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Additive manufacturing (AM) has revolutionized numerous industrial fields by enabling the production of intricate shapes that were previously impractical to manufacture using traditional methods. Recently, AM has been adopted in the construction industry. One of the key challenges in researching additively manufactured (AM'd) parts is accurately modeling and analyzing their thermal and mechanical responses and considering the imperfections resulting from the temperature variation during the printing process. This requires a comprehensive understanding of the interplay between various parameters, such as the printing process, and material properties. Overcoming these challenges is crucial for improving the reliability and performance of AM'd parts. Consequently, this research provides a step-by-step modeling and simulation of AM'd parts using ABAQUS software. Specimens with different test setups and printing directions were used for simulation. Four simulations had been created for specimens using layer-by-layer method to represent the 3D printing process fabricated using wire and arc additive manufacturing (WAAM). Also, finite element modeling was performed to investigate the specimen response under the application of tension and compression loads. This research provided insights into the differences in modeling the mechanical properties relative to the printing directions and where the tensile and compressive capacities were greatly influenced. [ABSTRACT FROM AUTHOR]

Small-sized anchors (typically 6 mm [0.24 in.]) are commonly used for nonstructural applications. There has been increasing demand for seismic performance of fastenings for nonstructural applications; however, there have been no 6 mm (0.24 in.) size screw anchors with seismic prequalification for large crack width. This study investigated the feasibility of small-sized screw anchors to perform under tension loading in crack widths of up to 0.8 mm (0.03 in.). Tension tests were conducted in cracked concrete with varying crack widths (0.3, 0.5, and 0.8 mm [0.01, 0.02, and 0.03 in.]) under monotonic, pulsating, and varying crack width load protocol. Based on the findings of this study, 6 mm (0.24 in.) screw anchors exhibited load drop and slip behavior in large crack width during the residual capacity test, even for anchors with a deeper embedment. Finite element analysis was conducted to investigate the feasibility of a larger-sized thread width to perform in 0.8 mm (0.03 in.) crack width. [ABSTRACT FROM AUTHOR]

The umbilical cable is a vital component of subsea production systems that provide power, chemical agents, control signals et al., and its requirement for reliability is exceedingly high. However, as the umbilical cable is a composite structure comprising multiple functional units, the reliability analysis of such cables involves numerous parameters that can impact calculation efficiency. In this paper, the reliability analysis of a new kind of umbilical cable with carbon fiber rod under tension is analyzed. The global dynamic analytical model is first established to determine the maximum tension load, then the local analytical model of umbilical cable including each unit are constructed by finite element method (FEM). Based on the mechanical analytical model, the reliability of umbilical cable under tension load is studied using response surface method (RSM) and Monte Carlo method. During the calculation process, a new tangent plane sampling method to calculate the response surface function (RSF) is proposed in this paper, which could make sampling points faster come close to the RSF curve, and it is proved that the calculation efficiency increases about 33% comparing with traditional method. [ABSTRACT FROM AUTHOR]

The base connection is flexible, not fully pinned/fixed, implying a nonlinear moment–rotation relationship. This deviates from a linear response, where rotation is not directly proportional to the applied moment. Numerical investigations using the commercial software ABAQUS were conducted to analyze the steel base plate connections. The finite element (FE) models were verified against previous experimental results. Moreover, numerical findings of a comprehensive parametric investigation were conducted. The studied connections were examined with different configurations, including variations in the diameter, spacing, and number of the anchor bolts; the thickness of the base plate; and the applied axial force. The current study aims to use numerical results combined with the whale optimization algorithm (WOA) and classical genetic algorithm (GA) to derive a formulation for the moment–rotation (M-θr) relationship. The distinctive aspect of this formulation is that it aims to simulate the nonlinear rotational behavior exhibited by flexible base connections under combined moment and tension loads, while also considering various parameters such as bolt number/diameter and plate thickness. The findings indicate that the WOA is capable of obtaining an optimal equation for accurately simulating the M-Ɵr relationship. This underscores the ability of the WOA to effectively address the complexity of the problem and provide a reliable equation for predicting the rotational behavior of such connections. Consequently, the WOA method can be utilized to calculate the rotational stiffness at H/150, offering valuable support for engineering design processes. [ABSTRACT FROM AUTHOR]

The static and fatigue analysis of plates made of 2D woven roving composites with holes is conducted. The parametrization of convex holes is proposed. The experimental results of the specimens without holes and with different shapes of notches are discussed. The experiments and the appropriate procedures are carried out with the aid of ASTM codes. The fatigue behavior is considered with the use of the low cycle fatigue method. The analysis is supplemented by numerical finite element modeling. The present work is an extension of the results discussed in the literature. The damage of plates with holes subjected to tension always occurs at the tip of the holes, i.e., (x = a, b = 0), both for static and fatigue failure. The originality and the novelty of this approach are described by the failure's dependence on two parameters: n and the ratio of the a/b ratio characterizing the hole geometry. The fuzzy approach is employed to reduce the amount of experimental data. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this paper, the effect of non‐relaxing torsion loadings on the fatigue lifetime reinforcement of carbon black filled natural rubber is fully addressed. Torsion fatigue tests with different loading ratios have been performed with highly notched axisymmetric‐shaped specimens. Finite element analysis is used to predict the mechanical state at any point in the specimens. The prediction is significantly improved by taking into account the heterogeneous accommodation. The first Haigh diagram under fatigue torsion is built and analyzed by calculating the minimum loading in terms of the Cauchy stress as the normal stress to the crack for the minimum angle prescribed during the cycle. A strong lifetime reinforcement has been observed, which is found to be of the same amplitude to the one obtained under uniaxial tension with the same material. This has been confirmed by specific tests that combined non‐relaxing torsion and non‐relaxing tension loadings. Post‐mortem analysis carried out at the macroscopic and the microscopic scales enabled us to identify damage mechanisms, especially in the cases where the lifetime reinforcement was observed. [ABSTRACT FROM AUTHOR]

