Numerical Modeling of a Servohydraulic Testing System for Structures

A realistic model of a dynamic testing laboratory for structures is presented, which includes the controller and the hydraulic loading equipment as well as the test specimen. The model provides a safe and easily controllable way of experimenting with a complex dynamic testing system, enabling the limits of the system to be explored prior to performing a physical test. The paper describes the representation of the proportional, integral, derivative, lag controller and the development of a detailed nonlinear model of the servovalve actuator system, together with their numerical implementation using the Matlab system-modeling package Simulink. Output from the model is compared with experimental results of both open-loop tests and real-time substructure tests, in which a physical test of part of a structure is coupled in real time to a numerical model of the remainder of the structure.