Secondary Development Of ABAQUS Research Articles

Triple-Shear Elastoplastic Constitutive Models for Normally Consolidated Unsaturated Soils Based on the Coordinate Translation Method

The unified triple-shear strength criterion for unsaturated soils was established with the single-stress variable method and the double-stress variable method, and the corresponding triple-shear failure stress ratios were derived with the coordinate translation method. Then the triple-shear failure stress ratios were combined with the modified Cambridge model for unsaturated soils, the triple-shear elastoplastic constitutive models for normally consolidated unsaturated soils under the single-stress variable and double-stress variable were built, and the secondary development of ABAQUS was carried out. With the Nanchang unsaturated remolded clay as the research object, the consolidation and drainage (CD) test verification and true triaxial CD test simulation of unsaturated soils were done, and the effects of intermediate principal stress influence coefficient b and matrix suction s on the calculation model for the gravity retaining wall were studied. The results show that, the proposed 2 constitutive models can well describe the deformation characteristics of normally consolidated unsaturated soils in CD tests, and the simulation results of the coordinate translation method under double-stress variables are more close to the real test data. In the simulation of true triaxial CD tests, the shear stress and the volume strain obtained with the double-stress variable method are more close to the results of the single-stress variable method. With the increase of intermediate principal stress influence coefficient b, the shear stress and the volume strain of the 2 constitutive models will also increase. The gravity retaining wall calculation model with the double-stress variable method is more stable. With the increase of intermediate principal stress influence coefficient b or matrix suction s, the soil displacement of the retaining wall model will decrease, while the strength and stability of the soils behind the wall will increase.

Parametric design and analysis of a mortar base plate

In order to improve the efficiency of designing and analyzing a mortar base plate, parametric technology has been applied to the design and analysis of the base plate. By conducting characteristic analysis of the base plate, critical design parameters extracted have been driven as characteristics to perform secondary development on UG, so that the base plate could be automatically modeled in three dimensions. Meanwhile, Python has also been applied in the secondary development of Abaqus, so as to realize the automatic finite element modeling of the base plate. After conducting parametric analysis on the model established, sensitivities of design variables of the base plate have been analyzed using an approximate model in combination with the sample designed by the optimal Latin hypercube approach. Moreover, parametric optimization carrying out on results of sensitivity analysis could give feedback to parametric design for guiding parameter values of design variables to improve the design quality

Buckling Analysis of Variable Stiffness Composite Cylindrical Shells Based on Hermite Curves

Based on the Hermite curve, the buckling behavior of a variable stiffness composite cylindrical shell is investigated. Firstly, the cylindrical shell is unfolded into a plane, and the Hermite curve is taken as the basic reference path on the plane and the variation of the fiber orientation is obtained. Then, the finite element analysis pre-processing program of the variable stiffness composite cylindrical shell is written by Python to develop ABAQUS interactive interface. Finally, the GUI plug-in is developed successfully, the buckling analysis of the constant stiffness and variable stiffness cylindrical shells is carried out and the effect of buckling load on the initial tangential direction q1, the initial point tangential magnitude L1, the end point tangential direction q2, the end point tangential magnitude L2 is preliminarily explored. It is found that the buckling load of the variable stiffness cylindrical shell is improved greatly. The secondary development of ABAQUS by Python is used to realize the automatic modeling and calculation analysis of the variable stiffness cylindrical shell parts, which provides research ideas and processes for practical engineering research, and has certain practical significance.

Secondary Development and Application of Satellite Dynamic Simulation Platform Based on ABAQUS

As a strong coupling system, structure of the whole satellite has too many design parameters which are undetermined before initial design. In order to overcome the existing problems such as high update frequency of related parameters, complexity of the mouse operation and the low effectiveness of manual modelling, based on secondary development of ABAQUS, a satellite dynamic simulation platform is carried out. First of all, a convenient and friendly user interface is established by writing registration file and the dialog interface creation file based on Python scripting language. Besides, kernel execution scripts is also developed based on Python scripting language, therefore, the parametric and automation modelling as well as simulating process are realized and the efficiency of analysis can be improved.

A Modelling Method of Bolt Joints Based on Basic Characteristic Parameters of Joint Surfaces

Bolt joints are common in machine tools and have a direct impact on the overall performance of the tools. Therefore, the understanding of bolt joint characteristics is essential for improving machine design and assembly. Firstly, According to the experimental data obtained from the experiment, the stiffness curve formula was fitted. Secondly, a finite element model of unit bolt joints such as bolt flange joints, bolt head joints, and thread joints was constructed, and lastly the stiffness parameters of joint surfaces were implemented in the model by the secondary development of ABAQUS. The finite element model of the bolt joint established by this method can simulate the contact state very well.

Response Surface Stochastic Finite Element Method of Composite Structure

Response Surface Method (RSM) has been applied to structural reliability problems successfully in many areas. Finite Element Method (FEM) is one of the most widely used computational methods, which permit the analysis and design of large-scale engineering systems. In order to obtain a reliability analysis method of composite structure with satisfactory accuracy and computational efficiency, RSM and FEM were combined by secondary development of ABAQUS. Response Surface Stochastic Finite Element Method (RSSFEM) which can solve the reliability problems of composite structure was developed. The numerical accuracy and the computational efficiency of the developed method were demonstrated by comparison with Monte-Carlo Stochastic Finite Element Method (MCSFEM).

Reliability Optimization Design of Composite Transmission Shaft

In order to solve reliability-based optimization design of composite transmission shaft, the parametric finite element model of composite transmission shaft was built by secondary development of ABAQUS. The reliability analysis of composite transmission shaft was carried out with the first order reliability method (FORM). Using python language, the finite element program and reliability analysis program are combined. The reliability-based optimization model of composite transmission shaft was obtained. The feasibility and effectiveness of the optimization model was verified by the results of an example application.

Through process numerical simulation of a heavy hydro turbine blade casting

Heavy Hydro turbine castings, made of martensitic stainless steel, of spatially twisted shape, are susceptible to deformation during both casting and heat treatment processes. During production, uneven heating and cooling, phase transformation, stress and stain are responsible for the deformation of castings. However, the current research most focus on casting process or heat treatment process or both but separately, martensitic phase transformation is usually neglected in casting process. In this paper, a coupled thermo-martensitic phase transformation-stress model is established. And it is implemented by secondary development of ABAQUS, which deals the finite element model change and incorporates multi thermal and mechanical boundaries during casting and heat treatment processes as well, such as the contact pair between casting and mold during casting process. The stress analysis of a heavy hydro blade casting was performed by this system. The stress, displacement and phase are obtained. The effect of martensitic phase transformation on the stress and deformation is discussed. The simulated deformation is compared with measured results, and their agreement is improved by the through process simulation.