Effect of Adhesives on the Mechanical Behavior of Thick Composite Joints

2011 ◽  
Author(s):  
Sayed A. Nassar ◽  
Jianghui Mao ◽  
Xianjie Yang ◽  
Douglas Templeton
Keyword(s):  
Damage Mechanics ◽  
Resin Composite ◽  
Failure Process ◽  
Analytical Data ◽  
Interfacial Shear Stress ◽  
Continuum Damage Mechanics ◽  
Epoxy Adhesive ◽  
Failure Behavior ◽  
Damage Initiation ◽  
Damage Models

In this paper, experimental and numerical methods are used to study the deformation and interfacial failure behavior of an adhesively-bonded thick joint made of multi-layer S2 glass/SC-15 epoxy resin composite material. The adhesive material is 3M Scotch-Weld Epoxy Adhesive DP405 Black. Continuum damage mechanics models are used to describe the damage initiation at or near the interface and final failure process. The effect of adhesive overlap length, thickness and plasticity on the interfacial shear stress and normal stress are studied. Experimental and analytical data are used to validate the proposed damage models.

A Damage Model for Adhesively Bonded Single-Lap Thick Composite Joints

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Sayed A. Nassar ◽  
Jianghui Mao ◽  
Xianjie Yang ◽  
Douglas Templeton
Keyword(s):  
Damage Mechanics ◽  
Resin Composite ◽  
Analytical Data ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Epoxy Adhesive ◽  
Failure Behavior ◽  
Adhesively Bonded ◽  
Damage Initiation ◽  
Damage Models

A proposed damage model is used for investigating the deformation and interfacial failure behavior of an adhesively bonded single-lap thick joint made of S2 glass/SC-15 epoxy resin composite material. The bonding material is 3M Scotch-Weld Epoxy Adhesive DP405 Black. Continuum damage mechanics models are used to describe the damage initiation and final failure at or near the interface. The effect of adhesive overlap length, thickness, and plasticity on the interfacial shear and normal stresses is studied. Experimental and analytical data are used to validate the proposed damage models.

Geometry Transferability of Lemaitre's Continuum Damage Mechanics Model in the Plane Stress Specimens

2013 ◽  
Vol 592-593 ◽  
pp. 266-270 ◽  
Author(s):  
Nima Allahverdizadeh ◽  
Andrea Manes ◽  
Marco Giglio ◽  
Andrea Gilioli
Keyword(s):  
Plane Stress ◽  
Damage Mechanics ◽  
Numerical Models ◽  
Damage Model ◽  
High Strength ◽  
Experimental Tests ◽  
Continuum Damage Mechanics ◽  
Failure Behavior ◽  
Continuum Damage ◽  
Damage Models

Different damage mechanics models have been proposed by researchers to calibrate the failure behavior of materials. Continuum damage mechanics (CDM) models are one of the main categories of damage models that can be exploited in numerical simulations. In this paper Lemaitres damage model, has been applied to finite element models of flat specimens. These models allow assessing the geometry transferability of the previously calibrated CDM model investigating in different geometry and loading conditions. Four different types of plane stress specimens have been designed to get different stress triaxialities which cover shear dominant and high triaxiality failure. Experimental tests were also done and the obtained data were critically compared with the results from numerical models. The tested material is Ti-6Al-4V titanium alloy which is a widely used material in aerospace industry because of its high strength and low density.

scholarly journals Localization due to Damage in Two-Direction Fiber-Reinforced Composites

1996 ◽  
Vol 63 (2) ◽  
pp. 321-326 ◽  
Author(s):  
F. Hild ◽  
P.-L. Larsson ◽  
F. A. Leckie
Keyword(s):  
Damage Mechanics ◽  
Ceramic Matrix Composites ◽  
Continuum Damage Mechanics ◽  
General Criterion ◽  
Matrix Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Damage Models ◽  
Pull Out ◽  
Fracture Features

Fiber pull-out is one of the fracture features of fiber-reinforced ceramic matrix composites. The onset of this mechanism is predicted by using continuum damage mechanics, and corresponds to a localization of deformation. After deriving two damage models from a uniaxial bundle approach, different configurations are analyzed through numerical methods. For one model some very simple criteria can be derived, whereas for the second one none of these criteria can be derived and the general criterion of localization must be used.

Measuring of Damage Parameters in Adhesive Bonding

2006 ◽  
Vol 324-325 ◽  
pp. 275-278 ◽  
Author(s):  
I. Hilmy ◽  
M.M. Abdel Wahab ◽  
Ian A. Ashcroft ◽  
A.D. Crocombe
Keyword(s):  
Stress Level ◽  
Curve Fitting ◽  
Damage Mechanics ◽  
Adhesive Bonding ◽  
Low Cycle Fatigue ◽  
Extreme Points ◽  
Load Ratio ◽  
Continuum Damage Mechanics ◽  
Epoxy Adhesive ◽  
Least Square

In this paper, the characterisation of damage in an epoxy adhesive has been investigated. Bulk adhesive samples were used in this study for two reasons; firstly the stress distribution in the bulk adhesive sample is simpler than that in a joint, secondly, the specimen’s dimensions meet fatigue test specimen standards. Low cycle fatigue (LCF) tests with a load ratio of 0.1 and a frequency of 5 Hz were performed on bulk adhesive dumbbell specimens. Damage curves, relating damage in the specimen to number of cycles to failure, were plotted using an isotropic damage equation in which damage is a function of stress, which decreases as damage progresses. The damage curves were then fitted using a LCF damage evolution law. This equation was derived from a dissipation potential function using Continuum Damage Mechanics (CDM) theory. Curve fitting was performed using a Robust Least Square technique rather than ordinary linear least square because the damage curve has extreme points (usually at the breaking point). Two damage parameters α and β were found from the curve fitting process. This process resulted in different values of α and β for different stress levels. The logarithmic α and β points were then plotted respect against stress level and linear regression was used to determine α and β as a function of stress. With this function, damage parameters for other stress level can be predicted.

