Use Of ABAQUS Research Articles

Investigating the Effects of Geometrical Parameters of Re-Entrant Cells of Aluminum 7075-T651 Auxetic Structures on Fatigue Life

In this study, the effects of two geometrical parameters of the re-entrant auxetic cells, namely, internal cell angle (θ) and H/L ratio in which H is the cell height, and L is the cell length, have been studied on the variations of Poisson’s ratio and fatigue life of Aluminum 7075-T6 auxetic structures. Five different values of both the H/L ratio and angle θ were selected. Numerical simulations and fatigue life predictions have been conducted through the use of ABAQUS (version 2022) and MSC Fatigue (version 11.0) software. Results revealed that increases in both the H/L ratio and angle θ improved the average value of Poisson’s ratio. Increasing the H/L ratio from 1 to 1.4 and θ from 50° to 70° increased the values of Poisson’s ratio, respectively, 7.7% and 80%. In all angles, increasing the H/L values decreased the fatigue life of the structures significantly. Furthermore, in all H/L values, an increment in θ caused a reduction in fatigue life. The effects of H/L and θ parameters on fatigue life were dominant in the low cycle fatigue regime. Results also showed that the H/L ratio parameter had greater influence as compared to the θ angle, and the structures with higher auxeticity experienced higher fatigue resistance. It was found that the auxetic property of the structure has a direct relationship with the fatigue resistance of the structure. In all samples, structures with greater auxetic property had higher fatigue resistance.

Numerical Analysis of Slotted Wings Using Fluid-Structure Interaction

For shorter landing and take-off path in airports, the aircrafts should reduce their speed with keeping high lifting force. This paper is to identify solutions to increase the lift force of the wing significantly under several flight scenarios (such as takeoff and landing) using leading-edge slats and their relationship with the dynamic parameters of the aerodynamic wing. The study is performed by the use of ABAQUS 2016 software. The problem is solved for turbulent flow and 2-dimensional composite wing at constant Reynolds’s number of (6.49 × 105) and constant boundary conditions. Various depths have been used for the auxiliary airfoil at constant width and gap. All stresses at the wing base were obtained. The pressure distribution on the airfoil surface was determined, air velocity distribution was tracked over the surface, lift and drag forces and their coefficients were computed. The results show that the highest value of the lift coefficient is 0.489 at the depth (-3 %) of the wing chord, it decreases when the depth of the slat becomes zero %, and the rise returns with increasing depth to (4 %), but it does not reach the maximum value, while the highest drag coefficient was (1.89) at depth (4 %) of the wing chord. The maximum value of Von Mises stress was found at depth of 4 % with value of 1.605 × 105 Pa.

A phase field solution for modelling hyperelastic material and hydrogel fracture in ABAQUS

The phase field fracture model is attracting significant interest. To model fracture in hyperelastic material and hydrogel, we have implemented a robust two- and three-dimensional phase field method in the commercial finite element code ABAQUS/Standard. The method is based on the rate-independent variational principle of diffuse fracture and also exploits the analogy between the phase field evolution law and the heat transfer equation, enabling the use of Abaqus’ in-built features and sparing the need for defining user elements. The framework is shown to accommodate both staggered and monolithic solution schemes. The approach can properly simulate the fracture for both hyperelastic material and hydrogel under different boundary conditions. Several examples are provided to demonstrate the robustness of the method. The provided source codes and the tutorials make it easy for practicing engineers and scientists to model crack propagation in hyperelastic and gel materials.

