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During the forming of aramid paper honeycomb sandwich component of aircraft composites in the autoclave, the structure bears thermo-mechanical coupling case, and it may exist the phenomenon of the honeycomb crack during the forming. The tensile, compressive, shear and thermal properties of aramid paper honeycomb core are obtained by testing. Meanwhile, the numerical simulation of thermo-mechanical sequential coupling of the whole honeycomb sandwich component and the local core area are carried out by combining the finite element analysis method and the inversion method. The results show that the thermal stress during the forming process will not cause the adhesive layer between honeycomb cells to crack, but gas pressure will. The difference value of pressure difference between honeycomb cells required for adhesive layer′s slight destruction and complete destruction is positively related to the initial normal fracture stress of adhesive layer. The pressure difference required for the adhesive layer′s complete destruction is decreased with the increase of the number of loaded cells.

The disc-cutter is a finishing tool for the ultrasonic-cutting of paper honeycomb-core material. The cutting state directly affects the machining accuracy and surface quality of the workpiece. The cutting force is an important physical quantity and the cause of ultrasonic cutting defects of the honeycomb-core material. Due to differences in the mechanical properties and cutting performance of honeycomb-core materials and commonly used metal materials, existing metal-cutting-force models cannot be applied to the calculation of ultrasonic cutting forces in the processing of honeycomb-core materials. In response to this problem—combined with actual working conditions using the ABAQUS finite element analysis software—a finite element simulation model of the ultrasonic vibration-assisted cutting force of the disc-cutter on the honeycomb-core material was established, and the cutting curves and values were obtained. The experiment of ultrasonic vibration cutting of the disc-cutter proves that from the surface morphology of the honeycomb core, the milling-width has the greatest influence on the cutting force, and the cutting-depth has the smallest influence on the cutting force. The maximum error between the cutting force experimental results and the finite element simulation results under the same cutting conditions was 13.2%, which means that the established cutting-force finite element model is more accurate and can be used to predict the cutting in honeycomb ultrasonic vibration-assisted cutting-force value. Finally, based on the response surface method, a three-dimensional cutting force prediction model of the ultrasonic cutting honeycomb core of the disc-cutter was established by using the simulation model data. The results of this study can provide a useful basis for the improvement of cutting performance and processing efficiency in the processing of paper honeycomb-core materials.

As a basic mechanical component, the sealing ring is widely used in industrial, aerospatial, and other fields. In this study, an elastic metal C-shaped sealing ring with a wave structure was taken as an example, and its performance was analyzed theoretically and measured experimentally. First, an experimental study was performed on the C-ring seal. The proposed method for experimental measurement of the contact stress of the C-ring seal involved innovative use of a universal electronic testing machine and pressure sensitive paper, in conjunction with the hue⁻saturation⁻brightness (HSB) method. Based on the discoloration of the pressure sensitive paper after contact stress, computer software was used for analysis, the discoloration was digitized, and the contact stress was established. Second, a theoretical calculation model of the C-ring seal was established using ANSYS software, and a finite element theoretical calculation of the mechanical properties of the sealing ring was established. Finally, the contact stress results were compared with the model calculation results of the C-ring seal. The error between the two was small (4.8%), which proved the validity of the calculation model and the scientificity of the experimental method.

The paper presents a strength analysis of a pressed joint of two conical pipes with the aim of finding out whether this method of connection is suitable for telecommunication masts. In this paper, a solution using an engineering approach and a finite element method (FEM) numerical analysis for transversal direction will be compared.

Conventional uniform lattice structures are subject to non-uniform loads or concentrated loads alternating back and forth during service, which can no longer meet the refinement requirements. In this paper, SiCp/SiC gradient lattice structures are prepared by selective laser sintering (SLS) technology and polymer impregnation pyrolysis (PIP) process, and compression standard specimens with different tilt angles are prepared according to the structural model by changing the printing direction, to analyze the influence of the anisotropic properties of the materials due to the SLS molding technology on the load-bearing behaviour of the core rod, and to further study the mechanical properties of the gradient lattice structures and the Failure behaviour. The results show that: with the increase of the angle of printing direction, the compression performance of the densification specimen decreases gradually; the compression strength of the gradient lattice structure is 13.95 MPa. During compression, the core rods with tilt angles of 60° and 75° mainly exhibit shear failure and crushing failure, respectively. The theoretical and simulated compression strengths were 16.08 and 16.32 MPa, respectively. This paper provides a new insight into the research and application of gradient lattice structures.

Pipelines are crucial for transporting energy sources, yet corrosion especially stress corrosion cracking (SCC) poses a complex and potentially catastrophic form of material degradation. Traditional techniques like finite element analysis (FEA) have been utilized for SCC prediction, but it suffers from high computational cost and limited scalability. Deep learning (DL) with integration of FEA leverages large-scale data and learn complex nonlinear patterns for SCC prediction. Currently, literature on deep learning-enabled finite element analysis for pipelines SCC prediction is scarce, offering limited insights into this emerging approach and lack of comprehensive review. This paper reviews and investigates the current research directions and applications of DL-enabled FEA methodologies for simulation of SCC prediction. The importance of DL, technique type and network are also outlined in this review paper. This paper delves into integration of DL algorithms with FEA and their ability to grab complex interactions between mechanical stress, material properties, and environmental factors. Based on this comprehensive review, it was found that DL and FEA have proven to be strong prediction tools with high accuracy and lower training cost. DL-enabled FEA techniques are also being utilized to replace time-consuming methods and conventional codes. Furthermore, article discusses potential of this integrated approach for enhancing accuracy and efficiency of SCC prediction, leading to improved pipeline integrity management practices.Abbreviations: SCC: Stress corrosion cracking; FE: Finite element; FEA: Finite element analysis; FEM: Finite element method; ML: Machine learning; DL: Deep learning; EGIG: European gas pipeline incident data group; PHMSA: Pipeline and hazardous materials safety administration; DNNs: Deep neural networks; HpHSCC: High pH stress corrosion cracking; SMYS: Specified minimum yield strength; HE: Hydrogen embrittlement; NNpHSCC: Near-neutral pH stress corrosion cracking; ASME: American society of mechanical engineers; DNV: Det norske veritas; AI-FEM: Advanced iterative finite element method; CGR: Crack growth rate; ME: Mechanoelectrochemical; XGB: XGBoost; CAT: Catboost; CP: Cathodic Protection; AI: Artificial intelligence; ANNs: Artificial neural networks; CNNs: Convolutional neural networks; RNNs: Recurrent neural networks; ReLU: Rectified linear unit

