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多处损伤(MSD)严重危害老龄飞机的结构完整性。进行了多处损伤铝合金壁板的剩余强度试验研究。试验件包括加筋板和平板两种壁板,含有不同尺寸的主裂纹和MSD裂纹,裂纹为钼丝切割预制的穿透裂纹。壁板承受拉伸载荷直到破坏,通过载荷传感器和计算机记录破坏载荷。以试验数据为基础,提出了一种改进的评估多处损伤壁板剩余强度模型。用塑性区连通准则和提出的改进剩余强度模型分别计算了多处损伤壁板的剩余强度。与试验结果的比较表明:对不同的主裂纹长度、MSD裂纹长度,以及不同的主裂纹与相邻的MSD裂纹之间的韧带长度b,塑性区连通准则和改进的剩余强度模型预测结果的最大误差分别为53.63%和23.08%,而平均误差则分别为20.74%和8.6%。可以看出,对不同的裂纹尺寸,改进的剩余强度模型大大提高了预测结果的精度,可以直接应用于工程实践。
Multiple injuries (MSD) severely compromise the structural integrity of older aircraft. The residual strength of aluminum alloy siding has been tested. The test pieces include two kinds of panels, namely stiffened plate and flat plate, which contain different sizes of the main crack and MSD crack, and the crack is a pre-cracked crack penetrated by the molybdenum wire. Siding withstand tensile load until damage, through the load cell and computer record damage load. Based on the experimental data, an improved model for evaluating the residual strength of several damaged panels is proposed. Based on the plastic zone connectivity criterion and the proposed improved residual strength model, the residual strength of multiple damaged panels was calculated. Compared with the experimental results, it is shown that for the different lengths of the main crack, the length of the MSD crack, the ligament length b between the different main crack and the adjacent MSD crack, the prediction of the plastic zone connectivity and the prediction of the improved residual strength model The errors were 53.63% and 23.08% respectively, while the average errors were 20.74% and 8.6% respectively. It can be seen that for different crack sizes, the improved residual strength model greatly improves the accuracy of prediction results and can be directly applied to engineering practice.