Optimization of Adhesively Bonded Single Lap Joints by Tapering of Adherends

2002 ◽  
Author(s):  
Prasad Nirantar ◽  
Erol Sancaktar
Keyword(s):  
Lap Joints ◽  
Material Behavior ◽  
Experimental Results ◽  
Shear Stresses ◽  
Lap Joint ◽  
Adhesively Bonded ◽  
Single Lap Joints ◽  
Single Lap Joint ◽  
Joint Deformation ◽  
Normal And Shear Stresses

The effect of tapering the ends of the adherend on the joint strength and joint deformation behavior of the single lap joint geometry was studied. First, the joints were geometrically modeled using finite element (FE) techniques involving linear, as well as nonlinear (bilinear) material behavior. Then, the FEA results were compared with the experimental results for different configurations of the single lap joints, and the FEA results were found to be consistent with the experimental results with the normal and shear stresses significantly decreasing in the modified geometries over those in unmodified geometries leading to increased loading capacity in modified joints, especially with small-angle taper (~10°).

A Coupled Peel and Shear Stress-Diffusion Model for Adhesively Bonded Single Lap Joints

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Emad Mazhari ◽  
Sayed A. Nassar
Keyword(s):  
Shear Stress ◽  
Diffusion Model ◽  
Adhesive Layer ◽  
Lap Joints ◽  
Fickian Diffusion ◽  
Lap Joint ◽  
Adhesively Bonded ◽  
Single Lap Joints ◽  
Single Lap Joint ◽  
Stress Diffusion

In this study, the Fickian diffusion formulation is extended to the adhesive layer of a single lap joint (SLJ) model, in order to develop a coupled peel and shear stress-diffusion model. Constitutive equations are formulated for shear and peel stresses in terms of adhesive material properties that are time- and location-dependent. Numerical solution is provided for the effect of diffusion on shear and peel stresses distribution. Detailed discussion of the results is presented.

Modeling of Moisture Diffusion Effect on Peel and Sheer Stresses in Adhesively Bonded Single Lap Joints Under Shear-Tensile Loading

2017 ◽  
Author(s):  
Emad Mazhari ◽  
Sayed A. Nassar
Keyword(s):  
Adhesive Layer ◽  
Moisture Diffusion ◽  
Lap Joints ◽  
Fickian Diffusion ◽  
Lap Joint ◽  
Adhesively Bonded ◽  
Adhesive Material ◽  
Single Lap Joints ◽  
Single Lap Joint ◽  
Stress Diffusion

In this study, the Fickian diffusion formulation is extended to the adhesive layer of a single lap joint model, in order to develop a coupled peel and shear stress-diffusion model. Constitutive equation are formulated for shear and peel stresses in terms of adhesive material properties that are time and location-dependent. Numerical solution is provided for the effect of diffusion on shear and peel stresses distribution. Detailed discussion of the results is presented.

Effect of interface non-flatness on the fatigue behavior of adhesively bonded single lap joints

2017 ◽  
Vol 233 (7) ◽  
pp. 1277-1286 ◽  
Author(s):  
SMJ Razavi ◽  
MR Ayatollahi ◽  
M Samari ◽  
LFM da Silva
Keyword(s):  
Fatigue Life ◽  
Bearing Capacity ◽  
Fatigue Behavior ◽  
Fatigue Loading ◽  
Lap Joints ◽  
Lap Joint ◽  
Adhesively Bonded ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Single Lap Joints

This paper addresses numerical and experimental examination of the role of zigzag interface shapes on the load bearing capacity and fatigue life of adhesively bonded single lap joints. Aluminum adherends with non-flat zigzag interfaces were tested under both quasi-static and fatigue loading conditions. The quasi-static test results revealed that the non-flat adhesive joints have higher load bearing capacity compared to the conventional flat single lap joints. Comparative fatigue tests with different loading levels revealed that the non-flat zigzag single lap joint had considerably higher fatigue life than the conventional lap joint.

Numerical Study of the Prestressed Connectors and Their Distribution on the Strength of a Single Lap, a Double Lap and Hybrid Joints Subjected to Uniaxial Tensile Test

2013 ◽  
Vol 58 (2) ◽  
pp. 579-585 ◽  
Author(s):  
T. Sadowski ◽  
P. Golewski
Keyword(s):  
Mechanical Response ◽  
Numerical Study ◽  
Lap Joints ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Shear Stresses ◽  
Lap Joint ◽  
Positive Effects ◽  
Single Lap Joint ◽  
Hybrid Joints