The paper studies the piezoelectric output performance of a piezoelectric harvester with four piezoceramic layers, assessing if the piezoelectric material can be reduced. The shape optimization regards cantilevers with trapezoidal or triangular longitudinal sections, maintaining comparable electric response with the original rectangular structure. The piezoelectric material is subjected to maximum mechanical stress in the fixed constrained area, decreasing gradually down to null stress towards the free tip. It is worthwhile to study if the material reduction would result in an increased effectiveness in terms of voltage output per unit volume of piezoelectric material. The simulations conducted in COMSOL Multiphysics employ Structural Mechanics – Piezoelectric Devices module, in a Multiphysics approach through Piezoelectric Effect, coupling Solid Mechanics with Electrostatics. It was found that the electric response increases per unit volume of piezoelectric material in triangular configuration with material reduction. A comparable voltage output is obtained after reducing the amount of piezoceramic material towards the free tip, while using an inertial mass of the same value. Hence, the piezoelectric material is used more effectively in the case of triangular cantilever with material cutdown than the traditional rectangular shaped cantilever. The paper also addresses shape optimization while maintaining the same mechanical stress, studying the response when increasing the tip mass for the purpose. All the structures render an even more significantly increased power output for matching optimum load resistor.

This paper describes a method for continuously measuring the contact position between the wheel and rail using strain gauges. The authors investigated the relationship between the bridge output sensitivity rate and the change in the placement of strain gauges using the result of finite element analysis for the instrumented wheelset. It is noted that the bridge output sensitivity rate is defined as the bridge output change per unit distance of the contact position (load position). Based on the result, strain gauges position suitable for measuring contact position was identified. On the other hand, static load tests were conducted on the instrumented wheelset with strain gauges attached to measure contact forces (wheel load, lateral force, and tangential force) and positions, respectively. The test results were found to be generally consistent with the finite element analysis results, and it was also observed that the load position of each contact force influenced each bridge output. Finally, this paper proposes a method for calculating the contact position by solving a nonlinear equation. The calculation uses the results of the load tests and also wheel rotation angle, bridge outputs, wheel load, lateral force and tangential force which measured in running railway vehicle. Simulations were performed for various cases, and the contact positions were obtained stably and continuously. This suggests that the proposed method is reasonable and applicable to various situations.

The safety of aviation platforms has always been a major concern in the design of aviation vehicles. Airborne high-speed maneuvering targets are currently the most significant threat to all types of aviation platforms due to their high flexibility and anti-jamming capability. This paper presents a new technology of airborne flexible net for high-speed maneuvering target capture. The analysis of flexible net dynamics in this paper includes two aspects: net-expansion dynamics and capture collision dynamics. To solve the technical difficulties of the airborne unfolding of the flexible net, two symmetric design schemes, namely, the traction method and the rotation method, are developed. The mechanical analyses of the two net-expansion methods are carried out. Meanwhile, this paper establishes a collision dynamics model based on the continuous contact force method, and carries out several collision capture tests using two flexible nets. The results show that a transient acceleration is applied in all directions of the target during the collision, capable of reaching the magnitude of 104. The maximum stress inside the target aerodynamic surface reaches the magnitude of GPa, and the strong impact produced in the capture process will cause damage to the aerodynamic parts. Finally, the flight experiments of damaged targets are carried out based on six-degree-of-freedom-model, and the effect of damaged targets on the safety of aircraft platforms after contact collisions is further analyzed. The results of this paper can provide a theoretical reference for the research and development of airborne flexible nets.

Abstract The main contribution of this paper is the development and demonstration of a novel methodology that can be followed to develop a simulation twin of a railway track switch system to test the functionality in a digital environment. This is important because, globally, railway track switches are used to allow trains to change routes; they are a key part of all railway networks. However, because track switches are single points of failure and safety-critical, their inability to operate correctly can cause significant delays and concomitant costs. In order to better understand the dynamic behaviour of switches during operation, this paper has developed a full simulation twin of a complete track switch system. The approach fuses finite element for the rail bending and motion, with physics-based models of the electromechanical actuator system and the control system. Hence, it provides researchers and engineers the opportunity to explore and understand the design space around the dynamic operation of new switches and switch machines before they are built. This is useful for looking at the modification or monitoring of existing switches, and it becomes even more important when new switch concepts are being considered and evaluated. The simulation is capable of running in real time or faster meaning designs can be iterated and checked interactively. The paper describes the modelling approach, demonstrates the methodology by developing the system model for a novel “REPOINT” switch system, and evaluates the system level performance against the dynamic performance requirements for the switch. In the context of that case study, it is found that the proposed new actuation system as designed can meet (and exceed) the system performance requirements, and that the fault tolerance built into the actuation ensures continued operation after a single actuator failure.

With the increase of satellite power, the current-carrying and heat dissipation of power cable is increasing significantly and the thermal safety problem becomes prominent. Therefore, the need for accurate modeling and fine design of power cable becomes increasingly urgent. In this paper, the thermal analysis modeling method for high-power cable bundle is proposed based on ground test data, and the heat transfer parameters at the installation and bundling points are obtained. At the same time, the thermal effect of cable bundling is quantitatively analyzed by simulating the splitting and binding power cable bundle. The result indicates that enhancing the radiation heat transfer between cables and the surrounding environment is the most effective means to improve the heat dissipation condition of cable bundles. The thermal model of high-power satellite power cable proposed in this paper can be used as an important basis for the prediction of on-orbit temperature and fine laying design of the power cable.

Cracking in concrete box girder bridges will have a significant impact on the safety and durability of the structure, and many box girder bridges which are in service have undergone varying degrees of cracking. Currently, the safety design of actual bridge projects place an emphasis on the stress or the load value of a cross section at the limit value specified in the code for safety control. This design method assumes that the member itself is of uniform and continuous material and is internally undamaged. However, the bridge structure is more or less cracked to varying degrees during the period from casting to construction to operation of the concrete members. In this paper, a finite element computational model of a three-span prestressed concrete box girder bridge with existing cracks is established based on the fracture mechanics theory, and the critical parameters of crack extension are introduced to evaluate the extension state of cracks. At the same time, the extended stability of the existing cracks of the box girder bridge is analyzed by considering the temperature effect, vehicle loading, and prestressing loss, and the sensitivity of crack extension under each working condition is investigated. The results show that, with the increase in crack length and depth, the crack expansion is promoted, but the effect is relatively small, and the maximum stress intensity factor is only 6.48 MPa mm1/2. Under the multi-factor coupling effect, the cracks show a composite crack expansion dominated by type I cracks, the longitudinal cracks of the existing base plate are in a stable state, the maximum value of the crack expansion critical parameter of the vertical cracks of the webs reaches 1.087, and there is a tendency to expand locally. The maximum value of the critical parameter for crack extension of the vertical crack in the web plate reaches 1.087, and there is a tendency towards local expansion. The crack extension evaluation criteria proposed in this paper have a certain reference value for crack extension research on similar concrete box girder bridges and provide a scientific basis for the optimized design of similar bridges.

