ABAQUS Platform Research Articles

A novel approach to enhance the structural integrity of a bottom-edge cracked I-beam with piezoelectric actuators

Structural health monitoring and repair have become increasingly crucial in confirming the safety and longevity of damaged structures. This study presents a novel approach to enhancing the structural integrity and extending the fatigue life of a bottom-edge cracked I-beam by applying piezoelectric actuators strategically placed along the crack location by actively suppressing crack propagation. An innovative actuation system induces controlled deformations in the I-beam, effectively reducing the Stress Intensity Factor (SIF) and preventing crack propagation. The efficacy of the proposed approach is validated through a series of numerical results on the ABAQUS platform, including static loading, fatigue loading, and crack growth monitoring. Various parameters, like maximum loading capacity under static loading, interpretation of crack growth rate, and service life, are monitored and analyzed throughout the cyclic loading process. The results demonstrate that the application of 500 V to the piezoelectric actuators significantly reduces the SIF by 16.62% under a 2 kN total load, a 2.86% enhanced maximum load-carrying capacity is obtained, delayed crack propagation is found after repair, and a 72.67% extended service life is achieved under a load range of 0.2 kN to 2 kN. Overall, the outcomes of this research lead to the development of innovative and efficient techniques for delaying the propagation of cracks, thereby preventing the premature onset of catastrophic failure of cracked I-beams.

Prediction of rotational bending fatigue life of bearing steel based on damage mechanics

Based on the theory of continuous damage mechanics, this paper proposes a fatigue damage evolution model and numerical calculation method considering the influence of vacuum chemical heat treatment process, and studies the rotational bending fatigue damage analysis and life prediction method of M50NiL bearing steel. Firstly, the constitutive model, fatigue damage evolution equation and material parameter calibration method in the theoretical model are given. Secondly, based on the ABAQUS platform, the damage mechanics-finite element numerical calculation method of fatigue damage analysis considering the influence of hardened layer is realized by writing the UMAT subroutine; then, the rotational bending fatigue test of M50NiL bearing steel treated by vacuum chemical heat treatment of quenching and tempering, carburizing and carbonitriding is carried out, and the influence of heat treatment process on fatigue performance is analyzed; finally, based on the proposed fatigue damage model and numerical calculation method, the rotational bending fatigue life of M50NiL bearing steel is predicted, and the results are compared with the experimental results to verify the correctness of the proposed method.

Prediction of rotational bending fatigue life of bearing steel based on damage mechanics

Based on the theory of continuous damage mechanics, this paper proposes a fatigue damage evolution model and numerical calculation method considering the influence of vacuum chemical heat treatment process, and studies the rotational bending fatigue damage analysis and life prediction method of M50NiL bearing steel. Firstly, the constitutive model, fatigue damage evolution equation and material parameter calibration method in the theoretical model are given. Secondly, based on the ABAQUS platform, the damage mechanics-finite element numerical calculation method of fatigue damage analysis considering the influence of hardened layer is realized by writing the UMAT subroutine; then, the rotational bending fatigue test of M50NiL bearing steel treated by vacuum chemical heat treatment of quenching and tempering, carburizing and carbonitriding is carried out, and the influence of heat treatment process on fatigue performance is analyzed; finally, based on the proposed fatigue damage model and numerical calculation method, the rotational bending fatigue life of M50NiL bearing steel is predicted, and the results are compared with the experimental results to verify the correctness of the proposed method.

Influence of local scour on the dynamic responses of OWTs under wind-wave loads

Offshore wind turbines (OWTs) often operate in complex marine environments, where they are not only subjected to wind and wave loads, but also adversely affected by scour. Therefore, it is of great significance to explore the effect of scour on the dynamic responses of OWTs under external loads to ensure structural safety, improve performance, and extend service life. In this study, a comprehensive numerical model of a 5-MW OWT, including tower, monopile, and soil-structure interaction (SSI) systems, is established by using ABAQUS platform. Aerodynamic loads is generated using blade element momentum, while wave loads is generated using the P-M spectral. The depth of scour is obtained based on on-site measured data. A comparative analysis is conducted between fixed foundations and SSI systems when conducting dynamic response analysis of OWTs under wave loads. Subsequently, the effect of scour on dynamic responses of OWTs under aerodynamic and wave loads is investigated. Results demonstrate that SSI can significantly influence the natural frequency and dynamic responses of the OWT. Therefore, it is essential to thoroughly consider SSI when evaluating the dynamic response of the OWT with local scour. The tower-top displacement and acceleration of the OWT with show a significant increasing trend compared to the non-scoured OWT. An increase in scour depth leads to higher maximum stress and stress amplitude in the steel monopile, which could potentially cause fatigue issues and should be given due attention.

