铝合金由于具有密度低、耐腐蚀高、比强度高等特点，近来作为重要的轻质材料在汽车制造中被广泛使用。破裂、起皱和回弹是板料冲压成形中的三大主要质量缺陷。铝合金和钢板相比，总伸长率更小，在室温下铝合金的成形性比钢板的差，更容易出现破裂现象。准确模拟板料成形过程中的破裂现象，对成形工艺和模具设计具有重要意义，金属材料的断裂主要可以分为脆性断裂和韧性断裂，多数铝合金属于韧性断裂。韧性断裂准则从细观损伤力学角度出发，认为材料内部孔洞的缺陷在外力作用下不断地形核、长大并聚合,终引起了材料的损伤，可以较好地预测塑性差的板料成形性能。
Aluminum alloy is widely used in automobile manufacturing as an important lightweight material because of its low density, high corrosion resistance and high specific strength. Cracking, wrinkling and springback are the three main quality defects in sheet metal stamping. The total elongation of aluminum alloy is smaller than that of steel plate. At room temperature, the formability of aluminum alloy is worse than that of steel plate, and it is more prone to fracture. Accurately simulating the fracture phenomenon in the sheet metal forming process is of great significance to the forming process and die design. The fracture of metal materials can be divided into brittle fracture and ductile fracture, and most aluminum alloys belong to ductile fracture. From the perspective of meso damage mechanics, the ductile fracture criterion considers that the defects of holes in the material continuously nucleate, grow and aggregate under the action of external force, and finally cause the damage of the material, which can better predict the formability of sheet metal with poor plasticity.
一、影响韧性断裂的因素很多，主要可以分为两大类。
1、 There are many factors affecting ductile fracture, which can be divided into two categories.
1.一类与材料相关，如应变硬化水平、空穴体积分数和相粒子组成等；
1. One is related to materials, such as strain hardening level, hole volume fraction and phase particle composition;
2.二类与工艺相关，如应变速率、摩擦和成形温度等。
2. Class II is process related, such as strain rate, friction and forming temperature.

二、铝合金拉伸试样断口两种类型的韧窝
2、 Two types of dimples on the fracture surface of aluminum alloy tensile specimens
1.一种韧窝的外形大而深，说明5052铝合金属于韧性断裂；
1. The shape of a dimple is large and deep, indicating that 5052 aluminum alloy belongs to ductile fracture;
2.二种韧窝外形较小，在韧窝的底部和四周分布着一定量的球形颗粒，说明5052铝合金有部分脆性断裂。由于二种韧窝比例较少，因此5052铝合金的主要断裂机制属于韧性断裂。
2. The shape of the two dimples is small, and a certain amount of spherical particles are distributed at the bottom and around the dimple, indicating that 5052 aluminum alloy has partial brittle fracture. Due to the small proportion of the two dimples, the main fracture mechanism of 5052 aluminum alloy belongs to ductile fracture.
三、铝合金球头胀形仿真与试验结果
3、 Simulation and experimental results of aluminum alloy ball joint bulging
板料在成形至断裂的过程中出现了明显的颈缩，宏观断口表现为沿着与厚度方向成45°方向断裂，开裂部位断口比较平整，没有出现不规则的起伏，板料厚度在刃口附近出现了明显的减薄。有限元仿真结果与试验结果较吻合，板料开裂处裂纹的位置和形状大小与试验结果接近。
During the process from forming to fracture, the sheet metal has obvious necking. The macro fracture is broken along the 45 ° direction with the thickness direction. The fracture of the cracked part is relatively flat without irregular fluctuation. The sheet metal thickness has obvious thinning near the edge. The finite element simulation results are in good agreement with the experimental results, and the location, shape and size of the crack at the plate crack are close to the experimental results.
四、铝板成型开裂结论
4、 Aluminum sheet forming cracking conclusion
1)对铝合金板进行了单向拉伸试验，使用Voce模型对试验应力应变曲线进行了拟合。将Cockcroft-Latham韧性断裂准则引入到单向拉伸有限元模型中，结合试验结果，反求了5052铝合金材料失效参数。
1) The uniaxial tensile test of aluminum alloy plate was carried out, and the test stress-strain curve was fitted by voce model. The Cockcroft Latham ductile fracture criterion is introduced into the unidirectional tensile finite element model. Combined with the test results, the failure parameters of 5052 aluminum alloy are inversely calculated.
2)采用拟合的Voce模型参数和韧性断裂准则参数对5052铝合金板料球头胀形开裂进行了仿真预测，并进行试验验证，结果表明仿真预测板料开裂位置及裂口形状与试验结果吻合。
2) The bulging cracking of 5052 aluminum alloy sheet metal ball joint is simulated and predicted by using the fitted voce model parameters and ductile fracture criterion parameters, and the experimental verification is carried out. The results show that the simulation prediction of sheet metal cracking position and crack shape are consistent with the experimental results.
3)使用该方法进行铝合金板料的成形开裂极限预测具有材料参数求解方便，计算精度高的优点，可为相关研究提供参考。
3) Using this method to predict the forming cracking limit of aluminum alloy sheet has the advantages of convenient solution of material parameters and high calculation accuracy, which can provide reference for relevant research.