Hygro-thermo-elastic behavior for stiffened metal doubly-curved shallow shells with porous microcapsule coating under low-velocity impact considering in-plane initial load

Abstract

Low-velocity impact response of stiffened metal doubly curved shallow shells with porous microcapsule coating in hygrothermal environment is analyzed considering the in-plane initial load. A modified nonlinear Hertzian contact law which ignores the influence of friction is considered for the low velocity impact problem. Based on the classical shell theory considering the von Kármán geometric nonlinearity, the governing equations of motion for this structure are derived from the Hamilton’s variation principle while the finite difference method (FDM) and Newmark-β algorithm are used to solve the equations. The effects of temperature and moisture, initial velocity of impactor, properties of metal substrate, initial load, geometry parameters of microcapsules, geometry parameters of the stiffened shell and porosity on the transient impact response of the stiffened shell are examined and analyzed. Initial impact velocity, properties of metal substrate and porosity have a significant effect on contact force and central deflection. Normal stress is greatly affected by temperature, properties of metal substrate, geometry parameters of the stiffened shell and porosity. Moreover, the impact resistance of stiffened shells is enhanced by the in-plane initial tensile load while the effect of in-plane initial compressive load is opposite.