恒幅载荷下棒料V型槽尖端裂纹起始寿命的估算

Estimation of initial life of V shaped notch tip crack under constant amplitude load

针对带V型槽金属棒料下料中需要较精确计算下料时间的问题,获得了包含V型槽几何参数在内的V型槽尖端理论应力集中系数的计算公式,并在此基础上,建立了恒幅载荷下V型槽尖端裂纹起始寿命的完整的数学表达式。分析了理论应力集中系数和棒料的材质对该始裂寿命的影响规律。45号钢棒料下料实验证明,利用该文提出的V型槽尖端裂纹起始寿命公式所计算的下料时间和实际的下料时间十分吻合。

To calculate accurately the cropping time in variable-vibration cropping, The mathematic expression of theoretical stress concentration factor in the tip of the V shaped notch containing its geometric parameters is built theoretically by analyzing stress field distribution of V shaped notch tip. Based it, for the bar with V shaped notch, the whole formula of crack initial life is established. The influences of theoretical stress concentration factor and material of the bar on the crack initial life are analyzed. The cropping experimental results for 45 steel bar show that the time obtained by formula of crack initial life is consistent with the practical cropping time on the whole.