Analysis and Characterization of Adhesively Bonded Mg-Steel Lap Joints

2004 ◽  
Author(s):  
Niat M. Rahman ◽  
Ahsan Mian ◽  
Golam M. Newaz
Keyword(s):  
Stress Distribution ◽  
Failure Modes ◽  
Lap Joints ◽  
Computational Method ◽  
Substrate Thickness ◽  
Cohesive Failure ◽  
Adhesively Bonded ◽  
Lap Shear ◽  
Out Of Plane

Dissimilar material joints are of significant interest in automotive applications. An investigation was carried out to determine the peculiarities of an adhesively bonded Mg-steel system for lap shear configuration. Both experimental approach and computational method (FEA) were utilized to evaluate and analyze the Mg-steel bond. The adhesive used was Betamate 1480 — an epoxy based adhesive. The tests were done according to ASTM D 1002-99 method using MTS machine at room temperature. For computational analysis, finite element modeling techniques using ABAQUS processor was utilized. Failure modes were studied for different systems. Results were compared with Mg-Mg and steel-steel systems. It is observed that Mg-Mg balanced system (system with equal adherend or substrate thickness) failed either at interface (adhesive failure) or at substrate and system is flexible with lower failure load. While steel- -steel balanced system failed only at substrate and system is rigid with higher load and lower displacement. Mg-steel system provides flexibility in between them and only adherend failure (either out of plane Magnesium failure or steel-betamate in plane substrate failure) observed. Cohesive failure was not observed in any of the systems. For Mg-Mg, the shear stress distribution in the adhesive is poor (stress distribution is steeper) while for steel-betamate-steel it is much better. The FEA models were compared and rationale was forwarded to assess the failure modes observed in each case.

Effect of aluminium substrate thickness on the lap-shear strength of adhesively bonded and hybrid riveted-bonded joints

2020 ◽  
pp. 095440892091343
Author(s):  
VC Beber ◽  
N Wolter ◽  
B Schneider ◽  
K Koschek
Keyword(s):  
Shear Strength ◽  
Failure Process ◽  
Lap Joints ◽  
Substrate Thickness ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Lap Shear Strength ◽  
Lap Shear ◽  
Definition Of ◽  
Structural Adhesive

For lightweight materials, e.g. aluminium, the definition of proper joining technology relies on material properties, as well as design and manufacturing aspects. Substrate thickness is especially relevant due to its impact on the weight of components. The present work compares the performance of adhesively bonded (AJ) to hybrid riveted-bonded joints (HJ) using aluminium substrates. To assess the lightweight potential of these joining methods, the effect of substrate thickness (2 and 3 mm) on the lap-shear strength (LSS) of single lap joints is investigated. An epoxy-based structural adhesive is employed for bonding, whilst HJs are produced by lockbolt rivet insertion into fully cured adhesive joints. The stiffness of joints increased with an increase of substrate thickness. HJs presented two-staged failure process with an increase in energy absorption and displacement at break. For HJs, the substrate thickness changed the failure mechanism of rivets: with thicker substrates failure occurred due to shear, whereas in thinner substrates due to rivet pulling-through. The LSS of 2 mm and 3 mm-thick AJs is similar. With 2 mm-thick substrates, the LSS of HJs was lower than AJs. In contrast, the highest LSS is obtained by the 3 mm-thick HJs. The highest lightweight potential, i.e. LSS divided by weight, is achieved by the 2 mm-thick AJs, followed by the 3 mm-thick HJs with a loss of ca. 10% of specific LSS.

BOND STRENGTH DEGRADATION OF ADHESIVE- BONDED CFRP COMPOSITE LAP JOINTS AFTER LIGHTNING STRIKE

2021 ◽  
Author(s):  
WENHUA LIN ◽  
YEQING WANG ◽  
SPENCER LAMPKIN ◽  
SRIHARI GANESH PRASAD ◽  
OLESYA ZHUPANSKA ◽  
...  
Keyword(s):  
Bond Strength ◽  
Failure Modes ◽  
Lap Joints ◽  
Adhesive Joints ◽  
Current Work ◽  
Lightning Strike ◽  
Adhesively Bonded ◽  
Shear Tests ◽  
Lap Shear ◽  
Lightning Current

