Software ABAQUS Research Articles

Dynamic response analysis of ship reef hard grounding

Abstract With the rapid growth of the world economy, the shipping industry has developed rapidly on a global scale, and the water traffic has become increasingly busy. Therefore, the risk of ship transportation has become bigger and bigger, and ship grounding and collision occupy about 50% of the total number of all accidents, among which the consequences of oil tanker grounding accidents are more serious, which not only jeopardize the safety of the personnel but also cause a large area of pollution to the sea. Therefore, it is particularly important to study the ship grounding and collision of oil tankers. Based on the nonlinear finite element software ABAQUS, a calculation model for oil tanker grounding is established, and simplified boundary conditions that can be used for grounding simulation analysis are determined. At the same time, material strain rate sensitivity and material hardening properties are considered. Based on the quasi-static tensile test data of Q235 steel used in ships, material parameters that meet the requirements of collision simulation calculation are calibrated and calculated. The dynamic response of hard grounding is analyzed from both external and internal mechanisms. The research results can provide a reference for improving the grounding collision performance of oil tankers.

Numerical analysis of the effect of bar anchorage length on bond behavior in pull-out test

This paper presents a numerical simulations of a pull-out test conducted using ABAQUS software. The purpose of the simulations was to evaluate the effect of anchorage length on the bond behavior of ribbed bars in this test, based on the experiments performed. The interaction at the bar-concrete interface was modeled using a contact cohesive surface and calibrated bond-slip curves obtained from experiments. Material models were defined using mechanical parameters obtained from in-house tests on concrete and steel. The analysis shows that the bond behavior is significantly influenced by the anchorage length. Numerical simulation results demonstrate excellent convergence with laboratory tests, both in terms of the bond-slip curve and material behavior

The effect of concrete compressive strength to the strengthening efficiency of RC beams using CFRP in slits

The near-surface mounted technique (NSM) is one of the most effective techniques to strengthen concrete structures, mainly in bending and shear. ABAQUS software has been used to establish a numerical model for the mechanical behavior of a RC beams strengthened by CFRP NSM. In this paper, three rectangular CFRP strengthened RC beams were simulated using ABAQUS and tested in four-point bending scheme in order to investigate the impact of concrete compressive strength to the strengthening efficiency. The results showed that increasing the Concrete compressive strength induced a positive impact to the peak load. further changing the compressive strength influence the failure criteria of the tested specimens.

Modeling of Wire EDM Using an Integrated Approach for Machining of AISI304 Stainless Steel

A non-traditional method of thermal machining called wire electrical discharge machining (WEDM) is utilized for the production of intricate and complex components, particularly those composed of difficult-to-machine materials. Stainless steel has gained widespread usage in various applications in contemporary industry owing to its exceptional properties. In this present investigation, a numerical 3D finite element modeling simulation was conducted using the ABAQUS software to analyze the Material Removal Rates (MRR) for both single and multi-discharge scenarios of AISI 304 stainless steel. The findings indicate a close correspondence between the MRR values predicted by the numerical modeling and those obtained experimentally corresponding to the optimal process parameters: I = 6 A, Ton = 45 s, and Toff = 5 s. Hence, this numerical approach offers the potential to forecast outcomes before actual machining operations.

Component-based modelling of single-leg bolted steel angle connections at elevated temperatures

As a vital part of contemporary society, steel lattice transmission towers and communication towers play an important role in the power transmission grid and telecommunication, respectively. Being often located in rural areas, they are prone to bushfire attacks due to heatwaves and droughts, which are becoming increasingly commonplace. However, unlike the steel members found in a lattice tower, the behaviour and material properties of which at elevated temperatures have been comprehensively studied and codified in design standards, the semi-rigid behaviour of the bolted connection between such members at elevated temperatures has not been investigated thoroughly. Therefore, this paper aims to investigate both the axial and rotational behaviour of single-leg bolted steel angle connections at both ambient and elevated temperatures. A theoretical model using the component method is firstly proposed to model the axial load-slip behaviour incorporating the temperature increase, with the effects of the bolt shear, plate bearing, friction between clamped members, bolt slip, and member elongation being considered. Once the axial load-slip model is proposed, the component-based model for describing the moment-rotation behaviour of the bolted connection is derived based on the load-deformation relations of individual bolts in the bolt group. The reliability of the theoretical model is then validated by modelling the connection behaviour obtained from previous connection test results. A three-dimensional finite element model is also constructed using ABAQUS software to further validate the accuracy of the proposed theoretical model for predicting the axial and rotational behaviour of single-leg bolted angle connections at elevated temperatures. It is demonstrated that the proposed component-based theoretical model for the bolted angle connection accounting for axial and rotational semi-rigidity as well as temperature elevation is capable of effectively capturing the load-deformation relationship for the single-leg bolted angle steel connections, and would be applicable to the study of steel lattice towers under bushfire attack.

