Experiments and Simulations on Tensile Properties and Fracture Toughness of 7050-T7451 Aluminum Alloy Hole Specimens

摘要:

针对飞机用7050高强铝合金含孔板件进行拉伸性能与断裂韧性的模拟分析与实验研究，并基于裂纹尖端塑性钝化能将常见拉伸性能与平面断裂韧性联系起来，在常规拉伸性能参数的基础上，定量计算出了含孔连接板的断裂韧性值，通过引入与试样几何形状、孔型大小有关的Z参数，表征了含孔构件断裂失效过程中的平面应力和平面应变分布状态与组成比例。研究表明：（1）Z参数联系了材料断裂韧性与构件断裂韧性，反映了含孔构件的几何形状与开孔大小对构件断裂韧性值的影响；（2）含孔拉伸试样的断裂韧性敏感于开孔在垂直于拉伸方向上的尺寸，并随该尺寸的增加而降低；（3）含孔拉伸试样的屈服应力，强度极限等强度指标主要受开孔沿垂直于拉伸方向的尺寸影响，而几乎与开孔在拉伸方向上的尺寸变化无关，但含孔拉伸试样的延伸率则正好与此相反

Abstract:

The experiment and the simulation of the tensile properties and the fracture toughness of 7050-T7451 high strength aluminum alloy hole specimens for aircraft were conducted. The plastic dissipation energy of the crack tip associates tensile properties with fracture toughness KIC, which can be quantificationally calculated through the tensile parameters. The distribution of the deformation zone and the zone proportion of plane stress and plane strain were characterized by parameter Z, which is determined by the geometry of the hole specimen. The research shows (1) Z parameter is associated with the KIC of materials and components, and reflects the influence of the specimen geometry and hole size on the KIC of components; (2) KIC of the specimen is sensitive to the hole size perpendicular to the tensile direction, and decreases with the increase of the size; (3) the strength indexes such as yield stress and ultimate tensile strength are affected mainly by the hole size perpendicular to the tensile direction, and are almost irrelevant to the change of the hole size along the tensile direction, but the elongation is on the contrary