Abstract
An optimization approach is presented for design of a base-isolation device of a precision instrument against vertical seismic motions. A compliant bar joint structure is first generated through optimization so as to have a nonlinear equilibrium path which is close to a specified shape. The validity of the compliant bar joint structure as isolation system for vertical seismic motions is investigated in the numerical examples to show the response accelerations. The response accelerations are successfully reduced if an appropriate damping is assigned. The effect of mass variation of the instrument to the responses is also investigated.
