scholarly journals Modelling Microstructural Deformation and the Failure Process of Plastic Bonded Explosives Using the Cohesive Zone Model

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3661 ◽  
Author(s):  
Kaida Dai ◽  
Baodi Lu ◽  
Pengwan Chen ◽  
Jingjing Chen
Keyword(s):  
Mechanical Behavior ◽  
Cohesive Zone ◽  
Shear Failure ◽  
Cohesive Zone Model ◽  
Failure Process ◽  
Interface Debonding ◽  
Zone Model ◽  
Strain Rates ◽  
Cohesive Elements ◽  
Failure Evolution

A microstructure finite element method combining the cohesive zone model (CZM) is used to simulate the mechanical behavior, deformation, and failure of polymer-bonded explosive (PBX) 9501 under quasi-static loading. PBX 9501 consists of Cyclotetramethylene tetranitramine (HMX) filler particles with a random distribution packaged in a polymeric binder. The particle is treated as elastic and the binder as viscoelastic. Cohesive elements with a bilinear softening law are inserted into the particle/binder interface, the HMX particle, and the binder to study the interface’s debonding and failure evolution. Macroscopic stress–strain curves homogenized across the microstructure under tension and compression with different strain rates are basically consistent with the experimental data. The interface debonding approximately vertical to the loading direction is the primary failure mechanism under tension, while shear failure along the interfaces and particle fracture plays a significant role under compression. The effects of interface strengths and strain rates on the performance of PBX 9501 are also evaluated. The tensile and compressive strengths are dependent on the interface strength and strain rate, but the failure paths are insensitive. This model is shown to accurately predict macroscopic responses and improve our understanding of the relationship between the mechanical behavior and microstructure of PBX 9501.

Investigation on the Load Capacity and Failure Process of T-Joint by Experiments and Numerical Method

2011 ◽  
Vol 328-330 ◽  
pp. 1317-1321
Author(s):  
Ping Hu ◽  
Qi Shao ◽  
Qian Nie ◽  
Wei Dong Li
Keyword(s):  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Load Capacity ◽  
Failure Process ◽  
Adhesive Layer ◽  
Zone Model ◽  
T Joints ◽  
Damage And Failure ◽  
Automotive Structures ◽  
In The Beginning

Adhesive bonded T-joint is commonly applied in the manufacture of automotive structures. The objective of this work is the analysis of the load capacity of the adhesive-bonded T-joints under tension load and the influence causing by some parameters of adherend on the damage of T-joint. Thus, a series of tests were carried out and the balanced joint and the imbalanced joint concepts were proposed to illustrate the influence. And the results show that the imbalanced joints suffered greater stress concentration than the balanced one. Furthermore, by increasing the stiffness of adherends , one can increase the load capacity of a balanced joint. Meanwhile, in order to simulate the damage and failure processes in this type of joint, the cohesive zone model (CZM) based analysis was carried out using finite element method in ABAQUS. One can observed that only the upper end of adhesive layer transmits the load in the beginning.

Cyclic Cohesive Zone Model for Simulation of Fatigue Failure Process in Adhesive Joints

2014 ◽  
Vol 606 ◽  
pp. 217-221 ◽  
Author(s):  
Mahzan Johar ◽  
Mohamad Shahrul Effendy Kosnan ◽  
Mohd Nasir Tamin
Keyword(s):  
Fatigue Failure ◽  
Adhesive Joint ◽  
Cohesive Zone ◽  
Damage Evolution ◽  
Cohesive Zone Model ◽  
Failure Process ◽  
Interface Strength ◽  
Zone Model ◽  
Strength And Stiffness ◽  
Cyclic Damage

Progressive failure process of adhesive joint under cyclic loading is of particular interest in this study. Such fatigue failure is described using damage mechanics with the assumed cohesive behaviour of the adhesive joint. Available cohesive zone model for monotonic loading is re-examined for extension to capture cyclic damage process of adhesive joints. Damage evolution in the adhesive joint is expressed in terms of cyclic degradation of interface strength and stiffness. Mixed-mode fatigue fracture of the joint is formulated based on relative displacements and strain energy release rate of the interface. A power-law type variation for each of these cohesive zone model parameters with accumulated load cycles is assumed in the presence of limited experimental data on cyclic interface fracture process. The cyclic cohesive zone model (CCZM) is implemented in commercial finite element analysis code and the model is validated using adhesively bonded 2024-T3 aluminium substrates with epoxy-based adhesive film (FM73M OST). The CCZM model is then examined for cyclic damage evolution characteristics of the adhesive lap joint subjected to cyclic displacement of Δδ = 0.1 mm, R=0 so as to induce shear-dominant fatigue failure. Results show that the cyclic interface damage started to initiate and propagate symmetrically from the both overlap edges and degradation of interface strength and stiffness started to accumulate after 0.5 cycles of displacement elapsed. The predicted results are consistent with the mechanics of relatively brittle interface failure process.

scholarly journals Numerical Simulation of Fatigue Crack Growth Rate and Crack Retardation due to an Overload Using a Cohesive Zone Model

2014 ◽  
Vol 891-892 ◽  
pp. 777-783 ◽  
Author(s):  
Sarmediran Silitonga ◽  
Johan Maljaars ◽  
Frans Soetens ◽  
Hubertus H. Snijder
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Propagation ◽  
Crack Growth ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Crack Tip ◽  
Zone Model ◽  
Cohesive Elements

In this work, a numerical method is pursued based on a cohesive zone model (CZM). The method is aimed at simulating fatigue crack growth as well as crack growth retardation due to an overload. In this cohesive zone model, the degradation of the material strength is represented by a variation of the cohesive traction with respect to separation of the cohesive surfaces. Simulation of crack propagation under cyclic loads is implemented by introducing a damage mechanism into the cohesive zone. Crack propagation is represented in the process zone (cohesive zone in front of crack-tip) by deterioration of the cohesive strength due to damage development in the cohesive element. Damage accumulation during loading is based on the displacements in the cohesive zone. A finite element model of a compact tension (CT) specimen subjected to a constant amplitude loading with an overload is developed. The cohesive elements are placed in front of the crack-tip along a pre-defined crack path. The simulation is performed in the finite element code Abaqus. The cohesive elements behavior is described using the user element subroutine UEL. The new damage evolution function used in this work provides a good agreement between simulation results and experimental data.

Implementing a Cohesive Zone Interface in a Diamond-Coated Tool for 2D Cutting Simulations

2012 ◽  
Author(s):  
Feng Qin ◽  
Ninggang Shen ◽  
Kevin Chou
Keyword(s):  
Residual Stresses ◽  
Mechanical Behavior ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Chip Thickness ◽  
Zone Model ◽  
Cohesive Failure ◽  
Cutting Simulation ◽  
Coated Tool ◽  
Coating Delamination

Coating-substrate interface properties and deposition residual stresses may have significant effects on diamond-coated tool performance. However, it is still distant to understand how the interface mechanical behavior and deposition residual stress together influence the diamond-coated tool thermo-mechanical behavior during machining. In this study, a 2D cutting simulation incorporating deposition residual stresses and an interface cohesive zone model has been developed to demonstrate the feasibility of evaluating coating delamination of a diamond-coated tool during cutting. It has been shown that even the residual deposition stresses alone may result in crack initiations in the cohesive zone (i.e., the interface). In addition, the study further demonstrates that the feasibility of implementing cohesive zone interface in a diamond-coated tool in 2D cutting simulation. An example of cohesive failure occurred in the cutting simulation is shown. The result shows a large uncut chip thickness can cause cohesive delamination during cutting.

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