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Biomass composites are ever-increasing in agricultural engineering. This study aims to enhance the mechanical properties and aging resistance of bamboo-plastic composites (BPC), in order to realize the environmental friendliness and application of its pallet products. Firstly, three ratios of bamboo fiber (BF) and high-density polyethylene (HDPE) were used to prepare the BPC. Then mechanical property tests were conducted to determine the optimal ratio of BF to HDPE. Among them, nano-TiO2 was widely used to enhance the performance of plant fiber/thermoplastic polymer composites, due to its chemical inertness, anti-aging, anti-bacterial properties, and non-toxic nature. An organic-inorganic co-modification was also employed to enhance the BPC properties for strong compatibility with bamboo fiber and plastic matrix. Nano-SiO2 was coated onto nano-TiO2 to prepare SiO2@TiO2 nanoparticles for the high dispersion and aging resistance of TiO2 . Nano-SiO2@TiO2 modified BPC (KH550-ST-BPC) was prepared using the silane coupling agent KH550 as a reinforcing agent by a spray coating. The properties were evaluated to compare the mechanical properties, SEM images, and UV aging properties of BPC before and after modification. In addition, ANSYS Workbench software was used to perform the finite element analysis of BPC integrated pallets before and after modification, in order to verify the application performance of reinforced BPC pallets. The results indicated: 1) The bending and tensile properties of BPC shared an increasing trend with the increase of bamboo fiber content. The optimal mechanical properties of BPC were obtained at a 5:5 mass ratio of BF to HDPE, with a 38.34% increase in the bending strength and a 62.19% increase in the bending modulus, compared with the 3:7 ratio. The tensile strength and modulus increased by 14.95% and 101.18%, respectively. SEM images revealed that there was a smoother interface for BPC55, which was better consistent with the mechanical test. 2) The bending and tensile strength of BPC were enhanced by 31.11% and 11.86%, respectively, in the modified nano KH550-SiO2@TiO2, while the bending and tensile modulus were enhanced by 52.27% and 21.92%, respectively. The interfacial gaps of modified BPC were significantly reduced in the SEM images, indicating the strong bonding between the bamboo fibers and HDPE. The KH550-SiO2@TiO2 was introduced to fill the interface gaps for the BPC compatibility, which was better consistent with the mechanical property test. 3) The surface morphology revealed that KH550-SiO2@TiO2 modified BPC maintained better color stability for the high resistance to UV aging. While the unmodified BPC showed significant color fading after 1 200 h UV irradiation aging. Colorimetric analysis confirmed that the color stability of KH550-ST-BPC was significantly better during UV aging, with a color aberration change value 77.79% lower than before. 4) Finite element analysis indicated that the modified BPC pallet exhibited the better-bending properties and load-bearing capacity, with a 27.36% reduction in the maximum deformation under the rated load and a 23.41% reduction under the ultimate load in stacking simulation. These research findings can provide a strong reference for the application of nano-SiO2@TiO2 reinforced BPC as logistics turnover units. [ABSTRACT FROM AUTHOR]

With the development of 3D metal printers for rapid prototyping and industrial component production, heightened attention was directed towards post-processing operations for achieving precise surface quality and geometrical tolerances for these components. This paper investigated the orthogonal cutting of multi-material 3D printed workpieces using a coated cutting tool through finite element simulation. The workpieces featured different horizontal and vertical arrangements of layers composed of aluminum 7075-T6 alloy (Al), stainless steel 316 low alloy (SS), and Ti6Al4V alloy (Ti). The study explored the impacts of multi-material composition, coating thickness, and the rake angle of the cutting tool on machining forces, stress distribution, temperature distribution, and chip formation geometry. The results revealed a bimodal chip morphology in the machining process of horizontally arranged SS layers combined with other alloys. The SS layer resulted in a relatively uniform chip formation, while layers with two other materials exhibited a serrated chip formation. In contrast, a discontinuous chip formed when combining Al and Ti materials, as well as in the horizontally arranged layers made of Al, SS, and Ti alloys. The cutting force increased by 2.26 times when cutting workpieces with the horizontal arrangement of SS and Al layers compared to those with a single Al material. For the horizontal and vertical arrangement of layers made of Al and SS, von Mises stress values over the edge of the coated cutting tool significantly increased where the tool contacted the SS layer. Additionally, the horizontal arrangement of layers made of Al and SS materials caused the coated cutting tool to exhibit an extensive temperature distribution, with the maximum recorded temperature reaching 1448 °K. Increasing coating thickness led to a decrease in maximum principal stress at the surface of the tool and a rise in temperature at the cutting edge of the insert. [ABSTRACT FROM AUTHOR]

Poly ether ether ketone (PEEK) is a premier engineering plastic, which has gained considerable attention in recent years. Our prior research investigated crystallization template techniques and pore formation mechanisms within the PEEK/poly (ether imide) system, paving the way for the development of hierarchically porous membranes (HPMs). Compared to single‐porous membranes, HPMs demonstrate enhanced flux and high mass transfer efficiency simultaneously, effectively mitigating the trade‐off effects. In this study, we focused on fabricating PEEK HPMs through precise manipulation of a polymer ternary blend system. The meticulous tuning enables intricate control of the hierarchical pore morphology of PEEK at two distinct scales. The finite element simulations not only underscored the crucial role of hierarchical pores in bolstering separation efficiency, but also exhibited strong concordance with the experimental findings. This study provides guidance for future optimization of HPMs with superior separation performance. [ABSTRACT FROM AUTHOR]

Flexible pressure sensors are crucial force‐sensitive devices in wearable electronics, robotics, and other fields due to their stretchability, high sensitivity, and easy integration. However, a limitation of existing pressure sensors is their reduced sensing accuracy when subjected to stretching. This study addresses this issue by adopting finite element simulation optimization, using digital light processing (DLP) 3D printing technology to design and fabricate the force‐sensitive structure of flexible pressure sensors. This is the first systematic study of how force‐sensitive structures enhance tensile strain stability of flexible resistive pressure sensors. 18 types of force‐sensitive structures have been investigated by finite element design, simultaneously, the modulus of the force‐sensitive structure is also a critical consideration as it exerts a significant influence on the overall tensile stability of the sensor. Based on simulation results, a well‐designed and highly stretch‐stable flexible resistive pressure sensor has been fabricated which exhibits a resistance change rate of 0.76% and pressure sensitivity change rate of 0.22% when subjected to strains ranging from no tensile strain to 20% tensile strain, demonstrating extremely low stretching response characteristics. This study presents innovative solutions for designing and fabricating flexible resistive pressure sensors that maintain stable sensing performance even under stretch conditions. [ABSTRACT FROM AUTHOR]

