Structural optimization under equivalent static loads transformed from dynamic loads based on displacement (original) (raw)

All loads in the real world act dynamically on structures. Since dynamic loads are extremely dicult to handle in analysis and design, static loads are utilized with dynamic factors. The dynamic factors are generally determined from design codes or experience. Therefore, static loads may not give accurate solutions in analysis and design. An analytical method based on modal analysis in ®nite element analysis is proposed for the transformation of dynamic loads into equivalent static load sets. Equivalent static load sets are calculated to generate an identical displacement ®eld in a structure with that from dynamic loads at a certain time. The process is derived mathematically and evaluated. The method is veri®ed through numerical tests. Various characteristics are identi®ed to match the dynamic and static behaviors. For example, the opposite direction of a dynamic load should be considered due to the vibrational response. A dynamic load is transformed into multiple equivalent static load sets according to the number of critical times. The places of the equivalent static loads can be dierent from those of the dynamic loads. An optimization method is de®ned to use the equivalent static loads. The developed optimization process has the same eect as dynamic optimization which uses the dynamic loads directly. Standard examples are solved and the results are discussed.