Fatigue Life Estimation of Adhesively Bonded Scarf Joints Based on a Continuum Damage Mechanics Model

2005 ◽  
Vol 13 (4) ◽  
pp. 359-370 ◽  
Author(s):  
Makoto Imanaka ◽  
Makoto Taniguchi ◽  
Tatuyuki Hamano ◽  
Masaki Kimoto
Keyword(s):  
Fatigue Strength ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Estimation Method ◽  
Adhesive Layer ◽  
Epoxy Adhesive ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Scarf Joints

An estimation method of fatigue strength of adhesively bonded joints with various stress triaxialities in the adhesive layer has been proposed based on a damage evolution model for high cycle fatigue. To realize various triaxial stress states, fatigue test was conducted for adhesively bonded butt and scarf joints with various scarf angles bonded by a rubber-modified epoxy adhesive. An equation for estimating the damage evolution in the adhesive layer of the butt and scarf joints was derived from the damage model, where undefined parameters in the equation were determined by comparing the experimentally obtained damage evolution curves of the butt joints with the estimated damage evolution curves. Furthermore, an equation for the estimation of fatigue strength was derived under the assumption that fatigue failure occurs when the damage variable reaches to a critical value. When compared the experimental S-N data of scarf joints with the estimated ones, the estimated fatigue strengths agree well with the experimental data with various scarf angles. This finding suggests that the CDM model is applicable for estimating fatigue strength of adhesively bonded joints with different stress triaxialities.

scholarly journals Viscoelastic Analysis of Adhesively Bonded Joints

1981 ◽  
Vol 48 (2) ◽  
pp. 331-338 ◽  
Author(s):  
F. Delale ◽  
F. Erdogan
Keyword(s):  
Adhesive Layer ◽  
Shear Loading ◽  
Bonded Joints ◽  
Lap Joint ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Viscoelastic Analysis ◽  
Laplace Transform Technique ◽  
External Loads ◽  
Peak Value

In this paper an adhesively bonded lap joint is analyzed by assuming that the adherends are elastic and the adhesive is linearly viscoelastic. After formulating the general problem a specific example for two identical adherends bonded through a three parameter viscoelastic solid adhesive is considered. The standard Laplace transform technique is used to solve the problem. The stress distribution in the adhesive layer is calculated for three different external loads namely, membrane loading, bending, and transverse shear loading. The results indicate that the peak value of the normal stress in the adhesive is not only consistently higher than the corresponding shear stress but also decays slower.

Stress Analysis of Bonded Joint Using Solid Element Combinations

2013 ◽  
Vol 467 ◽  
pp. 332-337
Author(s):  
Xiao Cong He
Keyword(s):  
Finite Element ◽  
Mechanical Behaviour ◽  
Adhesive Layer ◽  
Smooth Transition ◽  
Triangular Prism ◽  
Suitable Model ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Bonded Joint

This paper describes some finite element combinations to analyse the mechanical behaviour of bonded joints. In finite element models five layers of solid elements were used across the adhesive layer in order to increase the accuracy of the results. The finite elements were refined gradually in steps from adherends to adhesive layer. In these models, most of the adherends and adhesive were modeled using solid brick elements but some solid triangular prism elements were used for a smooth transition. Comparisons are performed between different types of first-order element combinations in order to find a suitable model to predict the mechanical behaviour of adhesively bonded joints.

Effect of Alkali on the Impact Toughness of Adhesively Bonded Joints

2012 ◽  
Vol 166-169 ◽  
pp. 1904-1907
Author(s):  
Min You ◽  
Chun Zhi Mei ◽  
Wen Jun Liu ◽  
Jing Rong Hu ◽  
Ling Wu
Keyword(s):  
Impact Toughness ◽  
Moisture Absorption ◽  
Adhesive Layer ◽  
Epoxy Adhesive ◽  
Alkali Solution ◽  
Lap Joint ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Single Lap Joint ◽  
The Impact

The effect of the temperature and immersed time of the alkali solution on the impact toughness of the adhesively bonded steel single lap joint under impact loading is studied using the experimental method. The results obtained show that the impact toughness of the specimen increased when the immersed time increased then it decreased as it beyond 3 days. When the immersed time is longer than 72 h, the higher the temperature is, the lower the impact toughness of the joint. The moisture absorption of the adhesive layer with the immersed time was also investigated and it was found that there is a relationship to the impact toughness of the adhesively bonded single lap joint. The epoxy adhesive layer was analyzed with FT-IR and it was found that the hydroxyl enhanced and bonding strength may increase after 72 h immersed in alkali solution.

