【摘要】 结构中裂缝的存在使其局部刚度减小、阻尼增大、固有频率降低,故振动特性随之改变.利用扭曲弹簧模型对裂缝进行模拟,对工程中三种典型裂缝梁(简支梁、自由梁和悬臂梁)的前三阶固有频率的变化率与裂缝位置和深度的关系进行了计算和分析.计算结果表明:裂缝梁的边界条件不同,其振动特性就不同,固有频率的变化规律也不同.因此可以利用振动特性的变化以及固有频率的变化规律来进行损伤识别,为进一步研究无损诊断提供理论依据.更多还原

【Abstract】 The presence of crack in structure usually causes a local reduction in stiffness, an increase in damping , and a reduction in natural frequencies, and thus results in a change in vibration characteristic of structure In this study, the effects of cracks upon the change of the first three natural frequencies of the three typical beams are discussed The calculation results show that the different boundary conditions have different vibration characteristics and different change rules of natural frequencies So we can utilize the change of vibration characteristic and change rules of the natural frequencies as the basis of the nondestructive diagnosis in the future更多还原