The paper presents experimental investigations and numerical analysis of bearing type lap joint behaviour with one bolt and two shear planes joining thin-walled steel parts. The aim of the study is to describe the actual force-displacement F-Δ relationship for the tested joints and to represent it numerically by validated models with varying degrees of geometry detailing in the finite element analysis. Validation involves determining properties of plates, bolts and the entire shear joint based on individual experimental testing. The obtained shear characteristic include all main stages of F-Δ connection behaviour, as elastic phase, friction, slip and bearing. Although bearing joints are analysed, friction-slip mechanism resulting from tightening of the bolts is also examined. Analyses also take into account existence of threaded portion of the bolt shank in bearing. FEA model with bolt thread confirmed its validity in terms of predicting load-bearing capacity with an overestimation of 1% with respect to the experimental average. However, simplified cylindrical model of the bolt shank appeared to be more reliable in terms of initial bearing stiffness, where the value was 20% higher comparing to the empirical results. An analytical characteristic of the considered joint was also derived based on the component method, which required certain assumptions and adjustments to include the actual phases of connection behaviour. This approach provided a satisfactory match to the experimental results, characterised by underestimations of maximum force and initial bearing stiffness of 2.5 and 7.6% respectively.

This paper details the conceptualization, design, topology optimization, manufacturing, and validation of a hydraulic brake caliper for Formula SAE race cars made of Scalmalloy®, an innovative Al-Mg-Sc alloy which was never adopted before to manufacture a brake caliper. A monoblock fixed caliper with opposing pistons was developed, focusing on reducing mass for a fixed braking force. The design process began with a theoretical analysis to establish braking force and pressure requirements, followed by preliminary design and topology optimization. The caliper was then manufactured using laser powder bed fusion (LPBF). Comprehensive experimental validation, including testing with static and rotating brake discs on an inertial dynamometer, confirmed the expected caliper’s performance, with the results showing strong alignment with finite element analysis estimations. In particular, strain and displacement measurements showed excellent correlation with numerical estimates, validating the design’s accuracy and effectiveness.

Abstract Aiming at the requirements of strong mobility and high flexibility of rescue and relief mobile pump trucks, this paper designs a new type of mobile pump truck frame based on existing mobile vehicle frame models. The materials used for the frame are 40Cr and Q235, and the finite element method is utilized to carry out static mechanical analysis and dynamic characteristic analysis. Simultaneously utilizing topology optimization and multi-objective genetic algorithm to optimize the design of the frame structure. The results show that the optimized pump truck frame can meet the strength design requirements of four typical working conditions: full load bending, full load torsion, emergency turning and emergency braking, while avoiding resonance phenomena caused by road surface and diesel engine vibration. Compared with the original frame model, the weight of the optimized frame is reduced by 87.88 kg, with a weight reduction rate of 10.89%, realizing the lightweight design requirements.

This paper presents the process of conducting the structural analysis of AlAinSat-1 CubeSat through a numerical solution using Siemens NX. AlAinSat-1 is a 3U remote-sensing CubeSat carrying two earth observation payloads. The CubeSat is scheduled for launch on SpaceX Falcon 9 rocket. To ensure the success of the mission and its ability to withstand the launch environment, several scenarios should be analyzed. For AlAinSat-1 model the finite element analysis (FEA) method is used, and four types of structural analyses are considered: modal, quasi-static, buckling, and random vibration analyses. The workflow cycle includes idealizing, meshing, assembling, applying connections and boundary conditions, and eventually running the simulation utilizing the Siemens Nastran solver. The simulation results of all analysis types indicate that the model can safely withstand the loads exerted during launch. Also, the numerical results of the Command and Data Handling Subsystem (CDHS) module of AlAinSat-1 are experimentally validated through a vibration test conducted using an LV8 shaker system. The module successfully passed the test based on the test success criteria provided by the launcher.

In laboratory practice, several standards for testing the bending stiffness of corrugated board are used. There are often cases of tests where the results depend on the way the sample is placed on the supports. The problem arises when the board is five-ply (with two corrugated layers with different corrugation heights) or when the board has asymmetrically selected papers on the flat layers. This article focuses on the problem related to boundary conditions, with particular attention to the local effects of the support of the sample. Because the cardboard layers, both flat and corrugated, have a small thickness, a slight deformation of the papers can always be observed at the point of contact between the sample and the support, which affects the readings of the measured stiffness. The paper presents theoretical and numerical analyses showing how much the method of supporting the sample affects the measured bending stiffness of various samples. Numerical observations were compared with the results of analyses presented by other scientists as well as with experimental results.

In laboratory practice, several standards for testing the bending stiffness of corrugated board are used. There are often cases of tests where the results depend on the way the sample is placed on the supports. The problem arises when the board is five-ply (with two corrugated layers with different corrugation heights) or when the board has asymmetrically selected papers on the flat layers. This article focuses on the problem related to boundary conditions, with particular attention to the local effects of the support of the sample. Because the cardboard layers, both flat and corrugated, have a small thickness, a slight deformation of the papers can always be observed at the point of contact between the sample and the support, which affects the readings of the measured stiffness. The paper presents theoretical and numerical analyses showing how much the method of supporting the sample affects the measured bending stiffness of various samples. Numerical observations were compared with the results of analyses presented by other scientists as well as with experimental results.

Due to the limitations of planar mode wharfs, this paper proposes a new type of wharf—the three-dimensional cantilevered wharf. The proposed wharf is defined as an improvement of the traditional wharf, extending the traditional wharf upward and cantilevering out to the sea. The three-dimensional cantilevered wharf is a composite truss structure that meets structural and functional requirements. The composite truss structure is formed by connecting the beams of frame structures as a whole. The material consumption of the three-dimensional cantilevered wharf is decreased by controlling stresses and optimizing components. A finite element model of the proposed wharf, with a length of 200 m, width of 105 m, and cantilever length of 80 m, was established to analyze the basic mechanical performance. In this paper, the force distribution of the pile foundation, the vertical force transfer efficiency of web members, the structural stiffness, and the natural frequencies of the proposed wharf are analyzed. Tests regarding the stress and stiffness of different plane cantilever trusses are carried out, and finite element analysis is used for comparison. The test results show that the high-rise cantilever truss has a great in-plane stiffness and a reasonable component stress distribution. Additionally, the three-dimensional cantilevered wharf significantly improves the utilization efficiency of the wharf.