This work focused on the leakage of the composite pressure vessel with a structure consisting of an aluminum alloy inner liner, a composite winding layer, and an aluminum covering. Through applying the finite element simulation approach and leakage rate test, it was found that the average strain of the winding layer in the lap region at the pressure of 46 MPa is 0.0078. Additionally, the leakage rate of the covering adhesive joint was investigated by considering the deformation, revealing that the leakage rate increases with increasing test pressure. The leakage rate at the lap region with a length of 18 mm is 2.05 × 10−7 Pa·m3/s at 0.0078 strain decreasing by 1.46 and 2.31 times compared to those under 12 and 7 mm lengths, respectively. The leakage rate exhibits a strict inverse correlation with the length of the leakage path under a pressure of 0 MPa. Additionally, when the deformation remains below the critical strain threshold (approximately 0.6%), the relationship between pressure and leakage rate shows a linear positive correlation. When the deformation of the component exceeds the critical strain threshold, the leakage rate of the component is significantly affected by its deformation and an increase in overall deformation results in a greater increase in leakage rate. The relationship between the two exhibits a non‐linear trend. This work provides strong technical support for the leakage assessment of composite pressure vessels. Highlights: Deformation of the pressure vessel was analyzed through theoretical and simulation approaches.Establishing the relationship between deformation and pressure in metal–metal lap structures.Leakage analysis for different metal–metal lap lengths and deformation conditions. [ABSTRACT FROM AUTHOR]

This study aims to investigate the bending performance and evaluation of aluminum‐carbon fiber reinforced plastic (Al‐CFRP) riveted laminates under varying parameters via self‐pierce riveting and three‐point bending tests. Through the self‐pierce riveting process test, a riveted joint meeting standard requirement was obtained. Based on this joint combination form, Al‐CFRP self‐pierce riveted laminates were prepared. The bending performance test showed the riveted laminate with a span of 80 mm had the greatest bending resistance at a thickness of 2 mm, and the overall strain of the Al‐CFRP self‐pierce riveted laminates was observed by digital image correlation (DIC) technology. Subsequently, validated numerical simulation modeling was conducted by correlating with the test results. On this numerical simulation model basis, further parametric studies and bending performance evaluations (including number of rivets, CFRP lay‐up angle, and laminates width) of the Al‐CFRP self‐pierce riveted laminates were systematically carried out. It was found that the peak load F and bending strength R improved by 1.32% and 26.66%, respectively, while the mass M reduced by 8.99%, for the design variables of var1 of 20 mm, var2 of 6, and var3 of [0/90°]2s. Highlight: An Al‐CFRP riveted laminate structure is proposed to improve the bending properties of riveted laminates by changing the rivet parameters and laminate parameters.The bending properties of riveted laminates with different spans were investigated under three‐point bending loading conditions.The DIC technique observed the changes in the strain field of riveted laminates during bending.The effects of different structural parameters on the bending performance of Al‐CFRP riveted laminates were investigated by numerical simulation.An evaluation method combining the gray correlation degree and the combination assignment method is proposed to obtain the optimum riveted laminate structure under bending load conditions. [ABSTRACT FROM AUTHOR]

This paper investigates experimentally and numerically structural performance of reinforced concrete (RC) circular column under double curvature buckling moment. RC circular columns are popularity embraced in RC structures not only owing to its esthetic, attractive appearance and easy for construction, but also for its better contribution for stress resistance. However, the corner or edge columns may be exposed to edge moment (EM) transferred from beam–column joint with double curvature effect. The current investigation proposes to understand the structural exhibition of such columns subjected to double curvature buckling edge moment generated at beam–column joint considering some parameters. A total number of 11 full-scale RC circular columns were constructed, installed, and then tested up to failure studying four parameters. These parameters were: clear height-to-diameter ratio (λ), longitudinal and lateral steel ratios (μ and ρ, respectively) and concrete type. The λ ratio has been introduced with: 4.89, 4.51 and 4.14. The μ ratio has been presented by: 2.2%, 2.3%, 2.6%, and 3.1%, while the ρ ratio was employed with: 0.84%, 0.93%, 1.00% and 1.18%. Three concrete types were studied; one of them was normal concrete (NC), while the other ones were high-performance concretes (HPCs) which were engineered cementitious composite (ECC) and high-strength fiber reinforced concrete (HSFRC). Experimental outcomes revealed that all studied parameters could affect and upgrade the structural performance; however, both longitudinal reinforcement and height-to-diameter ratio provided significant enhancement (about 51%–64%). Parallel to those exploited experimentally, nonlinear three-dimensional finite element models (FEMs) were installed, executed and established considering experimental outcomes producing an acceptable model with an under/over-estimation of about 4%. [ABSTRACT FROM AUTHOR]

Damage modeling techniques are essential tools for revealing the impact pattern of damage on structural responses. Currently, different damage level parameters are defined for different damage modeling techniques, but there is no established equivalence among them. This might plague researchers in their selection of damage modeling techniques for theoretical and numerical studies. To address this challenge, comparative studies of different damage modeling techniques for beam-like structures were conducted, and their impact on vehicle-bridge-interaction (VBI)-based structural health monitoring was analyzed. First, the theoretical basis of four damage modeling techniques, that is, element stiffness loss, element mass increase, cracked beam element, and crack spring element, were analyzed, and equivalent damage level relationships were established based on beam frequencies. Then, a finite element simulation of the VBI system consisting of a two-axle vehicle and a beam-like structure with damage was formulated and verified. Finally, the impacts of different damage modeling techniques with unified damage levels on the dynamic responses were studied, and the feasibilities of damage identification using vehicle and bridge responses under different damage modeling techniques were compared. The results indicated that the dynamic responses generated by different damage modeling techniques varied under the same damage level. The damage modeling technique using the crack spring element posed the most significant impact on the VBI responses, the cracked beam element and element stiffness loss techniques had the equivalent impact, but the element mass increase technique showed a negligible impact. Damage location and severity could be well detected by the cracked beam element and element stiffness loss techniques. However, the dynamic responses generated by the element mass increase technique could not be used to identify the damage. Vehicle responses were more useful than bridge responses for damage identification, demonstrating the advancement of indirect monitoring of bridge health conditions using an instrumented passing vehicle. [ABSTRACT FROM AUTHOR]

The modal characteristics of the crusher rotor and shell constitute the crucial factors influencing vibration and noise. Based on the principle of simplification, the rotor component model was established. Through mesh optimization, the model accuracy and calculation efficiency can be ensured, and the calculation of natural frequency and modal shapes was completed based on ANSYS. To verify the accuracy of the finite element model, the modal test was carried out by the hammering method. Sensors were set in three different directions to obtain the frequency response function and the modal assurance criterion matrix mode confidence criterion. Using the same research method, the modal characteristics of the shell model were simulated and analyzed. The research results show that the modal parameters identified by the modal test are basically consistent with the simulation model. The natural frequencies of the rotor and the shell are quite different from the excitation frequency of the motor, and resonance problems will not occur when the crusher is proper functioning [ABSTRACT FROM AUTHOR]

