Analytical Description of Multidegree Bilinear Hysteretic System

Physically based analytical models capable of describing the behavior of general bilinear hysteretic systems are formulated. The formulation includes the effects of pinching, stiffness degradation, and load deterioration. The type of pinching considered is the one due to unequalness of strengths for loading in opposite directions. This pinching is represented in terms of a strength ratio. Stiffness degradation and load deterioration are described in terms of functions of total absorbed hysteretic energy. All of the system parameters are in terms of definite physical materials or system properties, which can be measured through tests. To show that the proposed analytical model can provide realistic descriptions of the performance of multi-degree-of-freedom systems, examples of a three-degree-of-freedom system subjected to harmonic loads as well as blast loads are presented.