Loading Behavior Investigation of Composite Single Lap Adhesive Joints

2013 ◽  
Vol 387 ◽  
pp. 202-207
Author(s):  
Hai Xiao Hu ◽  
Yun Dong Ji ◽  
Ai Qing Ni ◽  
Ji Hui Wang
Keyword(s):  
Shear Stress ◽  
Adhesive Bonding ◽  
Nonlinear Behavior ◽  
Adhesive Bond ◽  
Adhesive Joints ◽  
Surface Strain ◽  
Strain Gages ◽  
Composite Joint ◽  
Fbg Sensors ◽  
Peel Stress

Adhesive bonding as a promising join technique for composites is not widely used for the absence of absolutely understanding of loading behavior. In this paper both electric-strain gages and FBG sensors were employed to get the internal and surface strain of adhesive joint. In the experiment, nonlinear behavior is observed. Then the test data were compared with FEM results. It is showed that they meet each other well, FEM could get the stress distribution in adhesive bond composite joint, and both biggest peel stress and shear stress are appear at the end of adhesive.

NON-DESTRUCTIVE EVALUATION OF MECHANICAL DAMAGE OF ADHESIVES USING MAGNETO-ELECTRIC NANOPARTICLES

2021 ◽  
Author(s):  
GONZALO SEISDEDOS ◽  
BRIAN HERNANDEZ ◽  
JULIETTE DUBON ◽  
MARIANA ONTIVEROS ◽  
BENJAMIN BOESL ◽  
...  
Keyword(s):  
Adhesive Joint ◽  
Adhesive Bonding ◽  
Mechanical Damage ◽  
Adhesive Bond ◽  
Tensile Tests ◽  
Adhesive Joints ◽  
Adhesive Bonds ◽  
Magnetic Signatures ◽  
Looper System ◽  
Lock In

Adhesive bonding has been shown to successfully address some of the main problems with traditional fasteners, such as the reduction of the overall weight and a more uniformly distributed stress state. However, due to the unpredictability of failure of adhesive bonds, their use is not widely accepted in the aerospace industry. Unlike traditional fastening methods, it is difficult to inspect the health of an adhesive joint once it has been cured. For adhesive bonding to be widely accepted and implemented, there must be a better understanding of the fracture mechanism of the adhesive joints, as well as a way to monitor the health of the bonds nondestructively. Therefore, in-field structural health monitoring is an important tool to ensure optimal condition of the bond is present during its lifetime. This project focuses on the advancement of a non-invasive field instrument for evaluation of the health of the adhesive joints. The tool developed is based on a B-H looper system where coils are arranged into a noise-cancellation configuration to measure the magnetic susceptibility of the samples with a lock-in amplifier. The B-H looper system can evaluate the state of damage in an adhesive bond by detecting changes in surface charge density at the molecular level of an epoxy-based adhesive doped with magneto-electric nanoparticles (MENs). Epoxy-based adhesive samples were doped with MENs and then scanned using the B-H looper system. To evaluate the health of the adhesive joint, microindentation and tensile tests were performed on MENs-doped adhesive samples to understand the relationship between mechanical damage and magnetic signal. Correlations between magnetic signatures and mechanical damage were minimally observed, thus future studies will focus on refining the procedure and damaging methodology.

Adhesive bond strength of end grain joints in softwood with varying density

Holzforschung ◽  
2008 ◽  
Vol 62 (2) ◽  
pp. 237-242 ◽  
Author(s):  
Jürgen Follrich ◽  
Alfred Teischinger ◽  
Wolfgang Gindl ◽  
Ulrich Müller
Keyword(s):  
Bond Strength ◽  
Compression Wood ◽  
Adhesive Bonding ◽  
Adhesive Bond ◽  
Adhesive Joints ◽  
Mechanical Interlocking ◽  
Cross Sectional ◽  
Wall Area ◽  
Spruce Wood ◽  
Adhesive Bond Strength

Abstract Norway spruce wood specimens covering a wide density range, including density samples between 300 kg m-3 (low density wood) and 750 kg m-3 (high-density compression wood), were joined at end grain surfaces and tested in tension perpendicular to the bonded surface to estimate the effect of mechanical interlocking on the adhesive bond strength. It was hypothesised that the higher the density of the specimens the lower will be the mechanical interlocking of the adhesive joints due to a reduced penetration of the adhesive into the cell cavities. An increase of tensile strength was observed with increasing density. These results demonstrate that in the specific case investigated here the cross-sectional cell wall area available for adhesive bonding, which correlates with density, is probably more important than mechanical interlocking.

