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A dynamic 3D finite element model for the calculation of profile degradation in the switch panel is presented. The model includes the contact between wheel and rail, as well as the contact between switch rail and stock rail to allow an elastic relative movement between the two rails. Break-outs of the switch rail tip can be facilitated by this relative movement and the stresses and strains at this interface are calculated. The profile degradation of the switch rail due to contact loading between wheel flange and switch rail is numerically simulated considering the cyclic plastic deformation of the rail material. The sliding wear is evaluated separately and superimposed to the geometrical change caused by the plastic deformation. [ABSTRACT FROM AUTHOR]

This paper presents a numerical investigation of the shear creep behavior of the adhesive joint in concrete structures strengthened by externally bonded fibre-reinforced polymers (FRP) composites. Based on experimental data collected in a previous study, creep constitutive equations were developed for the adhesive layer and implemented into a finite element code. The proposed model extends the classical one-dimensional formulation of Burgers creep model to a fully 3D model and introduces the nonlinearity of the model parameters. This numerical approach was first used to simulate the nonlinear creep behavior of bulk epoxy samples; it was then extended to predict the nonlinear creep response of the FRP-concrete interface in double lap shear specimens. Globally, a fair agreement was obtained between numerical results and experimental evidences. As a main result, it was found that creep induces a redistribution of the interfacial shear stress along the FRP-concrete lap joint, leading both to a stress relaxation near the loaded end of the adhesive joint and to an increase in the effective transfer length. [ABSTRACT FROM AUTHOR]

Tungsten is extensively used as a plasma facing material in fusion energy reactors. A finite element model was created to simulate the machining of tungsten for the first time by estimating the cutting forces and observing the impact of the variation in tool rake angle. The model was validated through machining experiments involving a specially designed single flute fly cutter which indicated errors of 6% – 34%, depending on the rake angle. This investigation is the first step in understanding the impact of cutting parameters on machining of tungsten. However, the model is affected by the unpredictable impact of tungsten's deformation behaviour and especially the effects of its brittle nature and low fracture toughness. [ABSTRACT FROM AUTHOR]

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As rock bursts are unavoidable in deep mines and excavations with high in-situ stresses, ground support systems are implemented to manage and mitigate rock bursts. Cable bolts are commonly used as reinforcing elements in ground support systems, which are subject to dynamic loads in burst-prone excavations. To design an efficient cable bolt in burst-prone conditions, shear and energy absorption capacity must be considered. Numerical modelling is an advantageous method of repeatable testing and it is inexpensive and non-destructive. This study develops a statically and dynamically loaded numerical model of a double shear test in ABAQUS/Explicit. A total of 36 static and 576 dynamic tests are carried out, which examine the influence of bolt diameter, steel yield and ultimate strength, dynamic load velocity and dynamic load mass on the displacement, shear force and energy absorption capacity of cable bolts. As bolt diameter and steel yield strength increases, the maximum shear force resisted and bolt displacement increases. Similarly, as the mass and velocity of the dynamic load increases, the amount of energy absorbed by the cable bolt increases. The main novelty of the current research is to suggest a reliable computational tool to investigate the influence of the different key parameters in the cable bolts on the ultimate capacity. The suggested method is a significantly cost-effective technique compared with the experimental investigations. [ABSTRACT FROM AUTHOR]

Since the 1980s, calcium silicate element masonry has been commonly used in Dutch buildings, and vertical continuous joints have been usually located at the corner of perpendicular walls. Since the shear failure of these joints may significantly reduce the seismic performance of the flanged wall and therefore of the entire building, the assumption of rigid connection may be inaccurate, unlike for the traditional interlocking of bricks in running bond textures. In this paper, analytical and numerical approaches to study the failure of vertical joints in the seismic assessment of URM buildings are presented. The first part of the work focuses on two different numerical models to study the nonlinear behaviour of the vertical connection; the related critical numerical issues are then discussed. The second part introduces an analytical method able to estimate the lateral force–displacement curve of a flanged wall, which considers the possible failure of the connection. In particular, the method is derived from the section analysis approach developed for controlled rocking deformable systems. The comparison between the numerical simulations and the analytical method proves the capacity of the latter to provide a quick but sufficiently accurate estimate of the force–displacement curve of a URM U-Shaped wall. [ABSTRACT FROM AUTHOR]

Failure of tall slender masonry structures during earthquakes often involves partial collapse of the structure well-above ground level. Consequently, the elastic response of the structure needs to be considered, which often requires modal analysis using finite element models — the generation of which can be labour-intensive and time-consuming. This paper presents a new integrated modelling approach which combines finite element analysis with rocking dynamics to model the seismic response of complex structural geometries in a computationally-efficient manner. The modelling strategy is implemented within the open-source computational framework COMPAS and is incorporated within the broader framework of a tool being developed for the seismic collapse assessment of masonry structures. The framework of this tool is first outlined, and the utility of the new modelling approach then demonstrated through application to the seismic assessment of a three historic masonry towers in North-Eastern Italy. The importance of accounting for elastic amplification effects, as well as the influence of varying boundary conditions on the dynamic response, is also illustrated. [ABSTRACT FROM AUTHOR]

