A reduction and recovering methods of degree-of-freedom in structural dynamic analysis is proposed. Reduction of degree-of-freedom in structural dynamic analysis could saves computing time and cost for doing the analysis. Therefore, it is important to seek for a simple dynamic analysis method which can be used for practical design. The results of numerical studies showed that the reduction into an equivalent SDOF system can predict the behavior of the original MDOF system accurately within

more »

... gible errors. The recovering process from the SDOF system computed back to their corresponding degree-of-freedom in MDOF system could be done easily. In this paper, the equivalent SDOF system is obtained from a reduction process of the MDOF system of a structure in which the nodal displacement, velocity and acceleration terms are transformed into their corresponding element strain fields. The reduction scheme was conducted on the fundamental dynamic governing equation of elasticity theory by considering vibration characteristic in each member element. As a conclusion, this new strain reduction method which derived from the fundamental theory can take into account the history of damping characteristic history. At the end, an example is given to show the ability of present proposed method, thus recommended for practical dynamic analysis design purpose.