Turbine systems equipped with doubly fed induction generation (DFIG) are becoming increasingly vital in wind power generation, with the reliability of the devices serving as a pillar in the industrial sector. Thermal stress and lifetime assessment are fundamental indicators in this regard. This paper primarily addresses the thermal stress and lifespan of power semiconductor devices utilized in a DFIG grid-side converter (GSC) and rotor-side converter (RSC). PLECS (Piecewise Linear Electrical Circuit Simulation) is employed to validate the electrical and thermal stress of the power devices. Additionally, Ansys Icepak, a finite element analysis (FEA) software, is utilized to confirm temperature fluctuations under various operations. The power consumption and junction temperature of the power devices in the GSC and RSC of a 2 MW DFIG are compared. It is evident that the most stressed power semiconductor is the IGBT for the GSC with a temperature swing of 3.4 °C, while the diode in the RSC is the most stressed with a temperature swing of 10.1 °C. This paper also presents a lifetime model to estimate the lifespan of the power device based on the annual wind profile. By considering the annual mission profile, we observe that the lifetime of the back-to-back power converter is limited by the diode of the RSC, whose B10 lifetime is calculated at 15 years.

Skewed supports complicate load paths in continuous steel I-girder bridges, causing secondary stresses and differential deformations. For a continuous bridge where tensile stresses are developed in the top flange of the steel girders over the intermediate supports, these effects may exacerbate potential fatigue issues for the top flanges. There is a gap in knowledge regarding the level of stress one can expect at these locations, and the stress level can render the problem either serious or trivial. This paper has been successful in providing this information, which was not available before. The study examines the fatigue performance of the top flange in girders over skewed supports. Results are presented from a detailed investigation consisting of 3D finite element modeling to evaluate 26 skewed bridges in the State of Florida that represent the wide range of geometries found in practice. The analysis focused on stress ranges in the top flanges and axial demands on end cross-frame members under fatigue truck loading. A preliminary analysis helped to select the appropriate element type and support conditions. The maximum factored stress range of 3.63 ksi obtained for the selected group of bridges remains below the 10 ksi fatigue threshold for an AASHTO Category C connection, alleviating the concerns about the fatigue performance of the continuous girder top flange over the intermediate pier. Hence, fatigue is unlikely to be a concern in the flanges at this location. Statistics on computed stress ranges and cross-frame forces that provide an understanding of the expected values and guidance for detailing practices are also presented. A limited comparative refined FE analysis on two different types of end cross-frame to girder connections also provided useful insight into the fatigue sensitivities of the skew connections. Half-Round Bearing Stiffener (HRBS) connections performed better than the customary bent plate connections. The HRBS connection reduces girder flange stress concentration range by at least 18% compared to the bent plate connection. The maximum stress concentration range in bent plate components is significantly higher than in the HRBS connection components. The work documented in this paper is important for understanding the fatigue performance of the cross-frames and girders in support regions in the upcoming 10th edition of the AASHTO Bridge Design Specifications that may include plate stiffeners oriented either normally or skewed to the girder web, or Half-Round Bearing Stiffeners.

In this paper, a 20kW vehicle built-in permanent magnet synchronous motor is taken as an example, and a magnetic barrier structure is added to the rotor of the motor to solve the uneven saturation problem of the rotor side magnetic bridge. This structure improves the air-gap flux density waveform of the motor by influencing the internal magnetic flux path of the motor rotor, thus improving the sine of the no-load back EMF waveform of the motor and reducing the torque ripple of the motor. At the same time, Taguchi method is used to optimize the structural parameters of the added magnetic barrier. In order to facilitate the analysis of its uneven saturation phenomenon and improve the optimization effect, a simple equivalent magnetic network (EMN) model considering the uneven saturation of rotor magnetic bridge is established in this paper, and the initial values of optimization factors are selected based on this model. Finally, the no-load back EMF waveform distortion rate, torque ripple and output torque of the optimized motor are compared and analyzed, and the influence of magnetic barrier structure parameters on the electromagnetic performance of the motor is also analyzed. The results show that the optimized motor can not change the output torque of the motor as much as possible on the basis of reducing the waveform distortion rate of no-load back EMF and torque ripple.

This paper takes the application techniques of non-heritage paper-cutting elements on modern clothing fabrics as an example, analyzing and outlining the symbiotic trend of non-heritage elements and clothing design, i.e., personalization, ethnicity, and the unity of tradition and popularity. It is proposed to utilize the unique performance of bionic scale knitting structure fabrics in bionic technology, combined with the combination of non-heritage techniques, to innovate the clothing design process of non-heritage and to form a new way of bionic interaction and symbiosis between non-heritage and clothing textile. Simulate the performance of bionic scale knitting structure fabrics and explore the advantages of bionic technology in clothing textiles from the perspective of flexibility. Explore the market operation effect of clothing design works of non-heritage technology from the aspects of consumer demand, market evaluation, and market operation, respectively. From the load-displacement curve of the flexibility test, it can be obtained that when the loading value is 55N, the displacements of the bionic knitted structural fabric and the separate scale layer are all greater than 11mm, and the bionic scale knitted structural fabric possesses good bending deformability. The evaluation results of the enterprise experts show that the clothing works integrating the non-heritage elements have obvious market demand.

In order to solve the integration problem of lifting point layout, 3D dynamic simulation and safety assessment, a multi-functional integrated design system for ship lifting process is developed. Based on the discrete data extracted from AM model (The three-dimensional ship block created through AVEVA Marine), lifting process information and lifting equipment information, this paper develops an automatic design module with the optimization algorithm of lifting point layout as the core, and retains the interactive design module. To solve the problem of automatic finite element mesh generation, the proposed system uses the highly reliable AFT-Delaunay algorithm as the finite element mesh generation algorithm. In addition, the proposed system combines the control algorithm, unit calculation and constitutive calculation extension interface to build a finite element analysis framework. Taking the deck block of a crude oil tanker as an example, this paper compares the functions of commercial finite element software MSC.NASTRAN and the proposed system in the finite element calculation results, mesh generation and finite element visualization. The comparison results shows that the proposed system has reached a level comparable to MSC.NASTRAN in the safety evaluation of block lifting.