Different methods can be applied to strengthen the weakened structure in perforated composite plates. A comparison of the four reinforcement models around the hole (ring, daisy, square and ellipse) under pure tension, pure shear, and combined (both tensile and shear loads) loadings was presented using Tsai-Wu failure criteria and calculations by finite element method (FEM). Before FEM analysis, tensile tests were performed with 12 tensile- and 6 shear-test specimens made of woven carbon fiber epoxy prepreg. During the tests of shear-test specimens, the strain distribution was obtained using the digital image correlation (DIC) method. Finite element verification was performed with both the applied force-deformation curve determined in the tensile test and the strain distribution obtained by the DIC technique. It was observed that four different reinforcement models, which have 38% volume of the created lightening hole, provide at least by 30% strength improvement to the unreinforced structure under tensile and shear loadings. Under combined loadings, according to the tensile/shear load ratio, the reinforcement types provide improvements at different rates. [ABSTRACT FROM AUTHOR]

Railway transportation is widely recognized as an environment-friendly and sustainable means for conveying freight and passengers over long distances. This article investigates the effectiveness of utilizing scrap tire rubber granules and geosynthetics to enhance track performance in response to the growing demands for railway transport and the consequent escalation of train-induced loading. A multi-faceted methodology, incorporating experimental, numerical, and analytical techniques, is employed to examine the efficacy of these sustainable approaches. Results from three-dimensional (3D) finite element (FE) analyses conducted on slab tracks for high-speed railways reveal that the addition of a resilient layer, comprising scrap tire rubber granules, reduces vertical stress within the track substructure. Laboratory investigations on an innovative composite material consisting of soil, scrap rubber granules, and polyurethane demonstrate its potential to enhance track performance. Findings from two-dimensional (2D) FE analyses conducted on pile-supported railway embankments highlight an enhanced transfer of load to the pile head following the installation of a geogrid layer at the embankment base. Finally, the results from the analytical approach indicate a reduction in track settlement and a decrease in the track geometry degradation rate on reinforcing the ballast layer with 3D cellular geoinclusion. The novelty of this study lies in the comprehensive assessment of the innovative composite material under drained and cyclic loading conditions, the investigation of the influence of train loading on geosynthetic tension and the load transfer mechanism in railway embankments, and the development of an innovative computational methodology capable of assessing the effectiveness of 3D cellular inclusions in improving the ballasted railway track performance. The findings from this article underscore the effectiveness of these sustainable approaches in mitigating the challenges posed by increased loads on railway tracks, providing valuable insights for the ongoing efforts to optimize railway transportation infrastructure. [ABSTRACT FROM AUTHOR]

This paper deals with the problem of stress concentration at the weld toe of non-load-carrying-type plate cruciform joints under tension, bending, and shear. Theoretical stress concentration factors were derived using the finite element method. Five of the most important geometrical parameters: the thickness of the main plate and the attachments, the weld throat thickness, the weld toe radius, and the weld face inclination angle were treated as independent variables. For each loading mode—tension, bending, and shear—parametric expression of high accuracy was obtained, covering the range used in real structures for cruciform connections. The maximum percentage error was lower than 2.5% as compared to numerical values. The presented solutions proved to be valid for the toe radius ρ tending to zero. [ABSTRACT FROM AUTHOR]

In this study, a micromechanical cyclic constitutive model for accurately describing the ratchetting deformation of polymeric composites is proposed. The model is based on the mean‐field homogenization method and incorporates the nonlinear viscoelastic‐viscoplastic (VE‐VP) cyclic constitutive model of the polymeric matrix and the imperfect interface. First, the nonlinear VE‐VP model was linearized using the incremental affine method and then was introduced into the homogenization process. The imperfect interface was represented using a linear spring model. A modified Mori‐Tanaka model was developed to incorporate the nonlinear VE‐VP model and imperfect interface into the micromechanical constitutive model. To implement the proposed micromechanical model, a numerical algorithm was developed. The model is capable of capturing the influence of the imperfect interface on the ratchetting deformation of polymeric composites. Furthermore, it is applicable to simulate various loading histories, including monotonic tension, stress relaxation, creep, and uniaxial ratchetting loads. The proposed model was validated by comparing its simulations with those obtained from the full‐field finite element method (FEM) model. The proposed model can predict the ratchetting deformation of polymeric composites and promote the practical application of these material in structures. Highlights: A micromechanical cyclic constitutive model is developed to describe the ratchetting deformation of polymeric composites with imperfect interface.Nonlinear viscoelastic‐viscoplastic deformation of polymeric matrix is considered.A modified Mori‐Tanaka method is employed to incorporate the nonlinear constitutive model and imperfect interface into the process of homogenization.Good agreement between simulations of the proposed model and the full‐field FEM model under various loading histories. [ABSTRACT FROM AUTHOR]

The deep energy method (DEM), a type of physics-informed neural network, is evolving as an alternative to finite element analysis. It employs the principle of minimum potential energy to predict an object's behavior under various boundary conditions. However, the model's accuracy is contingent upon choosing the appropriate architecture for the model, which can be challenging due to the high interactions between hyperparameters, large search space, difficulty in identifying objective functions, and non-convex relationships with the objective functions. To improve DEM's accuracy, we first introduce random Fourier feature (RFF) mapping. RFF mapping helps during the model's training by reducing bias toward high frequencies. The effects of six hyperparameters are then studied under static compression, tension, and bending loads in planar linear elasticity. Based on this study, a systematic automated hyperparameter optimization approach is proposed. Due to the high interaction between hyperparameters and the non-convex nature of the optimization problem, Bayesian optimization algorithms are used. The models trained using optimized hyperparameters and having Fourier feature mapping can accurately predict deflections compared to finite element analysis. Additionally, the deflections obtained for tension and compression load cases are more sensitive to variations in hyperparameters than bending. [ABSTRACT FROM AUTHOR]

Surface cracks are commonly observed in coatings and films. When structures with coatings are subject to stretching, opening mode cracks are likely to form on the surface, which may further lead to other forms of damage, such as interfacial delamination and substrate damage. Possible crack forms include cracks extending towards the interface and channeling across the film. In this paper, a two-dimensional numerical model is proposed to obtain the structural strain energy at arbitrary crack lengths for bilayer structures under uniaxial tension. The energy release rate and structural stress intensity factors can be obtained accordingly, and the effects of geometry and material features on fracture characteristics are investigated, with most crack patterns being confirmed as unstable. The proposed model can also facilitate the analysis of the stress distribution in periodic crack patterns of films. The results from the numerical model are compared with those obtained by the finite element method (FEM), and the accuracy of the theoretical results is demonstrated. [ABSTRACT FROM AUTHOR]

