1.前言 主起落架半轮叉(简称构件A),是一个箱形变截面的构件,如图1所示,承受有两个方向的弯曲和较大的扭转载荷,使用中常有疲劳破坏发生。 按载荷谱进行试验的两个实际构件的疲劳源均在支臂焊缝边缘,危险截面的角点处,如图1中的C点。裂纹是由角点处开始向内发展,其断裂部位如图中虚线所示。 1. Foreword Main gear half wheel fork (referred to as component A), is a box-shaped variable cross-section of the member, shown in Figure 1, to withstand bending in both directions and a larger torsional load, the use of fatigue damage often occur. The fatigue sources of the two actual components tested on the load spectrum are at the edge of the arm weld and at the corner of the dangerous cross-section, as point C in Figure 1. The crack starts to develop inwardly from the corner point, and the fracture site is shown by the dashed line in the figure.