce mineralization after thermo-cycling, but these bridging processes limited breakdown zones at the interface. TDg-based NPs are then proposed for effective dentin remineralization and tubular seal, from a viscoelastic approach. [Display omitted] • Undoped NPs in load cycled dentin provoked frictional pullout around tubules. • Tideglusib-NPs in load cycled dentin favored dissipation of energy at the interface. • Tideglusib-NPs facilitated mineralization in zones with stress concentration. [ABSTRACT FROM AUTHOR]

In this paper, a crystal plasticity finite element method (CPFEM), considering the grain morphology and orientation, as well as the dislocation density, is used to research the tensile deformation behavior of GH4169 based on Electron Backscatter Diffraction (EBSD). The stress, plastic strain, and dislocation density distributions are obtained for different levels of deformation. Results show that the stress, plastic strain, and dislocation density exhibit obvious heterogeneous plastic deformation, and stress concentration and dislocation pileup mainly occurs near grain boundaries. The initial dislocation density mainly affects the stress–strain curve of the material, and it can obviously effect the yield strength but cannot influence the hardening ability of the material. The total dislocation density increases with plastic strain. However, the texture evolution has no evident change with increasing plastic strain, except for the increase of texture content in Cube (001)[100]. [ABSTRACT FROM AUTHOR]

This article is aimed at understanding of the complex design of metalorganic chemical vapour deposition ‐grown InGaN‐based red light‐emitting diode (LED) structure. The contribution of different elements of red LED structure to the stress distribution and threading dislocation density (TDD) evolution is theoretically investigated. For this purpose a self‐consistent modeling of the structure growth process is used, taking into account stress‐modulated indium incorporation, mismatch stress relaxation by threading dislocations and V‐pits, and nucleation of new threading dislocations. The simulation results, consisting of composition, stress, and TDD profiles, are then utilized for modeling of device operation, which allows to analyze contribution of different elements to the heterostructure operation. [ABSTRACT FROM AUTHOR]

Compressive testing of specimens taken from relatively thin composite plates is difficult, especially due to the occurrence of buckling. To prevent buckling, the central portion of the specimens used for the compression test has smaller dimensions, and the specimens can be guided along their entire length. For these reasons, optical methods, such as digital image correlation (DIC), cannot be used for the compression test and strain rosettes cannot be glued onto the samples to determine Poisson's ratio. In this study, compression tests of a glass fiber-reinforced polymer (GFRP) were conducted using both the ASTM D695 (Boeing version) and a newly proposed method. The new method involves using special specimens that allow T-type rosettes to be bonded to determine Poisson's ratio, whose value of 0.14 was thus determined. SEM images of the failure surfaces were presented and interpreted. A finite element analysis (FEA) of the specimens tested in compression is also presented. The first analyzed case considers the homogeneous and orthotropic composite, loaded with a uniformly distributed force. The normal stress in the central section of the specimen, determined with FEA, has an error of 6.52% compared to that determined experimentally. Additionally, the strain in the center of the strain gauge, determined with FEA, has an error of 4.76% compared to the measured one. In the second case studied with FEA, the sample is loaded with a quasi-concentrated force, which can move in the direction of the symmetry axes of the cross-section, to study the effect of the eccentricity of the compression force on the state of stress. It was shown that the eccentricity of the force has a great influence: the stress distribution in the section of the specimen becomes strongly non-uniform. For a force eccentricity of 0.4 mm in the direction of the OX axis, the minimum stress decreases by 53.7%, and the maximum stress increases by 55.4%. In order to analyze the influence of some manufacturing defects, two other cases were analyzed by FEA, in which it was assumed that the thicknesses of the outer resin layers were modified, making them asymmetrical. For this final FEA, the specimen was considered to be composed of laminates. These results demonstrate the special attention that must be paid to the centric application of force in compression testing. [ABSTRACT FROM AUTHOR]

This study investigated the internal stress distribution of unidirectional fiber-reinforced plastics (UD-FRP) at the micro level using principal component analysis (PCA). The composite material was simulated using a representative volume element model together with the embedded cell approach. Two fundamental quasi-static load cases, transverse and longitudinal tensile deformation, were considered. The experimental results show that mechanical failure occurred at 2.15 ± 0.06% transverse tensile strain and at 1.52 ± 0.07% longitudinal tensile strain. Furthermore, the undamaged state and a combination of matrix and interface damage, as well as fiber breakage, were simulated. From the simulations, the octahedral shear stress and octahedral normal stress were computed at the integration points of the matrix elements, constituting what is known as the octahedral stress field. A modification on the PCA to obtain mesh-independent eigenvalues is presented and was used to investigate the effects of damage events on the octahedral stress field. The results indicate that each damage mechanism had a distinct signature in the redistribution of the stress field, characterized by specific changes in the eigenvalues and orientation of the principal component (θ1). Furthermore, the PCA suggests that the accumulation of matrix damage began to be relevant at the 1% strain, while fiber breakage began at an average longitudinal strain of 0.98 ± 0.12%. Additionally, it is shown that the first principal component served as an indicator of the predominant stress state of the stress field. This investigation suggests that the PCA can provide valuable insights regarding the complex damage mechanisms of UD-FRP that may not be captured by conventional mechanical analysis. [ABSTRACT FROM AUTHOR]

