| In order to investigate interface fracture behaviors of jointed area in multi-material components with rubber core under thermal and mechanical mixed loading, a modified virtual crack closure technique (MVCCT) was proposed. This method could take both material nonlinearity and geometric nonlinearity into consideration. The energy release rate of the typical rubber specimen with double crack under pure shear loading was calculated and compared with experimental data from literature, which validated the accuracy of MVCCT.Meanwhile, through calculating the energy release rates and comparing the results of single leg bending (SLB) specimen and single leg sandwich bending (SLSB) specimen respectively, the influence of rubber core on interface fracture was studied.Moreover, the interface fractural analysis of typical multi-material cylindrical shell skirt, which combined by composite-rubber-metal-rubber-composite, under a combined thermal and mechanical loading was carried out using MVCCT. The influences of positions of delamination and thickness of the rubber core on the energy release rate of each interface were discussed, and a size effect of rubber thickness on interface toughness was observed.Finally, another kind of multi-material cylindrical shell skirt, which combined by composite-rubber-metal-rubber-honeycomb sandwich plates, were simulated. Energy release rates of these two kinds of multi-material cylindrical shell were calculated and compared. Then the strengths and weaknesses of the structure with honeycomb sandwich panels were given out respectively. The findings of this thesis are valuable to some extend for aerospace multi-material joint structure design and safety assessment.This study is part of the project of National Basic Research Program of China973Project (No.2006CB601205,2010-2011) and special funding of State Key Laboratory of Structural Analysis for Industrial Equipment (S S13205,2013-2014). |
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