Adhesive bonding to join fiber reinforced polymer matrix composites holds great promise to replace conventional mechanical attachment techniques for joining composite components. Understanding the behavior of these adhesive joints when subjected to various environmental loads, such as lightning strike, represents an important concern in the safe design of adhesively bonded composite aircraft and spacecraft structures. In the current work, simulated lightning strike tests are performed at four elevated discharge impulse current levels (71.4, 100.2, 141, and 217.8 kA) to evaluate the effects of lightning strike on the mechanical behavior of single lap joints. After documentation of the visually observed lightning strike induced damage, single lap shear tests are conducted to determine the residual bond strength. Post-test visual observation and cross-sectional microscopy are conducted to document the failure modes of the adhesive region. Although the current work was performed on a limited number of specimens, it identified important trends and directions for future more comprehensive studies on lightning strike effects in adhesively bonded composites. It is found that the lightning strike induced damage (extent of the surface vaporization area and the delamination depth) increases as the lightning current increases. The stiffness of the adhesive joints and shear bond strength did not show a clear correlation with the lightning current levels, which could be due to many competing factors, including the temperature rise caused by the lightning strike and the surface conditions of the adherends prior to bonding. The failure modes of the adhesive regions for all specimens demonstrate a mixed mode of adhesive and cohesive failure, which may be due to inconsistent surface characteristics of the adherends before bonding. The energy absorbed during the lap shear tests generally increases as the lightning current increases.

Characterization of Laser Processed Sub-Millimeter Lap Joints Between Copper and Aluminum Under Tensile Load

2010 ◽  
Author(s):  
A. Mian ◽  
M. Hailat ◽  
G. Newaz ◽  
R. Patwa ◽  
H. Herfurth
Keyword(s):  
Stress Distribution ◽  
Tensile Load ◽  
Lap Joints ◽  
Filler Materials ◽  
Element Analysis ◽  
Full Field ◽  
Fea Model ◽  
Lap Shear ◽  
Copper Aluminum

This paper presents the results of laser joined copper-aluminum lap shear samples without filler materials using an IPG 500W SM fiber laser. The length of the processed laser joint was about 20 mm and the width was about 200 μm. Laser-joined samples were tested under tensile loading to determine joint strengths. In addition, finite element analysis (FEA) was conducted to understand the stress distribution within the bond area under such loading. The FEA model provides a full-field stress distribution in and around the joint that cause eventual failure. We are still working on the topic, and more data will be published soon.

Evaluation of Shear Debonding in Double Lap Joints of Sandwich Type

2015 ◽  
Vol 760 ◽  
pp. 293-298
Author(s):  
Dragos Alexandru Apostol ◽  
Dan Mihai Constantinescu ◽  
Marin Sandu ◽  
Adriana Sandu ◽  
Florin Stuparu
Keyword(s):  
Failure Modes ◽  
Experimental Testing ◽  
Pure Shear ◽  
Lap Joints ◽  
Image Correlation ◽  
Adhesively Bonded ◽  
Type Specimens ◽  
Lap Shear ◽  
Sandwich Type ◽  
Shear Type

Experimental and numerical investigations were conducted to characterize the joint strength and failure modes in adhesively bonded double lap shear type specimens. As bonded joints are more efficient when designed for pure shear, the used specimens consisted of double lap joints to be used for moderately thick to thick foam core sandwich components. The foam thickness and overlap length are parameters investigated hereby. For such an experimental testing setup, in which peeling is reduced considerably, we combined finite element (FE) simulations and digital image correlation (DIC) for obtaining a more complete insight on the peeling and shear strain distribution in the foam, at the interface with the adherend and in the whole overlap region.

Analytical stiffness analysis of adhesively bonded single-lap joints subjected to out-of-plane deflection due to tensile loading

2021 ◽  
pp. 1-28
Author(s):  
J. Zimmermann ◽  
T. Schalm ◽  
M. Z. Sadeghi ◽  
A. Gabener ◽  
K.-U. Schröder
Keyword(s):  
Tensile Loading ◽  
Lap Joints ◽  
Adhesively Bonded ◽  
Stiffness Analysis ◽  
Single Lap Joints ◽  
Out Of Plane

Directly bonded single lap joints of SiCp/AA2124 composite with glass fiber-reinforced polypropylene: Hole drilling effects on lap shear strength and out-of-plane impact response

2021 ◽  
pp. 002199832110316
Author(s):  
Nahit Öztoprak
Keyword(s):  
Glass Fiber ◽  
Matrix Composite ◽  
Lap Joints ◽  
Hole Drilling ◽  
Fiber Reinforced ◽  
Single Lap Joints ◽  
Lap Shear ◽  
Glass Fiber Reinforced ◽  
Out Of Plane ◽  
The Impact

Joining dissimilar materials to achieve lightweight design and energy efficiency has been increasingly popular. A joint formed by components of particle-reinforced metal and polymer matrix composite combines the merits of both materials. This paper is mainly focused on the research of the tensile lap shear and impact behavior of the dissimilar single-lap joints (SLJs) between SiCp/AA2124 composite and glass fiber-reinforced polypropylene (PP). The effects of out-of-plane loading applied from different surfaces of SLJs on impact responses are evaluated. Hot pressing technique is introduced to manufacture metal/polymer assembly without using any adhesive. The hole drilling effect is investigated with the idea that it may provide weight reduction and also increase the strength of the dissimilar SLJs. The results indicate that the dissimilar SLJs show more Charpy impact strength when the impact is performed on the metal-matrix composite (MMC). Mechanical properties of SLJs are adversely affected by a drilled hole in the MMC adherend.