To investigate the reasonable width of a coal pillar in the downward mining section of close-distance coal seams, the stress state of any point below the residual coal pillar in the overlying goaf and the width of a small coal pillar were studied by theoretical calculation, numerical simulation, similar simulation and field monitoring. The findings indicate that the width range of the small coal pillar is 7.92~11.42 m. The 4-1 coal seam is in the stress reduction zone when it is more than 16.6 m horizontally from the border of the residual coal pillar above it. In addition, the peak stress is situated inside the elastic zone of the coal pillar and is lower than the coal pillar's bearing limit when a small coal pillar of 8 m is maintained. With the help of distributed optical fiber monitoring to model the coal pillars' stress distribution, it is found that 8 m simulated coal pillars have a certain bearing capacity. The practical findings demonstrate that the 8 m small coal pillar that was left on the site satisfies the demand, and the convergence of the roadway's floor and roof, and its two sides fall within the controllable range. The findings of the study offer a reference for the location of a return air roadway and the width of section coal pillars in the downward mining of close-distance coal seams. [ABSTRACT FROM AUTHOR]

To explore the mechanical properties and fracture modes of basalt fiber-reinforced concrete, single-doped and hybrid-doped basalt fiber-reinforced concrete was prepared, and uniaxial failure tests under different basalt fiber-reinforced concrete contents were carried out. At the same time, the smooth kernel function in the traditional SPH method was improved, and the basalt fiber random generation algorithm was embedded in the SPH program to realize the simulation of the progressive failure of basalt fiber-reinforced concrete. The results show that under the circumstance with no basalt fiber, the specimen final failure mode is damage on the upper and lower surface, as well as the side edge, while the interior of the specimen center is basically intact, indicating that there is an obvious stress concentration phenomenon on the upper and lower surface when the specimen is compressed. Under the circumstance with basalt fiber, longitudinal cracks begin to appear inside the specimen. With the increase in the content, the crack location gradually develops from the edge to the middle, and the crack number gradually increases. This indicates that appropriately increasing the fiber content in concrete may improve the stress state of concrete, change the eccentric compression to axial compression, and indirectly increase the compressive strength of concrete. The numerical simulation results are consistent with the test results, verifying the rationality of the numerical simulation algorithm. For the concrete model without the basalt fiber, shear cracks are generated around the model. For the concrete model with basalt fiber, in addition to shear cracks, the tensile cracks generated at the basalt fiber inside the model eventually lead to the splitting failure of the model. The strength of concrete samples with basalt content of 0.1%, 0.2%, and 0.3% is increased by 1.69%, 5.10%, and 4.31%, respectively, compared to the concrete sample without basalt fiber. It can be seen that with the increase in the content of single-doped basalt fiber, the concrete strength is improved to a certain extent, but the improvement degree is not high; For hybrid-doped basalt fiber-reinforced concrete, the strength of concrete samples with basalt content of 0.1%, 0.2%, and 0.3% is increased by 14.51%, 15.02%, and 30.31%, respectively, compared to the concrete sample without basalt fiber. Therefore, compared with the single-doped basalt fiber process, hybrid doping is easier to improve the strength of concrete. [ABSTRACT FROM AUTHOR]

In this study, the effects of the length-to-width ratio on the magnetic and microstructural properties of die-upset Nd–Fe–B magnets were examined. A die-upset magnet with a uniform shape and no significant cracking was successfully developed. During the die-upset process, the applied pressure was not uniform across the magnet and varied depending on its shape and position. In the case of the magnet with a 4:1 ratio, which had the largest length-to-width ratio, there was a higher concentration of stress at the edges compared to the center, resulting in easier grain deformation and growth at the edges, which led to the lowest remanence and (BH)max. As the length-to-width ratio approached 1:1, the grain size increased slightly, reducing the coercivity; however, the magnets maintained a uniform grain-size distribution. The change from a rectangular to a square pressing surface resulted in a more uniform stress distribution, particularly at the center and corners, which improved the consistency of the magnetic properties across different regions of the magnet. Consequently, an 11.9% enhancement in (BH)max, reaching 285.6 kJ/m3, was achieved in the 1:1 ratio die-upset magnet, which is attributed to the uniform grain size and improved grain alignment. [ABSTRACT FROM AUTHOR]