Continuum damage mechanics modelling incorporating stress triaxiality effect on ductile damage initiation

2020 ◽  
Vol 43 (8) ◽  
pp. 1755-1768 ◽  
Author(s):  
Nicola Bonora ◽  
Gabriel Testa ◽  
Andrew Ruggiero ◽  
Gianluca Iannitti ◽  
Domenico Gentile
Keyword(s):  
Damage Mechanics ◽  
Stress Triaxiality ◽  
Continuum Damage Mechanics ◽  
Ductile Damage ◽  
Continuum Damage ◽  
Damage Initiation

A nonlinear strain rate and pressure-dependent micro-mechanical composite material model for impact problems

2017 ◽  
Vol 31 (12) ◽  
pp. 1634-1660 ◽  
Author(s):  
Sandeep Medikonda ◽  
Ala Tabiei
Keyword(s):  
Composite Material ◽  
Strain Rate ◽  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Material Model ◽  
Distribution Functions ◽  
Failure Behavior ◽  
Nonlinear Strain ◽  
Impact Problems ◽  
The Impact

A micro-mechanical composite material model is developed to simulate the behavior of unidirectional composites under impact loading conditions in the nonlinear finite element solver (LS-DYNA®). The nonlinear strain rate and pressure dependency in the composite material model is accounted by the resin, which uses previously developed state variable viscoplastic equations. These equations have been originally developed for metals; however, these are modified to account for the significant contributions of hydrostatic stresses typically observed in polymers. The material model also uses a continuum damage mechanics (CDM) based failure model to incorporate the progressive post-failure behavior. A set of Weibull distribution functions are used to quantify this behavior, and a methodology of assigning physical significance to the choice of damage/softening parameters used in these functions is presented. The impact response of composite laminate plates has been simulated and compared to the experiments. It has been observed that the predicted results compare favorably to the experiments.

Material orthotropy effects on progressive damage analysis of open-hole composite laminates under tension

2017 ◽  
Vol 36 (20) ◽  
pp. 1473-1486 ◽  
Author(s):  
Song Zhou ◽  
Yi Sun ◽  
Boyang Chen ◽  
Tong-Earn Tay
Keyword(s):  
Composite Laminates ◽  
Damage Mechanics ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Tensile Loading ◽  
Progressive Damage ◽  
Cohesive Elements ◽  
Damage Initiation ◽  
Proposed Model ◽  
Open Hole

The sizes effects on the strengths of open-hole fibre-reinforced composite laminates subjected to tensile loading (OHT) have been investigated widely. However, little attention has been paid to the influence of material orthotropy. This paper presents a progressive damage model for the model failure of notched laminates under tensile loading based on continuum damage mechanics and cohesive elements. The effects of orthotropy on the failure of notched laminates with seven different ply sequences are investigated by our proposed model. The prediction results adopting the Hoffman and Pinho failure criterions to determine matrix damage initiation are compared with the results of experiments. Our proposed models are able to predict the strong influence of orthotropy on strengths of open-hole laminate under tension, and model using Pinho criterion can predict the open-hole tension strength most accurately.

Continuum damage mechanics predictions of creep damage initiation and growth in ferritic steel weldments in a medium bore branched pipe under constant pressure at 590 °C using a five-material weld model

2005 ◽  
Vol 461 (2060) ◽  
pp. 2303-2326 ◽  
Author(s):  
D.R Hayhurst ◽  
R.J Hayhurst ◽  
F Vakili-Tahami
Keyword(s):  
Heat Affected Zone ◽  
Ferritic Steel ◽  
Damage Mechanics ◽  
Constant Pressure ◽  
Creep Damage ◽  
Continuum Damage Mechanics ◽  
Coarse Grained ◽  
Continuum Damage ◽  
Damage Initiation ◽  
Type Iv

The paper reports three-dimensional creep continuum damage mechanics (CDM) analyses of creep failure in a medium bore Cr–Mo–V low alloy ferritic steel welded branched-pressure vessel that has been tested under a constant pressure of 4 MPa, at a uniform temperature of 590 °C. The use of the CDM computer software Damage XXX to analyse the initiation and growth of creep damage and subsequent failure in the branch weld is reported for a five-material model that includes: parent, Type IV, refined heat affected zone (R-HAZ), coarse grained heat affected zone (CG-HAZ) and weld materials. The results of the analyses are presented for two cases: the first without the CG-HAZ; and, the second with the CG-HAZ included. For both cases, lifetimes are conservatively, yet accurately predicted. It is shown that it is necessary to use a Type IV thickness of 0.7 mm to accurately predict the failure location and mode. The results of metallographic examinations of a tested vessel and the predicted damage fields are in close accord. Failure is predicted to take place, by steam leakage, from the interior of the vessel, through the Type IV zone adjacent to the main pipe, connecting through the R-HAZ to the CG-HAZ, where leakage takes place at the weld toe in the crotch plane.

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