Plastic wrinkling of thin-walled tubes under axial compression in non-uniform temperature field

Abstract

The main purpose of this paper is to reveal the wrinkling behavior of thin-walled tubes under axial compression in a non-uniform temperature field formed by induction heating on a local position. The distribution of non-uniform temperature fields induced by induction heating and the wrinkling behavior of tubes under axial compression were studied by combining experiments and simulations. Moreover, the thickness and hardness distribution of the wrinkled tube were analyzed. The results show that the maximum temperature difference along axial direction of 5052 aluminum alloy and AZ31B magnesium alloy tubes can reach 129.1°C and 134.7°C in experiments, respectively. In the non-uniform temperature field with a maximum temperature of 250°C, axisymmetric wrinkles can be formed under axial compression on the tubes. With the increase of axial compression, the wrinkle width gradually decreases and its height gradually increases. The contour shape of wrinkles can be fitted accurately with GaussAmp function. There is an obvious thickening phenomenon on the wrinkles and the thickest point is located on the wrinkle top, where the thickness gradually increases with increasing the axial compression. In addition, the microhardness at the wrinkles is lower than that of the original tubes. It decreases with the increase in axial compression. The maximum reduction of microhardness of 5052 aluminum alloy and AZ31B magnesium alloy tubes at the wrinkles are 41.6% and 17%, respectively. This study not only can provide tube blank with useful wrinkles for hydroforming, but also can provide experimental data for establishing buckling theory of inhomogeneous tube shells.