含单边裂纹构件脉冲放电止裂相变应力分析

发布时间：2018-05-14 03:35

本文选题：脉冲放电 + 相变应力　；参考：《塑性工程学报》2017年03期

【摘要】：对含单边裂纹的40Cr Ni Mo钢构件进行脉冲放电止裂,分析了脉冲放电止裂后结晶区、相变区和基体区的显微硬度变化。结果可知,止裂后的裂纹尖端变得圆钝,曲率半径增大,应力集中得到消除,有效地阻止了裂纹的继续开裂;结晶区晶粒得到细化,相变区晶格畸变及位错密度增大导致塑性变形抗力增大,两者的显微硬度得到了不同程度的提高。应用Eshelby等效夹杂原理对脉冲放电止裂后单边裂纹尖端发生组织转变的相变应力进行了理论和数值计算,最终获得相变应力的计算方程;采用ANSYS有限元软件对于含单边裂纹构件脉冲放电止裂进行数值模拟,验证体积变化和屈服强度变化对相变应力的影响。最后,简述了含单边裂纹构件脉冲放电止裂技术对于异种材料焊接裂纹的止裂修复工程应用。
[Abstract]:The microhardness changes of crystallization zone, phase transition zone and matrix region of 40Cr Ni Mo steel with unilateral cracks were analyzed by pulse discharge. The results show that the crack tip becomes round and obtuse after crack arrest, the curvature radius increases, the stress concentration is eliminated, and the crack continues to crack is effectively prevented, and the grain in the crystalline region is refined. The increase of lattice distortion and dislocation density in phase transition region leads to the increase of plastic deformation resistance, and the microhardness of both increases in varying degrees. Based on the Eshelby equivalent inclusion principle, the phase transition stress at the tip of a single edge crack is calculated theoretically and numerically. Finally, the equation of phase transition stress is obtained. The effect of volume change and yield strength change on phase transition stress is verified by using ANSYS finite element software to simulate the pulse discharge crack arrest of the member with unilateral crack. Finally, the application of pulse discharge crack arresting technology in dissimilar materials is briefly introduced.
【作者单位】：燕山大学机械工程学院;
【基金】：河北省自然科学基金资助项目(E2015203217,E2014203223)
【分类号】：O346.1;O461.25

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