VERIFICATION OF FINITE ELEMENT PREDICTIONS OF RESIDUAL STRESS BONDLINE FAILURES IN ANALOG SPECIMENS

Several analytical efforts have recently focused on evaluating residual stresses in bondlines (specifically the bondlines of the Space Shuttle's Reusable Solid Rocket Motor nozzle). These analyses involved consideration of both time and temperature dependent constitutive and failure properties of the adhesives. The three dimensional nature of the possible stress fields also adds complexity to the analyses. These analyses can play a key role in ensuring the safety and integrity of a given bonded system. Until now, there has been very little data which could be used for verification of these analyses. This paper describes the analysis, design, and use of analog cone residual stress test specimens. The analog cone residual stress tests provide needed data for verification of analytical techniques used to predict bondline residual stress failures. Detailed descriptions of test procedures and test results are provided. The techniques used in the analysis of these test specimens are also described. The correlation between the actual and analytically predicted failure times is shown to be good considering the variability in available test data used to define the failure criterion.