A simple and robust Abaqus implementation of the phase field fracture method

The phase field fracture method is attracting significant interest. Phase field approaches have enabled predicting - on arbitrary geometries and dimensions - complex fracture phenomena such as crack branching, coalescence, deflection and nucleation. In this work, we present a simple and robust implementation of the phase field fracture method in the commercial finite element package Abaqus. The implementation exploits the analogy between the phase field evolution law and the heat transfer equation, enabling the use of Abaqus’ in-built features and circumventing the need for defining user elements. The framework is general, and is shown to accommodate different solution schemes (staggered and monolithic), as well as various constitutive choices for preventing damage under compression. The robustness and applicability of the numerical framework presented is demonstrated by addressing several 2D and 3D boundary value problems of particular interest. Focus is on the solution of paradigmatic case studies that are known to be particularly demanding from a convergence perspective. The results reveal that our phase field fracture implementation can be readily combined with other advanced computational features, such as contact, and deliver robust and precise solutions. The code developed can be downloaded from www.empaneda.com/codes.

Strength analysis of the drive wheel hub of a hydrogen-powered prototype hyper-light vehicle

This article presents a strength analysis of the rear wheel hub of the prototype vehicle for the Shell Eco-Marathon competition. Due to only one wheel in the vehicle’s driving axle, all drive components and the wheel are subjected to higher loads. Therefore, the rear hub must withstand the loads generated by the rear part of the vehicle and the powertrain. The aim of the paper was to develop a hub with the minimum possible weight while fulfilling the strength conditions. The low weight of the hub is particularly important because of the efforts to achieve the highest possible efficiency of the drive system, which generates less energy loss and the ability to travel a longer distance on the same amount of fuel. The article presents the developed three-dimensional model of the hub. The suitable materials for the individual elements that are parts of the whole hub were selected. The three-dimensional model was tested to strength analysis using the finite element method with the use of Abaqus® software. The developed calculation mesh as well as the assumptions and boundary conditions of the modelling carried out are presented. The results of the simulation tests, which are the basis for further design work are also described.

Biaxial reinforced concrete constitutive models for implicit and explicit solvers with reduced mesh sensitivity

A new set of constitutive models named TsingHua University Concrete 2D (THUC2) is developed for use in ABAQUS. THUC2 has reduced mesh sensitivity and is based on the decoupling assumption and the fixed-angle crack assumption in order to consider the pinching effect, confinement, strength degradation, and shear softening of concrete. In the developed biaxial reinforced concrete models, the uniaxial model is first established, and the biaxial model is subsequently assembled from the uniaxial model. First, the proposed uniaxial constitutive model of concrete is reported. The mesh sensitivity of the model is reduced by adjusting the descending branch of the concrete model based on mesh size. Second, a total of five biaxial constitutive models of concrete are reported to cover a wide range of simulation requirements in engineering design. Third, the numerical implementation of the proposed concrete model in both ABAQUS implicit and explicit solvers is discussed. Subsequently, the modified two-way fixed angle crack model is validated by monotonic and hysteretic panel tests. The FE model exhibits little mesh sensitivity when the element number increased from 4 to 400. The developed model accurately predicts the pinching effect and the softening effect of the panels. Finally, previous tests on two nuclear containment vessels under lateral loads are simulated, and the modified two-way fixed angle crack model demonstrates adequate accuracy in terms of predicting the initial stiffness, ultimate capacity, and pinching effect. The proposed subroutine package for simulating RC members includes the dominant mechanical behaviors of concrete and can be adopted for high-efficiency simulation of RC shear wall structures.

Experimental investigation and finite element analysis of cold-formed steel channel columns with complex edge stiffeners

Abstract Presented in this paper are results obtained from experimental and numerical investigations on the axial behavior of cold-formed thin-walled steel channel columns with complex edge stiffeners, which are referred to as G-section columns. In the experimental investigation, a total of 36 G-section columns, with and without perforations, were tested under pin-ended boundary conditions, and their structural behavior was described. In these tests, the perforations were found to affect the ultimate strength and deformed shape of the G-section columns. In the numerical investigation, finite element models for G-section columns with and without perforations were developed with use of ABAQUS. The models were validated based on the test results. The calibrated finite element model was subsequently adopted for an extensive parametric study by varying the dimensions and locations of perforations. The numerical results indicated that increasing the perforation dimension resulted in a greater reduction on the column ultimate strength than changing the perforation location. But the location of the perforation could affect the deformed shape of the column significantly. Based on the results obtained from the parametric analysis, it is recommended that the spacing of circular holes is between three and six times the nominal diameter of the hole for engineering practice.

