Experimental Research on Fatigue Behavior of Adhesively Bonded Steel Single-Lap Joints

2012 ◽  
Author(s):  
Xiaoli Jiang ◽  
Miroslaw (Mirek) Lech Kaminski
Keyword(s):  
Adhesive Bonding ◽  
Fatigue Behavior ◽  
Fatigue Loading ◽  
Lap Joints ◽  
Loading Frequency ◽  
Adhesively Bonded ◽  
Marine Structures ◽  
Promising Alternative ◽  
Shipbuilding Industry ◽  
Adhesive Bonds

The introduction of aluminum, Fiber-Reinforced Plastics (FRP), and other new materials to the shipbuilding industry has meant that joining materials with adhesive bonds has become a promising alternative to welding. However, unlike the aerospace and automotive industries, the application of adhesive bonds in ship structures remains sporadic because of limited practical knowledge, relatively high amplitude cyclic loads, and a severely corrosive marine environment. In order to investigate the potential of adhesive bonding for marine structures, representative structural details have been selected and tested. The present paper discusses the results of a series of fatigue tests on steel single-lap adhesively bonded joints, including the effects of loading frequency, stress level, and random fatigue loading. These results will be used to construct a guide for the design of adhesive bonding in marine structures.

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.

Normalized strength reserve principle for variable amplitude fatigue life prediction of adhesively bonded aluminium joints/Normalisiertes Festigkeitsreserve-Prinzip für die Vorhersage der Lebensdauer von geklebten Aluminiumverbindungen bei variablen Lastamplituden

Bauingenieur ◽  
2019 ◽  
Vol 94 (05) ◽  
pp. 184-192
Author(s):  
Nenad Stojkovic ◽  
Radomir Folic
Keyword(s):  
Fatigue Life ◽  
Adhesive Bonding ◽  
Fatigue Loading ◽  
Good Alternative ◽  
Lap Joints ◽  
Engineering Industry ◽  
Adhesively Bonded ◽  
Variable Amplitude ◽  
Strength Reserve ◽  
Variable Amplitude Fatigue

Abstract Over the last several decades, adhesive bonding has been validated as a good alternative to traditional joining methods in metallic construction. On the other hand, the main factor that limits the wider use of structural adhesives in civil engineering industry is scepticism about their long-term performance, especially when subjected to variable amplitude fatigue loading. Most of the research on predicting the fatigue life of adhesive joints subjected to this type of loading dealt with composite adherends. In this paper, straightforward method for prediction of strength degradation and fatigue failure under random spectrum loading is presented and validated for the case of adhesively bonded single lap joints made of aluminium adherends. It is based on the normalized strength reserve principle, proposed by the same authors in their previous research. The normalized strength reserve model is expanded to the case of variable amplitude fatigue, incorporating the cycle mix parameter in order to account for load interaction effects. Very good agreement was obtained between the fatigue life predictions of the presented method and experimental results from the literature.

Fatigue behavior of adhesively bonded glass fiber reinforced plastic composites with different overlap lengths

2015 ◽  
Vol 229 (7) ◽  
pp. 1292-1299
Author(s):  
E Kara ◽  
A Kurşun ◽  
MR Haboğlu ◽  
HM Enginsoy ◽  
H Aykul
Keyword(s):  
Glass Fiber ◽  
Fatigue Behavior ◽  
Laminated Composite ◽  
Element Model ◽  
Treatment Method ◽  
Epoxy Adhesive ◽  
Lap Joints ◽  
Adhesively Bonded ◽  
Glass Fiber Reinforced Plastic ◽  
Glass Fiber Reinforced

The joining techniques of lightweight and strong materials in the transport industry (e.g. automotive, aerospace, shipbuilding industries) are very important for the safety of the entire structure. In these industries, when compared with other joining methods, the use of adhesively bonded joints presents unique properties such as greater strength, design flexibility, and reduction in fuel consumption, all thanks to low weight. The aim of this study was the analysis of the tensile fatigue behavior of adhesively bonded glass fiber/epoxy laminated composite single-lap joints with three different specimen types including 30, 40 and 50 mm overlap lengths. In this study, composite adherents were manufactured via vacuum-assisted resin transfer molding and were bonded using Loctite 9461 A&B toughened epoxy adhesive. The effect of a surface treatment method on the bonding strength was considered and it led to an increment of about 40%. A numerical analysis based on a finite element model was performed to predict fatigue life curve, and the predicted results showed good agreement with the experimental investigation.

