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 Analysis on Failure Mechanism of Scarf Joints With Brittle-Ductile Adhesives Subjected to Uniaxial Tensile Loads

2013 ◽  
Author(s):  
Lijuan Liao ◽  
Toshiyuki Sawa ◽  
Chenguang Huang
Keyword(s):  
Failure Mechanism ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Adhesive Layer ◽  
Uniaxial Tensile ◽  
Zone Model ◽  
Displacement Curve ◽  
Failure Energy ◽  
Complete Failure ◽  
Scarf Joints

The failure mechanism of scarf joints with a series of angles and brittle-ductile adhesives subjected to uniaxial tensile loads is analyzed by using a numerical method which employs a cohesive zone model (CZM) with a bilinear shape in mixed-mode (mode I and II). The adopted methodology is validated via comparisons between the present simulated results and the existing experimental measurements, which illustrate that the load-bearing capacity increases as the scarf angle decreases. More important, it is observed that the failure of the joint is governed by not only the ultimate tensile loads, but also the applied tensile displacement until complete failure, which is related to the brittle-ductile properties of the adhesive layer. In addition, failure energy, which is defined by using the area of the load-displacement curve of the joint, is adopted to estimate the joint strength. Subsequently, the numerical results show that the strength of the joint adopting ductile adhesive with higher failure energy is higher than that of the joint using brittle adhesive with lower failure energy.

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.

scholarly journals Improvement of a Cohesive Zone Model for Fatigue Delamination Rate Simulation

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 181 ◽  
Author(s):  
Alessandro Pirondi ◽  
Fabrizio Moroni
Keyword(s):  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Adhesive Layer ◽  
Zone Model ◽  
Bonded Joints ◽  
Initial Stiffness ◽  
Modified Model ◽  
Entire Thickness ◽  
Order Of Magnitude ◽  
New Formulation

The cohesive zone model (CZM) has found wide acceptance as a tool for the simulation of delamination in composites and debonding in bonded joints and various implementations of the cohesive zone model dedicated to fatigue problems have been proposed in the past decade. In previous works, the authors have developed a model based on cohesive zone to simulate the propagation of fatigue defects where damage acts on cohesive stiffness, with an initial (undamaged) stiffness representative of that of the entire thickness of an adhesive layer. In the case of a stiffness that is order of magnitude higher than the previous one (for instance, in the simulation of the ply-to-ply interface in composites), the model prediction becomes inaccurate. In this work, a new formulation of the model that overcomes this limitation is developed. Finite element simulations have been conducted on a mode I, constant bending (constant G)-loaded double cantilever beam (DCB) joint to assess the response of the new model with respect to the original one for varying initial stiffness K0 and cohesive strength σ0. The results showed that the modified model is robust with respect to changes of two orders of magnitude in initial stiffness and of a factor of two in σ0.

Predicting the Strength of Adhesively Bonded T-joints Under Cyclic Temperature using a Cohesive Zone Model

2015 ◽  
Vol 92 (11) ◽  
pp. 892-907 ◽  
Author(s):  
Weidong Li ◽  
Bo Pang ◽  
Xiao Han ◽  
Liping Tang ◽  
Kunmin Zhao ◽  
...  
Keyword(s):  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Zone Model ◽  
Adhesively Bonded ◽  
T Joints ◽  
Cyclic Temperature

Analysis of the performance of adhesively bonded corrugated core sandwich structures using cohesive zone method

2017 ◽  
Vol 22 (1) ◽  
pp. 104-124
Author(s):  
Ganiy Akhmet ◽  
Ye Yu ◽  
Ping Hu ◽  
Wen-bin Hou ◽  
Xiao Han
Keyword(s):  
Stress Distribution ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Sandwich Structures ◽  
Adhesive Layer ◽  
Geometrical Parameters ◽  
Zone Model ◽  
Adhesively Bonded ◽  
Joint Width ◽  
Panel Thickness