ABSTRACT: Temporal indentations are the most impacting craniofacial complication after coronal flap dissection. It is mainly due to a temporal fat pad or temporalis muscle dissection.Because of the great improvements achieved recently in CAD-CAM-aided surgery and the possibility of performing accurate pre-surgical virtual planning, it is now possible to correct it with a customised virtual approach. Furthermore, advancements in material science have allowed surgeons to rely on biocompatible materials like PEEK (showing a low complication and recurrence rate) for the manufacturing of patient-specific implants.We hereby describe our experience on a case of secondary and corrective surgery after a fronto-orbital remodelling, in which we used PEEK implants designed by CAD and optimized by finite element modelling.

Concrete-encased concrete-filled steel tube (CECFST) columns have recently been regarded as the optimum option for high-rise or heavy-loaded buildings due to superior structural resistance over traditional concrete-filled steel tube (CFST) and reinforced concrete (RC). Thus, in developed countries with severe manpower shortages such as Singapore, advanced precast dry connections were proposed for the CECFST columns to facilitate construction and tackle manpower crunch. Moreover, current research shows that the proposed connection has comparable structural resistance with conventional cast-in-place (CIP) connections, demonstrating huge application potential. However, the existing research is only limited to the performance of precast connections without any experimental studies on jointed columns, which hinders the implementation of the precast connections in engineering of practices. In this paper, to address this research gap, a comprehensive experimental programme was initiated, followed by extensive numerical studies. A total of six intermediate and slender jointed precast columns were tested to investigate the effect of precast connections on load-carrying behaviour of the jointed CECFST columns by considering column slenderness, connection detailing, connection position and load eccentricity. Besides experimental studies, extensive 3D finite element (FE) simulations were performed to investigate the relationship between connection integrity, constructability, and load-carrying performance of the jointed CECFST columns. The numerical studies showed that implementing the conventional "Equivalent to CIP" concept into the design of jointed precast CECFST columns would significantly compromise the constructability of such columns. To address this concern, a performance-based design method was proposed for jointed CECFST columns. Parametric studies showed that adopting the performance-based design method could not only improve constructability but also achieve sufficient column resistance. • Six jointed precast CECFST columns were tested under eccentric compression. • Column slenderness ratio, load eccentricity, connection detailing and connection position were considered in the testing. • Elaborate 3D finite element modelling was established to simulate precast CECFST columns. • Extensive parametric studies were carried out to discuss compression performance of the precast CECFST columns. • Performance-based design approach is recommended for the design of precast CECFST columns. [ABSTRACT FROM AUTHOR]

• Innovative quantification of FE modelling images through computer vision. • Rapid and highly accurate image processing completed in seconds. • Efficiency improved by 40 times over traditional manual analysis. • Developed and analysed FE models at macro, Meso , and micro levels on impact. In finite element (FE) modelling, the visual assessment of images of contour plots is widely used for qualitative comparison and analysis. However, this approach has limitations in conducting in-depth and comprehensive analysis, which is rigorously made based on objective, massive, and quantitative data. To tackle the problems, we propose a methodology based on computer vision with k -means clustering algorithms, providing an effective quantitative strategy to improve the efficiency and accuracy of the analysis. To demonstrate the application of this methodology, three levels of FE models on impact, viz. macro (homogenous UD laminate model), meso (yarn-level fabric model), and micro (fibre-level yarn model), are developed, where the images with both simple and complex morphologies and backgrounds are all be considered. The contour plots of stress and transverse deformation are clustered into k categories based on the RGB values of the pixels in the images. Notably, the quantification of one image using the proposed methodology is completed in seconds, and the efficiency is enhanced by approximately 40 times compared with that using the manual method, without the accuracy sacrificed. This methodology enables the researchers to efficiently and precisely understand the ballistic behaviours of the textile materials from the perspectives of fibres, yarn, fabrics, etc., and has great potential to apply in other research fields, where computational simulation is widely used. [Display omitted] [ABSTRACT FROM AUTHOR]