Single-point incremental forming (SPIF) is a technology that allows obtaining complex parts using a hemispherical end tool by applying a local deformation process in sheet metal. This dieless process presents the advantage of high formability limits and low cost. The increasing need for micro-components, namely, in the medical industry (implants and medical tools and accessories), has contributed to the development of the micro-single-point incremental forming (µ-SPIF) technique. However, this technique requires meeting certain challenges related to tool wear, resistance and precision of the manufactured parts, and increased formability. So, understanding the deformation and failure mechanisms in µ-SPIF is important to achieve improved formability. This paper is aimed at improving the predictions of the shear-modified GTN damage model by proposing an identification procedure for its numerous material parameters based on an inverse method coupling the numerical predictions with experimental results. The extended GTN model is first implemented into the finite element code Abaqus. The numerical approach is assessed through numerical simulations under shear and uniaxial tension loading. Then, a complete methodology is proposed to identify the set of material parameters using tensile and micro-single-point incremental forming (µ-SPIF) experimental results. The identification approach is based on the comparison of the numerical and experimental forces used to carry out the micro-incremental forming test with a pyramidal shape tool. To show the pertinence of the identification procedure, the numerical predictions of the modified GTN model with these material parameters are compared to the experimental results of µ-SPIF tests with different tool paths and geometrical forms. Finally, it is shown that the shear modification of the GTN model can predict the failure of sheets during metal forming. [ABSTRACT FROM AUTHOR]

In this paper, stress intensity factor (SIF) solutions of eccentric annular external cracks in elliptical notched round bars under tension loading have been obtained from 3D finite element analysis, along with their relation to the energy release rate obtained with the J-integral contour. The analysis variables have been the ligament diameter, its eccentricity, and the elliptical notch aspect ratio. The maximum SIF increases with the ligament eccentricity, the presence of the notch (compared to when the bar is smooth), and the elliptical notch axial semi-axis (for the same notch depth); it decreases with the ligament diameter. For external cracks, eccentricity induces bending of the bar subjected to tensile loading, which can produce partial and full contact of the crack surface, relevant phenomena in terms of the SIF value at the different points of the crack front. [ABSTRACT FROM AUTHOR]

Hot-stamped steel is currently the most widely used lightweight material in automobiles, and accurately predicting its failure risk during the simulation is a bottleneck problem in the automobile industry. In this study, the fracture failure behavior of the hot-stamped PHS2000 steel manufactured by Ben Gang Group (Benxi, China) is investigated by experiments and simulation. Static tension and high-speed tension tests are conducted to obtain the elastic-plastic stress-strain relations, and a Swift + Hockett–Sherby model is proposed to describe the hardening behavior under static and high-speed loads. Tests under five kinds of stress states, namely static shear, static tensile shear, notched static tension, center-hole static tension, and static punching, are conducted to obtain the ultimate fracture strains under different stress states for establishing a failure model. The finite element method (FEM) is used to inversely achieve the fracture parameters of the material, and the GISSMO model in LS-Dyna is adopted to describe the fracture characteristics of the material. A fracture card is further established for simulation analysis by combining fracture characteristics with high-speed tension curves and simultaneously loading size effect curves of meshes. Finally, the card is applied in the simulation of the three-point bending test. High-precision results of fracture simulation matching the experimental results are obtained. This research proves that the proposed fracture card is accurate and can be widely used in the simulation of fracture behaviors of the hot-stamped PHS2000 steel. [ABSTRACT FROM AUTHOR]

In this study, cyclic tension tests were conducted on ordinary Galfan cables and locked coil Galfan cables with diameters of 40 mm to evaluate their mechanical properties under cyclic tension. The mechanical behavior of the two kinds of Galfan cables under monotonic loading and cyclic tension was analyzed, while the differences in strength and the mechanical properties of the two kinds of Galfan cables and the effects of different loading systems on the mechanical properties of the two kinds of cables were obtained. The Ramberg–Osgood model was used to fit the skeleton curve. The elastic and inelastic behaviors during loading and unloading were studied. The change in elastic modulus of the Galfan cable with respect to cyclic load is proposed, and the exponential model of strain and elastic modulus under cyclic load is established, which lays a foundation for the accurate finite element analysis of cable structure response under strong earthquake and other accidental loads. [ABSTRACT FROM AUTHOR]

This paper presents the mixed mode I/II stress intensity factors (SIFs) of slanted cracks/notches under tension loading. A two‐dimensional finite element analysis (FEA) was employed using the ABAQUS program. Based on the literature survey, there is a lack of solutions for SIFs of slanted cracks in plane stress plates. The strain energy approach (SEA) was adopted to analyze the notched cases. Mode I and II SIFs are derived via the SEA method from the strain energy computed using the FEA technique. The results show excellent agreement with other researchers' work. The key contribution of the present paper is the presentation of the effect of the crack/notch length to plate width ratio on the mode I and II SIFs of a slant‐edge‐cracked/notched plate under different boundary conditions. Sets of new data of mode I and II SIFs are provided herein in tabular and graphical formats. Highlights: Stress intensity factors (SIFs) of single edge‐cracked/notched plates under mode I/II loading computed.Parametric and comparative analysis of SIFs of pinned/clamped boundary conditions (BCs).SIFs derived from finite element analysis (FEA) computed elemental energies by strain energy approach.Effects of pinned and clamped BCs on mode I/II SIFs of cracked/notched plates shown. [ABSTRACT FROM AUTHOR]

In this paper, a fatigue crack growth (FCG) behavior under variable amplitude loadings and for mixed modes is analyzed in terms of residual compressive stress zone. For that, the Chaboche non-linear kinematic hardening model is used to evaluate the crack behavior on AA2024-T3. At first, a series of FCG simulation is performed for a single edge notched tension specimen to highlight the influences of the crack length, the overload ratio, the stress ratio, the mean stress, the mixed mode, and the load sequence on the crack tip residual -stress zone under variable amplitude loadings. Besides, the size and shape of crack tip residual-stress zone are simulated for low/high, high/low block loadings and with/without overloads. Moreover, and according to the findings, a FCG code using the Python script and the extended finite element method (XFEM) Is improved. The developed code processes FCG behavior under variable amplitude loadings using the shape of residual stress distribution near the crack tip. The predicted results show a good agreement in simulating fatigue crack path under variable amplitude loadings with those published in the literature. The originality of this study is to simulate the fatigue crack path of cracked structures under variable amplitude loadings with the compressive residual stress model coupled with the XFEM for mode I and different mixed mode. [ABSTRACT FROM AUTHOR]

