Papers by Author: Jun Liu

Abstract: Aiming at Pbfree solder Sn4.0Ag0.5Cu (in short, SAC405), the uniaxial tensile tests are accomplished with constant strain-rate under different temperature and strain-rate load conditions. The elastic-viscoplastic behaviors of SAC405 solders are studied. The rate-dependent material main properties are analyzed, such ad yield limit, tensile strength, saturation stress, etc. Partitioned constitutive model is accepted to describe the constitutive behavior of SAC405 solder. The seven parameters in partitioned model are determined by experiment data. The results of numerical simulation are fitted with the experimental values.

Abstract: The postbuckling behavior and progressive failure of thin-walled box-shape composite beams (BSCBs) have been studied using a simplified composite panel model. It is shown that the carrying capacity of BSCBs under bending and torsion mainly depends on the postbuckling and progressive failure of panels. It is often necessary to identify and follow secondary buckling of tailored panels for correct estimation of carrying capacity. The failure process of stiffened composite panels is simulated in following path. The criterion of local failure in flange of stiffeners is applied to predict the ultimate failure of stiffened composite panels and thin-walled BSCBs. The comparison of the modeling and test shows that the prediction of BSCBs failure is satisfactory.