In this paper, a performance optimization model for sportswear based on the learning curve effect is proposed on the learning curve base model, which is a systematic method for improving and optimizing sportswear’s comfort performance and sports functionality compared with the traditional model. Laplace’s law measurement method is used to predict the garment comfort pressure in terms of comfort measurement. The finite element method was used to analyze the sports apparel’s functionality. The results show that the most obvious deformation under the pressure of sportswear occurs in the middle section of the inner thigh, with a maximum value of 1.786E-002mm and a mean square error of 3.0875×10−14 .The research findings of this paper can serve as a reference for sportswear designers and manufacturers and encourage the development and innovation of the sportswear industry.

An underground integrated pipeline corridor is a long-line structure that accommodates various municipal pipelines such as water supply, reclaimed water, storm water, communication, heat, electricity, and natural gas. Seismic hazard is the main factor affecting the safety of this important urban lifeline project, so the seismic analysis of the underground integrated pipeline corridor is urgent. To this end, in this paper, based on the generalized reaction displacement method, the finite element model of the standard section of the pipe corridor under the action of the earthquake is established, and the displacement, as well as the internal force response of the pipe corridor under the action of the earthquake, is obtained. The results show that the junction between the top of the standard section of the integrated pipe corridor and the outer slab is the key part for shear and bending tests, and the reinforcement in the span of the outer slab also needs to be focused on. Simulation and calculation by the physical stochastic seismic model in this paper show that the generalized reaction displacement method is more applicable and suitable for seismic finite element analysis of integrated pipe corridor, which lays the foundation for realizing refined analysis of dynamic reliability of underground integrated pipe corridor.

In the context of the apparition of new materials used in manufacturing the elements that form the vehicles’ steering systems, both in the design and prototyping stages, the tests regarding their behavior from the tribology viewpoint represent an essential stage in the development of a product. The stands are generally dedicated to a specific configuration regarding the contact and/or the dynamics of the movements that the product can achieve. This paper presents a universal stand for such trials, which can be adapted to more extensive research.

Based on the propagation of laser-induced tensile waves in materials and the principle of material ply cracking, nondestructive testing technology for measuring the interfacial bonding force of composite materials can be developed. The study of the ultra-high strain rate dynamic response model of composite materials under the action of laser shock waves is crucial to this technique. Therefore, this paper proposes a method for constructing a dynamic response prediction model for composites based on data and a physical model driven by comprehensively considering the strain rate effect of materials. The constructed model can accurately predict the peak velocity and duration of the initial pulse of the velocity curve under the condition of ultra-high strain rate. The relative error between the predicted and simulated peak values is within 3%, and the relative error between the predicted and simulated initial pulse durations is within 5%. In addition, laser impact experiments were conducted on specimens of various thicknesses to validate the accuracy of the predicted data at ultra-high strain rates. The results show that the relative errors between the predicted and experimental peak values are all within 2%, and the relative errors of the initial pulse duration are within 9%.

Drive systems are an important part of general mechanical engineering, automotive engineering, and various other fields, with shaft–hub connections being an important part of such systems. Decisive aspects in the development of such systems today are, for example, high transmittable forces and torques, low masses, and the cheapest possible production of components. A possibly threefold increase in the force and torque transmission capacity can be achieved by using press–fit connections with an elastic–plastic design as opposed to regular elastically designed alternatives. An elastic–plastic design of the press–fit connection is achieved by using a large interference. A large transition geometry on the shaft (which replaces the conventional chamfer) is required to join such an interference. The material and space requirements have a negative impact on lightweight applications and limited building spaces. Therefore, the objective of the research presented in this paper is to design and analyze a detachable joining device that substitutes this geometry. A simulation study was conducted to determine the geometry of the joining device that improves the stress state and consequently the force and torque transmission capacity of the connection. Moreover, the influence of manufacturing tolerances of the joining device and the shaft, corresponding risks, and measures to mitigate them are analyzed using finite element analysis. The results show that large transition radii, enabled by using a joining device, lead to a homogenous distribution of plastic strain and pressure in the press–fit connection, even for large interferences ξ and soft hub materials like wrought aluminum alloys. The influence of manufacturing tolerances on the stress state was quantified, leading to design guidelines that minimize the risk of, e.g., the front face collision of a shaft and hub, while maximizing the power transmission of the connection. The results show the capability of a detachable joining device to enable elastic–plastic press–fit connections and the corresponding threefold increase in the force and torque transmission capacity in lightweight applications, resulting from the substitution of the installation space consuming and mass increasing the transition geometry of the shaft.

For linear motion applications, particularly in aerospace, this study outlines the creation of an essential Quadrupole Electromagnetic System (QES) as a substitute for a four-track electromagnetic launcher. The QES design is compared with a four-track system to address concerns regarding rail-armature contact sliding. In a QES, four coils provide a homogeneous electromagnetic field, resulting in a Lorentz force on the slider. The QES was designed using the three-dimensional modeling capabilities of the ANSYS software. The results of the magnetic properties show a high potential for scaling this model to various levels. Additionally, the QES power circuit was simulated using ANSYS Simplorer. The circuit uses silicon-controlled rectifiers (SCR) and a pulse-width modulation (PWM) pulse generator. A force of 4kN was achieved, and this paper presents the current and force plots in detail. The study includes finite element analysis, electromagnetic and current characteristics simulation, and monitoring of the skin and proximity effects. Performance is increased by optimizing the QES design parameters using Particle Swarm Optimization (PSO). The simulation results demonstrate the feasibility and scalability of the QES design.

Spur gear, helical gear, worm gear, and bevel gear are all important components in industrial applications such as vehicles, pushes, conveyors, elevators, bowl mill, rolling mills, ribbon blender, machine tools, aeroplanes, and windmills. When various types of defects, such as wear, tooth breakage, corrosion, and scratches on bearings, appear in gearboxes, normal machine function may be abruptly terminated. As a result, output and dependability suffer. As a result, several quality tracking and evaluation approaches have been adopted by companies. Finite element analysis (FEA) is one of the approaches. This research paper presents the FEA of a ribbon blender worm gear pair by using Ansys 18.0 to identify the weak gear of the worm gear pair, natural frequency, and deformation. Proe-5 utilized for creation of three-dimensional geometry of threaded worm and toothed worm wheels, as well as other related elements such as shafts and bearings. Steel is used for the worm, shaft, and bearing, whereas bronze is used for the worm wheel. Ansys 18.0 is implemented to carry out worm gear pair model analysis. The results demonstrate that the worm wheel had the most deformation when compared to the worm, and that the natural frequency is greater than the operational frequency of the worm gear pair. The findings of the research study, worm wheel deteriorate early than worm, model analysis plays a significant role in vibration monitoring of worm gear pair, and this work is valuable for further fault analysis of ribbon blender worm gearbox utilising vibration response.

