关键词: 空心铝型材, 拉弯, 起皱, 几何参数, 能量准则

Abstract: Based on the plate and shell theory， the expression of wrinkling energy and external force work functions of hollow aluminum profiles in stretch-bending were derived. Combined with the energy criterion， the theoretical prediction model of wrinkling was established for hollow profiles in stretch-bending and the accuracy of model was verified by bending experiments. The formation mechanism of wrinkling defects in stretch-bending of hollow profiles was revealed and the influences of geometric parameters on wrinkling limit and morphology were quantitatively studied. The results show that the theoretical predictions of the number and height of wrinkling under three different bending radii are in good agreement with those of the experimental ones. The maximum differences are as 1.2 and 0.55 mm， respectively， with relative errors of 16.93% and 11.28%， respectively. The growth rate of external force work in the bending stages is greater than that of wrinkling energy. With the increase of bending time， the external force work is greater than the wrinkling energy， resulting in the appearance of wrinkling instability. With the increase of thickness-to-height ratio and thickness-to-width ratio of the profiles， the wrinkle ratio and wrinkling number decrease， while the wrinkling limit and wrinkling height increase. With the increase of the aspect ratio， the wrinkle ratio and wrinkle height increase， while the wrinkling limit and wrinkling number decrease. The wrinkling limit might be increased by adding inner reinforcement rib in the profile cavities， while the wrinkling number increases and the wrinkling height decreases. 

Key words: hollow aluminum profile, stretch-bending, wrinkling, geometric parameter, energy criterion