Abstract
Through the investigation of the random response of single-degree-of-freedom systems having five various restoring force characteristics subjected to the stationary white noises, the mathematical expressions of the expectation λ^^- and of the standard deviation σ_λ of the nondimensional accumulated plastic deformation λ have been derived. In addition, the nondimensional root mean square velocities and the equivalent damping ratios have been evaluated. λ^^- is proportional to the product of nondimensional input intensity ξ and nondimensional time τ, and σ is approximately in proportion to ξ√<τ>. The proportional constants are peculiar to therestoring force characteristics. The coefficient of variation of λ is the least for the bilinear hysteresis, and increases in the order of the moderate slip, pure slip, origin oriented and progressive slip restoring force characteristics. The reliability function R(λ) which is defined prescribing λ as an index of the safety has been estimated using λ^^- and σ_λ. R(λ) monotonously decreases with increasing ξ/λ and τ. R(λ) is the greatest for the bilinear hysteresis, and decreases in the order of the moderate slip, pure slip and origin oriented characteristics. R(λ) for the progressive slip hysteresis is in a defferent fashion from the others.