A Lennard-Jones potential based cohesive zone model and its application in multiscale damage simulation of graphene reinforced nanocomposites

A new mixed-mode cohesive zone model based on Lennard-Jones potential (LJCZM) is proposed to simulate the interface failure between graphene and epoxy matrix. The values of model parameters are obtained from a large number of molecular dynamics simulations, and a UMAT subroutine is programmed and validated to introduce this model into the ABAQUS platform. This process spans from the nanoscale to the microscale, which provides a new routine for the multiscale damage modeling of the graphene reinforced epoxy nanocomposite at microscale. In addition, the continuous damage phase-field model is used to simulate the matrix damage, and the values of model parameters are determined from the molecular dynamic simulations of the bulk epoxy at nanoscale. At last, the effects of parameters such as volume fraction, aspect ratio, orientation, and curvature of graphene nanoplatelets are investigated. The results indicate that the nanocomposite reinforced with high content and large aspect ratio graphene nanoplatelets presents the lower ultimate stress and fracture strain. In addition, the orientation and waviness of the graphene also significantly affect the mechanical properties of the nanocomposites. The nanocomposite reinforced with graphene platelets with greater waviness has higher stiffness and strength but lower toughness. The rationality and effectiveness of the model are verified through comparison with other existing results.

Mechanism analysis for scaling effect on the impact behaviors of RC beam: From material properties to component response

Scaling effects on the resistance response of RC components have been found under impact, penetration, and blast. To investigate the mechanism and origins of the scaling effect on the impact response of RC beams, numerical models of geometrically similar beams were established on the ABAQUS platform by considering the strain rate effect. The influence of material properties such as elasticity, plasticity, and strain rate effect on the similarity of beam impact response was accessed and analyzed. Then, the scaling effects of impact characteristics such as time history, damage, effective mass, and span length of RC beams were discussed and compared from the local and global stages. The numerical findings revealed that material properties influence the scaling effect on the impact response and strain rate distribution. The inhomogeneity of strain rate distribution and the difference in dynamic strength caused by the non-uniform scaling for the strain rate effects (DIFs) contribute to the scaling effect. In addition, the two-stage analysis results indicated that the scaling effects exhibited in the local and global responses of RC beams are not entirely consistent. As the scale factor increases, for the large-sized beams, the normalized deformation profile shrinks, the equivalent mass factor decreases, the effective span length changes slower, and the moving velocity of the plastic hinge slows down. Several impact performance characteristics, such as strain rate distribution within the beam and the damage and deformation curve of the beam, will reflect localization as the scale factor increases. It is expected that the preliminary mechanism analysis of this study could provide a reference for analyzing the impact response of prototype beams.

Failure behavior and probabilistic safety assessment of containment structure under internal pressure considering time-varying prestress loss

This paper adopts a refined method to calculate the prestress loss of containment and evaluates the impact of time-varying effects on the mechanical properties and safety of containment under accident pressure. Firstly, a new method for converting the commonly used creep model into the Kelvin chain creep model is proposed, and rate-type constitutive relationships considering time-varying factors are established. Utilizing the developed subroutine scripts, these constitutive relationships are incorporated into the ABAQUS platform. Subsequently, the prestress losses of containment at different service times are calculated. Finally, the failure behavior and the probabilistic performance of containment under prestress loss and internal pressure conditions are systematically discussed. Results show that the proposed method exhibits high applicability, and the fitted creep compliance function based on the Kelvin chain model agrees well with the original creep compliance function. For the investigated containment, the time-varying prestress loss is most pronounced in the horizontal tendons near penetrations. Under design pressure, the containment remains elastic for all investigated prestress loss conditions, but the structural deformation, steel liner strains, and principal tensile stresses in concrete increase with the increase in time-varying prestress losses. At the limit state, greater time-varying prestress loss makes the containment more prone to functional failure at lower internal pressures. The time-varying prestress loss has a significant impact on the fragility and reliability of the penetrations in containment, while its impact on regular segments is relatively small.

