机翼结构件的疲劳测试

在交变载荷作用下, 在机翼腹板结构件表面粘贴应变花, 实时监测疲劳试验时试件的应力应变状况, 采用X射线确定了疲劳破坏后的试件表面和内部裂纹的大小与位置, 分析了结构件结构损伤的部位和损伤程度, 预测了结构件的裂纹扩展寿命。测试结果表明: 在40kN正弦交变压缩载荷作用下, 试件的疲劳寿命约为100万次, 符合疲劳寿命分布预期1万~100万次; 疲劳试验测得的应力与理论计算结果有相近的变化趋势, 误差约为10%;高锁螺栓和薄板断裂破坏是该处过大的载荷和绕x轴的弯矩共同导致的; 估算的疲劳裂纹扩展寿命为10 183次。

Fatigue test of structural part of airfoil

Under the alternating loads, the strain gauges were arranged on the test pieces' surfaces of airfoil web, the stresses and strains of test pieces were recorded, and the sizes and positions to fatigue damage in the test pieces were detected by X-rays. The positions and damage severities of test pieces were determined, and the crack growth lifes of airfoil structural parts were predicted. Test result shows that the fatigue lifes of test pieces are approximate one million cycles under 40 kN sinusoidal alternating compression load, and they are in good agreement with the expected distribution of fatigue life(ten thousand-one million cycles). The stresses and strains from fatigue test and theory calculation are similar in variation trends, and the errors are about 10%. The high load and the moment around x axis cause the rivet failure and sheet fracture of test pieces, and the predicted fatigue crack growth life is 10 183 cycles.