A MODIFICATION TO THE SENSITIVITY ANALYSIS ALGORITHM FOR KNOWN TARGETDISPLACEMENTS

The purpose of this note is to show that a secant approximation of the displacement state can be obtained by a simple modification of the se nsitivity analysis algorithm for static displacements and frequency re sponses, if the displacement state of the target design is known. When applied to the discretized equilibrium equations obtained by the fini te element method, this new approximation contains the target design e xactly, if the system matrices are linear functions of the design vari ables and all components of the displacement vector are known at the t arget design. Therefore, a single application of a numerical search pr ocess to this approximation will reach the target design. The displace ment state at the optimal design is not known in advance in design opt imization. However, for special applications, such as model updates or the creation of simplified models from very large models, this new ap proximation could be useful in augmenting the straightforward applicat ion of the conventional structural optimization techniques.