Oblique lumbar intervertebral fusion aims to decompress spinal nerves via an interbody fusion cage, but the optimal surgical strategy, including implant selection for specific patient characteristics, remains unclear. A biomechanical model was developed to assess how pathophysiological characteristics and instrumentation impact spinal realignment, indirect decompression, and cage subsidence risk. A finite element model of the L4-L5 segment was derived from a validated asymptomatic T1-S1 spine model. Five cases of grade I spondylolisthesis with normal or osteoporotic bone densities and initial disc heights of 4.3 to 8.3 mm were simulated. Oblique lumbar intervertebral fusion with cage heights of 10, 12, and 14 mm (12° lordosis) was examined. Postoperative changes in disc height, foraminal and spinal canal dimensions, segmental lordosis, and vertebral slip were assessed. Vertebral stresses and displacements under 10 Nm flexion and 400 N gravitational load were compared between stand-alone constructs and bilateral pedicle screw fixation using rods of 4.75, 5.5, and 6 mm diameters. Oblique lumbar intervertebral fusion significantly improved postoperative disc height, foraminal and spinal canal dimensions, with the greatest enhancements observed with 14 mm cages. Bilateral pedicle screw fixation markedly reduced cortical endplate stresses and displacements compared to stand-alone constructs, with added benefits from larger rod diameters. Low bone density increased displacements by 63 %. Thicker cages achieve better decompression but increase subsidence risk. Bilateral pedicle screw fixation with 6 mm rods minimizes endplate stresses and displacements, especially in osteoporotic cases. Future research will validate these findings and explore the model's potential for surgical planning. • Oblique lumbar interbody fusion expands intervertebral and spinal canal dimensions. • Thicker (14 mm) cages maximize decompression but increase the risk of subsidence. • Posterior fixation reduces stresses and displacements, reducing subsidence risk. • Osteoporotic models show higher displacements, emphasizing need for stabilization. [ABSTRACT FROM AUTHOR]

This paper presents an extensive experimental and numerical studies on the material properties and residual stresses distributions of Q690 HSS cold-formed EHS made from HSS plate with a nominal yield strength of 690 MPa to address the lack of information on the mechanical characteristics of these sections. A total of five Q690 HSS press-braked EHS were fabricated with 3 mm, 6 mm and 10 mm thick steel plates with transverse bending and longitudinal welding. The material properties were acquired by conducting tensile coupon tests with coupon specimens extracting from the critical regions within the cross-sections and from the parent plates as well. In addition, the membrane and bending residual stresses in the longitudinal direction were measured on half-section profile of representative EHS specimens. Sectioning method was utilised to manufacture the testing strips with a total of 71 strips cut by a wire-cutting machine and over 852 strain readings were recorded. In conjunction with the experimental tests, an integrated sequentially-coupled thermomechanical analysis was conducted by developing an advanced finite element (FE) model of manufacturing press-braked EHS specimen. The transverse bending was simulated with three-dimensional models underwent extensive plastic deformation to obtain the bending residual stress after press-braking and springback. The longitudinal welding was simulated using solid element and the technique of birth and death element was used to simulate the multi-passes welding and molten of welding electrode. Consequently, explicit residual stresses distributions in longitudinal direction against the perimeter due to the transverse bending and welding were ascertained. The experimental and numerical data were used to demonstrate and discuss the magnitudes and distribution patterns of the residual stresses. A predictive model for residual stress distribution within the Q690 HSS press-braked EHS was developed and proposed. • The first research study for Q690 press-braked elliptical hollow section (EHS). • The mechanical properties due to the manufacturing processes were studied. • The thermal and mechanical responses of Q690 press-braked EHS is carried out. • Multi-linear membrane residual stress model is proposed. [ABSTRACT FROM AUTHOR]

Thin-walled structures generally rely on cold-formed mild steel profiles. Due to cold forming, a significant formation of residual stresses impacts their overall fatigue behaviour. In this work, a state-of-the-art framework for fatigue life prediction is proposed and applied to both roll-formed and press-braked full-scale profiles. In summary, the profile's manufacturing process is numerically simulated to obtain a representative residual stress field. These results are then used as the initial state during a subsequent structural and fatigue analysis. A clear detrimental residual stress effect is verified. Importantly, however, is to note that prediction accuracy increases significantly when these effects are considered. • An advanced framework for fatigue life prediction in full-scale profiles is presented. • Residual stress fields due to cold-forming and pre-forming processes are investigated. • Manufacturing straining history and structural loading unified in a single model. • A clear residual stress effect on numerical fatigue life estimations is verified. • The inclusion of residual stresses increased the predicting accuracy of the model. [ABSTRACT FROM AUTHOR]

• Cold-formed steel octagonal hollow section columns were fabricated through press-braking and subsequent welding. • Variations of material properties within the cross-section and initial global imperfection were measured and are presented. • A total of 10 octagonal hollow section long columns were tested. • The finite element modelling methodology for cold-formed steel octagonal hollow section columns was developed and a total of 608 numerical models were generated. • The applicability of current design methods was assessed and modified against the experimental and numerical results. This paper experimentally and numerically investigated the global buckling behaviour of cold-formed steel octagonal hollow section columns. A test programme was first conducted on 10 OctHS steel columns made of Q460 and Q690 high strength steels. Each steel grade comprised five specimens with distinct geometric dimensions. Material properties and initial global imperfection were measured and are reported herein. Axial load versus mid-height lateral deflection curves, axial load versus axial strain curves, and failure modes of OctHS specimens are presented and discussed. In conjunction with laboratory works, finite element models were subsequently developed to replicate the load-deformation responses and failure modes of OctHS columns against the experimental results. Following the validation of proposed numerical modelling technique, extensive parametric studies were performed to evaluate the effects of steel grade, cross-section slenderness, member slenderness, and initial global imperfection. Furthermore, results from 10 test specimens and 608 numerical models were used to comprehensively assess the applicability of current codes of practice on the design of OctHS long columns. Modifications and design recommendations were proposed based on the assessment results. Corresponding reliability analyses were also performed for each design method. [ABSTRACT FROM AUTHOR]