Challenges in Joining Thermoset Composite Piping

2010 ◽  
Author(s):  
Avinash Parashar ◽  
Pierre Mertiny
Keyword(s):  
Adhesive Bonding ◽  
Lap Joints ◽  
Fiber Reinforced Polymers ◽  
Potential Candidate ◽  
Loading Conditions ◽  
Adhesively Bonded ◽  
Technical Literature ◽  
Filament Wound ◽  
Piping Systems ◽  
Mechanical Properties And Corrosion

The aim of this paper is to examine solutions and challenges related to joining thermoset composite piping. Fiber reinforced polymers (FRP) have been used in piping systems for more than 40 years. Higher specific mechanical properties and corrosion resistance of FRP make them a potential candidate for replacing metallic piping structures. Despite the advantages associated with FRP, their application is still limited due to, in part, unsatisfactory methods for joining composite subcomponents and inadequate knowledge of failure mechanism under different loading conditions. Adhesively bonded joints are attractive for many applications since they offer integrated sealing, minimal part count and do not require pipe extremities with complex geometries such as threads or bell and spigot configurations. So far, the majority of work reported in the technical literature on adhesively bonded pipe joints is concerned with lap joints employing wrapping techniques to produce overlap sleeve connections. More recently, a joining technique was proposed that replaces the wrapping technique with filament-wound overlap sleeve couplers that are adhesively bonded to the pipe extremities. In the present article, various joining techniques for FRP piping through adhesive bonding are discussed, and damage mechanisms under different loading conditions are examined.

Integrity monitoring of adhesively bonded joints via an electromechanical impedance-based approach

2017 ◽  
Vol 17 (5) ◽  
pp. 1031-1045 ◽  
Author(s):  
Yitao Zhuang ◽  
Fotis Kopsaftopoulos ◽  
Roberto Dugnani ◽  
Fu-Kuo Chang
Keyword(s):  
Fatigue Loading ◽  
Mechanical Tests ◽  
Lap Joints ◽  
Piezoelectric Sensors ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Monitoring Method ◽  
Integrity Monitoring ◽  
Adhesively Bonded Joints ◽  
Electromechanical Impedance

Monitoring the bondline integrity of adhesively bonded joints is one of the most critical concerns in the design of aircraft structures to date. Due to the lack of confidence on the integrity of the bondline both during fabrication and service, the industry standards and regulations require assembling the primary airframe structure using the inefficient “black-aluminum” approach, that is, drill holes and use fasteners. Furthermore, state-of-the-art non-destructive evaluation and structural health monitoring approaches are not yet able to provide mature solutions on the issue of bondline integrity monitoring. Therefore, the objective of this work is the introduction and feasibility investigation of a novel bondline integrity monitoring method that is based on the use of piezoelectric sensors embedded inside adhesively bonded joints in order to provide an early detection of bondline degradation. The proposed approach incorporates (1) micro-sensors embedded inside the adhesive layer leaving a minimal footprint on the material, (2) numerical and analytical modeling of the electromechanical impedance of the adhesive bondline, and (3) electromechanical impedance–based diagnostic algorithms for monitoring and assessing the bondline integrity. The experimental validation and assessment of the proposed approach is achieved via the design and fabrication of prototype adhesively bonded lap joints with embedded piezoelectric sensors and a series of mechanical tests under various static and dynamic (fatigue) loading conditions. The obtained results demonstrate the potential of the proposed approach in providing increased confidence on the use of adhesively bonded joints for aerospace structures.

Effect of Impact-Fatigue on Damage in Adhesive Joints

2007 ◽  
Vol 347 ◽  
pp. 653-658 ◽  
Author(s):  
Juan Pablo Casas-Rodriguez ◽  
Ian A. Ashcroft ◽  
Vadim V. Silberschmidt
Keyword(s):  
Damage Evolution ◽  
Weight Ratio ◽  
High Strength ◽  
Fatigue Loading ◽  
Lap Joints ◽  
Adhesive Joints ◽  
Bonded Joints ◽  
Impact Fatigue ◽  
Adhesively Bonded ◽  
Low Velocity

In recent decades the use of structural adhesive joints in the aerospace industry has increased considerably thanks to their high strength-to-weight ratio, low stress concentration and capacity to join different adherends. There is increasing interest in damage due to low-velocity impacts produced in adhesively bonded components and structures by vibrating loads. This type of loading is known as impact fatigue. The main aim of this paper is to investigate damage evolution in adhesive joints subjected to impact-fatigue and to compare this with damage evolution in standard fatigue (i.e. non-impacting, constant amplitude, sinusoidal fatigue). In this work, adhesively bonded lap joints were subjected to multiple tensile impacts tensile and it was seen that this type of loading was extremely damaging compared to standard fatigue. A number of methods of studying damage evolution in bonded joints subjected to fatigue and impact fatigue loading have been investigated and various parameters have been used to characterise these processes. Two modifications of the accumulated time-stress model [1-4] are proposed and it is shown that both models provide a suitable characterization of impact-fatigue in bonded joints.