Prestressed joints are widely used in construction using connectors in the form of screws, whose task is to strong clamping of joined parts, thereby the internal forces in joint are transferred by surface friction contact of the elements. In the automotive and aerospace industries hybrid joints are more widely applied. Mechanical connectors are added to the adhesive joint in form of rivets, screws or clinch increasing its strength properties. The aim of this study was to determine how the prestressed connectors influence the mechanical response of hybrid, single and double lap joints. The influence of different distribution of the connectors was also investigated. Numerical study was conducted in ABAQUS program. Mechanical connectors were modeled by using fasteners, that allowed for a considerable simplification of the numerical model. In their application, there is no need for an additional submodels for connectors in the form of the rivet or the bolt. Prestressing is activated by direct application of the force to the connector. In the numerical examples the authors assumed that the diameter of the mechanical connectors was equal to 6mm and shear strength was equal 1kN. Adhesive layers were modeled by using cohesive elements for which maximum shear stresses and fracture energy were specified. The layer thickness was assumed to be equal 0.1mm and it was initially removed from the areas where mechanical connectors were placed. Two types of joints were analysed in the study: the single lap joint with lap dimensions 40x40mm as well as the double lap joint with lap dimensions 40x20mm, from which it results that theoretical strength of both connections should be the same. The prestressing of connectors was introduced by the force 1.5kN. For all pure - mechanical joints and for single lap joints positive effects were obtained. For double lap joints additional prestressing did not significantly affect for their strength. The influence of distribution of mechanical connectors was additionally analyzed by consideration of three configurations, where the rows of rivets were located at distances of 5, 10 and 15mm from the lap edge. The maximum increase of the load capacity by 24% was achieved for single lap joint as well as 35.7% for double lap joint. The obtained numerical results indicate the positive effects of additional pressure and allows for practical suggestions how to correct and optimize spacing distance of mechanical connectors in hybrid joints to get better mechanical response.

Distribution des contraintes dans les assemblages collés :

1996 ◽  
Vol 84 ◽  
pp. 47-56
Author(s):  
B. Fargette ◽  
Y. Gilibert ◽  
L. Rimlinger
Keyword(s):  
Test Specimen ◽  
Testing Machine ◽  
Tensile Load ◽  
Expansion Method ◽  
Lap Joints ◽  
Experimental Results ◽  
Stress Fields ◽  
Lap Joint ◽  
Single Lap Joints ◽  
Linear Behaviour

We have studied the agreement between theoretical computations and experimental results of surface strains of bonded joints of two types : tenon and mortise, and single-lap joints, for different lengths of the lap. For instance, with the single-lap joint, we have tested four lengths of the overlap from 14 mm to 88 mm. Surface strains are measured by an extensometrical method with electrical gauges, when the specimen is loaded in uniaxial traction on a universal testing machine. Experimental results and computations made by an improved method like the asymptotic expansion method agree, but only if the global traction load applied on the specimen is low, or if the overlap in respect with the others dimensions of the section of test specimen is long. In these joints, effectively, stress fields are disrupted near the butts and become very difficult to compute. Actually, near the ends of the overlap, stresses can reach high limits with only low global load applied on the test specimen. With a short length of the overlap, linear behaviour disappears almost totally because of a strong interaction of the two perturbed fields. On the contrary, with a high length of overlap, stress fields become linear on the major part of the overlap , even with a high tensile load applied on the specimen. So, the length of the overlap has a great effect on the linear behaviour of the joint.

Effect of Recessing in Bondline on Stress in Co-Axial Lap Joint

2010 ◽  
Vol 97-101 ◽  
pp. 952-955
Author(s):  
Xiao Ling Zheng ◽  
Mei Rong Zhao ◽  
Min You ◽  
Zhi Li ◽  
Jia Ling Yan
Keyword(s):  
Finite Element Method ◽  
Aluminum Alloy ◽  
Elastic Modulus ◽  
Middle Part ◽  
Lap Joints ◽  
Lap Joint ◽  
Single Lap Joints ◽  
Single Lap Joint ◽  
Significant Difference ◽  
Peel Stress

The effect of recessing on the stresses distributed along the mid-bondline in both standard single lap joints and co-axial ones were analyzed using elasto-plastic finite element method (FEM). The results obtained show that the values of the peak stresses of all the stresses distributed in the mid-bondline were changed greatly as the preformed angle in over lap zone was about 10 0 when the high elastic modulus adhesive is used. The effect of the elastic modulus level on the stress distribution (especially the peak stresses) is small in the middle part of the lap zone. When taken the stress distributed in the middle part of the lap zone into account, there is nearly no significant difference between the peel stress distributed in the standard joint and co-axial single lap joint when the adhesives with lower elastic modulus was used. It is recommended that a co-axial joint is suitable for the recessing joint made by aluminum alloy and a higher elastic modulus adhesive.