This study aims to explore the mechanical behaviour of polymeric gyroid structures under compression within the context of orthotic insoles, focussing on custom optimisation for lower peak plantar pressures. This research evaluates the compressive response of gyroid structures using a combination of experimental testing and numerical modelling. Stereolithography was used to manufacture gyroid samples for experimental tests, and explicit finite element analysis was used to model the gyroid’s response numerically. Hyperfoam, first-order polynomial, and second-order polynomial hyperelastic constitutive models were considered to homogenise the mechanical response of the structure. The homogenised properties of the structure were then implemented in an optimisation algorithm to obtain the optimal gyroid structure for a given subject by minimising the standard distribution of plantar pressures. Findings indicate that the compressive response polymeric gyroid structures can be represented with a homogeneous material. The hyperfoam model was chosen due to its accuracy and interpolation quality. The optimisation process successfully identified configurations that maximise the mechanical advantages of gyroid lattices, demonstrating significant improvements in plantar pressure distributions. The optimised insole showed a 30% reduction in the standard deviation of the plantar pressure and a 10% reduction in the peak stress. The optimisation method reduced peak pressures by 12.2 kPa compared to a traditional medium-density Poron orthotic insole, and 94.3 kPa compared barefoot conditions. The mechanical response of gyroid structures has successfully been modelled, analysed and homogenised. The study concludes that custom gyroid-based orthotic insoles offer a promising solution for personalised foot care. [ABSTRACT FROM AUTHOR]

This study examines the influence of high-energy laser shock peening (LSP) using 7 J and 10 J pulse energies on the sub-surface deformation characteristics of Inconel 718 superalloy. High-magnitude compressive residual stresses were induced into the samples after LSP with large residual stress depths of the order of 2 mm – the experimental observations were in good agreement with finite element analyses of the LSP process. The propagation of intense shock waves led to increased strain hardening and dislocation densities that were experimentally quantified by synchrotron diffraction and transmission electron microscopy. Microscopic analyses revealed highly refined grain structure only at the surface without much refinement observed in the residual depth region. Alongside a high degree of strain hardening, profuse amount of adiabatic shear bands was observed in the hardened depth, indicative of simultaneous strain localisation under such high laser pulse energy. These bands occurred along common slip planes in the Ni γ-matrix and could be potential areas of instability leading to failure. The LSP-treated samples exhibited improved corrosion resistance, with higher laser pulse energy peened samples performing better. [Display omitted] • The effect of high-energy laser shock peening was investigated. • Surface grain structures of L7 and L10 are refined and similar, with no notable differences. • Under high energy shock peening both strain hardening and softening are prevalent. • Laser shock peening improved the corrosion resistance with a trend proportional to laser energy. [ABSTRACT FROM AUTHOR]

The main objective of this research work is to propose a design analysis methodology for the structural analysis of storage tanks, focusing on the integrity of this structure in the presence of damages and their wind-induced buckling resistance considering the dynamic behaviour of non-deterministic wind loads. For that, a case study of a real tank containing deformations is conducted. These deformations are properly mapped using 3D laser scanning inspection technique, whose results are used to calibrate finite element models with point cloud processing methodology and model calibration. Several analyses using the finite element method are then performed, considering geometric and material nonlinearities, with the aim of studying the static and dynamic buckling phenomenon of tanks and verifying the differences between static and dynamic wind loads. The non-deterministic dynamic wind loads are generated using the Spectral Representation Method (SRM) and the results are assessed and discussed. Additionally, a discussion is held regarding the update of safety factors due to the latest revision of structural verification codes. Among various conclusions, the analyses have indicated that the safety factors adopted in the new revisions may not suggest the occurrence of buckling, whereas the analysis for the dynamic effects of non-deterministic wind loads points to the possibility of buckling taking place. • An analysis methodology was proposed to assess the dynamic structural behaviour of storage steel tanks. • Imperfections used for nonlinear buckling analyses were precisely determined based on experimental tests. • The non-deterministic dynamic structural response of a storage steel tank was assessed. • The integrity of a real storage tank was assessed considering the presence of damages. • The wind-induced buckling resistance of the storage tank was determined and investigated. [ABSTRACT FROM AUTHOR]