An elastoplastic damage ice material model based on modified Tsai-Wu yield criterion: Experiment, theory and numerical application

Ice, as a novel green and sustainable building material, has attracted more and more attention in building engineering. Appropriate ice material models are crucial for the performance analysis of the increasing ice structures. There is still challenging in modelling ice responses due to the complexity of ice. This study aims to present a nonlinear elastoplastic damage model for ice material. First, a triaxial compression test of artificial ice is conducted. Based on the test results, the modified Tsai-Wu failure criterion with better performance in the tensile zone and physical meaning for hydraulic strength is established. Then, combining plasticity theory with damage mechanics, an elastoplastic damage constitutive law considering the difference between tensile and compressive properties is proposed. The piecewise damage model and the Weibull exponential damage model are employed for compression and tension damage, respectively. Moreover, the numerical iterative algorithm is developed and a user-defined material subroutine (UMAT) is embedded in the finite element software ABAQUS to simulate the mechanical properties of ice. Furthermore, the constitutive model is verified by comparing the FEM results with the results of uniaxial compression, triaxial compression, and three-point bending tests. The results show that the constitutive model can well describe the stress-strain nonlinear behavior and capture the basic failure mode of ice materials. Finally, considering temperature affecting on the failure surface, a temperature dependent ice material model is developed. The current study would help in the design, operation and maintenance of ice structures.

Displacement and Internal Force Response of Mechanically Connected Precast Piles Subjected to Horizontal Load Based on the m-Method

Mechanically connected precast piles are a type of precast piles that utilise snap-type mechanical connectors to restrain the pile ends of two identical or different precast piles at the top and bottom so as to quickly realise the purpose of the connection. However, the gap problem in the connectors of mechanically connected piles can lead to uneven and uniform deformation of the piles under horizontal loading, resulting in additional displacements and rotation angles of the piles at the connection. Solving the problem of calculating the internal force response of discontinuous deformed piles is a prerequisite for promoting and applying mechanically connected precast piles. Firstly, the theoretical derivation of mechanically connected piles with fixed constraints at the pile bottom is carried out. Secondly, the pile response equations of mechanically connected piles are established, and the theoretical solutions of pile displacement and internal force response of mechanically connected piles under horizontal loading are derived. Thirdly, the pile-soil model of the test pile is established using ABAQUS software (ABAQUS 2016) in combination with the design data of the test pile. The numerical simulation displacements and angles of rotation are compared with the test results. Finally, the theoretical and numerical simulation displacements and internal forces of the ordinary pile and the mechanically connected pile are compared. The relative errors of the displacements and angles of rotation of the established pile-soil model are less than 10%, indicating that the established model has good accuracy. The relative errors of the theoretical and numerical simulation displacements and internal forces of the mechanically connected pile are less than 10%, proving the correctness of the theoretical calculation by the m-method. This study can provide effective theoretical support and methodological guidance for the displacement and internal force response of discontinuous piles.

