圆截面梁结构中裂纹局部柔度的测量

作为梁类结构动力学特性分析和损伤识别的重要参数之一,裂纹局部柔度可以有效地反映结构的损伤程度和特征。通过对梁结构进行动力学建模和振动测试,给出了一种基于固有频率的圆截面梁结构中裂纹局部柔度的测量方法。首先为了获得裂纹梁故障数据库,建立了圆形截面裂纹梁结构的有限元模型,进而绘制结构的前两阶固有频率影响曲面。然后对裂纹梁结构进行振动测试,采用测试所得的结构前两阶固有频率去截取结构的前两阶固有频率影响曲面,绘制出裂纹位置和裂纹局部柔度所对应的结构前两阶固有频率影响曲线,利用其交点测量出裂纹局部柔度。这种方法可以被用于圆截面梁中不同类型和形状裂纹的局部柔度测量。

The Measurement of the Crack Local Flexibility of the Beam Structure with Circular Section

As one of the important parameters of dynamic analysis and damage identification of beam structure,the crack local flexibility can effectively reflect the extent of damage and the characteristics of the structure. A measurement method of the local flexibility of crack in the beam with circular section based on the natural frequency is given by dynamic modeling and vibration test. A fault database of the crack beam is obtained by building the finite element model of the crack beam with circular section,and the first two order natural frequency influence surfaces are drawn. The natural frequencies influence surfaces can be obtained by testing the crack beam. The measured natural frequencies are adopted to cut natural frequency influence surfaces. Then the first two order natural frequencies influence curves of the crack local flexibility corresponds to the crack location are drawn. The crack local flexibility can be measured by the point of intersection of the natural frequencies influence curves. This method can be used to measure the local flexibility of the different type and shape cracks in the beam with circular section.