• The effect of heat treatment on the fatigue life of 3D printed SS 316 L is investigated. • Increased fatigue life of heat treated specimens is observed. • Heat treatment reduced the Young's modulus of the considered specimen. • Microhardness is increased after cycling while it decreases after heat treatment. • Peak stress vs cycle behavior is suitably predicted using Non-linear Chaboche model. The success of 3D printing relies on developing components with desired strength that heat treatment processes can further improve. While SS 316L is a widely used structural material for several industrial applications, the fatigue behaviour of its 3D-printed version is investigated herein. The low cycle fatigue (LCF) behaviour of heat-treated (HT) 3D-printed SS 316L specimens was carried out and compared with the without heat-treated (WHT) specimens thereof. The heat treatment considerably affected its LCF behaviour, which can be attributed to the microstructural changes post heat treatment. The cyclic softening is observed in both HT and WHT specimens. However, the degree of softening is lower (12.35 %) for HT compared to WHT specimens (25.30 %) and 62 % higher fatigue life for HT compared to WHT specimens. Further, the hardness values obtained are 176 and 169 HV for WHT and HT, respectively, while it is 238 and 223 HV for the same, before and after fatigue tests. Fractography revealed fewer pores and reduced fatigue striations in the HT specimens. Considering the Chaboche non-linear model, finite element modelling was employed to capture the specimens' fatigue behaviour. The proposed model is found to be suitable for predicting the cyclic behaviour of 3D-printed austenitic steels. [ABSTRACT FROM AUTHOR]

A new fire design method by Geometrically and Materially Nonlinear Analysis with Imperfections (GMNIA) and using strain limits is proposed for stainless steel columns in this paper. In the proposed design method, owing to their computational efficiency, beam finite elements are employed to carry out the GMNIA of stainless steel columns in fire whereby the material strength and stiffness deterioration at elevated temperatures, the spread of plasticity, global instability effects, indirect fire actions and thermal expansion are directly taken into account. Due to the inability of beam finite elements to consider local buckling effects, the use of strain limits determined based on a modified continuous strength method (CSM) is proposed to capture the deleterious influence of the local instability effects on the structural resistances of stainless steel columns in fire. The ultimate capacity of a stainless steel column in fire is determined by (i) the temperature level at which the CSM strain limit is attained or (ii) the critical temperature at which the column is no longer able to carry the applied initial room temperature loading, whichever occurs first. In this study, stainless steel square hollow section (SHS) and rectangular hollow section (RHS) columns with and without axial and/or rotational end-restraints are taken into consideration. The capacity predictions obtained using the proposed design method are extensively verified against the benchmark results from shell finite element modelling and also compared against the predictions from the European structural steel fire design standard EN 1993–1-2. • A new advanced fire design method for stainless steel SHS and RHS columns based on GMNIA with strain limits is proposed. • Extensive numerical parametric studies are carried out, considering 2268 stainless steel SHS and RHS columns in fire. • Accuracy, safety and reliability of the proposed fire design method for stainless steel SHS and RHS columns are verified. • The proposed fire design method leads to more accurate and reliable ultimate resistance predictions relative to EN 1993-1-2 provisions. • The proposed method leads to an advanced and streamlined fire design, directly providing the failure temperatures and failure modes. [ABSTRACT FROM AUTHOR]

The Mg alloy vascular clip has biodegradability and good biocompatibility, which can improve the convenience and safety of clinical application. However, the Mg alloy vascular clip also has some disadvantages, such as an unreasonable structure design and a degradation rate which is too fast. In this study, the process of clamping blood vessels with a biodegradable Mg alloy (Mg-Zn-Nd-Zr and Mg-Zn-Nd) general V-type vascular clip was simulated by finite element simulation software (Abaqus). A new type of vascular clip, the P-type vascular clip, was analyzed and investigated through simulation. The differences between Mg alloy vascular clips of V-type and P-type were analyzed by finite element simulation. In addition, the effects of Zr element on the mechanical properties and corrosion resistance of P-type vascular clips were also investigated to improve the mechanical stability. The results show that during the V-type vascular clip closure of Mg-Zn-Nd-Zr alloy, this clip has some problems, such as uneven distribution of blood vessel stress, crevices in blood vessels and stress concentration. The improved P-type vascular clip has uniform closure, and there is no gap in the blood vessel, which can effectively avoid stress concentration. The improved P-type vascular clip is well closed and can effectively avoid stress concentration. The corrosion resistance of the Mg-Zn-Nd-Zr alloy P-type clip was better than that of the Mg-Zn-Nd alloy P-type clip (degradation rate of 2.02 mm/y and 2.61 mm/y on the 7th day, respectively). Mg-Zn-Nd-Zr alloy The P-type vascular clip remained closed even on the 7th day, which could meet the requirements of clinical application.

The present work is undertaken to determine the ability of the small punch test to determine mechanical properties of CoNiCrAlY, a two phase bond-coat material found in thermal barrier coatings. It utilises a multi-scale modelling methodology in which 2-dimensional representative volume elements of CoNiCrAlY and finite element models of the small punch test are developed. Effective Young’s moduli and Poisson’s ratios are obtained from the representative volume elements and are compared with those obtained from analytical homogenization through the Voigt, Reuss and Voigt-Reuss-Hill schemes. The volume fraction of the β-Nial phase in CoNiCrAlY is varied and the force–displacement responses of representative volume elements are contrasted with those from small punch test finite element models, through comparison of ratios of discrete fréchet distances. The results of the study estimated Young’s modulus and Poisson’s ratio to be 178.56 ± 7.65GPa and 0.249 ± 0.037 respectively, and for an increasing β-Nial phase volume fraction, the Young’s modulus and Poisson’s ratio decrease. Lastly, the results suggest that the small punch test is insensitive to variations in material elastic behaviour because its results are more influenced by the yield properties of a material.