Summary: The coupling beam pile structure is a new type of foundation for high‐rise buildings that can be easily constructed. The vertical load‐bearing characteristics of the coupling beam pile structure are examined using indoor model tests and numerical calculations to optimize the beam structure's parameters. The validity of the finite element model is then confirmed, and the beam structure's width, length, and stiffness are changed to examine their effects on the load‐bearing capacity. The results show that the load–settlement curve of the structure varies slightly, with a 45.10% increase in load‐carrying capacity compared to a pile group foundation for the same load, and that the coupling beam can support heavier loads while also distributing the tension of the loads. The width and length of the coupling beam are proportional to the load‐carrying capacity of the structure. The width of the coupling beam should be kept at 3.5 times the pile diameter since any wider width results in the "wall group effect," which reduces the foundation's ability to support the weight. The coupling beam's short length, which should be kept above 4.5 times the pile diameter, can aid in reducing the "pile group effect." The coupling beam stiffness can be changed according to the scenario in practice; there is no upper limit. The coupling beam stiffness is 5 times the reference value when it has the strongest force transmission capacity but has essentially little impact on the structure's load‐carrying capacity. [ABSTRACT FROM AUTHOR]

Tubular Joints play quite a vital role in most marine structures. It is obvious that having full control about the capacity and strength of tubular joints would be very worthy to have good knowledge about the total performance of the structure. In recent years, the application of the finite element method has become very popular in the analyses of different types of welded circular tubular joints and many commercial and open-source FE systems have been profoundly involved in these regards. Most of these software shares so much in common that it is difficult to differentiate them. This study was performed to investigate and report the usefulness of the open-source software programs in implementing finite element modeling for design applications. In this regard, with aid of the open-source finite element package Code_Aster and its user-friendly interface Salome-Meca, the behavior of reinforced and unreinforced T-joint specimens subjected to axial brace load with different geometry and material property has been studied. In addition, different types of shell and solid finite elements with various mesh densities are considered in this research. In order to overlap the outcomes, the numerical results of this research are present in terms of load-ovalization curves along with the results of other references. Due to mesh sizes and the element types, 144 different simulations have been performed on 12 different specimens. The results show that Code_Aster can satisfactorily predict the nonlinear static behavior of reinforced and unreinforced joints under both tension and compression load. Hence, Code_Aster can be used as a reliable tool for the evaluation and analysis and design of complex offshore joints. [ABSTRACT FROM AUTHOR]

Accurate prediction of stress and displacement in plates with central cracks is vital for engineering design safety. However, the impact of finite plate size on stress and displacement distribution is an important factor that has not been fully addressed in previous studies, highlighting the need for further investigation. Thus, this study presents a closed-form elastic solution for a rectangular plate with a central crack under tension load. The solution uses complex polynomial functions satisfying equilibrium equations and boundary conditions. Numerical finite element models verify the analytical solution's accuracy for plates with varying crack lengths. The presented closed-form solution accounts for the impact of finite plate size on stress and displacement distribution accurately. Developing closed-form solutions for structural mechanics problems enables engineers to optimize designs for safety, efficiency, and cost-effectiveness more accurately. [ABSTRACT FROM AUTHOR]

This paper proposed a virtual testing method combining finite element procedure with heterogeneity weak bonding model to analyze the macroscopic responses of composite plates. Results show that weak bonding can induce out-of-plane displacement fluctuation when plates subjected to tension or shearing loads. However, it is less sensitive to transverse load. Further, much more distorted displacement map means more serious weak bonding interface. The fluctuated displacements can be used to measure and evaluate weak bonding under some specified loading modes. Since the computational framework considers the heterogeneity weak bonding, the statistical characteristics of results can be obtained by multiple computations. [ABSTRACT FROM AUTHOR]

Edentulism produces resorption of alveolar bone processes, which can complicate placement of dental implants. Guided bone regeneration techniques aim to recover the volume of bone. These treatments are susceptible to the surgical technique employed, the design of the autologous block or the tension of the suture. These factors can relate to major complications as the lack of primary closure and dehiscence. The present study, using finite element analysis, aimed to determine differences in terms of displacement of the oral mucosa, transferred stress according to Von Mises and deformation of soft tissue when two block graft designs (right-angled and rounded) and two levels of suture tension (0.05 and 0.2 N) were combined. The results showed that all the variables analyzed were greater with 0.2 N. Regarding the design of the block, no difference was found in the transferred stress and deformation of the soft tissue. However, displacement was related to a tendency to dehiscence (25% greater in the right-angled/chamfer design). In conclusion different biomechanical behavior was observed in the block graft depending on the design and suture tension, so it is recommended to use low suture tension and rounded design. A novel finite element analysis model is presented for future investigations. [ABSTRACT FROM AUTHOR]

The tension insulator string is an important component for transferring the load of the conductor to the transmission tower. The damage of tension insulator strings may dramatically affect the operation safety of the grid power. In this paper, the dynamic response and fatigue life of the tension insulator strings under stochastic wind were systematically studied. Firstly, finite element models of conductors and the tension insulator string upon the actual transmission lines were established. The effects of height difference ratios on the dynamic tension of conductors and the dynamic response of tension insulator strings under a 10 m/s stochastic wind were investigated, respectively. Secondly, a simplified calculation method of stress time history is proposed to simplify the fatigue life analysis for tension insulator strings. Finally, based on the Rayleigh distribution, wind farms with the annual mean wind speed of 7 m/s were established to evaluate the fatigue life of tension insulator strings. The stress results revealed the at-risk parts in tension insulator strings and their failure modes. The fatigue life results showed 17.1 and 33.4 years for the GD (Guan Dian)-fittings and the upper U-shackles, respectively. This study can provide a useful guideline for optimization and safety evaluation of fittings. [ABSTRACT FROM AUTHOR]

