This paper on "Using Component-Level Testing and Detailed Finite Element Analysis as a Replacement for Full-Scale Structural Testing - A Case Study" was presented at the NAFEMS World Congress on Effective Engineering Analysis - 25-28 April 1999, Newport, Rhode Island, USA.

Summary

In aerospace engineering, many current products are derivations of previously developed hardware. For most applications, modifications and/or improvements to qualified hardware require verification through full-scale structural testing. Full-scale testing, which is the preferred and most often-required verification method, usually eliminates the unknowns implicit in analytical methods that are derived and then applied with a multitude of assumptions. However, the cost of full-scale structural testing often prohibits implementation of improvements to existing hardware.
The goal of this discussion is to offer an alternative approach to full-scale structural testing that may be applicable in the evaluation of modifications to previously qualified aerospace structures. The proposed evaluation method relies on the combination of a test-verified finite element model (FEM) of the qualified configuration, a detailed FEM of the modified hardware and component-level structural testing.
The presentation is focused on the utilization of the proposed evaluation method through a case study of an actual application in the expendable launch vehicle industry. The project that was used as an example involved evaluation of a modified design for the fittings at a critical separation interface in the Atlas Payload Fairing. Initially, a test-verified FEM of the entire fairing was used to determine the primary structural responses in the areas of the fittings. The fairing model was then locally modified for the new fitting design to determine the critical interface loads. With a combination of a detailed FEM of the fitting interface and component-level testing, structural capabilities of the fitting redesign were verified.