In order to obtain the vibration response characteristics of the propeller spindle system effectively and accurately, and provide the basis for the subsequent fault diagnosis, the modal simulation and test of the spindle model were carried out. With the propeller set as eccentric mass, the amplitude and torsion angle of the spindle model were simulated under the condition of excited vibration and unexcited vibration respectively, and the frequency response of bending and torsion under the coupled condition was obtained. The newmark-β method was used to solve the transient response of the bent-torsional coupling model. The results shows that when the propeller spindle system undergoes rotation at a specific frequency and experiences bending vibration excitation force, the latter will induce torsional vibration response. Moreover, the amplitude of the torsional vibration response varies with changes in the frequency of the bending vibration excitation force. [ABSTRACT FROM AUTHOR]

The micromechanical properties (i.e., hardness, elastic modulus, and stress–strain curve) of AlCu films were determined by an instrumented indentation test in this work. For three AlCu films with different thicknesses (i.e., 1 µm, 1.5 µm, and 2 µm), the same critical ratio (hmax/t) of 0.15 and relative indentation depth range of 0.15–0.5 existed, within which the elastic modulus (i.e., 59 GPa) and nanoindentation hardness (i.e., 0.75 GPa, 0.64 GPa and 0.63 GPa for 1 µm, 1.5 µm and 2 µm films) without pile-up and substrate influence can be determined. The yield strength (i.e., 0.754 GPa, 0.549 GPa and 0.471 GPa for 1 µm, 1.5 µm and 2 µm films) and hardening exponent (i.e., 0.073, 0.131 and 0.150 for 1 µm, 1.5 µm and 2 µm films) of Al-(4 wt.%)Cu films for MEMS were successfully reported for the first time using a nanoindentation reverse method. In dimensional analysis, the ideal representative strain εr was determined to be 0.038. The errors of residual depth hr between the simulations and the nanoindentation experiments was less than 5% when the stress–strain curve obtained by the nanoindentation reverse method was used for simulation. [ABSTRACT FROM AUTHOR]

Previous experimental studies show that geotextile reinforcement can effectively mitigate the liquefaction of saturated sand under earthquake. In view of the research on liquefaction resistance of saturated sand, the previous research methods were often limited to indoor dynamic triaxial tests and lacked the research on liquefaction resistance of geotextile reinforced sand ground. Firstly, the parameter calibration of different geotextile reinforced sand was carried out combined with the results of corresponding cyclic triaxial test of liquefaction resistance. On this basis, using OpenSees, an open-source finite element numerical simulation platform, numerical research on liquefaction resistance of saturated sand ground under different geotextile reinforcement cases was carried out. The results show that geotextile reinforcement can reduce the excess pore pressure and displacement of sand ground, and the liquefaction resistance of sand ground increases with the increase of geotextile layers. This technique of realizing numerical modeling of geotextile reinforced sand by parameter calibration method can provide some valuable reference for numerical simulation of similar reinforced soil stratum. [ABSTRACT FROM AUTHOR]

3D Kagome lattice sandwich structure is recognized as the most excellent lattice configuration. However, the preparation method of 3D Kagome is complicated and the raw materials for its preparation are limited to materials with high plasticity. In this study, we developed a wood-based 3D Kagome lattice structure that combines discrete rods into a continuous core using reinforcement. Orthogonal tests, theoretical analysis, and finite element simulations were performed to investigate the correlation between the dimensional parameters, the mechanical properties, and the energy absorption capacity. The damage modes were found to be mainly bending fracture, core shear, and panel rupture, with the use of reinforcement affecting the damage modes. Compressive properties of the 3D Kagome lattice structure are increased by increasing core diameter and inclination degree, decreasing core in-cut diameter, and using high-strength reinforcements. Finite element simulations further confirm that the use of high-strength reinforcements changes the stress distribution of the lattice structure. The 3D Kagome lattice structure with an inclination degree of 65°, a core diameter of 10 mm, a reinforcement wall thickness of 2 mm, and a core in-cut diameter of 2 mm has the optimal compression performance and energy absorption capacity. [ABSTRACT FROM AUTHOR]

This study proposed novel designs for achieving self-centering (SC) behavior using superelastic shape memory alloy (SMA) buckling-restrained plates (BRPs). Compared with previous studies relying on small-diameter SMA bars, this study employed large-dimensional SMA plates that could provide sufficient strength for real construction projects. The design concept and configurations of SMA-BRPs were first introduced. Corresponding tests were then conducted. Three specimens were tested, including one that was unsatisfactory and two that were acceptable. Based on the initial examination of the behavior and failure mode of the unsatisfactory trial specimen, the corresponding modifications were made to achieve the improved performance of two acceptable specimens. Subsequently, the hysteresis and SC behaviors, energy dissipation capacity, and yielding strength degradation of the two acceptable specimens were investigated. Both specimens exhibited high-quality flag-shaped behaviors in their tension–compression cycles, with their strengths reaching around 200 kN under tension and more than 310 kN under compression, representing one of the largest strength values shown by a single SMA element in the literature. Asymmetric behavior was observed under tensile and compressive loadings, primarily due to the asymmetric behavior of the SMA base material, high-mode inelastic buckling under compression and friction between the SMA core plate and buckling-restraining device. After the tests, finite element models were developed to obtain an in-depth understanding of the detailed behavior of SMA-BRPs. The studies showed that SMA-BRPs successfully achieved the SC buckling-restraining design target. The design incorporating end restrainers was preferred due to its flexibility, which reduces application restraints. [ABSTRACT FROM AUTHOR]

Third ventriculostomy is the preferred treatment for obstructive hydrocephalus, but the biomechanics of brain tissue damage caused by fiber endoscopes remains unclear. In this study, brain tissue material parameters were tested based on the Ogden model to simulate needle puncture mechanics, and replicated the entire fiber endoscope advancement process during third ventriculostomy. It was found that a smaller diameter fiber endoscope, a perpendicular puncture angle, and a faster puncture speed would decrease the damage of brain tissue caused by the fiber endoscope. This study provides valuable insights for optimizing the instrumentation and surgical process of third ventriculostomy. [ABSTRACT FROM AUTHOR]

The mechanical performance of protective coatings is crucial in daily industrial environments, with transition metal nitrides being among the most commonly used hard coatings for machining tool protection. However, determining their elastoplastic properties via conventional methods can be challenging due to the thickness‐dependent response of film/substrate systems. In this study, we utilised two sputtering Ti‐Al‐N films as a model hard thin film/soft substrate system to showcase an alternative methodology to the Oliver and Pharr method. This alternative approach involves determining Young's modulus, yield stress and hardness through indentation stress–strain curves obtained from nanoindentation tests, effectively decreasing the substrate's contribution. This decrease was corroborated by finite element simulations conducted on films with thickness below 1.0 μm. The elastoplastic properties determined using our methodology fell within the range reported for typical Ti‐Al‐N films. Furthermore, by applying our methodology, we were able to correlate and discuss the observed differences in mechanical behaviour between the two films based solely on their microstructural, compositional and morphological properties. Thus, we have demonstrated a viable alternative methodology to address substrate contribution challenges in the mechanical characterisation of thin film/substrate systems when employing an indenter with a large radius of curvature (~650 nm). This research holds potential implications for the design of protective submicrometric films with industrial applications. [ABSTRACT FROM AUTHOR]