This study investigates the structural performance of the corner column-to-column connection made of VectorBloc under tensile axial load, which links corner columns between two consecutive floors. Nine full-scale specimens, comprising three distinct connection types one Axial Tension Single Column (ATSC) connection and two Axial Tension Bundle Columns (ATBC-MCC and ATBC-BCC) connections were tested under axial tension load. Failure in all specimens resulted from the rupture of Socket-Head-Cap Screws (SHCSs) connecting the upper and lower blocs of the connector. Despite identical SHCSs across all specimens, variations in their positions led to different outcomes due to differing column geometries and resulting load eccentricities. Notably, the eccentricity induced bloc rotation, leading to separation on the tension face. Axial tension single column exhibited the lowest average tensile capacity, while bundle column connections, despite similar section areas, exhibited contrasting load capacities, attributed to varying load eccentricities. A subsequent parametric study, using finite element analysis, was conducted to identify parameters critical for maximizing the tensile load capacity of this column connection. • This paper presents the performance of Vectorbloc connection subjected to axial tension. • This research was completed using full-scale tests and a detailed FE-based parametric study. • The SHCSs play the most important role in the tensile capacity of the connection. • Both eccentricity and parameter d must be minimized to maximise the tensile capacity. • The parameter d is developed and introduced for the first time in this paper. [ABSTRACT FROM AUTHOR]

Plate thickness influences the fatigue performance of welded components. In fatigue design standards and recommendations, the thickness effect and fatigue strength reduction have been considered by modifying the S N curve for plates thicker than a reference thickness. However, increasing fatigue strength due to the thinness effect is often disregarded. The current study focuses on the size effect in fatigue of butt welded and non-load carrying cruciform welded joints under constant amplitude tension load. Literature data is evaluated using the effective notch stress method with a reference radius of 1 mm, which is used for all finite element models to ensure that FAT-value corresponding to a 1 mm notch radius remains constant across all models. A probabilistic assessment of the results using the weakest-link theory is applied to improve the prediction accuracy of thinner members outside the recommended thickness range of the used radius. The method reduces the S N data scatter in comparison to the variation of test data and shows applicability also for thinner members. A comparison of the size effect for the current method with extrapolated values from standards and recommendations shows a difference in the size effect for thinner members. • Considering size effect for fatigue assessment of welded joints. • Using the probabilistic approach to better understand the thinness effect. • Using the effective notch stress method with a reference radius of 1 mm to study the size effect on welded joints. [ABSTRACT FROM AUTHOR]

Micro finite-element (μFE) simulations serve as a crucial research tool to assist laboratory experiments in the biomechanical assessment of screw anchorage in bone. However, accurately modelling the interface between bone and screw threads at the microscale poses a significant challenge. Currently, the gold-standard approach involves employing computationally intensive physical contact models to simulate this interface. This study compared nonlinear μFE predictions of deformations, whole-construct stiffness, maximum force and damage patterns of three different computationally efficient simplified interface approaches to the general contact interface in Abaqus Explicit, which was defined as gold-standard and reference model. The μCT images (resolution: 32.8 μm) of two human radii with varying bone volume fractions were utilized and a screw was virtually inserted up to 50% and 100% of the volar-dorsal cortex distance. Materially nonlinear μFE models were generated and loaded in tension, compression and shear. In a first step, the common simplification of using a fully-bonded interface was compared to the general contact interface, revealing overestimations of whole-construct stiffness (19% on average) and maximum force (26% on average), along with inaccurate damage pattern replications. To enhance predictions, two additional simplified interface models were compared: tensionally strained element deletion (TED) and a novel modification of TED (TED-M). TED deletes interface elements strained in tension based on a linear-elastic simulation before the actual simulation. TED-M extends the remaining contact interface of TED by incorporating neighboring elements to the contact area. Both TED and TED-M reduced the errors in whole-construct stiffness and maximum force and improved the replication of the damage distributions in comparison to the fully-bonded approach. TED was better in predicting whole-construct stiffness (average error of 1%), while TED-M showed lowest errors in maximum force (1% on average). In conclusion, both TED and TED-M offer computationally efficient alternatives to physical contact modelling, although the fully-bonded interface may deliver sufficiently accurate predictions for many applications. [Display omitted] • Materially-nonlinear micro finite element modelling of single bone-screw systems. • Comparison of general contact to simplified contact models in Abaqus Explicit. • Fully-bonded interface overestimated whole-construct stiffness and maximum force. • Different damage patterns between general contact and fully-bonded interface. • Simplified interface models improved predictions and are computational-efficient. [ABSTRACT FROM AUTHOR]

The nitriding process is a surface treatment that improves the surface properties of titanium alloys and increases wear/corrosion resistance. This study investigates the structural and mechanical property changes in titanium alloy after nitriding. Micro-hardness differences between the nitrided and non-nitrided surface and morphological changes on the surface were determined. In addition to evaluating the effect of vanadium and aluminum ions on the nonnitrided surface, the impact of nitrided and non-nitrided surfaces on biofilm layer formation was investigated. It was determined that the TiN layer formed on the nitrided surface showed superior properties to its non-nitrided surface in the biofilm tests performed for 6 h. As a result of the tensile tests, it can be said that the nitriding process increases the elasticity module of the Ti–6Al–4V alloy and provides the material to have a more rigid structure. It was also analyzed using finite element analysis (FEA) of mechanical behaviors of the test sample under the tension loads. [ABSTRACT FROM AUTHOR]

In many engineering fields such as aerospace, marine, automotive and mechanical, the design of planar structures consisting of rectangular plates commonly requires the use of holes as a technological solution in fastening assemblies. The major goal of this research is to examine the impact of stress concentration factors (SCF) in the specific case of planar structures, highlight their relevance as a potential source of structural failure, and compare the various techniques employed to gauge their magnitude. Particular emphasis will be placed on rectangular plates with holes since these plates' shape discontinuities alter the stress field, leading to a local increase in the stress field that, if not accurately predicted and analyzed at the design stage, could endanger the entire structure. For the studied case (rectangular plate with central hole subjected to uniform tensile field), a new finite element formulation based on 3-noded triangular element has been suggested to estimate the field variables (stress). MATLAB programming has been developed by considering this element. Analysis has been carried out for the same structure (rectangular plate) with analysis software Abaqus. Finding was compared to several analytical solutions published in the literature, based on Heywood, Howland, and Flynn formulations. Obtained results were in good agreement. [ABSTRACT FROM AUTHOR]

