Effects of hygrothermal environment on the shear behavior of composite stiffened panels

摘要

Hygrothermal effects on shear behaviors of composite stiffened panels are investigated experimentally and analytically. Firstly, a moisture absorption test of the stiffened panel is performed, and a new moisture absorption model of the stiffened panel is established based on the non-Fickian model. Compared with the existing model, the proposed model can better describe the moisture absorption behavior of the stiffened panel. Shear tests are then carried out on the virgin and hygrothermally aged stiffened panels. Observed effects on hygrothermally aged specimens include change in buckling mode, increase in skin-stiffener separation, and aggravation of local skin warpage. Compared with virgin specimens, the average buckling load and failure loads of aged specimens are reduced by 15.9% and 9.7%, respectively. In addition, a simplified, semi-analytical method is proposed to predict the critical buckling load of stiffened panels subjected to shear load in the hygrothermal environment. In this method, a micro-mechanical model is built considering the hygrothermal degradation of material properties and the hygrothermal strain of the material. The buckling load calculated by this method is in good agreement with both the FEM results and experimental results.