A hybrid technique to extract cohesive fracture properties of elasto-plastic materials using inverse analysis and digital image correlation

cohesive zone model;inverse analysis;Park-Paulino-Roesler model (PPR);Nelder-Mead scheme

Gain, Arun ; Paulino ; Glaucio H.

关键词: cohesive zone model;    inverse analysis;    Park-Paulino-Roesler model (PPR);    Nelder-Mead scheme;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/16010/1_gain_arun.pdf?sequence=2&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Current work utilizes cohesive zone modeling to study the fracture properties ofmetals. This study proposes a hybrid technique experimental/numerical to extractcohesive fracture properties of elasto-plastic material using inverse analysis and digitalimage correlation. Two approaches are suggested - a shape optimization technique and aparameter optimization for the PPR potential-based cohesive zone model. In shapeoptimization approach, CZM is obtained by piecewise interpolation of the optimizedinterpolation points whereas in parameter optimization for the PPR potential-based CZM,the CZM is obtained by using the PPR model which utilized the parameters coming froman optimization scheme. Unconstrained, derivative free Nelder-Mead scheme is used foroptimization purpose. The bulk material is modeled as plane-stress J2 plastic material.The proposed schemes are verified for various plausible cases, such as differentdisplacement field data, various initial guess and noisy displacement field data. As aproof of concept, both schemes are applied to Polymethyl Methacrylate (PMMA) quasistaticcrack growth experiment, which is modeled as elastic material, to substantiate itsutility. Near tip displacement field is obtained experimentally using DIC and used asinput to the optimization schemes. Computationally predicted global responses of thePMMA specimen, using the CZMs extracted from the inverse analysis, shows goodagreement with the experimental global response.