The development of a finite element based design sensitivity analysis for buckling and postbuckling of composite plates

1995 ◽  
Author(s):  
Ruijiang Guo ◽  
Aditi Chattopadhyay
Author(s):  
Douglas W. Stillman

Abstract Design Sensitivity Analysis (DSA) is a widely used technique in many areas of finite element analysis, but one that hasn’t yet become available for industrial problems in crashworthiness and automotive safety. In the following effort, an implementation of DSA in the automotive safety simulation program, Radioss, is described. Radioss is a non-linear structures program using an explicit time integration method. A full set of DSA equations are developed and integrated into Radioss so that the design sensitivities can be computed directly and accurately as a result of a single crashworthiness simulation. Some validation results are included. The resulting methodology promises to be an extremely useful tool for engineers involved in the design of safety and crashworthiness of automobiles.


1985 ◽  
Vol 107 (3) ◽  
pp. 334-339 ◽  
Author(s):  
R. J. Yang ◽  
K. K. Choi ◽  
E. J. Haug

A unified design sensitivity analysis theory and a linearization method of optimization are employed for structural component shape optimization. A material derivative method for shape design sensitivity analysis, using the variational formulation of the equations of elasticity and the finite element method for numerical analysis, is used to calculate derivatives of stress and other structural response measures with respect to boundary shape. Alternate methods of boundary shape parameterization are investigated, through solution of two test problems that have been treated previously by other methods: a fillet and a torque arm. Numerical experiments with these examples and a variety of finite element models show that component shape optimization requires careful selection of boundary parameterization, finite element model, and finite element grid refinement techniques.


1987 ◽  
Vol 109 (3) ◽  
pp. 385-391 ◽  
Author(s):  
K. K. Choi ◽  
J. L. T. Santos ◽  
M. C. Frederick

A numerical method is presented to implement structural design sensitivity analysis theory, using the versatility and convenience of existing finite element structural analysis programs. Design variables such as thickness and cross-sectional areas of components of individual members and built-up structures are considered. Structural performance functionals considered include displacement and stress. The method is also applicable for eigenvalue problem design sensitivity analysis. It is shown that calculations can be carried out outside existing finite element codes, using postprocessing data only. Thus design sensitivity analysis software does not have to be imbedded in an existing finite element code. Feasibility of the method is shown through analysis of several problems, including a built-up structure. Accurate design sensitivity results are obtained without the uncertainty of numerical accuracy associated with selection of finite difference perturbations.


1995 ◽  
Vol 1 (3) ◽  
pp. 255-274 ◽  
Author(s):  
Ruijiang Guo ◽  
Aditi Chattopadhyay

A finite element based sensitivity analysis procedure is developed for buckling and postbuckling of composite plates. This procedure is based on the direct differentiation approach combined with the reference volume concept. Linear elastic material model and nonlinear geometric relations are used. The sensitivity analysis technique results in a set of linear algebraic equations which are easy to solve. The procedure developed provides the sensitivity derivatives directly from the current load and responses by solving the set of linear equations. Numerical results are presented and are compared with those obtained using finite difference technique. The results show good agreement except at points near critical buckling load where discontinuities occur. The procedure is very efficient computationally.


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