疲劳载荷类型对Q235B钢磁记忆信号的影响
首发时间:2014-01-13
摘要:通过分析Q235B钢带缺口的拉伸试样表面不同载荷波形及应力比下的磁记忆信号法向分量Hp(y)及其梯度dHp(y)/dx的变化,探讨疲劳裂纹在萌生、扩展过程中试件内部应力集中的变化规律。结果表明:在裂纹萌生阶段,缺口尖端检测到的磁记忆信号没有出现过零点的现象,其强度梯度没有峰值;在裂纹扩展阶段,磁记忆信号会在裂纹处发生明显异变,其强度梯度出现峰值。磁记忆信号的幅值和其强度梯度峰值的绝对值都会随着损伤程度的增加而增加。载荷波形和应力比会对试件的应力集中程度和检测到的磁记忆信号有较大影响。
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Effect of Fatigue Load type on Metal Magnetic Memory Signals of Q235B
Abstract:This paper mainly analysis the changes of the normal component of magnetic memory signal(MMM) Hp (y) and its gradient dHp (y) /dx in notched specimen surface of Q235B under different load waveform and stress ratios of fatigue load, to investigate the changes of fatigue crack stress concentration in the process of initiation, propagation of the test piece.The results demonstrate: during the crack initiation stage, the MMM signals detected in the notched tip do not emerge zero points and the strength gradients have no peaks. Those phenomena occur in the crack extension stage. The amplitudes of MMM signals and peak values of their gradients increase with the increase of the damage degree. Load waveform and stress ratio can affect the stress concentration in the specimen and the detected MMM signals.
Keywords: nondestructive testing magnetic memory signal fatigue load stress ratio
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No.4579817948047138****
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