scholarly journals Impact of Selected Structural, Material and Exploitation Factors on Adhesive Joints Strength

2019 ◽  
Vol 252 ◽  
pp. 01006
Author(s):  
Anna Rudawska ◽  
Marek Maziarz ◽  
Izabela Miturska
Keyword(s):  
Structural Material ◽  
Present Article ◽  
Adhesive Bonding ◽  
Lap Joints ◽  
Light Industry ◽  
Substantial Impact ◽  
Adhesive Bonds ◽  
Strength Tests ◽  
Variable Factor ◽  
Adhesive Connections

Adhesive bonding is currently one of the most popular techniques of joining different materials. It is worth noting that this process is more and more often used in several industries: automotive, transport, mechanical engineering, medicine, electronics, light industry, as well as many others. The present article is aimed at determining an impact of selected structural, material and exploitation factors on adhesive bonds' strength. Strength tests were carried out on adhesive connections of pine wood. An exploitation factor under analysis was resistance to different temperature values - both positive and negative. Six different variants of a bonds' seasoning temperature value were used. Another variable factor was a structure of bonds, i.e. adhesive butt joints and adhesive half lap joints. Also, two types of adhesives were used: one of them was dedicated to wooden elements bonding, whereas the second one was a two-component adhesive composition based on epoxide resin. Strength tests described in the present article showed substantial impact of selected structural, material and exploitation factors on the adhesive bonds' strength.

A Probabilistic Strength Prediction Method for Adhesively Bonded Joints Composed of Wooden Adherends

2009 ◽  
Vol 417-418 ◽  
pp. 533-536 ◽  
Author(s):  
Simon Hehl ◽  
Till Vallée ◽  
Thomas Tannert ◽  
Yu Bai
Keyword(s):  
Adhesive Bonding ◽  
Load Transfer ◽  
Probabilistic Method ◽  
Prediction Method ◽  
Complex Stress ◽  
Lap Joints ◽  
Strength Prediction ◽  
Material Strength ◽  
Adhesively Bonded ◽  
Statistical Variation

Joining timber structural elements using mechanical fasteners goes against the anisotropic and fibrous nature of the material. Adhesive bonding is by far better adapted, since it permits a smoother load transfer. However, the strength prediction of adhesively bonded wooden joints is difficult brittle nature of the adherends, the complex stress distribution as well as the uncertainties regarding the associated material resistance. As a contribution to help close this research gap, the authors have carried out experimental and analytical investigations on adhesively bonded double lap joints composed of timber. This paper describes the experimental and numerical results and suggests a probabilistic method for the strength prediction of joints composed of brittle adherends and adhesives. The method considers the scale sensitivity of material strength modelled using a Weibull statistical function, and considers both the statistical variation and the size effect in the strength of the material. The probabilistic method presents a mechanical explanation for the increased resistance of local zones subjected to high strain or stress peaks.

scholarly journals Experimental and Numerical Failure Analysis of Adhesive Composite Joints

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Farhad Asgari Mehrabadi
Keyword(s):  
Adhesive Bonding ◽  
Strain Energy Release ◽  
Lap Joints ◽  
Mode I ◽  
Pure Mode ◽  
Bonded Joints ◽  
Lap Joint ◽  
Stress Concentrations ◽  
Adhesively Bonded ◽  
Mode I Loading

In the first section of this work, a suitable data reduction scheme is developed to measure the adhesive joints strain energy release rate under pure mode-I loading, and in the second section, three types of adhesive hybrid lap-joints, that is, Aluminum-GFRP (Glass Fiber Reinforced Plastic), GFRP-GFRP, and Steel-GFRP were employed in the determination of adhesive hybrid joints strengths and failures that occur at these assemblies under tension loading. To achieve the aims, Double Cantilever Beam (DCB) was used to evaluate the fracture state under the mode-I loading (opening mode) and also hybrid lap-joint was employed to investigate the failure load and strength of bonded joints. The finite-element study was carried out to understand the stress intensity factors in DCB test to account fracture toughness using J-integral method as a useful tool for predicting crack failures. In the case of hybrid lap-joint tests, a numerical modeling was also performed to determine the adhesive stress distribution and stress concentrations in the side of lap-joint. Results are discussed in terms of their relationship with adhesively bonded joints and thus can be used to develop appropriate approaches aimed at using adhesive bonding and extending the lives of adhesively bonded repairs for aerospace structures.

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