The locomotion mechanisms and structural characteristics of insects in nature offer new perspectives and solutions for designing miniature actuators. Inspired by the underwater movement of aquatic beetles, this paper presents a bidirectional self-propelled linear piezoelectric micro-actuator (SLPMA), whose maximum size in three dimensions is currently recognized as the smallest known of the self-propelled piezoelectric linear micro-actuators. Through the superposition of two bending vibration modes, the proposed actuator generates an elliptical motion trajectory at its driving feet. The size was determined as 15 mm × 12.8 mm × 5 mm after finite element analysis (FEA) through modal and transient simulations. A mathematical model was established to analyze and validate the feasibility of the proposed design. Finally, a prototype was fabricated, and an experimental platform was constructed to test the driving characteristics of the SLPMA. The experimental results showed that the maximum no-load velocity and maximum carrying load of the prototype in the forward motion were 17.3 mm/s and 14.8 mN, respectively, while those in the backward motion were 20.5 mm/s and 15.9 mN, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Micronanoelectronic Technology is the property of Micronanoelectronic Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fabric structure parameters have a significant impact on the comfort of heat and moisture transfer in garments. Previous numerical simulations required extensive mathematical calculations and mostly investigated one- or two-dimensional models of fiber assembly without considering the weave structure, which is a key parameter, that significantly influences the porosity of the woven structure and consequently its heat and moisture management. While the finite element method supports the simulation of the optimal shape and material properties with better visibility, previous finite element models focused on heat transfer and neglected water vapor transfer in fabrics. In this article, the finite element simulation of heat and moisture transfer in woven fabrics is established based on the testing principle of thermal resistance and moisture resistance tester using COMSOL Multiphysics software. In this simulation, three-dimensional parametric geometrical models of the fabric are created using curve interpolation methods by acquiring the control point coordinates of different weaves (plain, 2/2 balanced twill, and 4/1 unbalanced twill weaves). Heat and moisture transfer properties of fabric models in the horizontal and vertical directions were analyzed, including the heat flux, moisture resistance, water vapor permeability, and water vapor concentration. The article also deals with the effects of weave structure and fabric cover in a range of 72.1–85.1% on the fabric heat flux and water vapor concentration. Comparison between model and experimental results revealed that the three-dimensional simulation can accurately predict the impact of weave pattern and fabric cover on the fabric heat and moisture transfer performance. In addition, this model can be utilized to study the distribution of heat and water vapor within fabrics, providing a theoretical foundation for optimizing heat and moisture comfort in woven fabrics. [ABSTRACT FROM AUTHOR]

Accurately measuring cable forces is crucial for reliable bridge condition evaluation, yet it remains a challenging task. This study proposes the use of a High-strength Steel Wire Fiber Bragg Grating (HSW-FBG) sensor embedded in commonly-used cables composed of 5–7 mm parallel steel wires. The HSW-FBG sensor facilitates direct strain measurement, offering a simple and user-friendly packaging process for high-precision monitoring throughout the cable's lifespan. The results demonstrate excellent linearity and repeatability in strain detection of the HSW-FBG sensor. The length of the packaging layer has the most significant impact on the strain transfer efficiency (STE) coefficient and should be at least 60 mm required for optimal performance. Additionally, the elastic modulus of the packaging layer moderately affects the STE coefficient. Adhering to these packaging parameter requirements ensures that the STE coefficient of the HSW-FBG sensor is very close to 1, enabling for high-precision measurement without correction. A systematic analysis of the STE coefficient of the HSW-FBG sensor is conducted, determining reasonable values for the packaging parameters. These findings lay the groundwork for future engineering applications, facilitating accurate measurement of cable forces in practical scenarios. [ABSTRACT FROM AUTHOR]

A novel material testing concept is developed in order to provide tensile and compressive properties within a single mechanical test. A new specimen geometry is designed for testing in a universal testing machine. Under tensile load, both a homogeneous tensile stress condition as well as a homogeneous compressive stress condition occur in the specimen. Measurements accompanying the experimental test with digital image correlation provide tensile and compressive Poisson's ratio as well as tensile modulus. These properties are input parameters for subsequent finite element simulations. The compressive modulus is determined by iteratively adjusting finite element simulations in order to couple experimental and simulated results. For validating the concept, experimental tests are carried out on polyoxymethylene. While the tensile Poisson's ratio of the new concept shows the best agreement with the reference value, the compressive modulus is approximately 15% higher. Further work should focus on an appropriate material model in order to reduce the deviation. [ABSTRACT FROM AUTHOR]

Rail corrugation is a common form of rail damage discovered when servicing heavy-haul railways that seriously affects the safety of wheel–rail systems. To determine the characteristics of the deterioration of a corrugated heavy-haul railway, this study used ABAQUS simulation software to establish a three-dimensional elastic–plastic wheel–rail finite element model. We then simulated the stress and strain distributions of wheel–rail contact spots as C80 freight cars pass through various corrugated sections of heavy-haul railways, featuring different wavelengths and wave depths. The simulation results demonstrated that the stress and strain increase from the peak positions to the troughs, reaching a maximum somewhere behind the troughs, and then decreasing to the next peak. The stress and strain increase as the depth of corrugation increases. The wheel–rail contact exhibits a maximum stress of 1.312 to 1.770 GPa, and the maximum strain is 0.6470% to 0.9897%. Wheel–rail contact stress and strain occur at a maximum of 8–40 mm after the troughs, rather than at the trough position, forming "planing and rolling" effects. This mechanism revealed by the variation in the stress and strain distributions in this study provides a reference for the in-depth analysis of rail corrugation deterioration and for the exploration of the mechanisms of corrugation deterioration of heavy-haul railways. [ABSTRACT FROM AUTHOR]

