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.

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°).

Hybrid Adhesive Bonded and Riveted Joints – Influence of Rivet Geometrical Layout on Strength of Joints / Połączenia Hybrydowe Klejowo-Nitowe - Wpływ Geometrii Rozmieszczenia Nitów Na Wytrzymałość Połączeń

2012 ◽  
Vol 57 (4) ◽  
pp. 1127-1135 ◽  
Author(s):  
T. Sadowski ◽  
E. Zarzeka-Raczkowska
Keyword(s):  
Experimental Research ◽  
Lap Joints ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Stress Concentrations ◽  
Hybrid Joint ◽  
Riveted Joints ◽  
Hybrid Joints ◽  
Deformation Processes

The hybrid adhesive bonded and riveted joints have wider and wider application in different branches of engineering: aerospace, mechanical, civil etc. The hybrid joints’ strength is 1.5 to 3 times higher than only adhesive bonded joints’ strength. The hybrid joints characterize higher reliability during long-term working. In this article we present the influence of rivets’ lay-out geometry on the hybrid adhesive bonded/riveted joints response to mechanical loading. Experimental research was carried using 3-D digital image correlation system ARAMIS. This system enables monitoring of the deformation processes of the hybrid joint specimen up to failure. We analysed the state of deformation of the adhesive bonded double-lap joints reinforced by different numbers of rivets. The hybrid joint specimens were subjected to the uniaxial tensile test. Moreover, the influence of geometry of individual number of rivets’ layout (rivets arranged in one or more rows) for hybrid joint strength was studied. Experimental research was completed and supported by the computer simulations of the whole deformation processes of metal layers (aluminum), adhesive layers and rivets. Numerical simulations were conducted with the ABAQUS programme. The analysis of stress concentrations in different parts of the hybrid joint and their behaviour up to failure were investigated. Finally, the analysis and the comparison of the obtained results confirmed the influence of rivets’ lay-out geometry not only on rivets joints but also on the hybrid adhesive bonded/riveted joints.

scholarly journals Dynamic Characterization of Single Lap Joints in Composite Laminate over Experimental and Computational Approach

2018 ◽  
Vol 7 (3.12) ◽  
pp. 1062
Author(s):  
J V.Muruga Lal Jeyan ◽  
Akhila Rupesh ◽  
Jency Lal ◽  
. .
Keyword(s):  
Mechanical Characterization ◽  
Lap Joints ◽  
Computational Approach ◽  
Lap Joint ◽  
Dynamic Characterization ◽  
Single Lap Joints ◽  
Load Transmission ◽  
Single Lap Joint ◽  
Hybrid Joints

The purpose of the project investigates the mechanical characterization of single lap joints namely bonded, riveted & hybrid joints an experimentally and numerically. One of the primary entanglements in the investigation of the mechanics of the composite material is the multiphase disappointment conduct. In the meantime, it is hard to describe all the disappointment modes from a solitary situated example. The outcome of the present venture uncovers the way that the mechanical attributes of the half breed single lap joint is enhanced when contrasted and the qualities of adhesively fortified single lap joints in composite cover. The structure comprises of a get together of sub-structures appropriately masterminded and associated with frame a heap transmission way. Such load transmission way is accomplished utilizing joints. Joints constitute the weakest zones in the structure. Along these lines, to use the maximum capacity of composite materials, the quality and stress conveyance in the joints must be seen so reasonable arrangement can be decided for different applications, for example, aviation, car and marine enterprises.  

scholarly journals Ability of Constitutive Models to Characterize the Temperature Dependence of Rubber Hyperelasticity and to Predict the Stress-Strain Behavior of Filled Rubber under Different Defor Mation States

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 369
Author(s):  
Xintao Fu ◽  
Zepeng Wang ◽  
Lianxiang Ma
Keyword(s):  
Experimental Data ◽  
Temperature Dependence ◽  
Mechanical Response ◽  
Constitutive Models ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Chain Model ◽  
Stress Strain ◽  
Filled Rubber ◽  
Yeoh Model