The Use of Bilinear Cohesive Zone Model to Study the Fracture of Mode I in Adhesive Joints

Adhesively bonded joints can be numericallysimulated using the Cohesive Zone Model (CZM) concepts.CZM are widely used for the strength prediction of adhesivejoints. The critical strain energy release rate and criticalinterface strength are the parameters which must be knownwhen cohesive elements in ABAQUS software are used. Theformulation of the cohesive finite elements is based on theCZM approach with the bilinear traction-separation law. Inthis work, the parameters of two industrial adhesivesHuntsman Araldite 2015 and resin LY3505/XB3405 forbonding of epoxy composites are identified. DoubleCantilever Beam (DCB) test data was used for theidentification. Finally, cohesive parameters are identifiedcomparing numerically simulated load-displacement curveswith experimental data retrieved from literature.Parametric study is performed to evaluate the variation ofinput parameters like initial stiffness, element size, peakstress and energy release rate ‘G’. From the numericalevaluation, it was noted that CZM simulation relies largelyon element size and peak cohesive strength.

Hysteretic Performance Analysis of Prefabricated Steel-Concrete Composite Edge Joints Considering Floor Composite Effects

ABSTRACT This study conducts quasi-static tests and finite element (FE) analysis by using ABAQUS software to examine the effects of floor combination effect (FCE) on the seismic behavior of a novel type of prefabricated steel-concrete composite (PSCC) exterior joints. This analysis assesses PSCC exterior joints featuring bolted-welded hybrid connections, focusing on their seismic performance under the influence of FCE. The variables in this research include floor construction parameters, axial compression ratio (n), and core area concrete (CAC). The results indicated that these variables, particularly the floor construction parameters, n, and CAC, significantly influence stress distribution and magnitude within the joint core area (JCA) and the floor slab. Although the floor construction parameters exert a minor effect on seismic performance, increasing n markedly enhances the joints’ load-bearing and energy dissipation capacities. However, it also makes the joints more susceptible to brittle failure. Optimal bearing capacity and ductility for energy dissipation are achieved when n equals 0.3. In addition, CAC substantially increases the initial stiffness (IS) and bearing capacity, with a peak increase in bearing capacity of approximately 18% and an IS enhancement of around 25%. However, rising CAC strength has a relatively minor impact on seismic performance.

Investigation of soil damping for offshore wind turbine monopile-soil system in stiff clay on elastoplastic-damage model

Damping plays a crucial role in the design of offshore wind turbine (OWT) monopile foundations. The soil damping of the monopile-soil system (MSS) represents the energy dissipation mechanism arising from the interaction between the pile and the soil. It is typically derived by back-calculating from the overall damping measured in the entire OWT structure. However, few studies have independently examined the soil damping in MSS, and the impact of key parameters such as pile diameter, pile embedded depth, cyclic load amplitude, and load eccentricity on the variation of soil damping in MSS remains unclear. This paper introduces an elastoplastic-damage constitutive model for the numerical simulation of the damping ratio variation in seabed soil and MSS. The model is implemented in ABAQUS software and validated against cyclic triaxial tests on stiff clay soil. On this basis, a three-dimensional finite element sensitivity study was conducted to elucidate the effect of these key parameters on the MSS damping ratio. The results of the study reveal that the MSS damping ratio exhibits a nonlinear and asymmetric trend as the loading cycles increase. The MSS damping ratio decreases with increasing pile diameter and embedded depth but increases with increasing lateral cyclic load amplitude and load eccentricity from the mudline.

Characterization of resistance welded hybrid sandwich sheets with additively manufactured core structure

Abstract Production of additively manufactured sandwich sheets is limited to small sizes. In the new introduced process route, additively manufactured core structures are joined with rolled face sheets by resistance welding, and the formability of the hybrid sandwich sheets is investigated. The necessity of developing the humps to improve the quality of resistance welding is initially investigated. Two different core structures, namely honeycomb and hollow sphere, are selected, and electrical-thermal coupled simulations with the ABAQUS software are performed to study the temperature distribution during resistance welding without and with hump. The strength of the joints for the fabricated sandwich sheets is verified by a quasi-static shear test. It is experimentally proven that the sandwich sheets without a hump in the core structure are not fully joined, and desired temperature localization is possible only by applying the hump. This is because the hump reduces the contact area, which leads to an increase in current density at the point where the resistance ratios are changed. This leads to higher temperatures in the intended joining zone. Different hump geometries for the core structure are designed, fabricated, and joined to the face sheets under different process parameters. The spot contact yields up to 50% higher shear strength than the linear or area contact. The free air bending results show that the double weld is essential for successful subsequent bending. It is also concluded that increasing the resistance welding time by more than 120 ms does not affect the joining strength of hybrid sheets.

