目的：解决2A16铝合金锥形件常温充液成形困难、表面质量差的问题。方法介绍了充液热成形工艺，并提出了3种锥形件成形方案，通过专用有限元软件 Dynaform 对所有方案进行了数值仿真；同时，对一步成形方案进行了试验。结果通过试验验证了有限元模型的正确性。由仿真分析可知，成形缺陷包括悬空区起皱和凹模圆角及底部破裂，一步成形方案不可取，两步成形方案均可以将减薄率控制在13%以下。起皱危险主要发生在零件法兰以下30～55 mm 处。结论充液热成形与常温充液成形相比，可以显著提高材料的成形性；两步充液热成形方案可以获得2A16铝合金锥形件；预成形凸模的形状设计对零件的表面质量影响明显；最终确定用先热冲压筒形件，后充液热成形的工艺方案，来成形2A16铝合金锥形件。
A modified MK model combined with ductile fracture criterion（DFC-MK model） is proposed to compute the forming limit diagrams（FLDs） of 5A06-O aluminum alloy sheet at different temperatures.The material constant（C） of ductile fracture criterion and initial thickness imperfection parameter（f0） at various temperatures are determined by using a new computing method based on wide sheet bending test.The FLDs at 20 and 200 °C are calculated through the DFC-MK model.The DFC-MK model,which includes the influence of through-thickness normal stress,is written into the subroutine VUMAT embedded in Abaqus/ Explicit.The cylindrical cup hydroforming tests are carried out to verify the model.The results show that compared with experimental observations,the predicted FLDs based on DFC-MK model are more accurate than the conventional MK model;the errors between the simulations and experiments in warm hydroforming are 8.23% at 20 °C and 9.24% at 200 °C,which verify the effectiveness of the proposed model.