Abstract This paper presents a comprehensive analysis, electromagnetic evaluation, and prototyping of a novel motor structure called the sinusoidal rotor switched reluctance motor. In this innovative design, a significant departure from the conventional switched reluctance motor is observed, as modifications are made to the rotor with the goal of reduction torque ripple and radial force characteristics. Importantly, despite these advancements, the proposed motor retains the weight and volume characteristics of the traditional, type. The key attributes of these motors have been thoroughly assessed using the three‐dimensional finite element method, complemented by a sensitivity analysis aimed at identifying the most optimal configuration within the proposed design. The findings reveal that the suggested structure successfully achieves a notable reduction in torque ripple and radial force when compared to the traditional counterpart, albeit with an expected reduction in average torque. These features render the new topology particularly well‐suited for applications that prioritise noise and vibration reduction. Furthermore, the effectiveness of the proposed topology is corroborated through experimental tests, providing empirical evidence of its advantages and potential for practical applications.

To address the rapidly growing demands of traffic congestion, more highway bridges have been constructed, especially curved bridges. With more curved bridges designed and constructed, people have conducted a comprehensive analysis of the structural performance. Due to the nature of the structural complexity of curved bridges, dynamic responses of the curve bridges vary dramatically from the standard linear bridges. Although some work has been conducted to investigate the curved bridge dynamic analysis under seismic inputs, the framework for analyzing the curved bridges’ vulnerability under various angles of inputs is still lacking. In this paper, we conducted a series of curved bridge seismic analyses based on different inputs and conducted a parametric study of the bridge performance using finite element models. We conducted time history analyses by applying seismic inputs to investigate the bridge dynamic responses based on different angle inputs and other different structural parameters. We developed an approach identifying the most vulnerable direction of the seismic inputs and the strongest dynamic responses for curved bridges based on time series analysis. This approach was validated with the dynamic analysis of a simplified bridge model. The method developed in this paper will help improve the curved bridge design code and further provide suggestions about mitigating seismic response for device design.

This paper presents a stress analysis of a pressed joint of two conical pipes with the aim to find out whether this kind of connection is suitable for telecommunication masts. The analysis can be considered a complex spatial problem of a thin-walled shell, where the local bending stress influence might be dominant. In this paper a solution using engineering approach and numerical analysis with finite element method (FEM) will be compared.

With the development of electric drive technology, the integrated electric engine fuel pump on the aircraft has many potential advantages such as lighter weight, smaller volume and simpler configuration. This paper aims to optimize the parameters of the existing dual-winding fault-tolerant permanent magnet motor (DWFT-PMM) which merges the advantages of permanent magnet (PM) motor with high efficiency and dual-winding motor with strong fault-tolerance. The existing DWFT-PMM is designed with a rated speed of 5000 rpm, rated power of 10 kW and the cooling mode is natural air cooling. However, in practical application, because the aviation fuel pump motor needs higher speed and better heat dissipation performance. This paper mainly focuses on the design and optimization of the existing DWFT-PMM aviation fuel pump motor, and compares and analyzes it through simulation and experiment. The comparative analysis results before and after optimization are given in terms of moment, no-load back EMF in simulation and experiment, etc. Finally, the simulated and experimental results show that about 20% higher rated speed, 5.43% higher torque density, 35.85% smaller volume and better heat dissipation can be obtained for the optimized DWFT-PMM when compared with existing DWFT-PMM.

The variations in seismic response between deep soft soil sites with different shear wave velocities were not fully understood. This study focuses on the seismic response of deep soft soil sites in the lower reaches of the Yangtze River, China. A nonlinear dynamic finite element model was developed for two representative deep soft soil sites with borehole profiles and the shear wave velocity tested by the single borehole method. Two nonlinear cyclic constitutive models are used and thus compared through the site seismic response. To accurately calibrate the nonlinear cyclic model parameters, resonant column tests were conducted on 21 soil samples collected from the two boreholes. The results show that the peak ground acceleration (PGA) under low-frequency (Liuan) input motion was higher for soft soil sites compared to that under medium- and high-frequency (Kobe and Nahanni) input motions. The PGA amplification factor for deep soft soil sites under different input motions can be approximated by an exponential function. The peak ground acceleration tends to be lower as the equivalent shear wave velocity (Vse) decreases. The shapes of the spectral acceleration were similar for the two sites, despite a substantial difference in the Vse between them. Additionally, a crossover point was observed in the spectral acceleration for the two sites. The period corresponding to this crossover point increased with increasing intensity of input motions, indicating that the sites became softer with higher intensity and thus generally exhibited a longer characteristic period of the spectral acceleration. This paper also highlights the significance of selecting nonlinear constitutive models and the precise calibration of model parameters in the seismic response analysis of deep soft soil sites, providing a scientific basis for future similar site analyses.

Infrared thermography (IRT) is a non-destructive testing technique that can detect the internal defects of materials. In the detection of austenitic stainless-steel pipes with large curvature, image noise caused by uneven heating is difficult to avoid. Traditional image processing methods are less effective. According to previous works, a supervised neural network was proposed in this paper using Unet network and convolutional block attention module. Existing image processing method and networks were used to compare with the proposed method. The results show that the proposed method can remove the noise caused by uneven heating, and detect all subsurface defects in stainless-steel pipe.

Magnetic flux leakage (MFL) testing is a widely employed non-destructive testing (NDT) method, particularly for ferromagnetic materials. This paper proposes a systematic design procedure for the yoke-magnetization component in MFL systems utilizing permanent magnets. The dimensions of the yoke-magnetization are parameterized, and the design methodology is formulated in the form of analytical equations based on fundamental engineering principles and optimization techniques. The proposed design procedure outlines all the required parameters and metrics to establish a yoke-magnetization configuration tailored for a specified application, thereby facilitating scalability. The theoretical framework identifies the optimal operating point that maximizes leakage flux while minimizing the magnetic field amplitude. A genetic algorithm is employed to minimize the dimensions of the permanent magnets while maintaining a sufficient magnetic field strength for specimen magnetization. An experimental setup is constructed to validate the accuracy of the proposed design procedure. The experimental results exhibit consistency with finite element method (FEM) simulations conducted using a case study. Specifically, the findings reveal that the thickness of the magnetic bridge significantly impacts the leakage fluxes at defect sites within the specimen. When the thickness of the magnetic bridge is 10 mm, slightly smaller than the optimal thickness of approximately 11 mm, the leakage flux at the defect site leaks out towards the surrounding air insignificantly. In contrast, a thickness of 15 mm is observed to strongly improve the leakage flux at the defect site.

