STEADY-STATE OSCILLATION OF HYSTERETIC DIFFERENTIAL MODEL .2. PERFORMANCE ANALYSIS

The present study involves two aspects associated with the steady-stat e performance of the versatile Bouc-Wen hysteretic model. First, influ ence of the model parameters on steady-state responses and hysteresis loops of the single-degree-of-freedom (SDOF) hysteretic system is stud ied by the proposed Galerkin/Levenberg-Marquardt (GLM) method. The dyn amic behavior corresponding to five kinds of hysteresis loops is ident ified. Second, the steady-state characteristics of the Bouc-Wen hyster etic model used for representing inealstic constitutive laws are recog nized. As endochronic constitutive relationship, this smooth hystereti c model may locally violate the Drucker's (or Ilyushin's) stability po stulate of plasticity when the steady-state hysteresis loops are exhib ited with intermediate unloading-reloading. The study is emphasized on the energy dissipation properties in small unloading-reloading cycles starting at an arbitrary deformation previously reached. The extent o f local violation of the Drucker's postulate under steady-state circum stances is observed through numerical analysis. The mitigation of this violation is addressed by parameter studies.