Residual stress distribution and relaxation in U-rib full penetration welds by ultrasonic impact treatment

Ultrasonic impact treatment (UIT) as an effective method for alleviating welding residual stresses (WRS) is used to improve the fatigue performance of welded structures. However, its application to single- and double-sided U-rib welds in orthotropic decks has been limited. To address this, an experimental and numerical investigation on WRS and UIT was carried out for different deck thicknesses. A 3D thermo-elastic-plastic approach was employed to model the temperature and stress fields by the ABAQUS software. Additionally, a dynamic explicit calculation method was developed to simulate the UIT process, and its accuracy was verified by comparing the actual and numerical grooves and WRS after UIT. Ultrasonic stress measurement was employed to determine the distribution and magnitude of WRS before and after UIT. The results demonstrate that most relative errors of residual stress numerical and test results under different stress paths after UIT are within 10 %, confirming the reliability and effectiveness of this method. For single-sided U-rib welds after UIT, the reduction in WRS at the weld seam ranges from approximately 25.6 % to 87.4 %, while for double-sided U-rib welds, the reduction varies from about 22.2 % to 65.5 %. The impact of UIT on longitudinal residual stresses is more significant compared to its effect on transverse residual stresses. However, UIT results in a relatively smaller reduction in WRS away from the weld seam. Furthermore, it is observed that altering the deck thickness results in different disparities in WRS outcomes after UIT.

Determination traction-separation parameters and its sensitivity analysis of bilinear cohesive zone model through experimental and numerical peeling analysis of electrodes

The optimization of traction-separation parameters within the cohesive zone model (CZM) is crucial for accurately simulating electrode peeling failure in lithium-ion batteries. This study performed 180° peeling tests on NCM electrodes and used Abaqus software alongside the sim-flow optimization tool for simulation analysis, aiming to accurately replicate the failure behavior at the lithium-ion battery electrode interface. Experimental results were used to determine the fracture energy of the electrode interface, while numerical simulations analyzed the peeling performance of the electrode. By fitting the force-displacement curves from both simulation and experiment, the traction-separation parameters within the bilinear CZM were optimized. Additionally, the study analyzed the effects of traction-separation parameters, as well as the modulus and thickness of the current collector, on peeling behavior. The results showed that a significant increase in the interface stiffness and strength increased the steady-state peeling force. Among these, the fracture energy had the most significant influence on the steady-state peeling force. Furthermore, while the modulus and thickness of the current collector affected the maximum peeling force, their effect on the steady-state peeling force was negligible. These findings enhance the accuracy of simulating the failure behavior of the electrode interface.

Behavior of container berth structure under the influence of environmental and operational loads

Abstract Container docks, which are an essential component of the marine berth, are exposed to loads from various sources, such as self-weight, operation, and environment. In this study, four sets of combined loads to which the container berth is exposed were selected at the Um-Qaser Port in southern Iraq. The berth was constructed more than 40 years ago, which has to be verified according to latest specifications, and each set of combined loads was analyzed in three cases. In the first case, the piles were assumed to be fixed at the seabed, and in the second and third cases the piles were modeled as embedded in elastic and elasto-plastic sandy soil, respectively. The general-purpose finite-element software ABAQUS was used to model the various components to determine the maximum stresses, displacements, axial forces, shear forces, and bending moments due to dead, live, operate, berthing, mooring, waves, and seismic loads. It has been demonstrated that the impact loads of ships have a more significant impact on the structure compared to other loads. The calculated displacement when the piles are assumed to be fixed at the seabed level may be reduced by 50–94% of that calculated when the soil is modeled, meaning that assuming fixed piles yields inaccurate results, especially for deck displacements. However, this assumption was verified to yield reasonable results for shear forces at the pile head. It could also be noted that the elasto-plastic model of soil was more sensitive than the elastic model in displacement by 0.4–8% and bending moment by 0.3–34%, while it is less sensitive in axial force by 3–8%. The aim of this study is to obtain knowledge on the behavior and efficiency of container berth under the influence of different loads and the environmental conditions surrounding it.