With increasing emphasis on low-carbon environmental protection, CO2 enhanced coalbed methane production and methane reuse in abandoned mines (rich in N2) have gradually become one of the future development directions. These scenarios involve the coordinated migration of different gases such as CO2, CH4, and N2, and the differences in properties of different gases that affect the flow process. Previous studies often focused on the adsorption differences between gases, neglecting the differences during desorption process. In view of this, the current work conducted experiments and finite element numerical analysis on the desorption process of CO2, CH4, and N2, clarified the differences and influencing factors of desorption among the gases, and analyzed the flow change rules under different permeability and diffusion capabilities. The results indicated that the main differences among CO2, CH4, and N2 during desorption are reflected in the parameters of Langmuir volume, permeability, and diffusion coefficient. These parameters showed that CO2 has the highest value during desorption, while N2 has the lowest. The factors affecting the magnitude of differences between CO2, CH4, and N2 are mainly their compositions. Specifically, ash content significantly affects the difference in adsorption capacity, while moisture content influences permeability and diffusion coefficient. During desorption, permeability plays a continuous role throughout the whole process, while diffusion coefficient is exhibited mainly in the initial stage of desorption. Different gases have varying sensitivities to permeability and diffusion coefficients during desorption. Changes in permeability and diffusion coefficient significantly affect the CO2 desorption process. N2, on the other hand, is the least sensitive, especially to changes in diffusion coefficient. During gas flow, when reservoir permeability is less than 0.01 mD (= 9.869233 × 10−18 m2), permeability becomes the main factor that affects flow. When the diffusion coefficient is less than 5 × 10−9 m2/s, increasing the diffusion coefficient is necessary to effectively promote gas outflow. To effectively increase gas production, it is necessary to comprehensively consider the magnitudes of permeability and diffusion coefficient. [ABSTRACT FROM AUTHOR]

In this paper, in order to meet the engineering requirements of mechanical properties detection of materials with low power consumption, a novel incremental permeability detection system based on permanent magnet excitation is proposed to reduce system power consumption. Initially, a new incremental permeability sensor was designed to extract magnetic incremental permeability (MIP) signal. Through finite element simulation, experimental parameters were optimised, and a rational arrangement of double permanent magnets was devised to furnish an optimally strong AC bias field intensity. Subsequently, a practical detection platform was assembled to extract electromagnetic signal features. From the perspective of domain wall displacement, a characteristic value θ was proposed to predict the yield strength, with experimental results yielding a relative error of less than ±10%. These experiments have validated the capability of permanent magnet-type MIP to enable quantitative detection of the yield strength in ferromagnetic materials. [ABSTRACT FROM AUTHOR]

The forming quality of profiled ring rolling not only encompasses macroscopic accuracy but also emphasizes the microstructure. Due to the multiple process parameters and complex metal flow during profiled ring rolling, the various forming defects are difficult to control and difficult to study theoretically. The objective of this study is to establish a comprehensive method for evaluating the forming quality of profiled rings, which considers both the macroscopic forming accuracy and the microstructure. Firstly, the synthetic size factor was defined, and the evolutionary relation between the section forming rate and the diameter growth rate of E-section ring rolling was analyzed in detail. The synthetic size factor can be used to describe the dimensional evolution and evaluate the forming accuracy of the profiled ring rolling process. Taking into full consideration the features of intermittent deformation in local areas, a microstructure evolution model of the Inconel718 alloy during E-section ring rolling, which can accurately predict the recrystallization volume fraction and average grain size of the final ring, was established. Then, combined with finite element simulation, the influence of the rotation speed of the driving roll on the macro-size evolution and microstructure was systematically analyzed. The results indicate that there is often a discrepancy between dimensional accuracy and microstructure uniformity in the optimization trend. For instance, the higher the rotation speed of the driving roll is, the more uniform the microstructure is, but the more difficult it is for the section profile to form. Finally, combined with response surface methodology (RSM), multi-parameter optimization was carried out with section forming accuracy and grain uniformity as the optimization objectives. By using the optimal parameters, an E-section ring with a complete profile and a uniform microstructure was obtained, with a maximum prediction error of the recrystallization volume fraction lower than 5%. The results show that the macroscopic and microscopic quality evaluation methods proposed in this study, as well as the optimization method combining RSM, can be effectively applied to the process optimization of profiled ring rolling. [ABSTRACT FROM AUTHOR]

The restoration of large support rollers poses an industrial challenge due to the high energy consumption of traditional repair methods. Consequently, a novel approach for repairing support rollers has been introduced and tested on thick-walled components. Finite element simulations aided the study of welding repairs for large thick-walled components, examining element distribution, microstructure, mechanical properties, and residual stress distribution across various processes. The results indicate that employing ABAQUS2023 finite element software to analyze stress variations under different working conditions, the Dynamically Controlled Low-Stress No-Distortion method effectively mitigates residual stresses both during and post welding, reducing average transverse residual stresses by 14.5% and average longitudinal residual stresses in the weld zone by 29.1%. The Dynamically Controlled Low-Stress No-Distortion method narrows the high-temperature range of the heat source, consequently decreasing the size of the heat-affected zone by 33.3% compared to conventional welding. The microstructure featured dendrites and equiaxed columnar crystals, with the Dynamically Controlled Low-Stress No-Distortion method capable of grain refinement, transforming some equiaxed columnar crystals into cellular structures. As grains were refined, microhardness improved, with the covering layer's microhardness rising by 14.68%. A comparison between simulated and measured values of lateral and longitudinal residual stresses at corresponding points revealed discrepancies of 14.6% and 20.5% in accuracy, respectively. [ABSTRACT FROM AUTHOR]

Highlights A voronoi user material subroutine (VUMAT) was developed using the three‐dimensional Hashin damage criterion and exponential nonlinear damage evolution method. An interlayer damage model based on the quadratic nominal stress (QUADS) criterion and B‐K fracture criterion was introduced, and a finite element model of Z‐pin reinforced composite laminates under low‐velocity impact was established. The low‐velocity impact behavior of Z‐pin reinforced composite laminates with different impact velocities (0.6 m/s, 0.4 m/s, and 0.3 m/s), different layup forms ([0°/90°]4 and [0°/45°/90°/−45°]2), and different Z‐pin spacing (4 mm, 8 mm, and 16 mm) was studied using ABAQUS. The results indicate that different layup forms have little effect on the low‐velocity impact behavior of Z‐pin reinforced composite laminates. The Z‐pin spacing has a significant influence on the low‐velocity impact behavior of Z‐pin reinforced composite laminates. When the impact velocity is 0.4 m/s, the specific energy absorption of composite laminates with Z‐pin spacing of 16 mm is 85.93% and 87.7% lower than that of composite laminates with Z‐pin spacing of 4 mm and 8 mm. As the Z‐pin spacing decreases (Z‐pin density increases), the impact resistance of Z‐pin reinforced composite laminates first increases and then decreases.• The low‐velocity impact of Z‐pin reinforced composite laminates was studied.• Analyzed the effect of layup forms of laminates on their impact behavior.• Explored the influence mechanism of Z‐pin spacing on the impact behavior.• Studied the energy absorption of different Z‐pin spacing under impact velocity. [ABSTRACT FROM AUTHOR]

