Effects of Strain Hardening on Response of Skin Panels in Hypersonic Flow

This paper describes an effort toward characterizing the role of material plasticity on the structural response and operational life of compliant panels in high-speed flow. A fluid–thermal–structural–material interactions framework is used to investigate the response of elastic and elastic-plastic panels subjected to multiple loading cycles. The plastic material response is predicted using a nonlinear strain hardening law that accounts for cyclic loading. A fatigue analysis is conducted using a linear cumulative damage rule. A residual deformation on the order of one panel thickness is found to produce characteristically different responses for elastic and plastic panels. After several loading cycles, the onset of flutter for the permanently deformed panel increased beyond the time responses considered.