STRUCTURE OPTIMIZATION TO ENHANCE ITS NATURAL FREQUENCIES BASED ON MEASURED FREQUENCY RESPONSE FUNCTIONS

✍ Scribed by YONG-HWA PARK; YOUN-SIK PARK

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 397 KB
• Volume: 229
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.1999.2591

✦ Synopsis

A measured frequency response function (FRF) based structural modi"cation method is presented to obtain optimal structural changes to enhance its natural frequencies. Structural dynamics modi"cation (SDM) has been widely used for improvements of built-in structures. However, the optimum design obtained by SDM di!ers from the true optimal solution when large modal changes happen. In this paper, a substructure-coupling concept is used to get system equations in order to extend its use to large modal changes. FRF matrix of baseline structure and those of modi"cation structures are coupled at the connection points under the condition of force equilibrium and geometric compatibility constraints. Thus, exact modi"ed modal properties can be calculated even for the case of large modal changes. The optimal structural modi"cation is calculated by combining eigenvalue sensitivities and eigenvalue reanalysis technique iteratively. Special attention is given to the case where baseline structure has some unidenti"ed structural parameters to enlighten the advantage of this proposed method. An application to the case of beam sti!ener optimization indicates that the proposed method can provide an accurate optimal structural change just based on measured FRFs without any kind of numerical models.