This research introduced a novel precast shear wall designed to address prevalent challenges encountered in precast shear wall structures, such as issues with difficult installation, high expenses, and the uncertain quality of grouting by eliminating the connection of the vertical distributing bars. Early experimental verification of this novel structural system showcased favourable results concerning its seismic performance. Building upon this groundwork, the paper presented an elaborate horizontal joint deformation model, demonstrating its precise analysis of damage modes and interface slip in the novel structural system with high reliability. Furthermore, in an effort to enhance the damage mode of this novel precast shear wall under conditions of low axial compression ratio, the study introduced and evaluated two improvement measures through finite element parametric analysis. The findings indicated a noticeable enhancement in capacity and a simultaneous reduction in interface slip with the proposed improvement measures. Additionally, the section steel measures were more effective than the additional bars measures.

Mass-impregnated (MI) cables have been used for many years as cables in high-voltage direct current (HVDC) systems. In line commutated converter (LCC) HVDC systems, polarity reversal for power flow control can induce significant electrical stress on MI cables. Furthermore, the mass oil and kraft paper comprising the impregnated insulation have significantly different coefficients of thermal expansion. Load fluctuations in the cable lead to expansion and contraction of the mass, creating pressure within the insulation and causing redistribution of the impregnant. During this process, shrinkage cavities can form within the butt gaps. Since the dielectric strength of the cavities is lower than that of the surrounding impregnation, cavitation phenomena in impregnated paper insulation are considered a factor in degrading insulation performance. Consequently, this study analyzes the electrical conductivity of thermally aged materials and investigates the transient electric field characteristics within the cable. Additionally, it closely analyzes the formation and dissolution of cavities in MI cables during polarity reversal based on a numerical model of pressure behavior in porous media. The conductivity of the impregnated paper indicates that it has excellent resistance to thermal degradation. Simulation results for various load conditions highlight that the interval of load-off time and the magnitude of internal pressure significantly influence the cavitation phenomenon. Lastly, the study proposes stable system operation methods to prevent cavitation in MI cables.

Giga-casting, a revolutionary approach for manufacturing large, single-piece car body components from aluminium, has emerged as a potential game-changer in the automotive industry. However, these large, thin-walled castings are prone to distortions during solidification and heat treatment processes. Straightening these distortions is crucial to ensure structural integrity, facilitate downstream assembly, and maintain aesthetic qualities. This paper proposes a novel method for straightening giga-cast components using a multi-pin straightening machine. The machine’s versatility stems from its ability to adapt to various geometries through multiple strategically controlled straightening pins. This paper introduces the concept of a “straightening stroke decision algorithm” to achieve precise straightening and overcome the challenges of complex shapes. This algorithm determines the stroke length for each pin, combining a polynomial model representing the global stiffness of the component with a machine learning model that captures the stiffness changes arising from the current geometry. The effectiveness of the proposed approach is evaluated through comprehensive numerical experiments using finite element analyses. The straightening performance is assessed for the straightening algorithm with different machine learning models (deep neural network and XGBoost) and compared to a traditional optimisation method. The proposed surrogate models decided the straightening strokes so that the maximum remaining distortion became 0.02% of the largest dimension of each target geometry. The results of the numerical experiment showed that the proposed straightening method is suitable for straightening distortion in large thin-walled components.

In order to realize the automatic picking of shiitake mushrooms and reduce the risk of damage to shiitake mushrooms in the picking process, this paper designed a shiitake mushroom picking grasper. First, this paper carries out mechanical tests of compression and stress relaxation on sections of shiitake mushroom stipes, and establishes the component stress relaxation equations of shiitake mushroom stipes. The compression mechanical characteristics of the entire mushroom stipe are then analyzed using finite element analysis, with a mean square error of less than 5% compared to actual results. Second, based on the actual picking experience, this paper proposes an “L”-shaped three-finger picking grasper, and analyzes the mechanical relationship between the grasper’s gripping force, twisting separation torque, and servo output torque. Furthermore, according to the mechanical constitutive model of mushroom stipes, the optimal twisting separation torque and corresponding servo motor output torque for the grasper are determined. The picking grasper designed in this paper was tested for picking mushrooms of different growth periods, and the test results show that the picking grasper designed in this paper is able to grasp and separate the mushrooms quickly and without damage.

The fifth Industrial revolution (I5.0) prioritizes resilience and sustainability, integrating cognitive cyber-physical systems and advanced technologies to enhance machining processes. Numerous research studies have been conducted to optimize machining operations by identifying and reducing sources of uncertainty and estimating the optimal cutting parameters. Virtual modeling and Tool Condition Monitoring (TCM) methodologies have been developed to assess the cutting states during machining processes. With a precise estimation of cutting states, the safety margin necessary to deal with uncertainties can be reduced, resulting in improved process productivity. This paper reviews the recent advances in high-performance machining systems, with a focus on cyber-physical models developed for the cutting operation of difficult-to-cut materials using cemented carbide tools. An overview of the literature and background on the advances in offline and online process optimization approaches are presented. Process optimization objectives such as tool life utilization, dynamic stability, enhanced productivity, improved machined part quality, reduced energy consumption, and carbon emissions are independently investigated for these offline and online optimization methods. Addressing the critical objectives and constraints prevalent in industrial applications, this paper explores the challenges and opportunities inherent to developing a robust cyber–physical optimization system.

Cable-stayed bridges have been widely used in large-span bridge engineering because of their large span capacity and novel structure. The frequent traffic of vehicles transporting flammable and explosive materials has increased the incidence of bridge fires. After being burned, the cable-stayed bridge will suffer from varying degrees of damage, which affects its performance. Therefore, mechanical analysis and evaluation of the fire-damaged cable-stayed bridge are necessary. Due to the development of technology, the structural analysis of cable-stayed bridges has gradually shifted from experimental methods to numerical simulation or artificial intelligence methods, and from local performance research to holistic research. In this paper, a fire accident in the Sifangtai Bridge in Harbin, China, is taken as a case study. Finite element software and damage theory calculation methods were used, and the static and dynamic performances of the bridge under the condition of cable fire damage were analyzed. The results show that the variation of cable force during the movement of vehicle load along the bridge is relatively small, within the range of 7% to 12%. The fusing of the upper cables of the bridge tower has the greatest impact on the deflection of the beam, while the fusing of lower cables has the same impact on the deflection of the entire bridge as the undamaged state. Near the fused cables, cable forces change significantly, increasing by over 20%. As the degree of damage increases, the increase in deflection of the beam becomes more pronounced. The impact of different degrees of cable damage on the dynamic performance of cable-stayed bridges is reflected in quantitative changes. As the degree of cable damage and the amount of fusing increase, the change in structural frequency becomes more pronounced. This paper not only provides technical support and a theoretical basis for the performance analysis of cable-stayed bridges damaged by fire, but it also improves the research content of combining static and dynamic performance, which provides important reference values for similar research in the future.