This paper focuses on the development of a methodology for the directional structural modification of warp-knitted fabrics by sewing on carbon fiber tapes. Four-, five-, and six-axial geometric systems were designed to optimize the qualitative distribution of stresses on the surface of the tested product. Through a numerical experiment in the ANSYS environment, the impact of the change in the axiality of a textile structure on the mechanical properties of the modeled geometric configuration was assessed. This analysis was experimentally verified by measuring the multiaxial force distribution on the knitted surface, which demonstrated that Variant 7, with six axes 30° apart, was the most favorable. [ABSTRACT FROM AUTHOR]

A thorough procedure was developed to efficiently manufacture dogbone samples using focused ion beam (FIB) milling for micro-tensile testing. A Bruker PI 89 PicoIndenter, Billerica, MA, USA, was used as a case study, although the analysis and results are applicable to other micro-mechanical testing systems capable of mounting a standard, Ø12.7 mm × Ø3.2 mm pin, scanning electron microscopy (SEM) pin stub (Ted Pella, Redding, CA, USA). Nine dogbones were made from an Fe-45Cu alloy additively manufactured using powder-fed laser-directed energy deposition (DED-LB). Testing showed that fracture was confined to the gauge section for all dogbones and that the fracture mode, ductile vs. brittle, was entirely dependent on the grain orientation relative to the loading direction. The analysis showed that the measured plastic strain to failure can vary from >11% (optimal geometry) to <1% (non-optimal geometry) in micro-tensile testing of high-tensile-strength (>1 GPa) metallic materials. Subsequently, a finite element analysis (FEA) was conducted to identify the improved dogbone geometries. A total of ten thousand dogbone geometries were tested, and their dimensions were defined by a set of four adjustable parameters (corner radius, load surface angle, load surface length, and dogbone head length). The gauge width and gauge length were fixed to 4 µm and 10 µm, respectively. Three-dimensional surface plots of the stress concentration as a function of two parameters were used to identify the optimal ranges of parameter values. The addition of maximum width and length constraints, measuring 25 µm and 30 µm, respectively, allowed us to identify an optimal geometry at load surface angles of 30° and 45°. Their respective dimensions (corner radius, load surface length, and dogbone head length) are, in µm, 12, 6, and 7 and 10, 7, and 7. Testing these two optimal geometries with a range of gauge lengths from 4 to 20 µm showed that smaller gauge lengths only slightly reduced the detrimental stress concentration outside the gauge section. However, smaller gauge lengths will notably improve the FIB surface polishing step as tapering is reduced with smaller dogbone lengths. [ABSTRACT FROM AUTHOR]

Background: Although the specific relationship between the stress changes in the external fixator during tibial fracture treatment and the bone healing process remains unclear, it is believed that stress variations in the external fixator scaffold can, to a certain extent, reflect the progress of tibial healing. Objective: This study aims to propose a non‐invasive method for assessing the degree of fracture healing by monitoring the changes in stress transmission, the locations of stress‐sensitive points, and displacement in the external fixator‐tibia system during the healing process of tibial fractures. Methods: In this study, finite element models of tibial fractures at various healing stages were developed. Physiological conditions, including axial, torsional, and bending loads on the tibia, were simulated to evaluate stress and strain within the external scaffold‐tibia system under normal physiological loading conditions. Results: The results indicate variations in the stress distribution between the external fixator and the tibia during different stages of healing. In the early phase of fracture healing, the external fixator plays a crucial role as the primary load‐bearing unit under all three loading conditions. As the fracture healing progresses, the stress on the tibia gradually increases, concentrating on the medial part of the tibia under axial and torsional loading, and at the upper and lower ends, as well as the central part of the anterior and posterior tibia during bending loading. The stress at the callus gradually increases, while micro‐movements decrease. The stress within the external bracket gradually decreases, with a tendency for the connecting rod to transfer stress towards the screws. Throughout the fracture healing process, the location of maximum stress in the external fixator remains unchanged. Under axial and torsional loading, the maximum stress is located at the intersection of the lowest screw and the bone cortex, while under bending loading, it is at the intersection of the second screw and the connecting rod. Conclusion: During the bone healing process, stress is transferred between the external fixation frame and the bone. As bone healing advances, the stress on the connecting rods and screws of the external fixation frame decreases, and the amplitude of stress changes diminishes. When complete and robust fusion is achieved, stress variations stabilize, and the location of maximum stress on the external fixation frame remains unchanged. The intersections of the lowest screw and the bone cortex, as well as the second screw and the connecting rod, can serve as sensitive points for monitoring the degree of bone healing. [ABSTRACT FROM AUTHOR]

