Equivalent static load method for hierarchical stiffened composite panel subjected to blast loading

Hierarchical anisogrid stiffened panel (HASP) consists of three parts: main stiffeners, sub-stiffeners, and panel. The basis of HASPs' dynamic response calculation is equivalent to the orthotropic panel. There are mainly two methods to calculate the dynamic response of orthotropic panels. One is the modal superposition method, and this method is an accurate calculation; the other method is equivalent static load method, which is an approximate calculation of deflection. Equivalent static load method is equivalent to the structure as a single-degree-of-freedom (SDOF) system. Deflection and strain equivalent method were compared for structural failure analysis. On this basis, the dynamic amplification factor (Kd) was calculated and the effects of parameters on it were discussed. According to these two deflection calculation method, the pressure-impulse (P-I) curve was plotted and the variation of the P-I curve under different conditions was analyzed. These theories were applied to the composite HASP protective door, the deflection and P-I curve of the doors were obtained and verified by tests.