STRESS DISTRIBUTION OF SECONDARY BENDING IN SINGLE-LAP BOLTED JOINTS WITH DISSIMILAR JOINING PLATES AND PLATE TYPES

2016 ◽  
Vol 78 (5-5) ◽  
Author(s):  
Hilton Ahmad
Keyword(s):  
Fuel Efficiency ◽  
Plate Thickness ◽  
Stress Gradient ◽  
Lap Joints ◽  
Lap Joint ◽  
Single Lap Joints ◽  
Single Lap Joint ◽  
Joint Construction ◽  
Composite Joint ◽  
Composite Steel

Single-lap joints are an important class of bolted joint in the aerospace and civil engineering sectors. This type of joint is preferred as it can reduce weight and hence help to optimize fuel efficiency. However, bolted single-lap joints exhibit secondary bending due to eccentricity of the applied loads. Flexural of plates during tensile loading alters the contact regions in the single-lap joint significantly, resulting in more non-linear behaviour and a stress gradient across the plate thickness. 3-D bolted single-lap joint were modelled in ABAQUS CAE incorporating the effect of the bolt tension from application of a tightening torque. Current 3-D model used elastic properties based on smeared-out properties, the effect of joint construction is considered further by examining the stress in a composite-composite joint and comparing with a composite-steel joint. In a related investigation the effect of varying composite thickness in the composite-steel joints is also studied.  

scholarly journals Single Lap Joints Numerical Modelling and Comparison with Experimental Testing

2018 ◽  
Vol 2 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Daniel F. O. Braga ◽  
Lucas F. M. Da Silva ◽  
Pedro M. G. P. Moreira
Keyword(s):  
Structural Design ◽  
Adhesive Bonding ◽  
Experimental Testing ◽  
Lap Joints ◽  
Lap Joint ◽  
Joint Configuration ◽  
Single Lap Joints ◽  
Single Lap Joint ◽  
Different Types ◽  
Structural Adhesive

Adhesive bonding is a joining technique which has been extensively employed in structural design as its ability to join different types of materials allows higher freedom for designers when choosing materials. One of the most common joint configuration used is the single lap joint configuration. In this work a set of experimental procedures were undertaken to characterize a structural adhesive and model the behaviour of a single lap joint manufactured using this adhesive. Two types of surface preparations were used to study its effect in single lap joint strength.

Failure Analysis of Adhesively Bonded Single Lap Joints Embedded with Metal Component as Part of Fillet

2006 ◽  
Vol 324-325 ◽  
pp. 727-730 ◽  
Author(s):  
Min You ◽  
Yong Zheng ◽  
Xiao Ling Zheng ◽  
Zhan Mou Yan ◽  
Zhi Li
Keyword(s):  
Lap Joints ◽  
Lap Joint ◽  
Adhesively Bonded ◽  
Sem Images ◽  
Element Analysis ◽  
Single Lap Joints ◽  
Fea Model ◽  
Steel Wires ◽  
Ft Ir ◽  
Steel Joints

In order to understand the effects of the metal components embedded in adhesive fillets on the strength of adhesively bonded single lap joint, the failed surfaces were studied with diagrams of scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectrometer. The stress distribution along the length of the bondline of single lap steel joints was also studied with an elasto-plastic finite element analysis (FEA) model to understand its effect in the view of mechanics. The SEM images and the FT-IR spectra diagrams revealed that the failure in the interface was primarily mixture mode with fillets and they also presented the interface strength being higher and there were more polar links formed in the adhesive fillets with metal components. The result obtained from the numerical modeling is in compliance with it from experiment that the stress distributed in lap zone of the joint is gentler when a couple of steel wires embedded in fillet.

The Effect of Interface Geometry on the Mechanical Behavior of Adhesive Joints

2017 ◽  
Vol 754 ◽  
pp. 256-259 ◽  
Author(s):  
S.M.J. Razavi ◽  
M. Peron ◽  
J. Torgersen ◽  
F. Berto
Keyword(s):  
Wave Length ◽  
Variable Parameter ◽  
Lap Joints ◽  
Experimental Results ◽  
Adhesively Bonded ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Single Lap Joints ◽  
Wave Heights

The role of sinusoid interface shape on the load bearing capacity of the adhesively bonded single lap joints has been investigated experimentally. The experimental results showed that the interface non-flatness can considerably influence the adhesive joint strength. The main parameters that can affect the load bearing of the non-flat joints are wave heights, wave lengths and also mechanical properties of adhesives and adherends. In this paper, the effect of wave length was evaluated as the key variable parameter. According to the experimental results for the best studied case, non-flat sinusoid single lap joints had about 51% higher load bearing compared to the conventional flat single lap joints.

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