The effect of breakable particle corners is often overlooked in research on pile–soil interaction, which hinders the understanding of the uplift pile behaviors in calcareous sand. This research examines the breakable corner effects on uplift pile–soil interaction in calcareous sand from macro to micro, through model tests and coupled discrete element method–finite difference method. Results revealed that compared to that in silica sand, the higher bearing capacity and relatively abrupt failure behavior of uplift piles in calcareous sands were attributed to the corner interlocking effect and corner breakage effect, respectively. The unstable load transmission along piles in calcareous sand was thoroughly explained by a coupled effect of corner interlocking and breakage. Furthermore, the reduction in effective contacts and alterations in soil skeletons were identified as critical factors contributing to the distinctive soil behaviors in calcareous sand. Moreover, the relative sliding distance of particles was found to be the key factor in determining the amount of corner breakages due to stress concentration at corners. Lastly, a positive feedback loop involving corner breakage effects was proposed, successfully explaining the distinctive phenomenon of uplift piles in calcareous sand. This study provides new perspectives to clarify distinctive pile–soil interaction behaviors in calcareous sand. [ABSTRACT FROM AUTHOR]

In response to the unanswered relevant questions surrounding atherosclerosis, it becomes imperative to investigate arterioles using sophisticated mathematical modelling techniques to shed light on critical stress and strain patterns influenced by gravity. The primary objective of this study is to scrutinize flow characteristics and probe stress and strain distributions experienced by the intima layer of arterioles, encompassing coronary, renal, cerebral, mesenteric, and pulmonary arteries, under gravitational forces. This investigation employs a fluid-structure interaction methodology utilizing arbitrary Eulerian–Lagrangian formulation. The study delves into blood flow characteristics within coronary, renal, cerebral, mesenteric, and pulmonary arterioles using the fluid-structure interaction technique, employing an arbitrary Eulerian–Lagrangian formulation. It thoroughly examines various biomechanical parameters such as the Cauchy–Green stress tensor, Principal strain, Piola–Kirchoff stress tensor, deformation tensor, and volume strain along the intima layer under the gravitational influence, elucidating vulnerable regions prone to endothelial dysfunction. Higher values of δV are found at the left shoulder and in the intima's post stenosis area due to the pressure gradient along the flow channel, whereas other intima regions show a null volume strain. A thorough understanding of stress distribution is essential to create focused therapies to lessen vascular health problems. The stress in the post-stenosis region seems to affect the endothelial layer to a significant extent. [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 method of pull-out test has been used to identify the mechanical performance of hybrid and fiber-reinforced composite materials. This paper investigates the elastic phase preceding the pull-out of a rigid line inclusion from the polymer matrix with fixed top and bottom surfaces. The mode-III problem is investigated such that the pull-out force is applied from the out-of-plane direction and it can be either transient or static. By applying the singular integral equation technique, the semi-analytical elastic field expressions are obtained. Under the static pull-out force, the stress intensity factor (SIF) near the inclusion tip shows a monotonic increase as the length and height of the matrix increase, whereas for the transient pull-out force, the SIF displays an initial increasing and followed by a decline. The maximum SIF is obtained for (1) the matrix length is 2 to 2.5 times of the inclusion length, and (2) the matrix height is 1 to 2 times of the inclusion length. Moreover, this paper provides a solution approach that incorporates the elasticity of the inclusion, showing that there is an optimal shear stiffness that minimizes the stress singularity of system. The conclusions of this study hold significance for the design and performance evaluation of fiber-reinforced composite materials. [ABSTRACT FROM AUTHOR]

Modeling the lumbar facet capsular ligament's (FCL) mechanical behavior under various physiological motions has often been a challenge due to limited knowledge about the on-joint in situ ligament state arising from attachment to the bone or other internal loads. Building on prior work, this study presents an enhanced computational model of the lumbar facet capsular ligament by incorporating residual strain and joint pressurization strain, factors neglected in prior models. Further, the model can predict strain and stress distribution across the ligament under various spinal motions, highlighting the influence of the ligament's attachment to the bone, internal synovial fluid pressurization, and distribution of collagen fiber alignment on the overall mechanical response of the ligament. Joint space inflation was found to influence the total observed stress and strain fields, both at rest and during motion. A significant portion of the ligament was found to be in tension, even in the absence of external load. Additionally, the model's ability to account for residual strain offers a more realistic portrayal of the collagen fibers and elastin matrix's role in ligament mechanics. We conclude that (1) computational models of the lumbar facet capsular ligament should not assume that the ligament is unloaded when the joint is in its neutral position, and (2) the ligament is nearly always in tension, which may be important in terms of its long-term growth and remodeling. [ABSTRACT FROM AUTHOR]