scholarly journals Impact fatigue in adhesive joints

2008 ◽  
Vol 222 (10) ◽  
pp. 1981-1994 ◽  
Author(s):  
V V Silberschmidt ◽  
J P Casas-Rodriguez ◽  
I A Ashcroft
Keyword(s):  
Structural Integrity ◽  
High Energy ◽  
Epoxy Adhesive ◽  
Bonded Joints ◽  
Impact Fatigue ◽  
Adhesively Bonded ◽  
Low Velocity ◽  
Adhesively Bonded Joints ◽  
Aerospace Applications ◽  
Fatigue Crack Development

One of the forms of a vibro-impact effect in engineering components is impact fatigue (IF) caused by a cyclic repetition of low energy, low-velocity impacts, for instance, in aerospace structures. It can have a highly detrimental impact on performance and reliability of such components, exacerbated by the fact that in many cases it is disguised in loading histories by non-impact loading cycles with higher amplitudes. Since the latter are traditionally considered as most dangerous in standard fatigue, IF has not yet received deserved attention; it is less studied and practically unknown to specialists in structural integrity. Though there is a broad understanding of the danger of high-energy single impacts, repetitive impacting of components has been predominantly studied for very short series. This paper aims at the analysis of IF of adhesively bonded joints, which are becoming more broadly used in aerospace applications. The study is implemented for two types of typical adherends — an aluminium alloy and a carbon-fibre reinforced composite — and an industry-relevant epoxy adhesive. Various stages of fatigue crack development in adhesively bonded joints are studied for the conditions of standard and IF. The results obtained — in terms of crack growth rates, fatigue lives, and microstructures of fracture surfaces — are compared for the two regimes in order to find similarities and specific features.

scholarly journals Thermal Stresses in Adhesively Bonded Joints: Numerical and Analytical Analysis

2021 ◽  
pp. 83-95
Author(s):  
Francesco Marchione
Keyword(s):  
Adhesive Joint ◽  
Thermal Stresses ◽  
Fem Simulation ◽  
Adhesive Layer ◽  
Fundamental Aspect ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Thermal Compatibility ◽  
Good Agreement

The adhesive technique is observing a considerable increase in applications in various fields. Unlike traditional joining methods, this technology allows the stress peaks and the weight of the resulting structure to be reduced. Adhesive joints during their service life not only undergo mechanical but also thermal stresses. The thermal compatibility between the adhesive and the adherents used is a fundamental aspect to consider in the design phase. This paper reports on and analyses the results obtained from a linear Finite Element Method (FEM) simulation for a hybrid adhesive joint, as the thickness and characteristics of the adhesive layer vary. An analytical solution for adhesive free joints is presented according to both beam and plate theories. The analytical and numerical results, in case of no adhesive, are in good agreement with good approximation. The introduction of the adhesive layer allows to obtain higher displacement values than in the adhesive-free configuration. The increase in displacement and therefore in ductility confirms the effectiveness of the adhesive joint for real applications.

Computational Approach for Adhesively Bonded Composite Joints

2000 ◽  
Author(s):  
Iqbal Anwar ◽  
Golam Newaz
Keyword(s):  
Finite Element ◽  
Adhesive Layer ◽  
Limit Load ◽  
Element Model ◽  
Composite Joints ◽  
Bonded Joints ◽  
Failure Model ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Nodal Failure

Abstract A computational intensive study was performed to assess an efficient way to model adhesively bonded glass fiber reinforced composite joints in automotive applications. Three different finite element modeling techniques had been implemented. First, adhesive was represented by 1D-spring elements. Spring stiffness was calculated from adhesive property. This model is inadequate to assess stresses developed in the adhesive layer directly. So adhesive was modeled with 2D elements for better assessment of state of stress in the adhesive and the substrate. Both the model provide limit load, but crack initiation and failure of the bond can not be captured. The third approach adopted was the nodal failure model. In the nodal failure model, to understand the failure of adhesively bonded joints, bond strength had been specified to the interface nodes of the composite substrate. Combined failure criteria had been used. Cracks propagated and interface debonded when interface stress exceeded the failure limit. Finite element model results compared well with the experimental data. This modeling approach was later adopted for dynamic modeling of adhesively bonded joints, which shows promise.

Stress Distribution of Bonded Joint with Rubbery Adhesives

2011 ◽  
Vol 189-193 ◽  
pp. 3427-3430
Author(s):  
Xiao Cong He
Keyword(s):  
Stress Distribution ◽  
Stress Component ◽  
Adhesive Layer ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Shear Stress Component ◽  
Element Analysis ◽  
Adhesively Bonded Joints ◽  
Bonded Joint ◽  
Stress Components

This paper deals with the stress distribution in adhesively bonded joints with rubbery adhesives. The 3-D finite element analysis (FEA) software was used to model the joint and predict the stress distribution along the whole joint. The FEA results indicated that there are stress discontinuities existing in the stress distribution within the adhesive layer and adherends at the lower interface and the upper interface of the boded section for most of the stress components. The FEA results also show that the stress field in the whole joint is dominated by the normal stresses components S11, S33 and the shear stress component S13. The features and variations of these critical stresses components are discussed.

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