应用移动质量法与分形维数实现梁损伤检测

以简支裂纹梁为例，利用移动质量法结合分形维数方法实现结构损伤检测。由于质量块在振动梁不同位置时对梁固有频率的影响不同，所以当质量块沿着梁长度方向移动时可以得到一组梁－质量块系统的固有频率曲线，通过分析这组固有频率的分形维数曲线确定梁的损伤位置及其损伤程度。随后讨论附加质量块大小和分形方法参数选择对损伤检测精确性的影响。数值计算结果表明，该方法能准确的识别裂纹位置和损伤程度。该方法的主要优点在于不需要结构的模态信息，并可以在随机激励下实现。

Damage Detection for Cracked Beams by Using Auxiliary Mass Approach Combined with Fractal Dimension Method

Taking a cracked simply supported beam as an example, a new approach based on auxiliary mass combined with fractal dimension analysis is proposed for damage detection. When the auxiliary mass is mounted at different locations of the beam, the natural frequencies of the beam-mass system are changed. So, when the auxiliary mass transverses from one end of the beam to the other, a set of curves of the natural frequencies of the beam-mass system can be obtained. Then the fractal dimension method is imposed to analyze the natural frequency curves, and the location and depth of the crack can be detected. Furthermore, the effects of the auxiliary mass and the parameters of fractal dimension on the accuracy of the damage detection are investigated in detail. The simulation results demonstrate the efficiency and accuracy of the proposed method. The main advantages of the proposed method are that there is no need of the structural mode information and it can be realized in arbitrary excitation environment.