This study uses numerical simulations to investigate projectile shape's influence on the ballistic performance of 3D shallow bend-joint woven fabrics (3DSBWFs). The projectiles, including conical, flat, hemispherical, and spherical shapes, were analyzed for their impact on energy absorption, stress distribution, and deformation mechanisms. Results indicated that flat projectiles exhibited the highest total energy absorption, reflecting extensive energy transfer and broad impact force distribution. In contrast, conical projectiles caused localized energy absorption, concentrating stress at the tip and leading to early rupture of fabric yarns through minimal energy dissipation. Hemispherical and spherical projectiles demonstrated balanced energy absorption and uniform impact force distribution. Stress propagation varied significantly, with conical projectiles causing localized damage, while flat projectiles displayed broader stress propagation. Deformation patterns also differed, with conical projectiles causing severe localized deformation and flat projectiles resulting in extensive yarn deformation. Hemispherical and spherical projectiles induced more balanced deformations. These findings underscore the importance of projectile shape in designing protective materials, providing insights for optimizing fabric structures to enhance ballistic performance. [ABSTRACT FROM AUTHOR]

Soil salinization has been considered as a major environmental threat to plant growth. Different types of salt in saline soil have different effects on germination and seedling growth. Effect of NaCl on germination and seedling establishment in Suaeda liaotungensis have been reported, but its response to alkali stress remains unclear. Our results showed that brown seeds had higher germination rate, however, black seeds had higher germination recovery percentage under alkali stress. Na2CO3 had stronger inhibitory effect on germination and seedling growth than NaHCO3. As the concentration of alkali stress increased, the ROS level of brown seeds gradually ascended, while that of black seeds decreased first and then ascended. MDA content of dimorphic seeds significantly increased under alkali stress. The trend of SOD, POD and CAT activity between dimorphic seeds was similar under the same type of alkali stress. Alkali stress enhanced proline content of dimorphic seeds, and dimorphic seeds in NaHCO3 solution had higher proline content than Na2CO3 solution. Moreover, radicle and shoot tolerance indexes of seedlings in NaHCO3 solution were significantly higher than that of Na2CO3 solution. Under strong alkali stress, seedlings in NaHCO3 solution had significantly lower ROS level and MDA content as well as higher antioxidant enzyme activity than Na2CO3 solution. This study comprehensively compared the morphological and physiological characteristics in germination and seedlings to better reveal the saline-alkali tolerance mechanisms in S. liaotungensis. [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 rock–concrete interface serves as the weak point of concrete structures based on rocks; the initial failure of the interface under stress waves can easily cause instability and failure of rock concrete composite structures. This study conducted a range of numerical investigations using MAT-COHESIVE-MIXED-MODE cohesive element to describe the failure properties of rock–shotcrete's interface transition zone (ITZ). The research results can reveal ITZ's failure mechanism and mechanical property under different stress wave incidence orientations and confining pressures. It can be concluded that under multi-directional dynamic stress waves, the failure mode of the ITZ is represented as a complete failure with the angle from 0° to 45°, the local penetration failure of the ITZ with the angle from 60° to 90°, and the highest failure rate of only 4.89%. Under different confining pressure, the 40 MPa as a threshold can reduce the failure rate of the ITZ from 100% to 41.74%. The confining pressure delayed the stable stage initial angle of tensile and shear displacement from 60° to 75° under the coupling effect of the multi-directional stress wave and confining pressure. For interface displacement control, the incidence angle should be better than 75° under confining pressure, and the angle can be controlled above 60° without confining pressure. Therefore, for tunnel surrounding rock support, attention should be paid to displacement and deformation control at positions where the angle between the excavation blasting direction and the primary lining surrounding rock bonding surface is less than 75°. Highlights: The failure evolution law of rock–shotcrete ITZ subjected to multi-directional stress waves is investigated. The effect of confining pressure on the interface failure mechanism and the ITZ stress distribution of the rock–shotcrete was obtained. The interface stress and displacement of the rock–shotcrete acted upon by the coupling effect of stress waves and confining pressure were explored. [ABSTRACT FROM AUTHOR]

This study presents a novel framework for the optimal design of compliant mechanisms, specifically addressing the structural drawbacks of conventional single-point or de facto hinges. The hinges often lead to structural instability and stress concentration while deriving maximum motion. To overcome these issues, we introduce a new method that can design stable and elastic domains connected by either revolute or prismatic joints. The new method, called sequential analysis based on the reaction force, can successfully eliminate weak hinge points while optimizing joint locations. The efficiency of developed methodology is validated through several numerical examples, yielding compliant mechanisms with suppressed hinges. [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]

