The Research On Strain Measurement Algorithm Based On Digital Image Correlation

Digital image correlation method,as a kind of non-traditional optical measurement method,because of its simple operation,low requirement to the test environment,as a non-contact full measure,and many other advantages,in the short more than 30 years of history,a large number of scientific research workers are drawn to the study of the method.Was based on the joint efforts of various scholars,not only in the theory of this method has achieved many breakthroughs,so far,has formed a relatively complete theoretical system,is also fruitful,and in practical application of related scientific research units and commercial companies have developed many measurement products.It can be said that digital image correlation method is a broad and popular subject.In the current engineering field,there are many ways to measure displacement and strain,and each method has its own advantages and limitations.Compared with the conventional deformation measurement method,the digital image correlation method has incomparable advantage,but also has its own unique problems,such as:the displacement measurement accuracy affects the accuracy of measurement of strain and strain measurement accuracy is still far less than the current generic measured strain gauge technology level,research results on inhomogeneous strain is very little.This paper researched the digital image correlation method based on the existing problems.We first introduced the theory and the method of some basic,on the basis of numerical simulation experiment,the uniform deformation,general inhomogeneous deformation,and complex inhomogeneous deformation strain measurement model are analyzed.from the speckle graph parameters selection,production,to the calculation method of displacement measurement,displacement value of smoothing denoising,and then to strain problem so lving,have done in-depth discuss ion and re search.The research results of this paper mainly include:the preparation of a non-uniform amorphous speckle pattern generator for simulation studies;Put forward two kinds of displacement field smoothing denoising method,namely through displacement field denoising processing,to early to improve displacement measurement accuracy,reduce the displacement of positioning and algorithm error occurred during the operation,so as to realize the accuracy of strain rise;Extends the scope of the digital image correlation method of strain is not only simple deformation of homogeneous strain etc continue to explore,but also to study the linear strain,triangle function strain,the combination of the complex strain and so on the many kinds of new model of deformation.