Finite element model of a typical ultra-high voltage direct current transmission line section, in which buckling collapse of the tension plate took place during operation, is established. In the finite element model, the tension plate and the connected hardware fittings are discretized with 3D solid elements and the sub-conductors, spacers, clamps and insulator strings with spatial beam elements. Dynamic responses of the line after ice shedding are numerically simulated and the maximum loads on the tension plate in the cases with different ice thicknesses and ice-shedding are obtained. Buckling behaviors of the tension plate are analyzed and the conditions leading to buckling collapse are discussed. Finally, the topology optimization of the tension plate is performed and two optimized schemes of the tension plate are proposed based on the optimization result and manufacture cost. Efficiency analysis demonstrates that the buckling loads of the optimized tension plates increase more than 20% nearly without increasing weight. [ABSTRACT FROM AUTHOR]

Fatigue is an important factor leading to the structural failure of 3D braided composites during the service. In this paper, a meso-scale finite element analysis (FEA) model based on continuum damage mechanics (CDM) is developed to study the fatigue damage behavior and predict the fatigue life of 3D braided composites subjected to off-axial tension loadings. Stress analysis, failure criteria and material properties degradation scheme in the meso-scale model are implemented by a user-material subroutine UMAT based on ABAQUS/Standard solver. The damage initiation and propagation of 3D braided composites under diverse off-axial fatigue loadings are simulated and analyzed in detail and the corresponding off-axial fatigue lives are obtained from the predicted S - N curves. The proposed FE modeling provides a suitable reference for the numerical research on the off-axial fatigue problems in other textile composites. [ABSTRACT FROM AUTHOR]

In this investigation, a discrete element model of single-layer arranged particles, which is suitable for solving problems of plate structures, is proposed through the discrete element method (DEM) according to stress characteristics of thin plate structures. Additionally, mass of the particles and rotary inertia of the contact element corresponding to the discrete model are modified accordingly. Then, expressions of stiffness coefficient of the contact springs among the discrete particles of the plate are derived based on the energy equivalence principle. Afterward, the proposed discrete model is applied to solve elastic problems of plate structure, such as integrated plate and plate with an aperture under in-plane tension, cantilever plate under bending and large deformation plate subjected to transverse loads, the results of which are well consistent with results obtained through finite element method. The key of the discrete element model is interaction among the particles, which is obtained according to motion equations and contact relationships. Furthermore, the stiffness matrix and iteration are not required during the calculation process by adopting DEM. The model can automatically meet the requirements of large deformation. Therefore, it is suitable for solving highly nonlinear problems of plates with large deformation or large rotation. [ABSTRACT FROM AUTHOR]

Over the conventional limit equilibrium method and limit analysis method, the finite element method is advantageous, especially for slopes involving complex failure mechanisms where the critical slip surfaces cannot be represented by log spirals and other similarities. In the presence of tension cracks at slope crests, however, the finite element method encounters difficulties in convergence while handling Mohr–Coulomb's yielding surfaces with tensile strength cut-off. Meanwhile, the commonly used load-controlled method for the system of nonlinear equilibrium equations is hard to bring the slope into the limit equilibrium state. The two drawbacks drag down the finite element method in more extensive applications. By reducing the constitutive integration of plasticity with non-smooth yielding surfaces to the mixed complementarity problem, the convergence in numerical constitutive integration is established for arbitrarily large incremental strains. In order to bring the slope to the limit equilibrium state, a new displacement-controlled algorithm is designed for the system of nonlinear equilibrium equations, which is far more efficient than the load-controlled method. A procedure is proposed to locate tension cracks. Corresponding to the Mohr–Coulomb failure criterion with and without tensile strength cut-off, the failure mechanisms differ significantly, while the difference in the factor of safety might be ignorable. [ABSTRACT FROM AUTHOR]

A prefabricated concrete structure is a building structure designed for sustainability and low comprehensive carbon emission. The grouted sleeve splice is a major connection method for prefabricated concrete structures. However, construction defects occur easily in the grouted sleeve splice connection at construction sites because of complex construction environments and the high connection accuracy. To determine the influence of rebar in steel half-grouted sleeve connections with construction defects, investigations were conducted using four different test groups (rebar offset, rebar bended, insufficient fluidity of grout, and control group). The load-displacement curve and load-stress curve were analyzed on 24 different specimens through uniaxial tension experiments. The experimental results showed that rebar fracture was the failure of specimens. The load-displacement curves consisted of elastic, yield, strength, and tight stages. The curves were similar to rebar under uniaxial tension, except for the rebar bended group. The axial stress and circumferential stress on the sleeve surface consistently followed a linear response before the specimen yield, whereas the axial stress and circumferential stress showed a rebound response after the specimen yielded. Different finite element models were established based on the different defects. Compared with the experimental results, the finite element analysis results coincided with those of the experimental results, and the errors were within 8% to evaluate the performance of steel half-grouted sleeve connections in construction. [ABSTRACT FROM AUTHOR]

Pipeline repair plays an important role in safe pipeline operation. Composite material repair technology has been widely used in pipeline repair due to its advantage of light weight and low cost. In this paper, the failure loads of repaired pipe with composite under tension and internal pressure are analysed by experiments, Finite Element Method (FEM) and theoretical method, and simple formula of failure loads is obtained based on theoretical analysis and verified by FEM and experiments. First, the tension experiment shows that debonding happens in the repaired pipe before its fracture, and then the debonding details are showed in FEM results considering the adhesive debonding criteria, finally a simple formula expression is obtained for the failure tension loads based on the analysis of interface stresses, and the results are almost consistent with the experimental method and FEM. Similarly, for the case under internal pressure, the blasting failure loads are obtained for the repaired pipe based on the theoretical analysis, which are consistent with FEM results. [ABSTRACT FROM AUTHOR]