Efficient and accurate calculation of stress overload and stress redistribution near the fiber breakpoint is the basis for simulating the tensile damage evolution of unidirectional fiber reinforced plastic (FRP), and it is also the premise for predicting the tensile-tensile fatigue life. In this study, an efficient finite element (FE) model with a large number of fibers was developed based on the FE method to calculate stress concentration factor (SCF) near multiple breakpoints, and the calculation time only takes 3 min on average. The FE model is used to efficiently calculate multiple breakpoints and the stress distribution near the breakpoint considering the interface debonding. Based on the efficient FE model, an analytical model is developed to calculate the stress overload superposition around multiple breakpoints. In this analytical model, the shear stress distribution near the broken fiber elements is established based on the experiment, and the stress redistribution mechanism near the breakpoint in FRP with random distribution of fibers is established. Moreover, the calculation method of stress overload near multiple break points is established, and the FE method is verified. [ABSTRACT FROM AUTHOR]

This study examines how heat travels as thermoelastic waves in a uniform, isotropic, and infinitely large solid material due to a constant line heat source. We leverage the theory of thermoelasticity with two phase lags to account for the time difference between temperature changes and the material's stress response. By employing a potential function approach alongside Laplace and Hankel transforms, we can convert the governing equations into more manageable domains. This enables us to derive mathematical formulas for temperature, displacement, and stress distributions within the solid. Through a complex inversion process of the Laplace transforms, we obtain analytical formulas for these field distributions. These formulas, however, are only valid for short time periods and are most applicable in the initial stages of wave propagation. We then use these analytical formulas to visualize how temperature, displacement, and stress are distributed, revealing the influence of the heat source and phase lag parameters on these fields. This approach provides valuable insights into the characteristics of wave propagation, the heat source's impact, and the time-dependent nature of the thermoelastic response. Furthermore, to demonstrate the method's versatility and ability to connect with established theories, we incorporate specific examples from other thermoelasticity theories. This broadens our understanding of thermoelastic behavior under various conditions. [ABSTRACT FROM AUTHOR]

Effect of the external surface layer on the phase transition (PT) between the low pressure phase and high pressure phase (HPP) in a NiAl bicrystal is investigated. Using a phase field model, the external surface layer is included, within which the elastic properties and surface energy are properly distributed. After resolving a stationary layer, the coupled phase field and elasticity equations are solved to capture the HPP evolution. Residual stress concentrator is included as a shear band representing an inelastic shear strain. Due to the small grain size, the surface layer can influence the stress distribution and consequently, the critical inelastic shear strain γ cr for the HPP growth. Above a certain applied pressure, the surface layer width Δ ξ shows no effect on γ cr , e.g., P = 10 GPa for the grain size of L = 20 nm. For lower pressures, γ cr increases as pressure reduces. Due to the interplay of size addition by the surface layer and size reduction by the transformation strain, γ cr reduces versus Δ ξ and then increases for larger Δ ξ . For smaller grain sizes, the surface layer effect is promoted as it is imposed to a larger transformation work. The lowest γ cr is obtained for P = 19 GPa, in good agreement with the theoretical pressure of 20 GPa. Combining the external shear on pressure adds an extra shear term to the transformation work, which allows for the relaxation of the shear band and results in a nonlinear reduction of the PT pressure versus applied shear. [ABSTRACT FROM AUTHOR]

Modified Green–Lindsay generalized thermoelasticity theory was established by Yu et al. (Meccanica 53(10):2543–2554, 2018). On the basis of this theory, transient motions remove discontinuities in displacement fields. The goal of this article is to address a dynamical problem involving finite linear mode-I cracks in an isotropic and homogeneous elastic medium in a two-dimensional infinite space using the innovative framework of modified Green–Lindsay generalized thermoelasticity theory. There is a specified temperature and stress distribution on the crack's boundary. The integral transform techniques are used to obtain the numerical values of temperature, stress, displacement and stress intensity factor for copper material. These non-dimensional physical fields are explained graphically. Specifically, the present undertaking demonstrates its utility in addressing challenges related to fracture mechanics, geophysics and mining particularly in the context of coupling thermal and mechanical fields. This concerted effort proves valuable in exploring and resolving issues within these fields. [ABSTRACT FROM AUTHOR]

Owing to the direct exposure to complex atmospheric environments, the temperature field of composite box girder bridge with corrugated steel webs (CBGB-CSW) is likely non-uniformly distributed. Whereas, the current researches regarding the thermal responses of CBGB-CSW are insufficient, and the thermal responses of CBGB-CSW under solar radiation are still unknown. Therefore, this paper conducted a long-term temperature experiment on a scaled model to explore the temperature distribution characteristics in CBGB-CSW. Meanwhile, a three-dimensional thermal–mechanical coupling Finite Element (FE) model is established to simulate the temperature field in the experiment girder. The accuracy and effectiveness of the developed FE model has been verified by the measured temperature data. Therewith, the thermal responses (i.e., stress and displacement) of a full-scale continuous CBGB-CSW with a span of 150 m are numerically investigated. The results indicate that the maximum stresses always occur at the midspan section (with a depth of 5 m) of the continuous CBGB-CSW, and considerable concentrations of stress are observed in the steel-concrete junction. The maximum longitudinal tensile and compressive normal stresses within 0.4 m of the upper junction can reach 5.55 MPa and −8.46 MPa respectively, and those of the lower junction can reach 6.96 MPa and −7.05 MPa respectively. Besides, owing to the impacts of vertical and horizontal temperature gradients, significant displacements of the whole bridge can also be observed. The maximum vertical displacement (5.33 mm) of the CBGB-CSW is estimated at the top plate in the midspan, while the maximum horizontal displacement (0.74 mm) is estimated at the trough of the southern corrugated steel web in the midspan. Notably, the outcomes of this paper can provide some useful references for engineers and scholars to understand the thermal responses of the CBGB-CSW. [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]