Recrystallization behavior and strengthening mechanism of friction stir welded T-joint of Ti80 titanium alloy

In this study, Ti80 titanium alloy T-joints were produced by friction stir welding (FSW), and the joint temperature and residual stress distribution of the joints were analyzed by numerical simulation based on the ABAQUS platform, and the correlation between microstructure and performance of FSWed T-joint was investigated. The results show that the SZ is lamellar α grains due to the fact that the peak temperature of all joints exceeds β phase transus. The deformation and dynamic recrystallization behavior take place in the β phase region. During the subsequent cooling stage, the acicular α/α' phase is precipitated from refined prior β phase. The non-uniform heating and cooling results in the significant microstructure differences in the weld thickness direction. The top and middle of the SZ are composed of basketweave structure, while the bottom of the SZ shows a bimodal structure. The microhardness distribution along the skin shows a higher value in the weld area, and the weakest area is located in the HAZ due to recovery, resulting in a significant reduction in dislocation density of the weld. The tensile specimen breaks in the HAZ when it is stretched along the skin direction, while it breaks in a direction parallel to the skin when it is stretched along the stringer. The fracture mechanism of the joint changes from a hybrid mode of ductile and brittle fracture to ductile fracture as the rotation speed increases from 600 rpm to 750 rpm.

Characterization of Shear Damage and Channel Reinforcement of Circumferential Joints between Shield Tunneling Segments Based on Numerical Simulation

Shield misalignment is a common problem in shield tunnels, which seriously affects the safety and durability of tunnels. However, at present, there is a lack of research on the influence of shield misalignment on the shear capacity of the circumferential joint structure, and the failure mechanism of the circumferential joint structure before and after reinforcement is not clear. Therefore, this paper simulates the influence of misalignment on the performance mechanism of segmented circumferential connection and the effect of channel reinforcement on the ABAQUS platform. The simulation results are compared with the full-scale test results, and the results show that the shear failure process of the circumferential joint can be divided into three stages under the condition of no reinforcement. In the first stage, the vertical load increases, but the misalignment between the shield tunneling sections is very small. In the second stage, the load almost does not increase, but the degree of misalignment increases. In the third stage, the load–displacement relationship is nonlinear, indicating that the bending bolt has been sheared. Under the condition of unreinforced, the bolt will form two plastic hinges when it fails. After reinforcing the channel, the removal of the bolt forms only one plastic hinge. After channel steel reinforcement, the boundary area between the channel steel web and the steel plate first reaches the ultimate tensile strength of the steel plate, and the failure mode becomes channel steel reinforcement failure. Under the same shear load, the misalignment of the circumferential joint reinforced with channel steel is reduced. In this paper, the misalignment relationship of shear load and the yield of the bending bolt obtained through numerical calculation is consistent with the conclusion of the full-scale test. However, the circumferential connection misalignment obtained via numerical calculation is relatively small. The yield position of the bending bolt is also in good agreement with the test results, and the bolt strain obtained through the test is relatively small.

Experimental and numerical investigation of free vibration behaviour of sandwich plates with natural-fibre-based laminated composite cores

ABSTRACT This article presents an experimental and numerical investigation into the free vibration behaviour of fibre-reinforced composite sandwich plates. The proposed symmetrical three-layer sandwich plate contains aluminium as face layers and jute/epoxy laminated composite as a core layer. The experimental phase of this research involves the fabrication of jute/epoxy composite sandwich plates and the measurement of their natural frequencies through a non-destructive modal testing approach using the impact hammer technique. A numerical model is developed using the finite element method in the ABAQUS platform to simulate the free vibration response of the jute/epoxy composite sandwich plates. Comparisons between the experimental and numerical results demonstrate a good agreement, validating the accuracy and reliability of the finite element model. Furthermore, an extensive numerical investigation is conducted to examine the impact of various geometric and structural parameters on the dynamic response of the sandwich plates. The study’s outcomes aid in designing and optimising composite sandwich structures, facilitating the development of sustainable and high-performance engineering solutions.

