Research On Dynamic Stress Optimal Design Of Plate Structure

Sensitivity is one of the key techniques for structure optimal design. In order to get sensitivity with high accuracy, the formula of dynamic stress sensitivity for plate element is derived by directly taking derivative with respect to design variable based on stress formula. Subsequently the code of stress sensitivity calculation is developed based on structure analysis program.According to the characters of dynamic stress sensitivity calculation and dynamic structure optimal design, the realization scheme for program is intensive studied. Then the dynamic stress optimal design program of plate structure is developed.For the formula of dynamic stress sensitivity is derived by directly taking derivation with respect to design variable based on stress formula, the formula of stress sensitivity is more complicated, and its difficulty of implement is increased. But the dynamic stress sensitivity of this paper is high in accuracy, and that the calculating time is less and the accuracy of sensitivity is unrelated with the step of finite difference method.Better optimum direction and design variable increment can be provided by using sensitivity with high accuracy. Therefore, the numbers of iteration and re-analysis during the optimal process can be reduced and the computing time is less.By adopting the programming scheme of combining structure analysis to structure optimization, inheriting the characters of modularization and data management of original structure optimal design, the result data of structure analysiscan be fully used to increase the reuse efficiency of data. So the efficiency of solution is increased.The formula of dynamic stress sensitivity and the validity of sensitivity calculation procedure are verified by four examples with different load type, different ratio of thickness to width and different situation of sensitivity with regard to design variable (directly dependent or independent to design variable). Three examples are used to verify the general correctness of structure optimal design program developed. The results of examples indicate that the stress sensitivity precision in this paper is high, the numbers of optimal iteration is less. It also shows that the derived formula and the developed program are correct in this paper:This thesis is completed based on the former program.79 Having the extendable characters in fulfilling scheme and modularization, a good base and fulfill scheme for developing dynamic structure optimal design program with other type of elements is offered by this dissertation.