Direct Extraction of Cohesive Fracture Properties from Digital Image Correlation: A Hybrid Inverse Technique |
| |
Authors: | B Shen G H Paulino |
| |
Institution: | (1) Department of Civil and Environmental Engineering, Newmark Civil Engineering Laboratory, University of Illinois at Urbana-Champaign, 205 N. Mathews Avenue, Urbana, IL 61801, USA; |
| |
Abstract: | The accuracy of an adopted cohesive zone model (CZM) can affect the simulated fracture response significantly. The CZM has
been usually obtained using global experimental response, e.g., load versus either crack opening displacement or load-line
displacement. Apparently, deduction of a local material property from a global response does not provide full confidence of
the adopted model. The difficulties are: (1) fundamentally, stress cannot be measured directly and the cohesive stress distribution
is non-uniform; (2) accurate measurement of the full crack profile (crack opening displacement at every point) is experimentally
difficult to obtain. An attractive feature of digital image correlation (DIC) is that it allows relatively accurate measurement
of the whole displacement field on a flat surface. It has been utilized to measure the mode I traction-separation relation.
A hybrid inverse method based on combined use of DIC and finite element method is used in this study to compute the cohesive
properties of a ductile adhesive, Devcon Plastic Welder II, and a quasi-brittle plastic, G-10/FR4 Garolite. Fracture tests
were conducted on single edge-notched beam specimens (SENB) under four-point bending. A full-field DIC algorithm was employed
to compute the smooth and continuous displacement field, which is then used as input to a finite element model for inverse
analysis through an optimization procedure. The unknown CZM is constructed using a flexible B-spline without any “a priori”
assumption on the shape. The inversely computed CZMs for both materials yield consistent results. Finally, the computed CZMs
are verified through fracture simulation, which shows good experimental agreement. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|