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为研究航空铝合金梁腹板连接件的疲劳性能,进行了交变载荷下的疲劳试验。利用试件表面各测点的应变计算得到了试件各测点的应力,分析了试件各测点应力分布及演化,测得了试件的裂纹萌生寿命,并进行了裂纹扩展寿命的预测。试验结果表明:试件各处应力分布差异较大,腹板中部主要受剪力;在峰值为18 k N的正弦交变拉伸载荷作用下试件的裂纹萌生疲劳寿命约为3×105次;含裂纹试件在峰值为162 MPa的载荷下的裂纹扩展寿命Nc=7 379次。研究结果可为铝合金梁腹板连接结构的疲劳寿命分析提供参考。
In order to study the fatigue behavior of the web connector of aviation aluminum alloy beam, the fatigue test under alternating load was carried out. The stress of each measuring point of the test piece was calculated by using the strain of measuring points on the surface of the test piece. The stress distribution and evolution at each measuring point of the test piece were analyzed. The crack initiation life of the test piece was measured and the prediction of the crack growth life was carried out. The experimental results show that the stress distribution varies greatly around the specimen and the shear force is mainly affected in the middle of the web. The fatigue life of crack initiation specimen is about 3 × 105 under the sinusoidal alternating tensile load with peak value of 18 kN ; Crack propagation life of cracked specimen under the peak load of 162 MPa is Nc = 7 379 times. The results can provide a reference for the fatigue life analysis of aluminum alloy webs.