In this paper, some representative hyperelastic constitutive models of rubber materials were reviewed from the perspectives of molecular chain network statistical mechanics and continuum mechanics. Based on the advantages of existing models, an improved constitutive model was developed, and the stress–strain relationship was derived. Uniaxial tensile tests were performed on two types of filled tire compounds at different temperatures. The physical phenomena related to rubber deformation were analyzed, and the temperature dependence of the mechanical behavior of filled rubber in a larger deformation range (150% strain) was revealed from multiple angles. Based on the experimental data, the ability of several models to describe the stress–strain mechanical response of carbon black filled compound was studied, and the application limitations of some constitutive models were revealed. Combined with the experimental data, the ability of Yeoh model, Ogden model (n = 3), and improved eight-chain model to characterize the temperature dependence was studied, and the laws of temperature dependence of their parameters were revealed. By fitting the uniaxial tensile test data and comparing it with the Yeoh model, the improved eight-chain model was proved to have a better ability to predict the hyperelastic behavior of rubber materials under different deformation states. Finally, the improved eight-chain model was successfully applied to finite element analysis (FEA) and compared with the experimental data. It was found that the improved eight-chain model can accurately describe the stress–strain characteristics of filled rubber.

Modeling the Thermomechanical Response of Ore Materials During Microwave Processing

1994 ◽  
Vol 347 ◽  
Author(s):  
R. L. Williamson ◽  
J. B. Salsman ◽  
W. K. Tolley
Keyword(s):  
Power Density ◽  
Host Rock ◽  
Mechanical Response ◽  
Numerical Study ◽  
Particle Diameter ◽  
Microwave Energy ◽  
Uniaxial Tensile ◽  
Mineral Particle ◽  
Rock Materials ◽  
Uniaxial Tensile Strength

ABSTRACTA finite element numerical model is used to predict the thermal and mechanical response of mineral-bearing ores irradiated by microwave energy. The model considers a small, spherical, pyrite particle surrounded by a matrix of calcite. Power density data are determined from the dielectric properties of the mineral and host rock materials at typical microwave frequencies and power capabilities. The effects of varying power density and mineral particle diameter are studied. Using power densities within the expected achievable range for pyrite, significant temperature differences are predicted between the mineral particle and host rock. These temperature gradients lead to circumferential tensile stresses in the host rock well in excess of the reported uniaxial tensile strength of common rock materials. It is shown that, for a fixed microwave energy source, both the temperature difference between the mineral and host rock, and the peak tensile stress in the host rock are reduced as the mineral particle size is reduced. Recent experimental efforts to corroborate this numerical study are briefly described.

An Extension of the BWH Instability Criterion: Numerical Study

2015 ◽  
Author(s):  
Martin Storheim ◽  
Hagbart Alsos ◽  
Odd Sture Hopperstad ◽  
Jørgen Amdahl
Keyword(s):  
Numerical Study ◽  
Computational Cost ◽  
Offshore Structures ◽  
Instability Criterion ◽  
Forming Limit ◽  
Uniaxial Tensile ◽  
Stiffened Panel ◽  
Uniaxial Tensile Test ◽  
Large Element ◽  
Good Prediction

The BWH criterion for simulating instability prior to necking in sheet metal has been extended with a post-necking damage model, in which the effect of the local neck inside a large element is accounted for with low mesh dependency. The model is incorporated in the explicit FE code LS-DYNA. The material model can be calibrated from a single uniaxial tensile test, and gives good prediction of rupture for a range of stress triaxialities. This paper investigates the robustness of the criterion through numerical simulations of different experiments, from forming limit tests to large impact experiments on stiffened panel structures. A full-scale collision is simulated with two different mesh-sizes to investigate the robustness of the fracture prediction. The validation cases are simulated with good accuracy considering the coarse meshes involved. Based on the validation, the post-necking extension of the BWH criterion can readily be used for structural design of offshore structures in order to assess the technical safety level of the structure against collisions in all phases of the design process. The method has a good ratio of accuracy vs. computational cost, and is less prone to user-errors as the calibration is simple and the mesh-scaling is automated.

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.

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.

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