Development of a Finite Element Model for Thermal Analysis of Friction Stir Welding (FSW)

Almost 2 decades ago, TWI had successfully introduced the Friction Stir Welding (FSW). During FSW, temperature increases because the friction and plastic deformation which begin at the same time. There are various reports on the assumptions and hypotheses in modelling the heat generation and the deformation of the material, however a consensus about modelling of the process is still to be reached. Over the years, scholars had proposed many numerical approaches, particularly Lagrangian, Eulerian and Arbitrary-Lagrangian-Eulerian (ALE). Researchers have deemed that choosing the most suitable numerical approach is one of the most challenging phases for FSW thermal modelling. This is because using the wrong numerical model could lead to issues such as divergence problems and high mesh distributions. Such problems could escalate when the welding transverse or rotational speeds increase. Thus, in this paper, global (structural component) level analysis was conducted, defining the problem in the Lagrangian setting. Meanwhile, an apropos kinematic framework was used at the local level. This framework uses the efficient combination Eulerian and Lagrangian descriptions for various welding speeds through the use of ABAQUS® software. The results from the temperature evaluation of the welding process are detailed in the paper. The result of the comparison between the experimental and simulated model indicates that the numerical model demonstrates the prospective methodology and its ability to accurately examine the FSW processes during different welding speeds.

Finite element analysis of the dental pulp under orthodontic forces.

To evaluate the stress at the apical third of the pulp and neurovascular bundle (NVB) during 5 types of orthodontic movement at different levels of bone loss. Furthermore, correlations among bone loss, orthodontic appliances, and stress increase were assessed. Based on cone-beam computed tomography datasets, 10 models of the mandibular second premolar were created. Each of these models was subjected to a gradual horizontal bone loss simulation (0-8mm). Orthodontic forces of 20g, 60g, and 120g were applied during the finite element analysis (FEA). For each bone loss level, stress values were evaluated with the use of Abaqus at the apical third of the pulp and the NVB. The stress manifested at the apical third of the pulp was smaller than that at the NVB. The highest apical NVB stress was found for rotation (0.000546N/mm2 for 8mm bone loss) whereas the lowest stress resulted after translational movements (2.35E-04 MPa for 8mm bone loss). The FEA showed that Proffit's indicated orthodontic forces did not significantly disturb the pulpal blood flow and damage the apical NVB. Up to a doubling of the NVB stress, bone loss correlated with the force reduction to obtain similar stress levels compared with teeth with no bone loss. The present findings indicate that the stress manifested at the apical third of the pulp is smaller than that at NVB. Rotational movements induce the highest stress and translational forces develop the lowest stress related to the physiologic capillary blood pressure. Furthermore, in situations with reduced periodontium, lower forces are needed to reach the maximum tolerable stress compared with teeth with intact periodontium.

Influences of the Air in Metal Powder High Velocity Compaction

During the process of metal powder high velocity impact compaction, the air is compressed sharply and portion remains in the compacts. In order to study the Influences, a discrete density volleyball accumulation model for aluminium powder was established with the use of ABAQUS. Study found that the powder porosity air obstruct the pressing process because remaining air reduced strength and density of the compacts in the current high-speed pressing (V≤100m/s). When speed further increased (V≥100m/s), the temperature of the air increased sharply, and was even much higher than the melting point of the material. When aluminium powder was compressed at a speed of 200m/s, temperatures of air could reach 2033 K, far higher than the melting point of 877 K. Increased density of powders was a result of local softening and even melt adhesive while air between particles with high temperature and pressure flowed past.

