Reconciling the Difference Between Test and Real Environments: Improving Fixture Design Based on Modal Strain

With the recent push to make automobiles, aircraft, and other vehicles more fuel-efficient, the redesign of many components are currently underway to reduce the conservativeness of the design with an intent to reduce weight. Laboratory tests are performed to speed up the design qualification process. However, the fixtures used are typically rigid, which provides insight into how a component responds and fails in a “‘fixed” base manner. Laboratory tests need to be able to reproduce the same stresses and strains experienced to represent real environments. This work proposes that a fixture mimicking the local stiffness and dynamics is required to emulate the actual environmental conditions. This work postulates that the local modal displacements and strains need to match these local dynamics, and the best way to achieve this is through a truncated system.