Additive manufacturing (AM) enables the production of complex geometries that are not accessible by conventional processes. Fused deposition modeling (FDM) 3D printing is an important choice for many industries, particularly for additive manufacturing of microelectronic systems. The various physical properties of printing polymer materials, such as geometry, rheological behavior, and others, need to be taken into account in the printing process. In our study, a semi-crystalline polypropylene polymer PP is used in the FDM process, as it is characterized by deformability due to crystallization. We investigate the thermomechanical behavior of a semi-crystalline polymer PP (polypropylene) with different material deposition geometries ranging from a parallelepiped filament to a cylindrical filament in a numerical model developed. A coupling (to temperature vs. time evolution during printing) of solid mechanics, heat transfer, and crystallization kinetics equations was considered to build the Multiphysics numerical model capable of predicting temperature profiles, residual stresses, and degree of crystallization during the FDM process. The results obtained with the numerical model provide a reliable approach to predicting and adjusting the actual thermomechanical behavior of a printed electronics package. The values are calculated and compared to the six points in the two samples. The results show that the change in deposit shape resulted in a maximum deviation of 3.3 MPa for residual stress and 0.376 for the degree of crystallization, while a decrease was observed in the selected points with an average deviation of 1.81 MPa and 0.193 for residual stress and the degree of crystallization, respectively. This is due to the effects of the modification of the shape model on the temperature profile model, with the change in the 3D structures of the printed polymer material; the methodology presented in this paper allows the numerical model to be validated with an experimental study of the literature. The paper proposes future work and an experimental study to validate the results of the numerical model. [ABSTRACT FROM AUTHOR]

In this paper, the thickness debit and stress concentration effects of a nickel‐based directionally solidified superalloy were investigated through strain‐controlled low cycle fatigue (LCF) and creep–fatigue interaction (CFI) experiments. Compared to the fatigue lives of solid specimens provided in the existing literature, the results of this paper indicate that when the wall thickness of the specimen is reduced from 5 to 1.125 mm, the fatigue life with different strain amplitudes decreases by about 45%. When film‐cooling holes (FCHs) are introduced into the hollow specimens, the fatigue life is further reduced by about 25%. Based on the observation of the scanning electron microscope (SEM), the formation mechanisms of the thickness debit and stress concentration effects under LCF and CFI loads were revealed. Subsequently, two parameters, the "wall‐thickness coefficient" and "hole coefficient," were proposed to establish a new fatigue life prediction method. Highlights: LCF and CFI tests were investigated on hollow specimens with and without holes.The deformational behaviors of hollow specimens with holes were studied.Two parameters, the "wall‐thickness coefficient" and "hole coefficient," were proposed.A method for estimating the fatigue life of hollow specimens with holes was proposed. [ABSTRACT FROM AUTHOR]

Parts manufactured by wire arc additive manufacturing (WAAM) are characterized by a peculiar surface morphology, namely, surface waviness, that negatively affects the fatigue performance. To exploit the full potential of WAAM and minimize the need for postproduction work, it is crucial to utilize the components in the as‐built state. This is because conventional machining techniques, typically employed for postprocessing operations, severely curtail the freedom of geometry of the components. This study focuses on an experimental and numerical characterization of the notch effect of the surface waviness for an AISI 308 LSi stainless steel. This is done by quantifying the fatigue notch factor in a probabilistic fashion, considering the results of ad‐hoc designed fatigue tests. A finite element model is developed by considering a 3D scan of the geometry of WAAMed plates, allowing to determine the theoretical stress concentration factor. The fatigue notch factor is also estimated from the numerical model by making use of the gradient correction according to the FKM guidelines. To validate the numerical approach, test data produced for different testing conditions are correlated by using the local stress approach, showing that classical methods are also applicable to additive manufactured parts. Experimental determination of notch effect of as‐built surface in thick WAAMed plates. An FE model is formulated to estimate fatigue notch factor using FKM guidelines S‐N curves for WAAMed specimens of AISI308LSi steel at different load ratio. [ABSTRACT FROM AUTHOR]

