An Extension of the Material Derivative Method for Configuration Design Sensitivity Analysis

1992 ◽  
Vol 20 (4) ◽  
pp. 459-498
Author(s):  
Kyung K. Choi ◽  
Sung-Ling Twu
Author(s):  
Kyung K. Choi ◽  
Kiyoung Yi ◽  
Nam H. Kim ◽  
Mark E. Botkin

A continuum-based shape and configuration design sensitivity analysis method for a finite deformation elastoplastic shell structure with frictionless contact has been developed. Shell elastoplasticity is treated based on the projection method that performs the return mapping on the subspace defined by the zero-normal stress condition. An incrementally objective integration scheme is used in the context of finite deformation shell analysis, wherein stress objectivity is preserved for finite rotation increments. The penalty regularization method is used to approximate the contact variational inequality. The material derivative concept is used to develop continuum based design sensitivity. The design sensitivity equation is solved without iteration at each converged load step. Numerical implementation of the proposed shape and configuration design sensitivity analysis is carried out using the meshfree method. The accuracy and efficiency of the proposed method is illustrated using numerical examples.


Author(s):  
Kyung K. Choi ◽  
Nam H. Kim ◽  
Mark E. Botkin

Abstract A unified design sensitivity analysis method for a meshfree shell structure with respect to sizing, shape, and configuration design variables is presented in this paper. A shear deformable shell formulation is characterized by a CAD connection, thickness degeneration, meshfree discretization, and nodal integration. The design variable is selected from the CAD parameters, and a consistent design velocity field is then computed by perturbing the surface geometric matrix. The material derivative concept is used to obtain a design sensitivity equation in the parametric domain. Numerical examples show the accuracy and efficiency of the proposed design sensitivity analysis method compared to the analytical solution and the finite difference solution.


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.


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