Ridge Regression Strain Measurement Method with Initial Value in Digital Image Correlation

Abstract

The invention discloses a ridge regression strain measurement method with an initial value in digital image correlation, which belongs to the fields related to experimental mechanics, non-contact full-field strain measurement, and digital images. The method of the invention first obtains by building a digital image correlation measurement system Digital images of the specimen before and after deformation. Then divide the image into grid units and nodes, select the feature points in the unit, and obtain the displacement and strain of the feature points by digital image correlation method. Calculates the mean value of the strain at each feature point within the element. Select the type of displacement function in the unit, take the average value of strain as the initial value, perform ridge regression on the displacement field in the unit, and get the displacement field in the unit by fitting. The strains at each element are interpolated to obtain the full-field strains. The invention can improve the strain measurement accuracy and robustness of the digital image correlation method.

Description

technical field [0001] The invention relates to experimental mechanics, non-contact full-field strain measurement and a digital image correlation method, in particular to a ridge regression strain measurement method with an initial value in the digital image correlation. Background technique [0002] In many fields such as aerospace and building bridges, ensuring structural reliability is always the top priority. With the development of science and technology, it has become an important goal of many scientists to control and repair structures before irreversible damage occurs. The measurement results of material response load characterization provided by experimental mechanics have rich guiding significance for perfecting design, improving structure and monitoring damage. Displacement and strain, as important parameters of experimental mechanics, play a pivotal role in analyzing the mechanical properties of models, verifying basic assumptions, and identifying features. In ...

AI Technical Summary

Problems solved by technology

However, in the actual DIC measurement process, due to many reasons such as noise and pixel interpolation errors, there are certain errors in the displacement measurement results.

When the strain is differentially calculated from the displacement measurement results, the error in the displacement field will be further amplified, resulting in inaccurate strain measurement results

Relevant researchers have proposed a variety of displacement field smoothing methods to improve the accuracy of strain calculations, but most of them have complex mathematical forms or greatly increase the amount of calculation, which limits practical applications

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