The accuracy and precision of lifetime predictions for cyclically loaded technical components are still lacking. One of the main reasons for the discrepancy between the calculated life time and experimental results is that it is not yet possible to create a model capable of describing the microstructural damage process that occurs in the tested material and to subsequently incorporate this model into the calculation. All of the presently available research results recognize that the growth of microcracks is significantly influenced by the microstructure of the material. In order to take into account the influence of the microstructure on the damage process, research on the very early fatigue damage is carried out. The results are obtained from tension and torsion fatigue testing. For this purpose, the surfaces of the tested specimens are carefully observed to discover and analyze microcracks, which are classified according to their orientation. Moreover, the mechanisms of crack initiation and propagation are major points of interest. Through a mix of mechanical and metallurgical points of view, calculations and multi-level FEA modeling are carried out to gain a better understanding of the properties of the phases. The simulation is based on continuum mechanics, which considers the positions and mechanical metallurgy, which account for each constituent character's failure laws. It is concluded that both the experimental and computational approaches conform, showing that such an approach is indeed a necessity and should become a trend in the near future. Statistically, microcracks under tension modes are highest at 45° (approximately 30%), while under torsion they are highest at 0° (approximately 20%) with respect to the sample orientation. The influence of the microstructure is explained via the finite element analysis. [ABSTRACT FROM AUTHOR]

Composite material is a well-known structural material which is increasingly adopted as an engineering structure material. Glass fiber reinforced polymer offers the lightweight and high strength characteristics that is required for the modern industry, such as aviation, automotive, wind power, and marine technology. One of the important mechanical characteristics of the composite materials are the tensile properties, because it is well known as the material strength. Therefore, the investigation of mechanical response on the glass fiber reinforced polymer (GFRP) tensile test using numerical analysis is important for the estimation of structural response of the GFRP complex structure, such as boat construction. The objective of this research is to assess and estimate the mechanical response of the GFRP composite material subjected to tension load using finite element method. The linear transversely isotropic model is developed to estimate the unidirectional glass fiber GFRP with the configuration of fiber orientation angles of 0°, 30°, 45°, 60° and 90°. The results show that FE simulation are capable to detect the specimen response during the tensile test. The maximum discrepancy of the estimated stress strain diagram is about 16.5% to 32% compared to experimental data. The larger orientation angle has shown the larger discrepancy value. It is found that the increment of discrepancy value is generated by the nonlinearity behavior of the material due to the domination of polymer material behavior on the large orientation angle. Otherwise, the FE models have estimated accurately the ultimate strength, maximum displacement and fracture load. It can be concluded that the linear transversely isotropic model is adequately accepted as the estimation method of the GFRP composite structure response. [ABSTRACT FROM AUTHOR]

In curtain wall applications, anchor channels are frequently installed near the edge of composite slabs with profiled steel decking. The complex concrete geometry of these floor slabs affects the capacity of all concrete failure modes, but there are currently no guidelines or investigations available on this topic. The main objective of the present research is to investigate how the position of anchor channels and the complex slab geometry influence the tensile capacity of anchor channels. For this purpose, an extensive numerical parametric study was performed using the 3D nonlinear FE code MASA, which is based on the microplane constitutive model. In order to validate the numerical results, an experimental program was carried out for some of the configurations possible in practice. Based on the results, recommendations are given for the reduction in the tensile capacity of anchor channels in composite slabs with profiled steel decking. [ABSTRACT FROM AUTHOR]

The periodic truss structures in mechanical metamaterials have received widespread attention, yet stress concentration at nodes promotes the failure of truss structures, in particular under tension load. Here we report that tensile properties (in particular, ductility) of truss structures can be remarkedly improved by replacing the surface at the node with a triply periodic minimal surface (TPMS) structure. The intrinsic stress concentration at nodes in truss lattice structure can be readily dissipated at TPMS-modified nodes and transferred to the connected ligaments, leading to the enhanced tensile ductility. Moreover, the efficacy of TPMS modification is found to be correlated with the node coordination number, where lattice structures with a high coordination number of nodes possess better property improvements. The role of TPMS nodes on stress transfer and deformation de-localization behaviors is well interpreted by the in-situ microstructural analyses as well as finite element modeling simulations. [Display omitted] [ABSTRACT FROM AUTHOR]

• Introduced a novel formula for helical spring buckling under combined loads. • Experimental and numerical analyses confirm the formula's effectiveness. • Higher preload and prestretching enhance spring buckling torque resistance. A new formula is introduced to analytically determine the critical torsional load or angle of rotation that confers instability in a tension spring under combined tension and torsion load using the theoretical framework of Greenhill's problem applied to an elastic bar as a starting point. The formula's effectiveness is evaluated with experimental torsion tests and finite element method simulations in Abaqus. The results demonstrate the formula's accuracy in predicting instability within specific stretched operating ranges, and achieving a relative error in correlation below 10 % for most operating points. The study underscores the significance of preload and pre-stretching in enhancing the spring's resistance to buckling. [ABSTRACT FROM AUTHOR]

The potential of using specimens with a double-semicircular-notched configuration for performing tensile tests of orthodontic thermoplastic aligner materials was explored. Unnotched and double-semicircular-notched specimens were loaded in tension using a universal testing machine to determine their tensile strength, while finite element analysis (FEA) and digital image correlation (DIC) were used to estimate stress and strain, respectively. The shape did affect the tensile strength, demonstrating the importance of unifying the form of the specimen. During the elastic phase under tension, double-semicircular-notched specimens showed similar behavior to unnotched specimens. However, great variance was observed in the strain patterns of the unnotched specimens, which exhibited greater chance of end-failure, while the strain patterns of the double-semicircular-notched specimens showed uniformity. Considerable agreement between the theoretical (FEA) and practical models (DIC) further confirmed the validity of the double-semicircular-notched models. [ABSTRACT FROM AUTHOR]