Regarding the safety of casing during the production of hydrogen gas during the perforation operation in the curve section of ultra deep horizontal wells, the theoretical stress calculation formula near the perforation hole and the tensile strength, external extrusion strength, and internal pressure strength that three different sizes of casing can withstand were derived based on the plate hole theory and casing performance calculation formula; It also analyzed the stress distribution of the casing in the curve section before perforation operations, and found that under the worst working conditions, the stress on the casing body is less than the yield strength, and the high stress area of the casing is mainly concentrated in the axial direction. Increasing the wall thickness of the casing does not have a significant effect on reducing the high stress area, but reducing the diameter, density, curvature of the curve section, and using a single spiral distribution will effectively improve the stress distribution on the casing, which is more conducive to the safety of perforation operations in the curve section; Finally, physical and chemical properties and stress corrosion experiments were conducted on the casing used on site, and it was found that there will be a large number of pitting pits for the initiation of cracks in the casing underground. Therefore, an analysis was conducted on the crack propagation caused by the initial cracks generated by perforation operations. It was found that changing the initial crack length, angle, and casing wall thickness has little significance in reducing crack propagation, while reducing the curvature of the curve section has a significant impact on casing crack propagation. The research methods and achievements in the article provide theoretical guidance for the safety evaluation of casing during perforation operations in the curve section of ultra deep horizontal wells. • Analyzed the stress of casing in curved wells, it can guide construction operations. • Evaluated the casing after perforation, which can prevent downhole casing failure. • Corrosion experiments were conducted on casings with different chromium contents. • Explored the propagation of casing cracks after curved perforation operations. [ABSTRACT FROM AUTHOR]

AbstractAs a crucial load-bearing component, coupler’s safety is pivotal for sustainable railway industry development and is extensively scrutinized due to its complex loading environment. However, current research predominantly concentrates on the longitudinal dynamic behavior of couplers, neglecting factors such as nodding and shaking during traversals along curves and ramps. This study proposes an innovative method aimed at identifying multiple loads on couplers, which includes longitudinal tension and compression, lateral shaking, and vertical nodding forces. A theoretical load identification method based on strain sum and difference on coupler shank faces under various loading scenarios is established by finite element analysis. To facilitate accurate measurement, Wheatstone bridges are employed for three-dimensional force measurement, facilitating strain calculation and temperature compensation. The validity of the proposed approach is confirmed through comprehensive validation, encompassing finite element simulation, laboratory experimentation, and vehicle tests. Results demonstrate the robustness of the method, with maximum load deviations of 2.32% longitudinally, 22.52% horizontally, and 19.86% vertically observed during laboratory tests. Results indicate the proposed method’s accuracy and efficiency in heavy haul train coupler load assessment. [ABSTRACT FROM AUTHOR]

AbstractHallux valgus is a common foot deformity characterized by outward tilting and twisting of the big toe, often accompanied by a medial prominence at the base. Minimally invasive surgical techniques are widely utilized for treating metatarsus adductus due to their advantages of smaller incisions, faster recovery, and early weight-bearing. However, due to individual variations and limited sample size, the biomechanical effects of different Kirschner wire fixation methods and the underlying mechanisms of postoperative metatarsalgia remain unclear. In this study, a finite element method was employed to develop a biomechanical model of metatarsus adductus. The influence of various Kirschner wire entry points and angles on foot loading characteristics was investigated. Six different Kirschner wire fixation models, including two entry methods (along the adjacent fracture line and proximal-biased entry at the midshaft of the metatarsal) with different entry angles, were analyzed. Mechanical parameters such as metatarsal stress distribution, plantar pressure distribution, and displacement of the first metatarsal osteotomy plane were assessed. This research aims to enhance understanding of minimally invasive surgery and its fixation methods for metatarsus adductus. By providing scientific support and reliable evidence, it seeks to contribute to the development of minimally invasive surgical techniques and the improvement of clinical practice in metatarsus adductus surgery. Ultimately, the goal is to reduce complications, increase surgical success rates, and enhance patient satisfaction. [ABSTRACT FROM AUTHOR]

In contrast to conventional chemical adhesives, dry adhesive materials acquire adhesion by surface interactions such as van der Waals forces rather than chemical bonding. Dry adhesive materials demonstrate a wide range of applications across multiple areas owing to their simplicity in preparation and recyclability. For instance, biomimetic robots inspired by creatures like geckos exploit dry adhesive materials for space or outdoor scenarios. These materials are used in medical equipment, wearable materials, and transfer printing of micro/nano devices. However, when dry adhesive materials are subjected to normal tensile force, they may experience stress concentration at the edge of their contact interface with the substrate, which results in an adhesive strength being less than the theoretical value. To address this issue, this study designed micrometer-scale carbonyl iron powder particles/polydimethylsiloxane magnetorheological elastomer-based dry adhesive materials. By adjusting the mass fraction of carbonyl iron powder and applying an external magnetic field, disk-like composites in centimeter scale with variable Young's modulus along the radial direction in stages or continuously were prepared. The adhesive strength of the two test samples reached 8.0 N/cm² and 11.4 N/cm², respectively, which was 35% and 77% higher than that of control samples with the same carbonyl iron powder mass fraction (60%). Based on finite element simulation, the radial distribution of Young's modulus effectively reduces stress concentration along the edge region, which in turn homogenizes the normal stress distribution at interfaces, thus enhancing normal adhesion performances. Comparing to homogeneous and multi-stage composites, the continuously varying modulus samples exhibited a more uniform normal stress distribution at the interface, which further improved adhesion. Our design of radial distribution of modulus over dry adhesive materials and the achievement of a continuously change of modulus through spatial distribution of magnetic fields provides valuable insights into the optimization of dry adhesive materials for various engineering applications. [ABSTRACT FROM AUTHOR]

Medium‐speed wind generators in the MW‐range with high‐temperature superconducting excitation winding are analyzed by means of non‐linear 2D and 3D FEM models. Besides an inverter‐based sinusoidal stator current feeding, a grid connection via a diode rectifier is analyzed by using coupled FEM and circuit simulations. The newly proposed modeling techniques are used to determine the excitation requirement for speed‐variable, unity power factor operation at constant stator voltage, as required for a diode rectifier feeding of the stator winding. 2D FEM models in the H‐A‐formulation are developed and used for the calculation of the hysteresis loss in the superconducting field winding at stationary operation as well as for an investigation of field current variations in the HTS field winding. The major modeling challenges consist in very long settling times of voltage‐fed models, several strong model non‐linearities and high requirements on the spatial discretization. Approaches for overcoming these difficulties with reasonable computational efficiency are proposed. [ABSTRACT FROM AUTHOR]

The support frame of large agricultural vehicles was simulated using the finite element method to ensure stability and reliability. Modal experiments were conducted to verify the simulation accuracy, and mesh division and optimization were performed based on different size and structure types. Three types of loads were applied according to different working conditions. The natural frequency, vibration mode, stress, and deformation characteristics of the model under prestressed mode condition were calculated to determine the weak structure of the support frame. Modal measurement points for calibration during test modal analysis were used to generate a test modal model with force hammer, acceleration sensor, signal acquisition instrument, and other devices. The results showed that there was good agreement between finite element modal analysis and experimental modal analysis with a maximum error in natural frequency of 2.2 %, verifying the accuracy of the finite element model. [ABSTRACT FROM AUTHOR]

