Title: Determining Mode I Fracture Toughness of Adhesive Composite Joints: Autonomous Crack Tracking Using MATLAB Developed Program
Authors: Peter E. Caltagirone, Dr. Dylan Cousins, David Snowberg and Dr. Aaron P. Stebner
Abstract: Characterizing the fracture toughness of composite material joints is essential to informing design safety factors. ASTM D5528 defines how to calculate the Mode I fracture toughness of an adhesive using a double cantilever beam peel test. The standard specifies visual markers on the sample be inspected during the experiment to measure the crack length, which is needed to calculate the fracture toughness. While this method allows one to determine the fracture toughness, the process is extremely time consuming, tedious, and prone to human error when marking the sample and again when visually inspecting the crack growth relative to those markers. A MATLAB toolbox was written to automatically analyze crack propagation from digital images, create compliance plots, and export the fracture toughness using the modified beam theory method, the compliance calibration method, and the modified compliance calibration method. Rather than using 18 points of data as defined in the traditional method, the program computes the fracture toughness using hundreds of points, reducing noise and error. Different test types are compared i.e. ductile adhesive, brittle adhesive, crack jumping, inhomogeneous surface, etc.; and the results calculated using the ASTM standard method are compared to those exported by the MATLAB program.
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Conference: SAMPE 2020 | Virtual Series
Publication Date: 2020/06/01
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