Quantitative defect and damage reconstruction play a critical role in industrial quality management. Accurate defect characterisation in Infrared Thermography (IRT), as one of the widely used Non-Destructive Testing (NDT) techniques, always demands adequate pre-knowledge which poses a challenge to automatic decision-making in maintenance. This paper presents an automatic and accurate defect profile reconstruction method, taking advantage of deep learning Neural Networks (NN). Initially, a fast Finite Element Modelling (FEM) simulation of IRT is introduced for defective specimen simulation. Mask Region-based Convolution NN (Mask-RCNN) is proposed to detect and segment the defect using a single thermal frame. A dataset with a single-type-shape defect is tested to validate the feasibility. Then, a dataset with three mixed shapes of defect is inspected to evaluate the method's capability on the defect profile reconstruction, where an accuracy over 90% on Intersection over Union (IoU) is achieved. The results are compared with several state-of-the-art of post-processing methods in IRT to demonstrate the superiority at detailed defect corners and edges. This research lays solid evidence that AI deep learning algorithms can be utilised to provide accurate defect profile reconstruction in thermography NDT, which will contribute to the research community in material degradation analysis and structural health monitoring. [ABSTRACT FROM AUTHOR]

Dynamic (220–510 s−1) and quasi-static (0.001 s−1) compression experiments are conducted on alumina ceramics implemented with two types of tungsten carbide inserts, cylindrical and step-shaped. Split Hopkinson pressure bar (SHPB) tests with in-situ , high-speed optical imaging are adopted to capture the damage and failure of ceramic samples under dynamic compression. The compressive strength of alumina ceramic samples with step-shaped inserts is 15%–30% higher than that with cylindrical inserts commonly used in previous studies, under both dynamic and quasi-static loading. Damage occurs first at the two ends of ceramic samples with the cylindrical inserts, followed by edge fracture and splitting cracks penetrating the sample. However, damage is initiated in the sample region away from the sample ends for the step-shaped inserts, and oblique and secondary transverse cracks dominate the failure process. The different damage modes in the case of step-shaped inserts result in the delayed damage initiation and sample failure, and consequently high compressive strengths. Finite element modelling (FEM) of the SHPB tests provides strength and damage evolution features consistent with the experiment using the Johnson–Holmquist (JH-2) model. FEM reveals equivalent, tensile and shear stress concentrations at the two ends of samples with cylindrical inserts. The stress concentrations are responsible for the damage initiation and growth at the sample ends and the following splitting cracks, consistent with the high-speed images. In contrast, homogeneous stress distributions are achieved in the sample with the step-shaped inserts, ensuring simultaneous damage development across the sample. Overall, the step-shaped inserts in conjunction with cylindrical samples can yield reliable strength measurements for ceramics and ceramic-like materials. [ABSTRACT FROM AUTHOR]

Large diameter, short monopiles are the preferred foundation type for offshore wind turbines. These piles demonstrate a rigid response with significant rotation of the pile base under ultimate lateral load. As traditional empirical p-y curves used in lateral loaded pile analysis have been derived from tests on small diameter onshore piles, there is some doubt about their applicability to rigid monopiles, particularly in view of the significant difference in the response of the pile base compared with a typical onshore pile. To address this issue, this paper reports on a unique series of field tests using instrumented driven pipe piles, complimented by numerical analysis, which was performed to examine explicitly the contribution of the pile base to the response under lateral load. The field tests, which included tests on pipe piles that had the sand plug removed to below pile tip level prior to testing, confirmed that the influence of the base on the lateral response for the tested 273- and 457-mm-diameter piles was negligible. Numerical analyses that were calibrated using the field test data showed that the contribution of the base to the lateral capacity of a monopile with a diameter as large as 10 m is negligible. Results also indicated that p-y curves are not affected by the length to diameter ratio and can be used to predict the response of monopiles in sand. [ABSTRACT FROM AUTHOR]

The impedance-matching mechanism of the ossicular chain of the middle ear is disrupted by erosion of the incus, warranting prosthetic intervention. The present-day practice of straight rigid-rod is not competent to restore the required level of natural motion attenuation and force amplification between the tympanic membrane and stapes-footplate. In this work, we use finite element simulation of anatomically accurate middle ear to evaluate the efficacy. We compare the performance of differently shaped incus-prosthesis, T, C, and S in particular, using simulation. We find that the S-shaped incus-prosthesis gives the best performance. We also prototyped the prosthesis and performed a preliminary cadaveric study. The finite element simulation combined with the ability to 3D-print has the potential for effective personalized surgical intervention. [ABSTRACT FROM AUTHOR]