This study is intended to elucidate the mechanisms underlying fluid–structure interactions (FSIs) for a pontoon submerged floating tunnel (PSFT). To this end, a shear stress transport k-ω turbulence model was used to analyze the hydrodynamic force of the PSFT tube under the flow load. The finite element method was then used to predict the horizontal displacement of the PSFT tube under hydrodynamic action. In the calculation, the buoyancy of the PSFT pontoons was represented by an equivalent spring tension, and the fixed constraint was adopted at the shore wall of the tunnel tube. The FSI calculation results indicated that, when the flow load was larger, the pressure fluctuations of the flow field around the PSFT tube were stronger, resulting in greater dynamic effects on the horizontal direction of each tube segment. The smallest and largest deformations of the tunnel segment were observed at the mid-span and near the shore wall, respectively. It was also found that the barbell-shaped PSFT tube cross section may lead to intensify the pressure fluctuations near the tunnel tube as the flow load was increased. It is recommended that the appropriate number of pontoons and tunnel tube reinforcement can reduce the deformation of the PSFT. • The buoyancy of the PSFT pontoons is represented by an equivalent spring tension. • The hydrodynamic force is coupled to a finite element model to simulate the deformation characteristics of PSFT tunnel tube. • The smallest and largest flow load influences of the PSFT tunnel segments are observed at the mid-span and near the shore wall. [ABSTRACT FROM AUTHOR]

Based on the improved three-dimensional finite element model, this paper studies the load transfer mechanism of pile-supported reinforced embankments. The model uses an elastic medium to replace the soft soil subgrade, which reduces the calculation depth of the subgrade and improves the calculation efficiency of the model. The validity of the model is proven by field test results and theoretical calculation results. By changing the cohesion, internal friction angle, elastic modulus of the embankment filler, and geogrid strength, the effects of various influencing factors on the pile–soil stress ratio, the load-sharing ratio of the soil arching effect, and the load-sharing ratio of the membrane effect was analyzed, and the sensitivity of each influencing factor was evaluated. Based on the response surface optimization test, the multiple regression equation of influencing factors and evaluation indicators was established. The interaction between the parameters was analyzed, and the optimal combination of parameters was solved. The results show the following: Increasing the cohesion, the internal friction angle, and the elastic modulus of the embankment filler can promote the soil arching effect to a certain extent. However, for reinforced embankments, a large cohesion, a large internal friction angle, and a high elastic modulus of an embankment will reduce the pile–soil differential settlement and the pile–soil stress ratio; an increase in geogrid strength has a certain promoting effect on the pile–soil stress ratio. When the geogrid strength reaches 120 kN/m, the pile–soil stress ratio tends to be stable; the tested regression model can accurately reflect the changes in the relationship between the influencing factors and the response values, and it fits the actual situation well. Numerical simulation results show that the optimized pile–soil stress ratio increases by 13.4%. [ABSTRACT FROM AUTHOR]

Bending deformation gives rise to interwire slippage for spiral strands subjected to multi-axial loads, and further induces wear or fatigue phenomena in practice. The interwire friction would resist bending deformation and lead to uneven tension distribution of individual constituent wires but little research has quantified these effects. To figure out this issue, a beam finite element (FE) is established, into which a penalty stiffness algorithm and a Coulomb friction model are incorporated. A series of free bending simulations are developed for parametric study on deflection near the terminations and tension distribution of individual wire for strands with different levels of length and friction coefficient as well as external loads. Based on the simulation results, it is found that strand length has little influence on bending deformation and tension distribution if the strand length exceeds six times the pitch length. A deflection formula extended from the classical Euler beam model well predicts the sag deflections and the relative error with respect to experimental measurements is less than 10%. Furthermore, additional axial tension induced by the friction is clearly characterized and an approximate expression is proposed to estimate tension distribution for outer layer wires. Its predictions are encouraging for longer strands. [ABSTRACT FROM AUTHOR]

Here, we present a macroscopic model of a blind rivet joint. To develop this model, the load-displacement curves of the blind rivet joint in the tensile and shear directions were measured by a single lap shear test, and a cross-tension test and optimization process were conducted. The model enables us to simulate various blind joint connections in components with high efficiency and accuracy and propose a specific joint strength per unit joint from the simulation results. Moreover, we analyzed the effect of the tensile strength and thickness of the plate on the joint strength per unit joint. As a result, we provide a prediction method for the number of joints for the component along with the proposed joint strength per unit joint for various materials and plate thicknesses. [ABSTRACT FROM AUTHOR]

This paper investigates the behaviour of square hollow section (SHS) T-joints under static axial tension for the determination of stress concentration factors (SCFs) at the hot spot locations. Five empty and corresponding concrete-filled SHS-SHS T-joint connections were tested experimentally and numerically. The experimental investigation was carried out by attaching strain gauges onto the SHS-SHS T-joint specimens. The numerical study was then conducted by developing three-dimensional finite element (FE) T-joint models using ABAQUS finite element analysis software for capturing the distribution of the SCFs at the hot spot locations. The results showed that there is a good agreement between the experimental and numerical SCFs. A series of formulae for the prediction of SCF in concrete-filled SHS T-joints under tension were proposed, and good agreement was achieved between the maximum SCFs in SHS T-joints calculated from FE T-joint models and those from the predicted formulae. [ABSTRACT FROM AUTHOR]

We analyze specific features of the fatigue fracture of hybrid pumping rods with carbon-fiber cores and fiberglass shells intended for the oil extraction. It is shown that the fracture of rods under bending loads is accompanied by the intense formation of longitudinal cracks in the form of delaminations in the metal part of the rods and the initiation of up to 5–6 cracks in the fiberglass shell. We determine the conditions of cracking under the same cyclic load for the rods of different design. The finite-element method is applied to analyze the stresses formed in the joint of elements of the hybrid rods loaded by bending with tension. On the basis of the established regularities of fatigue-crack growth in hybrid pumping rods, we propose a method for prediction of their residual service life. [ABSTRACT FROM AUTHOR]

The stability of cable-net structures depends on the prestress of the system. Due to the large displacement and mutual effect of the cables, it is difficult to simulate the tensioning process and control the forming accuracy. The Backward Algorithm (BA) has been used to simulate the tensioning process. The traditional BA involves complicated and tedious matrix operations. In this paper, a new numerical method based on the Vector Form Intrinsic Finite Element (VFIFE) method is proposed for BA application. Moreover, the tensioning sequence of a complex cable-net structure is introduced. Subsequently, a new approach for BA application in the simulation of the tensioning process is presented, which combines the VFIFE approach and the notion of form-finding. Finally, a numerical example is simulated in detail and the results of different tensioning stages are analyzed to verify the feasibility of the proposed approach. This study provides a significant reference for improving the construction control and forming accuracy of complex prestressed cable-net structures. [ABSTRACT FROM AUTHOR]