（毕业学术论文设计）-商用车EQ1090曲轴裂纹故障分析论文.doc

湖 北 汽 车 工 业 学 院 毕 业 论 文 PAGE PAGE 31 摘要 本课题以机械振动模态理论为指导，以有限元分析软件ANSYS 9.0为研究平台，针对实际使用过程中曲轴因疲劳裂纹而引起断裂的事故，研究含裂纹曲轴的动力学特性。 课题探讨了利用固有频率变化识别等截面光轴上横向裂纹的可行性。结果表明，采用一定的数据处理方式，利用固有频率变化来识别等截面光轴上的横向裂纹是可行的，且识别精度很高。 在此基础上，基于CATIA软件创建的曲轴三维实体模型，探讨了无裂纹曲轴的动态特性，并以不同的裂纹深度研究了含横向裂纹曲轴的动态特性。结果表明，含裂纹曲轴较无裂纹曲轴固有频率有着明显的降低，但是各阶振型不改变。因此，固有频率的降低可以作为曲轴含裂纹的标志。 关键词：有限元分析，曲轴，模态分析，横向裂纹，固有频率  Abstract The accident often happened that the crankshaft ruptured in the course of using because of the fatigue crack. This thesis studies the dynamics characteristics of the crankshaft with the transverse crack, regarding mechanical vibration mode theory as guide, based on finite element software ANSYS 9.0 study platform. This thesis studied how to make use of the change of natural frequency to discern the transverse crack. The result indicates: adopting certain data processing method, it is feasible to make use of the change of natural frequency to discern the transverse crack in the shaft, and the precision discerned is very high. On this basis, this thesis is based upon the three-dimensional model that makes in the three-dimensional software CATIA. This thesis studied the natural vibration characteristic of the crankshaft without the transverse crack, and studied the natural vibration characteristic of the crankshaft with the transverse crack by using different depths of the transverse cracks. The result indicates: when the transverse crack was contained in the crankshaft, the crankshafts natural frequency reduced obviously, but does not change the vibration form of every type. So the crankshafts natural frequency reducing is a sign that indicates the crankshaft with the transverse crack. Keywords：finite element analysis，crankshaft，modal analysis，transverse crack， natural frequency  目录 TOC \o 1-3 \h \z \u HYPERLINK \l _Toc201513386 摘要 PAGEREF _Toc201513386 \h I HYPERLINK \l _Toc201513387 Abstract PAGEREF _Toc201513387 \h II HYPERLINK \l _Toc201513388 1 绪论 PAGEREF _Toc201513388 \h 1 HYPERLINK \l