The present contribution deals with the possibility of using the PI-Control method in order to perform a Hybrid Fire Test (HFT) with a force-controlled procedure (FCP). Such a method may be applied in two ways where the instantaneous error is calculated in term of displacement or in term of force. Like the displacement-controlled procedure (DCP), stability of the HFT results can be ensured by an appropriate design of the values of the gains matrix, which depends on the estimation of the initial stiffness of the Physical Substructure (PS) as well as the chosen value of the eigenvalues. This paper will demonstrate how it is possible to determine optimal parameters in order to ensure the stability of a HFT when using such a method. In addition, it will be shown that, on the contrary to the recommendations for the use of the PI-Control method with the DCP, the initial stiffness of the PS should be underestimated rather than overestimated when the FCP is used. For illustrative purpose, several virtual HFTs have been implemented and analysed. [ABSTRACT FROM AUTHOR]

The detection of surface cracks at or close to sample edges is a challenging problem because the interaction of the eddy current with the sample edge can make it difficult to distinguish changes in the eddy current signal due to a defect. Samples with poor electrical conductivity such as titanium alloys used extensively in aerospace applications can be more difficult to inspect due to the low amplitude eddy currents induced in them and increased electromagnetic skin depths due to lower electrical conductivity. As fatigue surface cracks or manufacturing surface defects can often occur close to edges, the challenges of detecting small defects close to sample edges is an important research area to address. High-frequency eddy currents of over 10 MHz are used in a transmit-receive configuration using two solenoid type coils adjacent to each other. While conventional eddy current sensors are commonly designed for operating at frequencies into the low MHz region, the supporting electronics here will be positioned immediately behind the coils to improve electrical stability and reduce induced noise. The magnitude and phase of the voltage on transmit and receiver coils are measured, and finite element modelling is used to validate the experimental measurements and gain insight into the system behaviour. Small defects of down to 1 mm are easily detected, on the edge and at the corner of a titanium alloy sample with excellent signal-to-noise. [ABSTRACT FROM AUTHOR]

The practical application of cold-formed high strength steel is becoming increasingly popular in structural engineering due to its great efficiency and cost effectiveness. However, cold-formed steel sections are usually associated with high slenderness, hence are susceptible to buckling failure. Consequently, the buckling resistance of steel struts made of cold-formed high strength steel must be determined with carefulness, particularly for complex compound sections. To this end, the present paper aims at investigating the behaviour of back-to-back channel sections made of S700 steel with a characteristic yield strength of 700 MPa. Compressive tests on such members are conducted for the purpose of validating the finite element models. Subsequently, a numerical parametric analysis is carried out on the buckling resistance of axially loaded cold-formed steel back-to-back channel sections, using the previously validated numerical modelling approach. In particular, the effects of stiffeners and number of bolts on the buckling resistance are investigated. Furthermore, the results of the parametric analysis are also compared with the codified buckling resistance determined based on the effective width method adopted in Eurocode 3 Part 1–3, in order to evaluate the reliability of the standardised design method for buckling resistance. [ABSTRACT FROM AUTHOR]

In the current paper, using finite element models (FEM), an extensive numerical study is performed on the behaviour of the steel plates with a circular hole in their centre subjected to compressive axial loading. For this purpose, 270 perforated steel plates were modelled and analysed using ABAQUS software. The effects of four main variables including plate length, hole diameter, plate thickness, and yield stress were discussed. Then, using the database provided by FEM, the artificial neural network (ANN) method was used to develop a predictive model to estimate the ultimate strength of steel plates with a circular hole in the centre. Finally, an ANN-based formula was proposed to predict the ultimate strength of perforated steel plates and its accuracy was compared with the formulations presented in previous studies. Based on the results, the proposed formula provided high accuracy and can be used as a reliable formula in practice. [ABSTRACT FROM AUTHOR]

Bearing walls in cold-formed steel buildings act as a transmitter of vertical loads of the building and as a retainer of the exterior of the building and also absorb the lateral loads of the building such as wind and earthquake loads. In this article, the behaviour of cold-formed steel frame walls under compressive axial load has been investigated numerically. First, the finite element model of the cold-formed steel wall was developed using ABAQUS software, and then, structural analysis was performed, taking into account the effects of geometric and materials nonlinearities. The results of the numerical model were compared with the experimental results to confirm the accuracy of the numerical model. In the following, parametric studies have been carried out considering some parameters affecting the behavior and the ultimate load of cold-formed steel frame walls such as type of sheathing, stud web depth, stud flange width and stud cross-section shape. The results of the structural analysis showed that the type of wall sheathing did not have a significant effect on the ultimate load of the wall, but increasing the web depth of the stud, has led to a decrease in the load-bearing capacity of the steel wall. The wall with hollow flange studs has a higher ultimate load than other sections, and also, the use of web stiffened stud leads to an increase in the final bearing capacity of the wall compared to typical sections. [ABSTRACT FROM AUTHOR]