Experimental and numerical study on mechanical properties of a modified type of energy-dissipative hold-down for CLT structures

The connections ensure lateral and shear resistance in CLT buildings, facilitating crucial interactions between walls and floors. CLT connectors are widely used at present and take strength as the control index, but they have poor energy dissipation performance and are not suitable for middle- and high-rise buildings in earthquake-prone zones. This study proposes a modified version of an existing energy dissipative hold-down connection that rectifies its flaws by incorporating innovative design and material solutions. An experimental study is conducted with quasi-static monotonic and reversed cyclic loading tests to investigate modified hold-down connection failure mechanisms and mechanical properties. Notable failure modes included steel rib ruptures and debonding between rubber and steel plate, with steel rib rupture as a dominant failure mechanism. Despite such failures, the connection maintained functionality, attributed to the effective bonding between the rubber and the steel bracket. The load-displacement curves of the hold-down exhibit a bi-linear pattern with the yielding point caused by the yielding of steel ribs. Almost all the specimens were classified as highly ductile, with ductility values exceeding 9.0 and an equivalent viscous damping ratio between 10 % and 18 %, indicating significant ductility and energy-dissipative capabilities. Furthermore, a simplified FEM model of the modified hold-down is established using ABAQUS software and validated against the experimental results. In addition, a parametric study was conducted to investigate the influences of modified design parameters on the mechanical properties and failure modes. The results of the comparison between the test and FEM model show the robustness of the proposed model in estimating the initial stiffness, post-yield stiffness, and yield force. Ultimately, the modified energy dissipation hold-down effectively rectifies former design flaws over its previous version, resulting in significantly improved performance, high energy dissipation capacity, and ductility by mitigating the brittle failures. This study provides a technical solution for future research to enhance the seismic resilience of modern high-rise CLT buildings through the real-world implementation of this type of modified hold-down connections.

Axial compressive behavior of reinforced hollow circular high strength concrete filled steel tubular short columns

This study aims to investigate the mechanical behavior of reinforced hollow circular high-strength concrete-filled steel tubular (RHCFST) short columns under axial compression. The axial compression test of 6 RHCFST short columns was carried out, and the bearing capacity, ductility and failure modes of the columns were analyzed. The results revealed that the failure modes of RHCFST short columns primarily included mixed failure, shear failure, and crushing failure. Comparatively, the failure modes of specimens with ordinary reinforcement exhibited a shift towards mixed failure, significant improvement in ductility, and a decrease in the increase trend of ultimate bearing capacity with the growth of steel tube thickness. Based on the test results, finite element models were developed using ABAQUS software for parameter analysis. The results demonstrated a positive correlation between the short column’s bearing capacity and parameters such as steel strength, sandwich concrete strength, steel tube thickness, and ordinary reinforcement diameter. Additionally, the initial stiffness of the short column increased with the increase of steel tube thickness. Considering the mechanical properties and engineering applicability of the member, the recommended design of steel tube yield strength, sandwich concrete strength, steel tube thickness and ordinary reinforcement diameter were given. Furthermore, the axial bearing capacity calculation formulae for RHCFST short columns were proposed. The calculated values were found to closely match both experimental and simulated values, with errors falling within 10 %. Consequently, the formulae can offer a reliable prediction of the member’s axial bearing capacity.

Design and Testing of Vehicle-Mounted Crop Growth Monitoring System

The aim of this study was to overcome the impact of vibration generated by agricultural machinery on the monitoring accuracy and performance of vehicle-mounted crop growth monitoring systems during field operation. This paper developed a vehicle-mounted crop growth monitoring system with vibration damping capability to achieve this goal. The system consists of a multispectral crop growth sensor, signal conditioning module, and truss-type sensor bracket with self-vibration damping capability. The commercial finite element analysis software ABAQUS 6.10 was used to conduct modal and dynamic simulation analyses of the sensor bracket, which indicate that the truss-type sensor bracket can damp vibrations effectively. The p-values (least significant differences) of crop canopy DNRE (red edge normalized difference vegetation index) under different operating speeds (1.5, 3, and 4.5 km/h) are 0.454, 0.703, 0.81, and 0.838, respectively, for four different crop growth stages. In a comparative experiment between the proposed monitoring system and two similar vehicle-mounted sensors (CropSpec and GreenSeeker RT 200) for measuring agronomic parameters at different stages of crop growth, the proposed monitoring system yielded R2 values of 0.8757, 0.7194, and 0.795, respectively, and RMSE values of 0.7157, 2.2341, and 2.0952, respectively, in the tillering stage, jointing stage, and tillering and jointing stage, outperforming the other two sensors.

