Quantifying the effect of dynamic boundary condition differences between the vibration laboratory and the field operating environment

Abstract

Vibration qualification testing of components or subassemblies is performed on shaker tables. The uncertainty associated with the boundary condition difference between the field and the shaker table is usually ignored. It will be shown with analytical and hardware demonstrations that component response can be significantly different even if controlled at one accelerometer. The quantification of this uncertainty would be useful for characterizing margin associated with the laboratory boundary condition. Assuming that a rigid body representation of the field base input is known, a method is proposed that uses a modified version of structural modification, to attempt to correct for the difference using a modal characterization of the shaker table. Disappointing results are shown for a first time implementation with actual hardware. However, the experience provides important insights to guide future efforts for the quantification of the response uncertainty due to the boundary condition difference between the field and laboratory. ©2010 Society for Experimental Mechanics Inc.