In order to enhance the stability and reliability of the vibrating screen, modal and harmonic response characteristics were simulated and analyzed using the finite element method. The final assembly model was established in Creo, serving as an intermediate format for material definition and mesh accuracy verification. The analysis of natural frequency and mode revealed that the overall structural stiffness was basically satisfactory. However, harmonic response analysis indicated issues related to excessive stress and stress concentration within the structure. Subsequent optimization of the frame structure confirmed nearly unchanged low-order natural frequencies, while maximum stress was reduced by 22.15 %, holding significant implications for process cost control. [ABSTRACT FROM AUTHOR]

In order to deeply understand the multi-physical field coupling behavior inside the LIB(Lithium-Ion Battery) and better provide reference for the manufacturing and optimization design of the LIB, a more physically realistic coupled ETM(Electrochemical-Thermal-Mechanical) model of the LIB is established and solved in the finite element simulation software COMSOL Multiphysics by means of numerical simulation in the present study. The model takes into account the stress generation in both electrode and particle scales during battery operation, which solves the problem of difficult calculation of stress at the electrode level in previous models, and better correlates the relationship between stress and electrochemistry by considering the correction of stress on lithium diffusion and overpotential. Based on this model, the effect of different positive electrode particle sizes on the battery performance is discussed in the study. The numerical results show that the performance index of each physical field during the discharge of LIB is better and the energy density of the battery is improved when the positive electrode particle size is small, which proves that the use of smaller positive electrode particle size can improve the performance of LIB. [ABSTRACT FROM AUTHOR]

Honeycomb structures made of carbon-fiber-reinforced plastic (CFRP) are increasingly used in the aerospace field due to their excellent energy absorption capability. Attention has been paid to CFRP structures in order to accurately simulate their progressive failure behavior and discuss their ply designability. In this study, the preparation process of a CFRP corrugated sheet (half of the honeycomb structure) and a CFRP honeycomb structure was illustrated. The developed finite element method was verified by a quasi-static test, which was then used to predict the low-velocity impact (LVI) behavior of the CFRP honeycomb, and ultimately, the influence of the ply angle and number on energy absorption was discussed. The results show that the developed finite element method (including the user-defined material subroutine VUMAT) can reproduce the progressive failure behavior of the CFRP corrugated sheet under quasi-static compression and also estimate the LVI behavior. The angle and number of plies of the honeycomb structure have an obvious influence on their energy absorption under LVI. Among them, energy absorption increases with the ply number, but the specific energy absorption is basically constant. The velocity drop ratios for the five different ply angles are 79.12%, 68.49%, 66.88%, 66.86%, and 60.02%, respectively. Therefore, the honeycomb structure with [0/90]s ply angle had the best energy absorption effect. The model proposed in this paper has the potential to significantly reduce experimental expenses, while the research findings can provide valuable technical support for design optimization in aerospace vehicle structures. [ABSTRACT FROM AUTHOR]

While it is well‐established that early detection and initiation of treatment of developmental dysplasia of the hip (DDH) is crucial to successful clinical outcomes, research on the mechanics of the hip joint during healthy and pathological hip development in infants is limited. Quantification of mechanical behavior in both the healthy and dysplastic developing joints may provide insight into the causes of DDH and facilitate innovation in treatment options. In this study, subject‐specific three‐dimensional finite element models of two pigs were developed: one healthy pig and one pig with induced dysplasia in the right hindlimb. The objectives of this study were: (1) to characterize mechanical behavior in the acetabular articular cartilage during a normal walking cycle by analyzing six metrics: contact pressure, contact area, strain energy density, von Mises stress, principal stress, and principal strain; and (2) to quantify the effect on joint mechanics of three anatomic abnormalities previously identified as related to DDH: variation in acetabular coverage, morphological changes in the femoral head, and changes in the articular cartilage. All metrics, except the contact area, were elevated in the dysplastic joint. Morphological changes in the femoral head were determined to be the most significant factors in elevating contact pressure in the articular cartilage, while the effects of acetabular coverage and changes in the articular cartilage were less significant. The quantification of the pathomechanics of DDH in this study can help identify key mechanical factors that restore normal hip development and can lead to mechanics‐driven treatment options. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To study the temperature and stress variation laws of fast-hardening concrete for bridge deck paving,finite element simulation was employed to model the temperature and stress changes of fast-hardening concrete at different ages,and the results were compared and analyzed with the measured data from sensing optical cables to verify the accuracy of the finite element simulation. The results indicate that the temperature cracking index for all ages is greater than 1.5,and the tensile strength of fast-hardening concrete at 6 h can resist the tensile stress caused by hydration heat,possessing a certain crack resistance capability. For the fast-hardening concrete in bridge deck paving,the bottom layer,middle layer,and surface layer reach their peak temperatures approximately 4h after pouring,with the highest temperatures being 39,37,32,respectively,after which the temperature in each layer gradually decreases over time. Within the first 0 to 3d,as the age increases,the strain in the middle and bottom layers of the fast-hardening concrete for bridge deck paving gradually increases,reaching a peak at 3 d,then decreasing by 7 to 28 d. The finite element simulation calculations are basically consistent with the measured values,which can provide a reference for the crack prevention and construction process optimization of fast-hardening concrete in emergency repairs of large scale bridge deck pavement. [ABSTRACT FROM AUTHOR]

In surgical scenarios such as thoracic procedures where target tissues locate behind sternums, the conventional rigid-long-straight ultrasonic scalpel is hard to operate. To solve the problem, this paper proposes a novel curved-waveguide ultrasonic scalpel (CWUS) with TC4 material. Through mathematical derivations and simulations, the dimension of CWUS is determined. Modal, transient, and fatigue life simulation by COMSOL demonstrate that the proposed CWUS effectively suppresses lateral vibrations in the scalpel body, and can output a comparable amplitude to conventional ultrasonic scalpels with an enough fatigue life. Consequently, the proposed novel CWUS is especially useful for doctors to perform complex operations in thoracic invasive surgery safer and more flexible. [ABSTRACT FROM AUTHOR]

Microscale parts made of Polyether-Ether-Ketone (PEEK) are widely used in biomedical, aerospace, and manufacturing industries. The formation mechanism of the chip and machining quality of PEEK are closely related during the micromilling process. However, they have not been sufficiently studied yet. Therefore, the chip shape during the micromilling process is investigated in this research to gain an in-depth understanding of the micromilling process of PEEK. Firstly, a finite-element simulation model is constructed and used to investigate the relationships of feed speed in relation to strain rate and chip shape. Secondly, the chip shape is classified from the experimental results and process intervals are explored corresponding to each kind of chip shape. Then, the relationships between the chip shape and evaluation indexes (milling force F, maximum cutting temperature T max, surface roughness R a) are investigated. It turns out that four main types of chip shapes are produced during the micromilling process of PEEK, namely, the flake chip, the ribbon chip, the curl chip, and the broken chip. Different kinds of chip shapes can be obtained by controlling the process parameters during the micromilling process. The stability of the cutting process can be judged and the machining quality can be initially discerned based on the chip shapes. [ABSTRACT FROM AUTHOR]

