scholarly journals Tensile-Shear Fatigue Behavior of Aluminum and Magnesium Lap-Joints obtained by Ultrasonic Welding and Adhesive Bonding

2011 ◽  
Vol 10 ◽  
pp. 3561-3566 ◽  
Author(s):  
Michele Carboni ◽  
Fabrizio Moroni
Author(s):  
Xiaoli Jiang ◽  
Miroslaw (Mirek) Lech Kaminski

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.


Holzforschung ◽  
2020 ◽  
Vol 74 (9) ◽  
pp. 865-880 ◽  
Author(s):  
Gaspard Clerc ◽  
Thomas Lüthi ◽  
Peter Niemz ◽  
Jan Willem G. Van de Kuilen

AbstractIt is generally assumed that the properties of wood against fatigue are good, but little is known about the properties of adhesively bonded wood, which represents today most of the wood-based products. Lap-shear samples glued with three common wood adhesives [two ductile one-component polyurethane (1C-PUR) systems and one brittle phenol resorcinol formaldehyde (PRF) adhesive] were tested under cyclical loads at three different climates [20°C, 35% − 50% − 85% relative humidity (RH)]. For the analysis of data, an empirical model based on reaction kinetics was developed. In addition, a probabilistic model was used to estimate the endurance limit and the expected run-out lifetime. Both models were combined to accurately model fatigue at high and low relative stress intensity. It was shown that ductile 1C-PUR adhesives perform better than the brittle adhesive system under dry climates (35%–50% RH). However, for higher RH, the brittle PRF adhesive showed better performance, most probably due to a better wood-adhesive adhesion in wet climate. An average endurance limit for tensile shear stresses between 20% and 48% of the mean tensile shear strength (TSS) was estimated for the tested adhesives. It was shown that the model parameters could be linked to fundamental physical constants through the reaction kinetics approach; however, further research is needed to correlate these parameters to specimen-specific quantities.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1008
Author(s):  
Francesco Musiari ◽  
Fabrizio Moroni

The low quality of adhesion performance on polymeric surfaces has forced the development of specific pretreatments able to toughen the interface between substrate and adhesive. Among these methods, atmospheric pressure plasma treatment (APPT) appears particularly suitable for its environmental compatibility and its effectiveness in altering the chemical state of the surface. In this work, an experimental study on adhesively bonded joints realized using polyamide as substrates and polyurethane as the structural adhesive was carried out with the intent to characterize their fatigue behavior, which represents a key issue of such joints during their working life. The single lap joint (SLJ) geometry was chosen and several surface pretreatments were compared with each other: degreasing, abrasion (alone and followed by APPT) and finally APPT. The results show that the abrasion combined with APPT presents the most promising behavior, which appears consistent with the higher percentage of life spent for crack propagation found by means of DIC on this class of joints with respect to the others. APPT alone confers a good fatigue resistance with respect to the simple abrasion, especially at a low number of cycles to failure.


Author(s):  
E Kara ◽  
A Kurşun ◽  
MR Haboğlu ◽  
HM Enginsoy ◽  
H Aykul

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.


Holzforschung ◽  
2010 ◽  
Vol 64 (3) ◽  
Author(s):  
Frank Stöckel ◽  
Johannes Konnerth ◽  
Wolfgang Kantner ◽  
Johann Moser ◽  
Wolfgang Gindl

Abstract The tensile shear strength of veneer lap joints was characterised. The joints were produced with an Automated Bonding Evaluation System (ABES) using urea-formaldehyde (UF) as well as melamine-urea-formaldehyde (MUF) adhesive formulated for particleboard production. At a fixed heating temperature of 110°C, a systematic increase in bond strength was observed for both adhesives with increasing cure time. The absolute bond strength was significantly higher for MUF compared to UF. Nanoindentation experiments with the same specimens used for ABES revealed a very hard, stiff and brittle character of the UF resin, whereas the MUF proved significantly less hard and stiff, and less brit-tle. Wood cell walls in contact with adhesive, i.e., where adhesive penetration into the cell wall was assumed, showed significantly altered mechanical properties. Such cell walls were harder, stiffer and more brittle than unaffected reference cell walls. These effects were slightly more pronounced for UF than for MUF. Comparing UF and MUF, the micro-mechanical properties of cured adhesive and interphase cell walls confirm earlier observations that tougher adhesives can lead to higher macroscopic bond strength. In strong contrast to that, no obvious correlation was found between micromechanical properties and the strong cure time dependence of macroscopic bond strength.


2021 ◽  
Vol 145 ◽  
pp. 106090
Author(s):  
Hao Dinh Duong ◽  
Masakazu Okazaki ◽  
Tra Hung Tran

Author(s):  
Avinash Parashar ◽  
Pierre Mertiny

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.


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