Verification of reliability of numerical analysis by comparison with actual crash impact test of rotorcraft fuel tank

Abstract

The general function of a fuel tank is to store fuel. However, the structural soundness of a fuel has a great influence on the survival of the crew in an emergency situation such as an aircraft crash. For this reason, countries with advanced aviation technology have developed crashworthy fuel tank for decades. The crashworthiness performance of fuel tank is demonstrated by the crash impact test, which has high risk of failure due to the high impact loads, so much effort has been made to minimize the possibility of failure in the actual test. Numerical analysis performed before the actual test is a part of such efforts. However, for the results of numerical analysis to be reflected in the design, a certain level of reliability of the numerical analysis is required. In this study, the results of a numerical analysis and actual crash impact test data were compared to verify the reliability of the numerical analysis. Crash analysis software (LS-DYNA) was used and the arbitrary Lagrangian–Eulerian (ALE) technique was applied as the analysis method. To obtain actual test data, strain gages were installed on the metal fittings of the fuel tank and linked to the data acquisition equipment. As a result of the numerical analysis, strain and stress of the fuel tank fittings were calculated. And, the reliability of the numerical analysis was enhanced by assessing the error between the strain measurement of the upper fittings obtained from an actual fuel tank test and the strain calculated from the numerical analysis.