Aims: In the finite element method, the mechanical behaviour of plant roots has been modelled by solid element or embedded beam element (EBE). However, the former is computationally expensive, whereas the latter is unable to capture the root pull–out failure mode. In this study, we modified the constitutive stress–strain relationship of an existing EBE to calculate uprooting resistance by considering the root–soil interfacial shearing and the strength decline as root pulls out. Methods: We introduced an elasto–softening constitutive law to describe the root–soil interface interaction and an improved damage model to capture post–peak softening behaviour in EBE. We validated the EBE against three case studies. Finally, we conducted parametric analysis to study how root geometries, morphologies and soil saturation affect the uprooting response. Results: Our new model captures the pre–peak uprooting behaviour up to the peak pull–out force (Pul). Root systems that failed by pull–out mode always had lower Pul than those that failed by breaking, irrespective of the root morphology. Reduction of soil effective stress following soil saturation always reduced Pul and could change the root failure mode, depending on the anchorage length and root–soil contact surface area. Conclusions: Root–soil mechanical interaction and root failure mode, including pull–out and breakage, can now be modelled with more accuracy. We show the importance of considering soil moisture variation, which translates to variations in root reinforcement effects. The reinforcement effectiveness of deep–rooted systems can be halved, and the root failure mode can switch from breakage to pull–out, following soil saturation and reduction of soil effective stress. [ABSTRACT FROM AUTHOR]

The main novelty of this study is producing Ultra High-Performance Self Compacting Mortar (UHPSCM) incorporated Recycled Steel Fibre (RSF) from waste tires. For this purpose, different mix compositions including 0%, 1%, and 3% RSF content in terms of volume were proposed. Self-compacting ability was assessed using mini-cone tests, while nondestructive testing has been used to evaluate the effect of RSF inclusion on the compaction of UHPSCM constituent materials. Mechanical performances were investigated using compression and unnotched flexural tests. Residual flexural strength in both service limit state (SLS), ultimate limit state (ULS), and two equivalent flexural strengths were evaluated under notched flexural tests and analysed using statistical approaches. Concrete Damage Plasticity (CDP) has been employed for the analysis behaviour of developed mortars under different loadings. Additionally, an element deletion approach was used to evaluate the fracture of UHPSCM under compression and flexural loadings. The experimental results showed that adding 1% and 3% of RSF resulted in decreasing workability by 3% and 22%, respectively. Improving compressive strength by 16% and 22% and flexural by 7% and 8% were noticed in the case of samples with 1% and 3% fiber, respectively, in 28 days. In spite of the significant improvement of post-cracking behaviour of samples with 3% of RSF, this behaviour was insignificant for the samples with 1% of RSF. However, with less amount of fibre inclusion, brittle failure can be altered to ductile failure. Moreover, the behaviour of the tested specimens under different loadings was successfully predicted using Finite Element (FE) simulations. [ABSTRACT FROM AUTHOR]

The dynamic behavior of osseointegrated implants can be used for the non-invasive evaluation of the condition of the bone-implant-interface (BII). The Advanced System for Implant Stability Testing (ASIST) is a vibration measurement system that relies on an impact technique and an analytical model to compute the interface stiffness and the ASIST stability coefficient ([Formula: see text]). The objective of this work is to develop a finite element (FE) model capable of capturing the dynamic behaviour of the bone-anchored hearing aid under the ASIST loading condition. The model was validated with previously collected in vitro and in vivo data which were compared to the model's acceleration responses and [Formula: see text] scores. Similar acceleration responses were obtained, and the maximum absolute differences in [Formula: see text] scores between the FE model and the in vitro and in vivo data were 1.15% and 5.48% respectively. The model was then used to show the existence of a relationship between the rod's acceleration response and the BII stress field. Finally, the model was used to interpret the factors that affect the stiffness parameters of the ASIST analytical model. The interface stiffness and the system's dynamic properties were more influenced ([Formula: see text]) by the BII material and friction coefficient compared to the implant geometry. In this work, a finite element model of the bone anchored hearing aid was used to simulate the dynamic behaviour of the bone-implant system under the ASIST's loading conditions. The model was first validated with previously collected experimental and clinical results. The validated model was then used to study the relationship between the impact rod's acceleration response and the response at the bone implant interface. Finally, the model was used to formulate a better understanding on the influencing factors on the interface stiffness. [ABSTRACT FROM AUTHOR]

Abnormal loads can produce localized damage that can eventually cause progressive collapse of the whole reinforced concrete (RC) structure. This might have devastating financial repercussions and cause numerous severe casualties. Numerical simulation, using the finite element method (FEM), of the consequences of abnormal loads on buildings is thus required to avoid the significant expenses associated with testing full-scale buildings and to save time. In this paper, FEM simulations, using ABAQUS software, were employed to investigate the progressive collapse resistance of the full-scale three-dimensional (3D) beam–slab substructures, considering two concrete mixes, namely: normal concrete (NC) and rubberized concrete (RuC) which was made by incorporating crumb rubber at 20% by volume replacement for sand. The FEM accuracy and dependability were validated using available experimental test results. Concrete and steel material non-linearity were considered in the FE modelling. The numerical study is extended to include eight new models with various specifics (a set of parameters) for further understanding of progressive collapse. Results showed that slabs contribute more than a third of the load resistance, which also significantly improves the building's progressive collapse resistance. Moreover, the performance of the RuC specimens was excellent in the catenary stage, which develops additional resilience to significant deformation to prevent or even mitigate progressive collapse. [ABSTRACT FROM AUTHOR]