This paper presents the design and dynamic simulation of a line-start, three-phase Interior Permanent Magnet Synchronous Motor (IPMSM) intended for pump applications in the oil and gas industry. The problem addressed in this paper pertains to the replacement of an existing induction motor (IM) in an oil and gas pump station with a more efficient and controllable solution, the IPMSM since IMs are known to be less efficient and IPMSM is easier to control. The chosen motor type employs a traditional salient-pole rotor with cage windings, known for its line-start capability, making it a feasible choice for constant-speed and pump applications. The dynamic simulation of the proposed IPMSM is carried out using MATLAB/Simulink, focusing on fundamental harmonic analysis in direct-phase variables. The results demonstrate rapid startup to synchronous speed with minor deviations effectively dampened by the rotor's damper windings. Torque characteristics exhibit some pulsations caused by magneto-motive force (MMF) harmonics; a phenomenon captured by Finite Element Analysis (FEA). The performance results show that the proposed IPMSM with a salient-pole rotor is viable and a promising replacement for induction motors in oil and gas pump stations.

Cable replacement is a key technique to solve the problems of cable corrosion and strand breakage. Cable removal causes structural changes. The choice of replacement method affects the safety of the bridge during cable replacement. A sensitivity analysis method was used to evaluate the force and deflection changes of Wohu Bridge. A reasonable method for the number and order of cable replacement was proposed; by comparing different cable removal schemes, it was revealed that the cable force and beam stress changes of the cables closest to the removed cable were the most significant. The results showed that the cable force increment of the surrounding cables was the largest when removing the longest cable. The structural impact change was small when removing the shortest cable. The maximum deflection at the top of the tower decreased with the decrease of the length of the removed cable. It was recommended to replace two cables symmetrically from the center of the tower, and the optimal replacement order was from the shortest cable to the longest cable. Furthermore, this paper also studied the influence of variable load on the cable replacement scheme, and demonstrated that the design scheme of opening part of traffic in this paper was safe and feasible.

This paper proposes an evolved quasi-3D analysis method (EQAM) that can extremely reduce analysis time by applying it to models where 3D analysis is essential. The conventional quasi-3D analysis is a method that can equalize a 3D analysis with multiple 2D analyses and is widely used for 3D models that take a long analysis time. However, the quasi-3D method still has the problem of taking a long time to interpret because it requires increasing the number of quasi segments to obtain accurate results. Therefore, this paper proposes a method of deriving a magnetic flux linkage, torque, voltage, torque-current phase angle curve (T- $\beta $ curve) by interpreting only one step rather than all steps in multiple quasi segments. Compared to the 3D analysis, the EQAM reduced the T- $\beta $ curve extraction time by 99.1% and reduced the capacity of the analysis file by 99.6%. In terms of analysis accuracy, the average torque error rate is 0.20% and the voltage error rate is 2.88% at the operating point. The validity of the proposed method was verified by confirming that the analysis time and file capacity reduction rate were significantly higher than the error rate. Therefore, EQAM is expected to be of great help to researchers facing time problems by being applied to various fields and studies that require 3D finite element analysis.

Wide-spread availability of low-cost digital sensors has made the acquisition of full-field experimental measurements less challenging, with modern measurement systems, such as X-ray computed tomography, capable of obtaining three-dimensional (3D) data fields. This presents difficulties when comparing computational and corresponding experimental data that often do not share the same, coordinate system or data pitch. This paper presents a method of orthogonally decomposing 3D data arrays into feature vectors using a pre-defined set of basis vectors, which are based on discrete Chebyshev polynomials. This allows one-to-one quantitative comparisons of 3D data fields with the same orientation but differing data pitch and coordinate system, irrespective of the source from which they are acquired. Two case-studies, each involving a pair of finite element (FE) model and experimental datasets, were used in this paper to demonstrate the capability of the method. The first case study represented the internal 3D strain fields in a reinforced-rubber matrix specimen under tensile load, measured using digital volume correlation, whilst the second study involved time-varying, surface displacements of an aerospace panel under resonance, which were measured using digital image correlation. From the two case studies, it was demonstrated that the decomposition method can be successfully employed to perform quantitative validation of 3D FE-predicted data using a validation metric, which was previously developed for two-dimensional data fields.

The porosity defects arising in objects produced by metal Material Extrusion (MEX) additive manufacturing affect the macroscopic mechanical behaviour. This paper presents a new approach integrating μ-computed tomography (μXCT) and multi-scale finite element analysis to evaluate the mechanical performance of components fabricated by metal MEX. The porosity information from μXCT is mapped into the finite element model, allowing to define the volume fraction of porosity to each finite mesh element. Then, the Mori-Tanaka homogenization technique is used to estimate the effective mechanical properties in each integration point, assuming a representative volume element composed by a metal matrix with a void. The reliability of the proposed approach was assessed using tensile specimens of stainless steel 316L produced by metal MEX. The numerical predictions were compared with experimental measurements, namely the strain field evolution measured by digital image correlation (DIC). The results highlight the detrimental influence of the porosity distribution, evaluated in the specimen using μXCT, on the strain distribution during the loading stage. The numerical predictions are in agreement with the experimental measurements, i.e. the difference is lower than 11%. Therefore, the proposed approach offers valuable insights for evaluating the mechanical performance of components produced by metal MEX, focusing on the detrimental effects of porosity defects.

Abstract An SHS-CFSHS X-joint is fabricated by welding two square hollow section (SHS) braces to a concrete-filled square hollow section (CFSHS) chord. In this paper, the stress concentration factors (SCFs) of SHS-CFSHS X-joints are investigated through experimental tests and finite element analysis (FEA), with the hot spot stress method serving as the analytical approach. Eight specimens are designed and manufactured, with FE models built in software ANSYS. These FE models are validated against the test results. The specimens are tested under brace axial tension to determine the SCFs of the X-joints. It shows that the concrete filled in the chord effectively reduces the SCFs of the X-joints. To further explore various load conditions and the influence of the parameters, FEA is carried out and a total of 64 FE models are built. Based on the FEA results, multiple regression analysis is used to obtain the SCF formulae of SHS-CFSHS X-joints under axial tension load and in-plane bending load in the brace, respectively. Comparison and analysis of the SCF results obtained from experimental tests, the proposed formulae, and FE simulations reveal that the formulae presented in this study are both conservative and suitable for predicting SCFs.