Experimental Assessment of the Dynamic Behavior of Polyolefin Thermoplastic Hot Melt Adhesive

2018 ◽  
Author(s):  
Raffaele Ciardiello ◽  
Andrea Tridello ◽  
Luca Goglio ◽  
Giovanni Belingardi
Keyword(s):  
Failure Modes ◽  
Industrial Applications ◽  
Lap Joints ◽  
Adhesive Joints ◽  
Dynamic Tests ◽  
Cohesive Failure ◽  
Static Tests ◽  
Piping Systems ◽  
The Many ◽  
Hot Melt

In the last decades, the use of adhesives has rapidly increased in many industrial fields. Adhesive joints are often preferred to traditional fasteners due to the many advantages that they offer. For instance, adhesive joints show a better stress distribution compared to the traditional fasteners and high mechanical properties under different loading conditions. Furthermore, they are usually preferred for joining components made of different materials. A wide variety of adhesives is currently available: thermoset adhesives are generally employed for structural joints but recently there has been a significant increment in the use of thermoplastic adhesives, in particular of the hot-melt adhesives (HMAs). HMAs permit to bond a large number of materials, including metal and plastics (e.g., polypropylene, PP), which can be hardly bonded with traditional adhesives. Furthermore, HMAs are characterized by a short open time and, therefore, permit for a quick and easy assembly process since they can be easily spread on the adherend surfaces by means of a hot-melt gun and they offer the opportunity of an ease disassembling process for repair and recycle. For all these reasons, HMAs are employed in many industrial applications and are currently used also for bonding polypropylene and polyolefin piping systems. In the present paper, the dynamic response of single lap joints (SLJ) obtained by bonding together with a polyolefin HMA two polypropylene substrates was experimentally assessed. Quasi-static tests and dynamic tests were carried out to investigate the strain rate effect: dynamic tests were carried out with a modified instrumented impact pendulum. Relevant changes in the joint performance have been put in evidence. Failure modes were finally analysed and compared. A change in the failure mode is experimentally found: in quasi-static tests SLJ failed due to a cohesive failure of the adhesive, whereas in dynamic tests the SLJ failed due to an interfacial failure, with a low energy absorption.

Adhesively bonded lap joints from pultruded GFRP profiles. Part I: stress–strain analysis and failure modes

2005 ◽  
Vol 36 (4) ◽  
pp. 331-340 ◽  
Author(s):  
Thomas Keller ◽  
Till Vallée
Keyword(s):  
Failure Modes ◽  
Strain Analysis ◽  
Lap Joints ◽  
Adhesively Bonded ◽  
Stress Strain

Predicting static strength in adhesively bonded single lap joints using a critical distance based method: Substrate thickness and overlap length effects

2016 ◽  
Vol 231 (1-2) ◽  
pp. 237-246 ◽  
Author(s):  
H Khoramishad ◽  
A Akhavan-Safar ◽  
MR Ayatollahi ◽  
LFM da Silva
Keyword(s):  
Longitudinal Strain ◽  
Critical Value ◽  
Critical Distance ◽  
Static Strength ◽  
Lap Joints ◽  
Substrate Thickness ◽  
Adhesively Bonded ◽  
Single Lap Joints ◽  
Failure Loads ◽  
Two Parameters

A critical distance based method was proposed for predicting the strength of adhesive single lap joints. Using this method, the failure of SLJs was predicted when the longitudinal strain along the adhesive mid-plane reached a critical value at a specific critical distance. The two parameters of the method including the critical longitudinal strain and the critical distance can be determined using experimental results. Several single lap joints with different overlap lengths and substrate thicknesses were manufactured and tested under quasi-static loading. It was found that the critical distance was independent of the overlap length and the substrate thickness while the critical longitudinal strain was found to be dependent on the substrate thickness. However, the effect of substrate thickness on the critical longitudinal strain decreased by increasing the substrate thickness. The correlation between the experimental and predicted failure loads was found to be very well.

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