Effect of Parameters on Strength of Composites Single-Lap Adhesive Joints

2012 ◽  
Vol 490-495 ◽  
pp. 2250-2253
Author(s):  
Yin Huan Yang
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Numerical Study ◽  
Maximum Shear Stress ◽  
Adhesive Layer ◽  
Adhesive Joints ◽  
Element Analysis ◽  
Adhesive Thickness ◽  
The Times ◽  
Peel Stress

Based on popular and maturate application of the finite element analysis method, a numerical study is presented for effect of parameters, that are composed of lap length, adhesive thickness and ply styles of adherend, on maximum peel/shear stress of T700/EXOPY composite single-lap adhesive joints in this paper. Finite element simulations are carried out to analyze the peel/shear stress fields along the interfaces between the adhesive and the adherends. The simulation results show that the joint maximum peel/shear stress decreases with increasing the lap length, and peel stress of the joint of adherends of ply style [0/90/±45/0]S is much less, and the maximum shear stress in the interfaces between the adhesive layer and the adherends do not dcreases all the times with increasing the adhesive thickness. Good agreements between the present simulations and the experimental results are found.

Adhesive bond strength between orthodontic resin and acrylic surfaces

2020 ◽  
pp. 1-5
Author(s):  
Evelyn Guadalupe Torres-Capetillo ◽  
Guadalupe Rosalía Capetillo-Hernández ◽  
Laura Roesch-Ramos ◽  
Flora Moreno-Marín
Keyword(s):  
Bond Strength ◽  
Adhesive Bonding ◽  
Statistical Processing ◽  
Adhesive Bond ◽  
Diamond Bur ◽  
Fine Diamond ◽  
Adhesive Bond Strength ◽  
Application Protocols ◽  
Made In

The use of orthodontic treatments in patients with temporary prostheses has been increasing, the purpose of this in vitro research is to measure the adhesive bond strength between orthodontic resin and acrylic surfaces by applying different procedures. Objective. To compare the adhesive bonding strength between orthodontic resin and acrylic surfaces under different application protocols. Methodology. Transversal, experimental, prospective study. In vitro with acrylic provisions, was carried out in the laboratory of the Faculty of Dentistry of the Universidad Veracruzana region of Veracruz. In the period of February-June of the year 2019. The sample was conformed by two control groups of specimens and four experimental ones, each group conformed by 20 specimens, in total 120 provisional ones were made in acrylic Nic Tone of quick self-cure. The tests performed by the ULTRATESTER machine were expressed in MPa. Later, the data obtained were processed in Excel tables (version) for statistical processing in SPSS version 24. Contribution. When comparing the pre-cutting protocol of acrylic surfaces with fine diamond bur and the protocol without pre-cutting, no statistically significant differences were found, therefore, this step could be omitted in clinical practice.

Failure Analysis of Laminates Single-Lap Adhesive Joints under Uniaxial Tensile Loading

2012 ◽  
Vol 490-495 ◽  
pp. 2201-2204
Author(s):  
Yin Huan Yang
Keyword(s):  
Shear Stress ◽  
Tensile Loading ◽  
Adhesive Joints ◽  
Experimental Results ◽  
Uniaxial Tensile ◽  
Tension Tests ◽  
Different Types ◽  
Uniaxial Tensile Loading ◽  
Overlap Area ◽  
Main Factor

Tension tests on three different types of T700/EXOPY unidirectional laminates single-lap adhesive joints under uniaxial tensile loading were performed and effect of adherend thickness and spew fillets on strength of single-lap adhesive joints were analyzed in this paper. According to the experimental results, it is found that joint strength was not linear with the adherend thickness and much affected by spew fillets in overlap ends. At the same time, finite element simulations are carried out to analyze the peel/shear stress fields along joint interfaces and the intermediate layer of adhesive. The simulation results show that it is the main factor to leading to joint failure that the maximum peel/shear stress is occurred at overlap area edges and peel/shear stress of joints with spew fillet at the overlap area edges is less than that of joints with no spew fillet. Good agreements between the present simulations and the experimental results are found.

