Embedded nonlinear ultrasonics for structural health monitoring of satellite joints

Abstract

Responsive space satellites must be assembled and tested in extremely short times. Integrity of structural joints is one of the major concerns during satellite assembly and qualification processes. A structural health monitoring (SHM) approach based on nonlinear ultrasonics is suggested for rapid diagnostics of structural connectors and joints. Embedded piezoelectric sensors are utilized to enable propagation of elastic waves through bolted aluminum panels. Signal parameters indicative of the nonlinear behavior are extracted from the received waveforms and are used for assessment of structural integrity. Experimental studies reveal variation of the nonlinear response of the joint due to applied structural loads. These changes are explored as diagnostic features of the method. We discuss theoretical aspects of the nonlinear wave propagation through joints and provide experimental data showing feasibility of the embedded nonlinear ultrasonics method for monitoring of structural integrity.