This paper examines the problem of a piezomagnetic right-angle plane with irregular boundaries using the boundary element method. It considers SH waves and line source loads as external forces acting on the piezomagnetic right-angle plane. The effectiveness of the boundary element method is demonstrated through two different numerical examples. Firstly, in the absence of line source loads, the paper analyzes the dynamic characteristics in the first example by employing the image method and Graf addition theorem. Then, it introduces Green's identities and solves the Green's function in infinite three-dimensional space. In the second example, the paper investigates the dynamic characteristics when irregular boundaries are subjected to line source loads using the boundary element method. The results elucidate the influence on the dynamic stress concentration factor and magnetic field intensity concentration factor under appropriate conditions. Additionally, the analytical solutions are compared with finite element solutions to validate the accuracy of the conclusions presented in this study. [ABSTRACT FROM AUTHOR]

This paper proposes a modified two-dimensional (2-D) shear-lag model considering unidirectional or bidirectional interfacial damage to analyze the stress transfer mechanism of rectangular patch-reinforced composites under tensile load. The semi-analytical solutions for bidirectional normal stresses and interfacial shear stresses are provided, accounting for interfacial orthotropic anisotropy and the stiffness variation in the damage stage. The study examines the influence of material parameters, including the difference in Poisson's ratios between the substrate and patch, thickness ratio, and aspect ratio, on interfacial damage in composite materials. The results show a good agreement between the stress distribution solutions predicted by the proposed 2-D model and finite element results. The model provides an effective solution to the 2-D stress problem in rectangular patch-reinforced composites with interface damage. [ABSTRACT FROM AUTHOR]

The thermal shock resistance of ceramics is a key factor for determining the durability of ceramic components under transient thermal conditions and is also one of the key factors for evaluating the stability of ceramics under extreme thermal conditions. After rapid heating or cooling, the surface and internal thermal stress mismatches of ceramics can cause severe thermal damage. Two main types of ceramic thermal shock exist: rapid cooling and rapid heating thermal shock. This article presents a broad understanding and insight into fundamental theory and experimental methods for ceramic thermal shock testing. The experimental equipment and procedures, test result evaluation, and material characterization of ceramic thermal shock are summarized. Moreover, outlooks and perspectives are discussed for testing and characterizing ceramic thermal shock resistance. This review will be helpful to researchers performing studies in the relevant fields of ceramics. [ABSTRACT FROM AUTHOR]

For the satellite antenna, a large aperture reflector is a contemporary need for space agencies worldwide. The space-borne membrane structures are the promising solution for the compact and lightweight reflector antenna. The objective of the study is to investigate the effect of dimension scaling on tension force with different anchor point configurations of the rectangular membrane reflector. The study also aims towards the development of the generalized tension force relation for the scaled dimensions of planar membrane reflectors. The numerical and experimental investigation for loading analysis of membrane reflector with different scale sizes and anchor point configurations is carried out. The study presents the novel equation for average diagonal stresses with different anchor points configurations of membrane reflector. The numerical results of loading analysis are found consistent with the experimental outcomes. Based on the results, the novel trend-line equation between the tension force and the scaling factor is developed. From the developed trend-line equation, the tension force can be directly calculated for any size of a reflector. The relation between the number of anchor points and the size of the reflector is discussed. The findings of this research provide insights to a novel relation for average diagonal stresses and tension force trend-line equations that can be implemented to any scaled sizes of the rectangular membrane reflector. [ABSTRACT FROM AUTHOR]

This study investigated the stress concentration phenomenon and the interlaminar stresses of laminated composite spherical, conical, and cylindrical shells using higher-order shear-normal deformation theory (HOSNT) and transverse stress recovery. The proposed theoretical model incorporates laminate deformations that account for the effects of transverse shear and normal strain/stress, thus modeling the deformation of laminated shells more accurately and eliminating the need for the shear correction factor. The governing equations are solved by applying a semi-analytical method based on the simple trigonometric series and a finite-difference method. In order to fulfill boundary conditions at both the bounding surfaces and local stress-equilibrium equations specified by elasticity theory, the transverse shear and normal stresses are reconstructed by integrating along the thickness direction three-dimensional equilibrium equations of elasticity theory with one-step stress recovery. The present mathematic model and computational procedure were validated by comparing obtained numerical results with those available in the literature. The main advantage of the proposed model is that it correctly predicts the stress components near the clamped boundary edges of laminated composite shells, where sharp changes may be observed. Using HOSNT and one-step stress recovery, this study presents the stress distribution of laminated composite shells of revolution in the clamped boundary zones and assesses the influence of main geometric and material parameters on the distribution of nondimensional deflection and stress components. The analysis results indicate that applying HOSNT in conjunction with one-step stress recovery is necessary for investigating the stress state of laminated shells of revolution. [ABSTRACT FROM AUTHOR]