Experimental Investigation of Adhesive Bonding for Post‐installed Rebars into Concrete at High Temperatures

2019 ◽  
Author(s):  
Thanyawat Pothisiri ◽  
Pitcha Jongvivatsakul ◽  
Vanichapoom Nantavong
Keyword(s):  
Experimental Investigation ◽  
High Temperatures ◽  
Mechanical Behaviour ◽  
Epoxy Resins ◽  
Adhesive Bonding ◽  
Elevated Temperatures ◽  
Adhesive Bond ◽  
Steel Rebar ◽  
Pull Out ◽  
Embedment Length

<p>The use of post‐installed rebars into existing reinforced concrete structures bonded with epoxy resins was constantly increasing due to the advantage of equivalent or even higher bearing capacities at service temperature, compared with conventional cast‐in‐place rebars. Previous studies have examined the effects of different parameters on the mechanical properties of bonded post‐installed rebars at normal temperature. These studies showed that, for rebar diameter equal to 10 mm, the load bearing capacity increases linearly with the embedment length up to 75 mm. However, upon exposure to high temperatures, the glass transition of epoxy resins may occur and affect the mechanical behaviour of the adhesive bond. Studying the mechanical behaviour of an adhesive anchor at high temperatures is therefore necessary. An experimental investigation is conducted herein to examine the characteristics of the adhesive bonding stress between steel rebar and concrete interface at elevated temperatures using a series of pull‐out tests with varying rebar diameters and embedment lengths.</p>

Shear Stress Discontinuities in Adhesive Joints

2015 ◽  
Vol 1088 ◽  
pp. 758-762
Author(s):  
Xiao Cong He
Keyword(s):  
Shear Stress ◽  
Stress Concentration ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Adhesive Layer ◽  
Adhesive Joints ◽  
Shear Stress Distribution ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

This paper deals with the stress discontinuities in shear stress distribution of adhesive joints. The three-dimensional finite element analysis (FEA) software was used to model the joints and predict the shear stress distribution along the whole beam. The FEA results indicated that there are stress discontinuities existing in the shear stress distribution within adhesive layer and adherends at the lower interface and the upper interface of the boded section. The numerical values of the shear stress concentration at key locations of the joints and the stress concentration ratio are discussed.

Some Aspects of Nonlinear Behavior in Lubricants Under Extreme Stress

1968 ◽  
Vol 90 (3) ◽  
pp. 549-552
Author(s):  
F. W. Smith
Keyword(s):  
Shear Stress ◽  
Nonlinear Behavior ◽  
High Shear ◽  
High Shear Stress ◽  
Arrhenius Activation Energy ◽  
Flow Process ◽  
Molecular Fluids ◽  
Extreme Stress ◽  
General Basis ◽  
The Continuum

A general basis for discussing nonlinearity in the flow of molecular fluids consists in applying the continuum mechanics of Coleman and Noll to a flow process governed by an Arrhenius activation energy equation. The theory predicts the familiar exponential increase of viscosity with pressure and a decrease in viscosity with high shear stress, and also predicts the existence of “normal stresses” under high shear stress. Schematic calculations are presented for the behavior of a lubricant under extreme stress.

scholarly journals Iosipescu Shear Test of Composite Joint Specimens in Tensile Loading

1995 ◽  
Vol 4 (4) ◽  
pp. 096369359500400 ◽  
Author(s):  
Jang-Kyo Kim ◽  
Joo Hyuk Park
Keyword(s):  
Shear Stress ◽  
Stress Field ◽  
Composite Laminates ◽  
Shear Test ◽  
Pure Shear ◽  
Maximum Shear Stress ◽  
Tensile Loading ◽  
Composite Joint ◽  
Loading Method ◽  
Iosipescu Shear Test

The stress field arising in tensile loading of the Iosipescu shear test is analyzed by means of finite element method. In a parametric study on a composite laminates-adhesive joint, the tensile loading method is shown more effective in creating a pure shear stress field with negligible normal stresses in the notched area than the conventional compressive loading method, although the maximum shear stress is marginally higher for the former method than the latter.

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