应用超声散斑相关法测量水下物内层界面位移

超声散斑相关法可应用于水下物体内层界面的位移测量,在工程建设中具有广泛的应用前景。根据所建立的测量实验系统,对位于水中的有机玻璃试件内层界面的面内位移和离面位移进行了实测,测量误差一般在7%以内。进一步研究结果表明:在刚体位移情况下,一般经粗磨、粗刨和粗铣加工或砂模铸造后的粗糙外层界面对超声散斑相关法内层界面位移测量结果的影响极小;当外层界面发生应变时,其变形前后内层界面上的散斑场的相关性将随应变量的增加而减弱,但外层界面应变小于0.05ε时,内层界面上超声散斑相关系数的减小不超过4%。

The displacement measurement of inner surface of an object in water using ultrasonic speckle correlation method

The ultrasonic speckle correlation method introduced in this paper can be applied to measure the displacement of inner surface of an object in water.Therefore,it has a potential extensive application future in engineering construction.An experimental system for ultrasonic speckle correlation measurement is set up.With this system the in-plane and out-of-plane displacement of the inner surface of a specimen made of polymethyl methacrylate in water are detected.The measurement error is less than 7%.The influence of the roughness and strain of the outer surface of the specimen upon the inner surface displacement measurement using this method is also examined in this paper.The experimental results show that under the condition of rigid-body displacement,the roughness of the outer surface normally processed by milling,grinding and casting etc.has little effect on the measurement.When strain on the outer surface is produced,the correlation between the speckle fields on the inner surface before and after strain on the outer surface decreases with the increase of the strain.If the strain on the outer surface is less than 0.05,the reduction of the correlation efficient of the ultrasonic speckles on the inner surface is not more than 4%.