On the Resistance Evaluation of Lateral-torsional Buckling of Bisymmetrical I-section Beams Using Finite Element Simulations

Evaluation of the lateral-torsional buckling resistance of bisymmetrical I-section beams using finite element method was widely discussed in the paper. Numerous FEM simulations with regard to the stability behavior of steel structural elements subjected to bending about the major principal axis were performed. The use of different finite element modeling techniques and their influence on obtained results were presented by the authors. The ultimate state of both perfect and imperfect elements was assessed. Considerations were concerned with hot-rolled wide flange HEB and narrow flange IPE section beams. Idealization of boundary conditions of FEM models complies with the assumptions used in the analytical formulation of stability problems of thin-walled beams. Geometrically and materially nonlinear analyses GMNA and GMNIA preceded by LBA analyses were carried out. Numerical simulations were conducted with use of ABAQUS/ Standard program.

A growing library of three-dimensional cohesive elements for use in ABAQUS

In this paper, we present the implementation of a small library of three-dimensional cohesive elements. The elements are formatted as user-defined elements, for compatibility with the commercial finite element software ABAQUS. The PPR, potential-based traction–separation relation is chosen to describe the element’s constitutive model. The intrinsic cohesive formulation is outlined due to its compatibility with the standard, implicit finite element framework present in ABAQUS. The implementation of the cohesive elements is described, along with instructions on how to incorporate the elements into a finite element mesh. Specific areas of the user-defined elements, in which the user may wish to modify the code to meet specific research needs, are highlighted. Numerical examples are provided which display the capabilities of the elements in both small deformation and finite deformation regimes. A sample element source code is provided in an appendix, and the source codes of the elements are supplied through the website of the research group of the authors.

Ship structure steel plate failure under near-field air-blast loading: Numerical simulations vs experiment

This paper deals with the numerical simulation of the dynamic failure of a ship structure steel plate under near-field air-blast loading. Various energetic levels of air-blast loading, involving variable explosive mass and charge-plate distance, were tested leading to the bulge of the loaded plate for the lowest energy level and to the failure of the loaded plate for the highest level. A modified version of the Gurson–Tvergaard–Needleman potential was used to reproduce the response of the material along the damage-plasticity process at stake. The 3D constitutive equations were implemented as user material in the engineering finite element computation code ABAQUS®, and numerical simulations were conducted and compared with experiments considering air-blast loaded plates. Several crucial numerical issues are addressed concerning notably the use of ABAQUS® conwep function, the hourglass control and the influence of the model constants. Numerical results clearly show the interest of the adopted modelling for the description of salient stages of dynamic structural failure.

The Thermal Stress Analysis of Langmuir Probe and its Heat Dissipation System Based on the Finite Element Method

In this paper, temperature field and stress field have been simulated on a Langmuir Probe and its dissipation system in certain diagnostic equipment under intense radiation in use of Abaqus. The results show that there are strongest thermal stresses on the ceramic barrels inside the system, which would be extremely easy to get broken. The reasons to have such dreadful stresses are discussed in the paper. And improving suggestions to avoid extra stresses are put forward for the structure design of Langmuir Probe and its heat dissipation system due to the simulation results.

Parametric Analysis of the Dynamic Response of Hot-Rolled H-Shaped Steel Beam under Lateral Impact Load

The analysis on the basic mechanical properties of hot-rolled H-shaped steel beam under lateral impact load was done by use of ABAQUS. The reliability of the FEA model was verified through comparing with the existing experiment of H-shaped steel beam subjected to lateral impact. And then, this FEA model was used to research the dynamic response of the H-shaped steel beam subjected to lateral impact. The main parameters include the impact energy, mass and impact velocity of the impact hammer. The results indicate that the finite element analysis model built in this paper could accurately simulate the process of hot-rolled H-shaped steel beam under lateral impact load and the impact energy, mass and impact velocity have different influences on the dynamic response of H-shaped steel beam.

