Interface Delamination of Diamond-Coated Carbide Tools Considering Coating Fractures by XFEM

2013 ◽  
Author(s):  
Ping Lu ◽  
Kevin Chou

Interface delamination is the major failure mode of diamond-coated carbide tools in machining. On the other hand, coating cracking is possibly accompanied during a tribological process that induces the delamination phenomenon. However, such an influence between the two failure behaviors has not been investigated in a quantitative way to better understand and design diamond coating tools. In this study, a three-dimensional (3D) indentation model combining cohesive interactions and extended finite element method (XFEM) was developed to investigate the diamond-coating, carbide-substrate interface behavior with the incorporation of coating cracking. The interface interaction was based on a cohesive zone model (CZM) with a bilinear traction-separation law. XFEM was applied to the coating domain to model cracking in the diamond coating with a damage criterion of the maximum principal stress. Deposition stresses were also included to investigate their effect on the coating delamination and fractures. The model was implemented in finite element (FE) codes to analyze the cone crack in brittle coatings, as well as the interface delamination of diamond coated carbide tools. The XFEM model was validated by the indentation testing data from literature in crack initiations and propagations in brittle materials. FE results from the indentation on diamond-coated tools show that the interface delamination size and the loading force become smaller when coating fractures are incorporated in the model, and the deposition stresses will increase the initial crack radius as well as the critical load for delamination in diamond coatings.

Author(s):  
Qiuyi Shen ◽  
Zhenghao Zhu ◽  
Yi Liu

A three-dimensional finite element model for scarf-repaired composite laminate was established on continuum damage model to predict the load capacity under tensile loading. The mixed-mode cohesive zone model was adopted to the debonding behavior analysis of adhesive. Damage condition and failure of laminates and adhesive were subsequently addressed. A three-dimensional bilinear constitutive model was developed for composite materials based on damage mechanics and applied to damage evolution and loading capacity analyses by quantifying damage level through damage state variables. The numerical analyses were implemented with ABAQUS finite element analysis by coding the constitutive model into material subroutine VUMAT. Good agreement between the numerical and experimental results shows the accuracy and adaptability of the model.


2015 ◽  
Vol 752-753 ◽  
pp. 125-129
Author(s):  
Noh Yu Kim ◽  
Sung Young

In this work, finite element calculations were carried out to simulate wire pullout process of the shape memory alloy (SMA) wire/carbon fiber reinforced polymer (CFRP) hybrid composite. Three-dimensional cohesive zone model was used for the bonding interface between the SMA and the CFRP. Phase transformation behavior of the SMA wire was accounted for by using a multi-variant constitutive model. The numerical parameters were fitted using an experimental measurement reported by Jang and Kishi. Young’s modulus of the wire affected the force vs. elongation curve most effectively. It is shown that the actual shear stress profile is not constant but it varies significantly along the axial direction of the wire. Additional toughness due to the SMA wire was higher than the case of a purely elastic wire, and the toughness increment was approximately 21 kJ/m2. This value is comparable to the typical toughness value of CFRP.


2021 ◽  
Author(s):  
Yonghang Jiang ◽  
Qinghua Song ◽  
Xichun Luo

Abstract Minimum Invasive Surgery is an important means of cytopathological examination. At present, there are few researches on three dimensional (3D) puncture simulation model base on suitable constitutive model, so a reasonable three dimensional puncture simulation model can reveal the internal deformation state of the tissue at the micro level. In this paper, a new viscoelastic constitutive equation suitable for muscle tissue and a method to define the fracture characteristics of muscle tissue material in the simulation process are proposed. The fracture of muscle tissue in contact with puncture needle is simulated by using the cohesive zone model, and a 3D puncture finite element model is established to analyze the deformation of muscle tissue. The stress nephogram and reaction force under different parameters were compared and analyzed to study the deformation of biological soft tissue, so as to guide the actual operation process and reduce pain.


2020 ◽  
Vol 57 (6A) ◽  
pp. 61
Author(s):  
Hoa Cong Vu

In this paper, a damage model using cohesive damage zone for the simulation of progressive delamination under variable mode is presented. The constitutive relations, based on liner softening law, are using for formulation of the delamination onset and propagation. The implementation of the cohesive elements is described, along with instructions on how to incorporate the elements into a finite element mesh. The model is implemented in a finite element formulation in ABAQUS. The numerical results given by the model are compare with experimental data


Author(s):  
Chris Bassindale ◽  
Xin Wang ◽  
William R. Tyson ◽  
Su Xu

Abstract In this work, the cohesive zone model (CZM) was used to examine the transferability of the crack tip opening angle (CTOA) from small-scale to full-scale geometries. The pipe steel STPG370 was modeled. A drop-weight tear test (DWTT) model and pipe model were studied using the finite element code ABAQUS 2017x. The cohesive zone model was used to simulate crack propagation in 3D. The CZM parameters were calibrated based on matching the surface CTOA measured from a DWTT finite element model to the surface CTOA measured from the experimental DWTT specimen. The mid-thickness CTOA of the DWTT model was in good agreement with the experimental value determined from E3039 and the University of Tokyo group’s load-displacement data. The CZM parameters were then applied to the pipe model. The internal pressure distribution and decay during the pipe fracture process was modeled using the experimental data and implemented through a user-subroutine (VDLOAD). The mid-thickness CTOA from the DWTT model was similar to the mid-thickness CTOA from the pipe model. The average surface CTOA of the pipe model was in good agreement with the average experimental value. The results give confidence in the transferability of the CTOA between small-scale specimens and full-scale pipe.


2019 ◽  
Vol 964 ◽  
pp. 257-262
Author(s):  
Victor D. Waas ◽  
Mas Irfan P. Hidayat ◽  
Lukman Noerochim

Delamination or interlaminar fracture often occurs in composite laminate due to several factors such as high interlaminar stress, stress concentration, impact stress as well as imperfections in manufacturing processes. In this study, finite element (FE) simulation of mode I delamination in double cantilever beam (DCB) specimen of carbon fiber/epoxy laminate HTA/6376C is investigated using cohesive zone model (CZM). 3D geometry of DCB specimen is developed in ANSYS Mechanical software and 8-node interface elements with bi-linear formulation are employed to connect the upper and lower parts of DCB. Effect of variation of number of elements on the laminate critical force is particularly examined. The mesh variation includes coarse, fine, and finest mesh. Simulation results show that the finest mesh needs to be employed to produce an accurate assessment of laminate critical force, which is compared with the one obtained from exact solution. This study hence addresses suitable number of elements as a reference to be used for 3D simulation of delamination progress in the composite laminate, which is less explored in existing studies of delamination of composites so far.


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