Seismic behavior of reduced beam section joints considering concrete floor effect

SummaryThis study investigates the seismic impact of concrete floors on reduced beam section beam‐to‐column joints through four quasi‐static cyclic tests. We examine mechanical properties, failure modes, and processes against specific criteria. Additionally, we analyze hysteretic response, energy dissipation, stiffness, capacity, and stress–strain mechanisms. Moreover, the ABAQUS platform was used to reproduce the specimen nonlinear finite element model to compare and analyze the test results. The results showed that the specimens exhibit excellent energy dissipation capacity and ductility (with a coefficient of 5.00); the column‐bar connection characteristics affect the maximum capacity and plastic hinge behavior in the reduced beam area. The reduced section of beam's upper flange could not improve the overall seismic performance of the joint. The observed failure sequence is as follows: concrete floor cracking, beam flange yielding, reinforcement fracture, lower flange yielding in the reduced beam area, and overall joint failure. This sequence confirms that the joint fulfills the design criteria of a “strong column‐weak beam” by achieving the target of plastic hinge outward movement.

Resilient seismic performance of self-centering hybrid rocking reinforced concrete wall: Numerical simulation

A reinforced concrete rocking wall is engineered to endure seismic forces, leveraging its motion to absorb earthquake energy and mitigate collapse risks. In earthquake-prone regions, self-centering walls offer a durable solution, capable of returning to their original positions post-event. This study proposes an innovative Self-centering Hybrid Rocking Wall (SHRW) integrated with a replaceable Flexural Plate Energy Dissipator (FPED) to minimize concrete wall damage during earthquakes and streamline subsequent repairs. Utilizing the ABAQUS platform, a validated finite element model, based on experimental data, was developed to analyze the robustness of the proposed FPED-SHRW, focusing on the FPED’s energy-dissipating capacity. Additionally, a series of FPED-SHRW samples underwent cyclic loading assessment to investigate resilient performance, considering factors such as initial prestressing force, post-tensioned strand location, and flexural energy dissipator device thickness. The results demonstrate that the suggested self-centering hybrid rocking wall with a flexural plate energy dissipator exhibits exceptional resilient properties, including high energy dissipation capacity, effective self-centering ability, and superior strength and stiffness. This design achieves the objective of minimizing damage during earthquakes and expediting rehabilitation afterward. Furthermore, simulation outcomes confirm the sensibility of the numerical model based on ABAQUS.

Research on Nonlinear Behavior of Local High-Performance Concrete Beam-Column Connections.

The seismic performance index of prefabricated structures is generally obtained via experimental analysis. However, in experimental research, it is impossible that every influencing factor can be taken into account. Therefore, the finite element analysis method can be used as a supplementary method for experimental research to carry out parametric analysis of joints. Based on this test, a hysteretic model of steel bars is developed on the ABAQUS platform; meanwhile, the model is used to simulate the seismic analysis of the proposed local reinforced joints. The hysteresis curve obtained via simulation exhibits a high degree of coincidence with the experimental results. Based on the validated model, a detailed parameter analysis of prefabricated local reinforced concrete frame joints is carried out. The analysis results illustrate that the axial pressure ratio at the top of the column has a minimal impact on the joint's performance. Decreasing the stirrup ratio within the core region, enlarging the diameter of the PC steel bar, and increasing the concrete strength that is poured in the keyway and the core region can raise the cumulative energy consumption of the joints, thereby reducing the damage degree of other units and improving the maximum bearing capability of the joints.