Collapse criteria of foam cells under various loading

AbstractRecently porous materials are widely used in civil and mechanical engineering. In particular, such porous materials as metal and polymer foams have applications in lightweight structures. From mechanics point of view foams can demonstrate unusual behavior such as strain localization related to foam cells buckling under certain loads.The aim of this work is the elaboration of the model of foam material taking into account the cell collapse. We consider the cell collapse initiation during the elastic instability and its further evolution under loading. The geometrical structure of foam is generated with the use of the Voronoi algorithm. Based on stochastic distributions of cells we create various geometrical models of foams. The influence of the cell volume, wall thicknesses and material properties of the foam material on critical loads is obtained. The calculations are performed with the use of Abaqus CAD/CAE system. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Synthesis Error Analysis of NC Manufacturing and Error Prediction Modelling Based on BP Neural Network Technology

The method was proposed by use of the finite element analysis software ABAQUS and the BP neural network technology to build a synthesis error prediction model of a machining-center. Firstly the finite element model of a vertical machining center CINCINNATI ARROW750 was created by use of ABAQUS ,and the cutting force induced error was analyzed which resulted from the deformation of the machining-center’s components that was caused by the cutting force ;Secondly the geometric error of the machining-center was measured by use of the laser interometer,and the sample of synthesis error was obtained. Finally the synthesis error prediction model was obtained by use BP neural network,and through the comparison of predicted value and actual value of 25 groups of samples, the feasibility of error prediction model was verified.

Microplane Model for Fracturing Damage of Triaxially Braided Fiber-Polymer Composites

AbstractA material model for the fracturing behavior for braided composites is developed and implemented in a material subroutine for use in the commercial explicit finite element code ABAQUS. The subroutine is based on the microplane model in which the constitutive behavior is defined not in terms of stress and strain tensors and their invariants but in terms of stress and strain vectors in the material mesostructure called the “microplanes.” This is a semi-multiscale model, which captures the interactions between inelastic phenomena such as cracking, splitting, and frictional slipping occurring on planes of various orientations though not the interactions at a distance. To avoid spurious mesh sensitivity due to softening, the crack band model is adopted. Its band width, related to the material characteristic length, serves as the localization limiter. It is shown that the model can realistically predict the orthotropic elastic constants and the strength limits. More importantly, the present model can also fit the tests of size effect on the strength of notched specimens and the post-peak behavior, which have been conducted for this purpose. When used in the ABAQUS software, the model gives a realistic picture of the axial crushing of a braided tube by a divergent plug.

FEM Simulation on Cold Rolling of Outer Spherical Bearing Ring

Ring rolling theory based on completion of the mold, rough and technical parameters of the design, application Abaqus software to build three-dimensional model of rolling, and the use of Abaqus / Explicit algorithm of external spherical bearing outer ring of cold ring rolling simulation and analysis come to different mold shape, size, structure and guide roller feed specifications on the forming process, reveals a spherical bearing outer ring of the mechanism of cold ring rolling, gets die structure is different, different size core roller, guide rollers with different combinations of cold rolling play a crucial role in forming quality. At the same time by rolling the solution results demonstrate the power of cold ring rolling of the nonlinear characteristics. Revealed the ring rolling process is a complex interaction of multi-parameter deformation coupling.

Finite Element Modelling of Complex 3D Static and Dynamic Crack Propagation by Embedding Cohesive Elements in Abaqus

This study proposes an algorithm of embedding cohesive elements in Abaqus and develops the computer code to model 3D complex crack propagation in quasi-brittle materials in a relatively easy and efficient manner. The cohesive elements with softening traction-separation relations and damage initiation and evolution laws are embedded between solid elements in regions of interest in the initial mesh to model potential cracks. The initial mesh can consist of tetrahedrons, wedges, bricks or a mixture of these elements. Neither remeshing nor objective crack propagation criteria are needed. Four examples of concrete specimens, including a wedge-splitting test, a notched beam under torsion, a pull-out test of an anchored cylinder and a notched beam under impact, were modelled and analysed. The simulated crack propagation processes and load-displacement curves agreed well with test results or other numerical simulations for all the examples using initial meshes with reasonable densities. Making use of Abaqus's rich pre/postprocessing functionalities and powerful standard/explicit solvers, the developed method offers a practical tool for engineering analysts to model complex 3D fracture problems.