Abstract
This paper deals with the stationary random response of two-degree-of-freedom systems having bilinear hysteretic restoring force characteristics, when subjected to white noises. The attention is focussed on the effect of mass distribution on expected hysteretic energy absorbed in each story. The other parameters which affect the energy of the lower story normalized by the total energy, ε_1, -stiffness ratio κ, plastic stiffness ratio γ_i and nondimensional input intensify ξ-are fixed respectively on 1, 1/10 and 1/10. The yield shear coefficient ratio, β, which is an additional important parameter, is taken as a variable which lies between 0 and 3. The relation between ε_1 and β is evaluated with the wide range of μ. The empirical formula which represents this relation is formed. The most probable values of parameters, a, b and c which appear in this expression are determined by "iterative substitution method". It is found that this formula is applicable also to the cases already studied where κ has been taken as various values with the constant μ. The effect of μ and κ is quantitatively estimated and investigated from the values of a, b and c. It is proved that the approximate mathematical expression for the optimum yield shear coefficient ratio, β_0, which has been already derived agrees well with digital estimate over the wide range of μ.
