数字散斑相关方法与应用研究进展

ADVANCE IN DIGITAL SPECKLE CORRELATION METHOD AND ITS APPLICATION

数字散斑相关方法(digitalspecklecorrelationmethod,DSCM)作为固体实验力学领域材料表面变形场测量的一种非接触式方法与其它技术相比具有一些独到的优点,其有效性已经在近20年中被众多的应用实例所证明.近年来该方法在理论上逐步完善,一些现代的数学理论和数学方法(例如:小波变换、遗传算法、神经网络等)逐渐被引入到该方法中;在实验中的各个技术环节上正在逐步的改进,其结果的精度逐步的提高,结果收敛的速度也逐渐的加快;其应用的领域正逐渐从常规材料的测试向一些新型材料测试、从宏观场逐渐向细微观尺度、从常规环境向比较恶劣的环境、从实验室测试逐步向工程现场应用、从静态准静态向动态准动态等方面发展.本文简要介绍了DSCM的基本原理和数学模型,在相关搜索的改进、相关系数的选择、灰度级的重建和图像识别方面的进展以及在材料力学性能测试,微尺度变形场测量等方面的应用.最后就这一实验测量技术的几个可能的发展趋势进行了预测.

As a non-contact optical measurement method in solid mechanics, the digital speckle correlation method (DSCM), or alternatively, digital image correlation method (DICM), has become an accepted method for measuring the surface displacements field and displacement gradients in materials owing to its outstanding features. The validity of the method has been shown by many instances in the last twenty years. Research to date on the DSCM has led to improvements in the theory, experimental techniques and application practices. The theory is becoming increasingly sophisticated. Some modern mathematical theories and methods (such as wavelet transform theory, genetic algorithms and artificial neural networks, etc) are being introduced into the DSCM. The convergence speed and the precision of the method is further improved. The application fields of the method are extending from general materials to some novel materials, from macro-field to meso-field and even micro-field, from general to severe environmental conditions and from laboratory conditions to engineering sites, etc. In this review article, the state-of-the-art of the technique is reviewed and illustrated by reference to recent publications on the developments and applications of DSCM. Especially, the applications of the method in micro-scale measurements and testing of mechanical properties of new materials are discussed in detail. Some conclusions and potential developing fields of the method are given in the end.