Abstract: The analytical model has the advantages of fast calculation speed and intuitive response to the influence of various parameters on mechanical properties. A compression analysis model for composite material repair in hygrothermal environment was established. The influence of hygrothermal on the mechanical properties of the composite and the wet thermal stress generated by hygrothermal were considered in the model. After the repair structure is under pressure, the model assumes that the structure′s failure mode is classified into three types: the compression failure of the motherboard, the compression failure of the patch and the shear failure of the adhesive. Any failure mode occurs first, and the corresponding load is the ultimate load. In hygrothermal environment, if the failure mode of the repair structure is the compression failure of the motherboard or patch, the model directly obtains its corresponding ultimate load first. Using the dichotomy method, the corresponding ultimate load in the shear failure mode of the adhesive in hygrothermal environment is obtained. The compression test of the composite repairing structure in different hygrothermal environments was carried out, and the analytical solution was obtained by the method of this paper. The test results were in good agreement with the analytical solution. The method of this paper can provide reference for the design of the composite glue repairing structure in hygrothermal environment.

Key words: composite material, hygrothermal environment, compression analytical model, glue repair, ultimate load, dichotomy