Abstract: In order to study the influence that aluminum alloy's strengthening range has on interference fit of aluminum alloy and pultruded composite materials, first of all this paper simplified the constitutive relation of the aluminum alloy as a bilinear model, and then worked out the relation between magnitude of interference and normal stresses on aluminum alloy and composite material interfaces via elastic-plastic mechanics. After that, it conducts verification through finite element and experiment, where the constitutive relation of the aluminum alloy is simulated through multi-linear isotropic strengthening (MISO). At last, the influence that the strengthening range has on normal stress is studied, and it concludes that (1) theoretical solution and finite element solution coincide well with the experimental values, which demonstrates the correctness of the theoretical derivation; (2) considering aluminum alloy strengthening range during interference fit of composite material and aluminum alloy, an even larger normal stress can be obtained on aluminum alloy and composite material interfaces; (3) during interference fit, non-uniformity of composite tube wall poses less influence on normal stresses of the interface, hence the influence non-uniformity of the tube wall has on the interference fit can be neglected.

Key words: interference fit, aluminum alloy, composite material, bilinearity, strengthening range