Parametric study of side collision-induced denting failures on the ultimate strength of a handy-size containership under vertical bending

This study focuses on analysing the collision behaviour and residual ultimate bending strength of a container ship following a collision. Initially, computational models employing nonlinear finite element analysis (NFEA) were used to consider dynamic material parameters like strain rate and crack strain. The accuracy of this numerical approach was verified by comparison with test results. Subsequently, various collision scenarios were analyzed using ABAQUS software, encompassing diverse impact velocities, indenter shapes, and boundary conditions. The aim was to evaluate the reduction in the residual ultimate bending strength of a container ship hull resulting from collisions at both sagging and hogging moments. Finally, empirical equations were formulated to forecast the residual ultimate bending strength based on numerical findings. These equations exhibited excellent accuracy when validated against numerical and experimental data. This methodology and its equations provide valuable tools for assessing the post-collision strength of container ships and enhancing maritime transportation safety.

Experimental and numerical research on seismic behavior of end-plate connection beam-column joints considering concrete floor effect

With the aims to study the seismic performance of the end-plate connection (EPC) joint with concrete floor, four full-scale specimens with different configuration (two specimens in major direction, and the other in minor direction) of the pseudo-static cyclic loading tests were conducted. Based on the failure criteria, the mechanical behaviors and failure modes of the specimens were investigated, including major and minor connection directions. The hysteresis response, bearing capacity, stiffness evaluation, and energy dissipation of the specimens were evaluated, and with a average ductility coefficient value of all specimens is about γ = 4.0. Meanwhile, to analyze and verify the accuracy of experimental results, the nonlinear models of the specimens were performed in ABAQUS software. In addition, a series of parametric analysis were performed to study the influence of axial compression ratios, thickness ratios (the ratio(η1) of end-plate thickness to column flange thickness, and the ratio(η2), of end-plate thickness to column web thickness), and concrete compressive strength on the joint seismic performance. This parametric analysis result indicates that increasing the thickness ratio and concrete compressive strength reasonably can effectively improve the seismic behavior of the overall joint with the concrete floor, especially in minor direction joints.

Characterizing Splitting Failure of Concrete Influenced by Material Heterogeneity Based on Digital Image Processing Techniques

Concrete, as a composite material, is subject to heterogeneity in its mechanical properties and damage characteristics responding to load. In this paper, a numerical approach for analyzing the heterogeneous characteristics and the mechanical behavior of concrete specimens in tensile splitting tests using DIP techniques is introduced. The experiment involves the preparation of three types of concrete specimens with different strengths and performances of the tensile splitting test. The contour and position information of the different components in the split surface of a concrete specimen are reflected in the numerical model using the DIP techniques and the fracture of the split surface is realized by three types of cohesive elements in the finite element software ABAQUS. The results of the proposed numerical model are highly consistent with the experimental results with a maximum error of 4.77%, whereby the evolution of the splitting process is discussed. The simulation shows that the concrete fracture develops from the periphery towards the center of the concrete and the ITZ region splits first at similar strain levels, followed by the mortar region and finally the aggregate region. In addition, a simplified modeling scheme with faster computational efficiency and higher accuracy is proposed, which indicates that the shape of the heterogeneous components in concrete has a low effect on mechanical strength. The proposed model can accurately reflect the splitting fracture process of concrete which is instantaneous in the actual process, contributing to the understanding of the mechanism of the splitting fracture process and proposing a new methodology for simulating the fracture process of heterogeneous materials (e.g., concrete, rock). This work contributes to the understanding of the effect of material heterogeneity on concrete’s mechanical behavior and fracturing process and provides valuable hints for the research on the non-destructive prediction of concrete strength.