(哈尔滨工业大学 材料科学与工程学院, 哈尔滨 150001)
摘 要: 采用实验和数值模拟研究5A02铝合金薄壁管材充液压弯成形过程中内压对缺陷的影响规律，分析内压对弯曲内侧起皱、截面畸变及壁厚分布的影响，获得壁厚变化规律；通过数值模拟给出的应力状态，揭示缺陷形成机制。结果表明：提高内压能降低轴向压应力的绝对值，减小失稳起皱趋势，当内压超过一个临界值时，皱纹完全消除。对于直径为63 mm、壁厚为1 mm的5A02-O铝合金管材，其内压临界值为2.8 MPa。充液有效地减小截面畸变程度，随内压的增大，截面畸变程度逐渐减小。弯曲后，壁厚最大减薄点位于弯曲外侧点，且随内压的增大，轴向和环向拉应力均呈增大趋势, 弯曲外侧壁厚度减薄的趋势也增大。
关键字: 内压；薄壁管；铝合金；充液压弯；起皱
thin-walled aluminum alloy tube
（School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China）
Abstract:The influence of internal pressure on faults was investigated for a 5A02 aluminum alloy thin-walled tube in hydro-bending process by experiment and finite element method. The effects of internal pressure on wrinkling on the inner arc, cross-section distortion and wall thickness distribution were analyzed, and the thickness variation regularity was achieved. The mechanism of defect was revealed through stress state given by numerical simulation. The results show that the absolute value of axial compressive stress can be reduced by improving the internal pressure, and the wrinkling tendency declines. The wrinkles can be completely eliminated while the internal pressure reaches a critical value, and the critical value is 2.8 MPa for a 5A02-O aluminum alloy tube with an outer diameter of 63 mm and a wall thickness of 1 mm. The cross-section distortion decreases with the internal pressure increasing. The biggest thickness thinning of the specimen appears at the bottom of the outer arc. The axial stress and hoop stress enhance as the internal pressure rises, and the tendency of thickness thinning on the outer arc increases.
Key words: internal pressure; thin-walled tube; aluminum alloy; hydro-bending; wrinkling