Different from the tensile and shear failures, the inelastic compaction of porous rocks is another important performance of rock deformation. Under compressive stress, high-porosity sedimentary rocks form compaction bands with significantly reduced porosity and permeability. This is not only related to the intermediate regime of the brittle-ductile transition of porous rocks but also has important impacts on the engineering application of fluid flow in reservoirs. To explore the influence of confining pressure and the initial pore structure on compaction localization, we establish a finite element model with the complex pore structure of the rock based on the in situ synchrotron CT images of the triaxial experiment of a Leitha limestone sample and conduct elastoplastic numerical simulations under different confining pressures. Our results show that the samples undergo heterogeneous deformation under the confining pressure of 20 to 60 MPa. As the confining pressure increases, the axial local compression inside the sample is restrained, while the radial local compression is promoted. Most of the nodes in the compaction band have the trend of being away from the quasi-uniaxial compression state under high compression stress, which restricts the development of compaction bands. [ABSTRACT FROM AUTHOR]

Based on the elastic–plastic thermal coupling finite element method, a two-dimensional model was established to simulate the hot rolling process of a TA1/Q235 clad plate. The evolution patterns of temperature field, stress field, strain field, and rolling force during the rolling process were studied. The results show that the temperature drop effect of heat transfer on the surface of the rolling plate is much greater than the temperature rise effect due to friction, while the temperature at the center of the rolling plate is primarily controlled by the temperature rise effect of plastic deformation; the maximum equivalent strain occurs in the titanium layer, and the cumulative plastic strain gradually increases with the increase in rolling passes. The strain distribution between the base material and the cladding metal tends to be uniform, and the strain difference gradually decreases; the values of equivalent stress are relatively high in the plastic deformation zone of the slab, gradually decreasing from the rolling center toward both sides. The maximum value appears near the Q235B steel base plate and the interface; the rolling force correlates with the compression ratio, reaching its peak value of 41,523 kN in the first pass with the highest compression ratio. The relative errors between simulated and measured values fall within acceptable limits, confirming the reliability of the model. [ABSTRACT FROM AUTHOR]

The welding effect of the laser on skin tissue is reduced by thermal damage to skin tissue, and greater thermal damage to skin tissue caused by the laser is prevented by predicting thermal damage. In this paper, a finite element model is established for the temperature field of skin tissue scanned by a femtosecond laser to obtain the influence of laser process parameters and scanning path on the thermal damage parameters of skin tissue and the thermal damage area, and verified experimentally. The results show that the established finite element model is accurate and can accurately reflect the temperature distribution during the process of femtosecond laser welding of porcine skin tissues; used to predict the thermal damage parameters of the skin tissues and the thermal damage area; and provide guidance for the study of the femtosecond laser welding of the skin tissues process to obtain the optimal process parameters. [ABSTRACT FROM AUTHOR]

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Visualization and analysis of damage in honey peaches is important to reduce the occurrence of impact damage during postharvest handling. The finite element simulation method was used to visualize impact damage of honey peach. Firstly, the mechanical parameters such as maximum force, damage area, damage volume and absorbed energy during the collision between honey peaches and the surfaces of alloy steel, high density polyethylene (HDPE) and expandable polyethylene (EPE) were obtained by the collision device. Then, the elastic modulus and Poisson's ratio were obtained by compression tests of honey peach pulp. Finally, the process of collision between honey peaches and different material surfaces were simulated by finite element method. The results showed that the maximum error between the measured and simulated values of parameters were less than 25.1%. The study provides a reference for the selection of packaging materials for honey peaches and the biomechanical properties of various agricultural products. Practical applications: Impact damage is one of the most common mechanical injuries in postharvest handling of honey peaches, and it is of great significance to quantitatively study the impact damage of honey peaches to reduce the occurrence of impact damage of honey peaches during packaging and transportation. The study shows the feasibility of using the finite element method for quantitative prediction and assessment of impact damage in honey peaches. In addition, the selection of suitable packaging materials can be used to effectively reduce the occurrence of impact damage of honey peaches in the transportation process. The results of the study can not only provide theoretical support for the packaging and transportation of honey peaches and other aspects, but also provide a reference for the biomechanical properties of various agricultural products. [ABSTRACT FROM AUTHOR]

Icing on transmission lines may cause damage to tower components and even lead to structural failure. Aiming at the lack of research on predicting mechanical characteristic parameters of weak components of transmission towers, and the cumbersome steps of building a finite element model (FEM), the study of prediction for mechanical characteristic parameters of weak components of towers based on a finite element simulation and machine learning is proposed. Firstly, a 110 kV transmission tower in a heavily iced area is taken as an example to establish its FEM. The locations of the weak components are analyzed, and the accuracy of FEM is verified. Secondly, meteorological and terrain parameters are considered as input parameters of the prediction model. The axial stresses and nodal displacements of four weak components are selected as output parameters. The FEM of the 110 kV transmission tower is used to obtain input and output datasets. Thirdly, five machine learning algorithms are considered to establish the prediction models for mechanical characteristic parameters of weak components, and the optimal prediction model is obtained. Finally, the accuracy of the prediction method is verified through an actual tower collapse case. The results show that ACO-BPNN is the optimal model that can accurately and quickly predict the mechanical characteristic parameters of the weak components of the transmission tower. This study can provide an early warning for the failure prediction of transmission towers in heavily iced areas, thus providing an important reference for their safe operation and maintenance. [ABSTRACT FROM AUTHOR]

A novel prefabricated segmental guardrail is proposed to facilitate connections between guardrails and between guardrails and bridge decks by casting ultrahigh-performance concrete (UHPC) joints in situ. Through finite element crash simulation analysis of three types of vehicles and crash tests of real vehicles, the prefabricated segmental guardrail with a UHPC connection was systematically evaluated in terms of its energy-absorbing capacity, vehicular acceleration, post-impact trajectory of the impacting vehicle, and behaviour of the guardrail upon impact. During the evaluation process, performance comparisons of the prefabricated segmental guardrails are made with the monolithic concrete guardrails. The results indicate that the performance of the prefabricated segmental guardrail with a UHPC connection was superior to that of the conventional concrete monolithic guardrails: it exhibited a higher level of crash performance, the occupants of the impacting vehicle were better protected, and the impacting vehicle exhibited better post-collision stability. Finally, the convenience of the prefabricated segmental guardrails with UHPC connections was proven in practical engineering applications. [ABSTRACT FROM AUTHOR]