Computing Parameters of Fracture Mechanics Based on a Heuristic Approach to Determining the Location of the Crack Тip

Authors: Gudkov N.A., Chernyatin A.S. Published: 20.03.2018
Published in issue: #2(119)/2018  

DOI: 10.18698/0236-3941-2018-2-4-16

Category: Mechanics | Chapter: Mechanics of Deformable Solid Body  
Keywords: crack tip, digital image correlation technique, stress intensity factor, T-stress, least-squares method, Williams expansion

We suggest a combined experimental and numerical technique for determining such parameters of fracture mechanics as stress intensity factor and T-stress, based on using the least-squares method to process tangential displacement fields occurring on the surface of a compact tension specimen in the vicinity of the crack tip. The key feature of the technique is a heuristic approach to locating the crack tip based on taking into account the specifics of configuration and representation of displacement fields, obtained generally by means of digital image correlation techniques. Williams expansion in eigenfunctions of the tangential displacement fields in the vicinity of the crack tip is the basis for determining the stress intensity factor and T-stress. We demonstrated the efficiency of the approach suggested and estimated the error of determining parameters of fracture mechanics depending on the accuracy of locating the crack tip. We developed an application implementing this approach, which in the future may become the foundation for a method of assessing crack resistance of full-scale structures featuring fracture-like surface defects


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