Stress analysis of adhesively bonded joints of sandwich structures is more complex. Only a few research works have studied this subject. The major obstacle is finding the stress distribution at the adhesive layer of sandwich structures under different loading conditions. This paper presents a study on stress distribution at the adhesive joints of the corrugated sandwich structure subjected to three-point bending using the cohesive zone model. Firstly, three cases of sandwich models with different types of glue on both longitudinal and transverse loading directions were calculated using cohesive zone model, and then the corresponding experiments were carried out and compared to prove the FEM results to validate the results through both load–displacement curves and failure deformation modes. Secondly, the cohesive zone model simulation was used to obtain the detailed stress distribution at the bonding joint with the effect of four major geometrical parameters: adhesive layer thickness, corrugated panel thickness, face panel thickness and adhesive joint width. Lastly, the results of stress analysis showed that the stress distribution is not uniform and is highly affected by the bonding joint's geometrical parameters, adhesive layer thickness and adhesive joint width.

scholarly journals Edge Debonding in Peeling of a Thin Flexible Plate From an Elastomer Layer: A Cohesive Zone Model Analysis

2016 ◽  
Vol 84 (2) ◽  
Author(s):  
Bikramjit Mukherjee ◽  
Romesh C. Batra ◽  
David A. Dillard
Keyword(s):  
Fracture Energy ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Load Capacity ◽  
Cohesive Zone Modeling ◽  
Interface Fracture ◽  
Rigid Base ◽  
Zone Model ◽  
Flexible Plate ◽  
Bending Rigidity

A cohesive zone modeling (CZM) approach with a bilinear traction-separation relation is used to study the peeling of a thin overhanging plate from the edge of an incompressible elastomeric layer bonded firmly to a stationary rigid base. The deformations are approximated as plane strain and the materials are assumed to be linearly elastic, homogeneous, and isotropic. Furthermore, governing equations for the elastomer deformations are simplified using the lubrication theory approximations, and those of the plate with the Kirchhoff–Love theory. It is found that the peeling is governed by a single nondimensional number defined in terms of the interfacial strength, the interface fracture energy, the plate bending rigidity, the elastomer shear modulus, and the elastomeric layer thickness. An increase in this nondimensional number monotonically increases the CZ size ahead of the debond tip, and the pull-off force transitions from a fracture energy to strength dominated regime. This finding is supported by the results of the boundary value problem numerically studied using the finite element method. Results reported herein could guide elastomeric adhesive design for load capacity and may help ascertain test configurations for extracting the strength and the fracture energy of an interface from test data.

scholarly journals Ultrasonic Deicing Efficiency Prediction and Validation for a Flat Deicing System

2020 ◽  
Vol 10 (19) ◽  
pp. 6640
Author(s):  
Zhonghua Shi ◽  
Zhenhang Kang ◽  
Qiang Xie ◽  
Yuan Tian ◽  
Yueqing Zhao ◽  
...  
Keyword(s):  
Lead Zirconate Titanate ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Lead Zirconate ◽  
Efficiency Factor ◽  
Zone Model ◽  
Shear Stresses ◽  
Stress Distributions ◽  
Total Energy Density ◽  
Average Shear

An effective deicing system is needed to be designed to conveniently remove ice from the surfaces of structures. In this paper, an ultrasonic deicing system for different configurations was estimated and verified based on finite element simulations. The research focused on deicing efficiency factor (DEF) discussions, prediction, and validations. Firstly, seven different configurations of Lead zirconate titanate (PZT) disk actuators with the same volume but different radius and thickness were adopted to conduct harmonic analysis. The effects of PZT shape on shear stresses and optimal frequencies were obtained. Simultaneously, the average shear stresses at the ice/substrate interface and total energy density needed for deicing were calculated. Then, a coefficient named deicing efficiency factor (DEF) was proposed to estimate deicing efficiency. Based on these results, the optimized configuration and deicing frequency are given. Furthermore, four different icing cases for the optimize configuration were studied to further verify the rationality of DEF. The effects of shear stress distributions on deicing efficiency were also analyzed. At same time, a cohesive zone model (CZM) was introduced to describe interface behavior of the plate and ice layer. Standard-explicit co-simulation was utilized to model the wave propagation and ice layer delamination process. Finally, the deicing experiments were carried out to validate the feasibility and correctness of the deicing system.

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