Method for Conservative Multiple-Input–Multiple-Output Vibration Testing Based on Damage Metrics

Multiple-input–multiple-output (MIMO) vibration qualification tests can recreate operating conditions more accurately than single-axis tests, though it is challenging to know if the test is conservative. In addition, MIMO specifications are often difficult to reproduce in the laboratory and may only represent a single load case among many that are possible. This paper presents a method for generating a controllable MIMO environment specification that conservatively reconstructs damage across multiple operational conditions. Tests are simulated on a finite element model case study, and stress and fatigue damage are calculated, demonstrating the method’s ability to provide reasonable levels of conservatism compared to traditional testing approaches. The method is also applied to an experimental case study, showing that it is applicable to real systems.