Dynamic responses of monopile offshore wind turbines in cold sea regions: Ice and aerodynamic loads with soil-structure interaction

Offshore wind turbines (OWTs) constructed in ice-covered sea areas are subjected to a multitude of challenges in complex marine environments. These challenges encompass not only strong winds and weak foundations but also the formidable task of withstanding the impact of floating ice. To address these issues comprehensively, this study introduces a dynamic analysis framework for OWTs that incorporates soil-structure interaction (SSI), stochastic ice loads, and aerodynamic loads. This framework takes into account the intricate interplay between these factors, providing a holistic approach to the analysis of OWTs in icy marine environments. The research holds significance in elucidating the dynamic response laws of OWTs situated in icy waters under diverse factors. This understanding is vital for ensuring the structural safety and reliability of OWTs and fostering sustainable development in this field. In the present study, stochastic ice loads are generated using a real ice load spectrum model, while the aerodynamic loads are determined through the Blade Element Momentum (BEM) methodology. A comprehensive numerical model of the NREL 5-MW OWT, which includes the blades, tower, monopile, and soil system, is constructed based on the ABAQUS platform. The dynamic responses of the 5-MW OWT are systematically investigated under ice loads alone, as well as under combinations of ice and aerodynamic loads. The results of the study demonstrate that considering SSI and greater water depth amplifies the dynamic responses of OWTs subjected to stochastic ice loads. Specifically, significant acceleration is observed at the tower-base, posing potential safety risks to operators on the OWT operating platform. Moreover, when ice and aerodynamic loads act in conjunction, the bending moment experienced by OWTs is lower compared to the cumulative effect of individual ice and aerodynamic load contributions. This finding highlights the possibility of overestimating structural responses when employing a summation analysis approach. Additionally, this study advances the comprehension of ice-induced vibration phenomena and establishes a theoretical foundation for the anti-ice design of OWTs in cold marine environments.

Very High Cycle Fatigue Life Prediction of SLM AlSi10Mg Based on CDM and SVR Models

A novel fatigue evolution model considering the effect of defect size and additive manufacturing building direction based on the theories of continuum damage mechanics and its numerical implementation in ABAQUS is proposed in this paper. First, the constitutive model, fatigue damage evolution model and their parameter calibration methods are presented. Second, using the ABAQUS platform, the proposed model is implemented with user-defined subroutines. After that, based on the proposed model and its numerical implementation, the fatigue life of additively manufactured AlSi10Mg is predicted and its applicability is verified through experimental results. Finally, a support vector regression model is established to predict the fatigue life, and its results are compared to those of the numerical finite element method. The results show that the support vector regression model makes better predictions than the finite element method.

Experimental, numerical and analytical investigation of bending performance of bolted demountable composite beams with profiled steel decking

This paper presents the results of a detailed experimental, numerical and analytical study to investigate the flexural bending performance of prefabricated demountable composite beams (PDCBs) with bolted shear connectors. Four full–scale tests were carried out for two profiled steel decking configurations (parallel and perpendicular to the steel section) with two different degrees of shear connection. The experimental results were used to validate a numerical simulation model established by the ABAQUS platform. A detailed parametric study was then performed using the validated numerical model to evaluate the effects of using different numbers of bolted shear connectors. The experimental results show that the final failure modes of the demountable composite beams are the same as conventional composite beams using welded shear studs, and the demountable composite beams behavior is ductile. The results of a comparison of load carrying capacity and elastic stiffness of the demountable beams calculated using the analytical equations for conventional composite beams against the experimental and numerical simulation results for the demountable composite beams confirm that the conventional composite beam theory can be used for the demountable composite beams. However, the experimental results indicate that longitudinal cracking in the grout between concrete slabs along the steel beam can happen, due to unsymmetrical location of the shear studs. Anti-cracking mesh would be necessary in practical applications for crack control.

Investigation on the Irradiation-thermal–mechanical coupling behaviors of the solid Microencapsulated fuel rod

Solid Microencapsulated Fuel (SMF) is a kind of new accident-tolerant fuel (ATF), where the TRISO coated fuel particles are dispersed directly into a type of matrix in the form of a solid rod. SMF is expected to provide improved performance because of the elimination of cladding tube and associated failure mechanisms. This study aims to investigate the irradiation-thermal–mechanical coupling behavior of SMF rod under normal operation of the 200 MW Nuclear Heating Reactor (NHR200-II) using finite element method (FEM). Two kinds of SMFs have been evaluated and compared -with the fuel particles dispersed into a silicon carbide matrix or a zirconium matrix. The finite element models, considering comprehensive coupling behavior (including irradiation-induced dimensional change, irradiation-induced creep, thermal expansion, fission gas pressure, heat generation and conduction, elasticity and plasticity, etc.), were developed based on the ABAQUS platform and accurately verified. The study also investigated the impacts of key parameters on the coupling behavior of SMF, including particle kernel diameter, non-fuel zone width, extent of particle aggregation, and operational conditions. The results revealed that SMFs exhibit excellent heat transfer capability, resistance to deformation, and a stress-relaxed state under normal operation. Specifically, SMF-Zr exhibited a higher centerline temperature but lower levels of deformation and stress compared to SMF-SiC. The effects of fuel kernel diameter and non-fuel zone width were found to be limited, whereas higher particle aggregation and harsher operational conditions indeed increase temperature, deformation, and stress, particularly during the initial irradiation stage. Moreover, a higher creep coefficient of pyrolytic carbon leads to a more relaxed stress state. This study lays a fundamental basis for the design and optimization of this kind of solid particle-dispersed fuel.

