Approximate analysis method for displacement responses of structures with
active variable stiffness systems
Wu Bo (吴波), Liu Fentao（刘汾涛) and Wei Demin (魏德敏)
Department of Civil Engineering, South China University of Technology,
Guangzhou 510640, China
Abstract: The performance of structures with active variable stiffness
(AVS) systems exhibits strong nonlinearity due to the variety with time of the
stiffness of each storey unit, in which the AVS system is installed. Hence, the
classical dynamic analysis method for linear structures, such as the
mode-superposition method, is not applicable to structures with AVS systems. In
this paper, an approximate analysis method is proposed for displacement
responses of structures with AVS systems. Firstly, an equivalent relationship
between single-degree-of-freedom (SDOF) structures equipped with AVS systems and
so-called fictitious linear structures is established. Then, an approximate
mode-superposition (AMS) method is presented for multi-degree-of-freedom (MDOF)
structures equipped with AVS systems. The accuracy of this method is
investigated through extensive parametrical study using different types of
earthquake excitations, and some modification is made to the method. Numerical
calculation results indicate that the modified AMS method is effective for
estimating the maximum displacements relative to the ground and the maximum
interstorey drifts of MDOF structures equipped with AVS systems.
Keywords: active variable stiffness (AVS) systems; approximate
mode-superposition (AMS) method; displacement response
