Development of a Micromechanics Based Cohesive Zone Model and Application for Ductile Fracture

2019-01-01
In this paper, derivation and implementation of a micromechanically motivated traction separation law for cohesive zone modeling of ductile fracture is discussed. The formulation of the framework is based on the growth of pores in an array of representative volume elements where pores are idealized as cylinders. Two relations are derived under normal and shear loading for mode-I and mixed-mode respectively, based on the upper bound for a perfectly plastic material (Yalcinkaya and Cocks (2015), Yalcinkaya and Cocks (2016)). The obtained traction-separation laws are used as the constitutive model for cohesive elements. Numerical simulations are conducted for a compact tension specimen to illustrate the performance of the model under mode-I loading where the effect of the size and the shape of the pores are illustrated explicitly. It was observed that increasing initial pore fraction or decreasing initial pore height has a detrimental effect on the material, which decreases the strength and the toughness as expected. (C) 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review line: Peer-review under responsibility of the 1st International Workshop on Plasticity, Damage and Fracture of Engineering Materials organizers.

Suggestions

Physics Based Formulation of a Cohesive Zone Model for Ductile Fracture
Yalçınkaya, Tuncay (2015-07-01)
This paper addresses a physics based derivation of mode-I and mode-II traction separation relations in the context of cohesive zone modeling of ductile fracture of metallic materials. The formulation is based on the growth of an array of pores idealized as cylinders which are considered as therepresentative volume elements. An upper bound solution is applied for the deformation of the representative volume element and different traction-separation relations are obtained through different assumptions.
Ductile fracture of metallic materials through micromechanics based cohesive zone elements
Tandoğan, İzzet Tarık; Yalçınkaya, Tuncay; Department of Aerospace Engineering (2020-9)
Gaining popularity after its coupling with the finite element method, cohesive zone modelling has been used extensively to model fracture, especially in delamination problems. Its constitutive relations, i.e. traction-separation laws, are mostly derived phenomenologically without considering the physical mechanisms of crack initiation and propagation. The approach could also be used for ductile fracture where the micromechanics of the phenomenon is explained by nucleation, growth and coalescence of pores. I...
Micromechanical cohesive zone relations for ductile fracture
Yalçınkaya, Tuncay (Elsevier BV; 2016-06-24)
This paper addresses the derivation of a micromechanically motivated incremental mixed-mode traction separation law in the context of cohesive zone modeling of crack propagation in ductile metallic materials. The formulation is based on the growth of an array of pores idealized as cylinders which are considered as the representative volume elements. An upper bound solution is applied for the deformation of the representative volume element and different incremental traction-separation relations are obtained...
3D Simulation of Dynamic Delamination in Curved Composite Laminates
Ata, Tamer Tahir; Çöker, Demirkan (Elsevier BV; 2019-01-01)
In this study, dynamic fracture of curved carbon fiber reinforced plastic (CFRP) laminates under quasi-static loading is investigated using explicit three dimensional (3D) finite element method in conjunction with Cohesive Zone Modelling (CZM). The simulations are based on the experimental studies conducted by Tasdemir (2018). Three dimensional finite element models of two different ply architectures (unidirectional and fabric laminate) are generated corresponding to the experimental configurations. The com...
Formulation and Implementation of a New Porous Plasticity Model
Yalçınkaya, Tuncay; Erdoğan, Can; Tandoğan, İzzet Tarık (Elsevier BV; 2019-01-01)
A new rate independent porous plasticity model is proposed for the modeling of ductile damage initiation due to void growth in metallic materials. The model is based on a simple yield description which includes two porosity functions that affect both deviatoric and hydrostatic stress evolution. The current version of the model predicts damage solely due to void growth and it should be extended to include the void initiation and coalescence criteria. The numerical examples study the performance of the develo...
Citation Formats
T. Yalçınkaya and İ. T. Tandoğan, “Development of a Micromechanics Based Cohesive Zone Model and Application for Ductile Fracture,” 2019, vol. 21, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/37134.