Three-Dimensional Temperature Field Simulation and Analysis of a Concrete Bridge Tower Considering the Influence of Sunshine Shadow

This paper forms a set of three-dimensional temperature field simulation methods considering the influence of sunshine shadow based on the DFLUX subroutine and FILM subroutine interface provided by the Abaqus platform to simulate the three-dimensional temperature field of concrete bridge towers and study its distribution law. The results show that the method has high accuracy for shadow recognition and temperature field calculation. The maximum difference between the shadow recognition results and the theoretical calculation value was only 19.1 mm, and the maximum difference between the simulated temperature and the measured temperature was 3.3 °C. The results of analyzing the temperature field of the concrete bridge tower using this algorithm show that the temperature difference between the opposite external surface of the tower column can reach 11.6 °C, which is significantly greater than the recommended temperature difference value of 5 °C in the specifications. For the concrete bridge tower, in the thickness direction of the tower wall, the temperature change was obvious only at a range of 0.3 m from the external surface of the tower wall, and the temperature change in the remaining range was small. In addition, the temperature gradient distribution of the sunshine temperature field in the direction of wall thickness conformed to the exponential function T(x) = T0e−αx + C. Additionally, the data fitting results indicate that using the temperature data at a distance of 0.8 m from the external surface as the calculation parameter in the function can achieve the ideal fitting result.

Seismic Performance of Self-reset Piers Assembled with External Replaceable Energy Dissipation Rings

In order to improve the shear and energy dissipation capacity, this paper proposes a kind of external replaceable energy dissipation ring segment assembly self-reset pier. The ABAQUS platform is used to simulate the refined model of pier and energy dissipation device. Then the influence of different energy dissipation modes on the seismic performance of bridge piers is studied by pseudo-static analysis. Finally, the influence of different parameters of energy dissipation ring on the seismic behavior of bridge piers is analyzed. The results show that the capacity of shear resistance and energy dissipation of the pier with two energy dissipation lines is significantly higher than that of the pier without energy dissipation devices. Reducing the radius of energy dissipation ring can effectively improve the lateral bearing capacity and cumulative energy dissipation of bridge piers. The thickness of energy dissipation ring has little effect on the seismic performance of bridge piers. Increasing a pair of energy dissipation rings can increase the cumulative energy dissipation of bridge piers by 31.1%. Although the residual displacement of pier top increases, the residual displacement angle is still less than 0.5%.

Fatigue life prediction for Al–Zn–Mg alloy butt welded joints based on a fatigue damage model accounting for the influence of interior porosity

AbstractThis paper proposed a high‐cycle fatigue life prediction method for Al–Zn–Mg alloy welded joints considering the thermal process of welding and the effect of welding pores. First, the welding process was simulated by a numerical thermal–mechanical analysis. The residual stresses were then obtained and applied as the initial stress field of the subsequent fatigue life calculation. Second, a fatigue damage model was constructed by introducing a dimensionless quantity to equivalently describe the effect of interior pores. Further, a corresponding damage mechanics–finite element numerical method was numerically implemented by the ABAQUS platform to calculate the high‐cycle fatigue life for Al–Zn–Mg alloy welded joints. The calculated lives have good consistency with test data, which validates the feasibility and applicability of the proposed model and the calculation method. Finally, the curves of the cyclic stress versus fatigue life of Al–Zn–Mg alloy welded joints with different interior pore sizes were calculated to explore the influence law of the welding pore.