Application Research Of Digital Image Correlation Method(DIC) In Materials Mechanics Experiment

Digital Image Correlation(DIC)is an optical testing technical over strain and displacement field of material structures in recent years.This method has many advantages in two-dimensional and three-dimensional stress-strain measurement of structure,such as full field,non-contact,high experimental accuracy,wide application of environment,economic and practical experiment,etc.,and it is widely used in solid mechanics,biomechanics,civil engineering,aerospace and other fields by scholars and researchers.This paper summarizes the research status and application of digital image correlation method,and compares the development and application of this method at home and abroad.Because of its special requirements for image speckle,it focuses on the production method of the collected speckle pattern.DIC method takes the gray value of the pixel as the analysis object,and improves the sub-pixel level of the deformation accuracy of the analyzed object,and analyzes the collected image information in a subset area.Based on the analysis of pure bending beam experiment,this paper analyzes the points for attention in the experiment,including interpolation deviation analysis,subset shape function,noise control,speckle production,camera optimization,image acquisition,filter processing and calculation analysis.By referring to the theoretical value and strain measurement results of strain gauge,it is confirmed that the digital image related methods are in the The experimental accuracy is satisfactory.DIC technology is used to test and analyze the pressure bar stability device,and it is determined that the error is mainly due to the large experimental error caused by the torsion force of the bar due to the unreasonable hinge support at both ends,so as to improve the pressure bar stability test device continuously,and obtain better improvement effect.Through the optimization and improvement of the pressure bar stabilization device,we can fully show the unique advantages of digital image correlation method in the measurement of stress field.We believe that the digital image correlation method will have a broad application prospect in the future engineering practice of related disciplines.