An electric analog type response spectrum analyzer for earthquake excitation studies

Abstract

The design of a response spectrum analyzer for earthquake excitation studies is described. Electric analog techniques are used, with a series inductance, capacitance, and resistance circuit forming a direct analog to the mechanical structure. The circuit arrangement permits a determination of system response for a sequence of periods at constant damping. Provision is made for obtaining zero damping in the circuit. An arbitrary function generator of the variable width film photoelectric cell type is described. The results obtained with the function generator- spectrum analyzer system for a half-sine wave pulse are compared with the mathematically obtained exact answers for the zero damping case, and the accuracy of the system is shown to be satisfactory.