Dissertations / Theses: 'Adhesive joints'

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Kon, Haruhiko. "Characterization of adhesively bonded joints using bulk adhesive properties." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-01242009-063346/.

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Su, Ning. "Durability and fatique performance of structural adhesives and adhesive joints." Thesis, University of Dundee, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240601.

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Kawashita, Luiz Fernando. "The peeling of adhesive joints." Thesis, Imperial College London, 2006. http://hdl.handle.net/10044/1/7720.

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Korenberg, Capucine Florence. "The durability of adhesive joints." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272387.

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Hutchinson, Allan Robert. "Durability of structural adhesive joints." Thesis, University of Dundee, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245438.

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Feih, Stefanie. "Design of composite adhesive joints." Thesis, University of Cambridge, 2002. https://www.repository.cam.ac.uk/handle/1810/284008.

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Bland, David Jonathan. "The durability of adhesive joints." Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/5687.

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One of the most important requirements of an adhesive joint is the ability to retain a significant proportion of its load-bearing capability for the long periods under the wide variety of environmental conditions encountered during its service-life. There exists a need to improve the understanding of the mechanics and mechanisms associated with the durability of adhesive joints in hostile environments, such as one of the most potentially damaging and frequently encountered, water, to further their future extensive use in engineering applications. In the present research, four important aspects in relation to the durability of adhesive joints have been investigated. These were: (a) developing sound short-term accelerated test methodologies to assess the durability of adhesive joints; (b) understanding the mechanisms of environmental attack on different types of surface pretreated adhesively bonded aluminium alloy substrates; (c) developing adhesive/primer/pretreatment systems which possess excellent long-term durability; and (d) investigating the potential of environmentally-friendly organosilanes as primers to enhance the intrinsic adhesion of adhesive joints. The results from these studies showed that: (a) constant displacement rate and cyclicfatigue tests provide excellent quantitative durability test methodologies; (b) fracture mechanics and advanced surface analysis of adhesive joints have proven surface pretreatments using phosphoric acid anodising (PAA) are far superior to those employing a grit blasting and degreasing (GBD) pretreatment which can be attributed to the increased surface area and excellent bonding morphology of the anodised oxide surface, allowing deep penetration of the viscous adhesive and impeding water ingress at the adhesive/substrate interface; (c) the durability performance of PAA pretreated adhesive joints employing a primer (PAAP) are superior to those without a primer specifically in water, and acid-based surface pretreatments are significantly advanced compared to simple GBD; and (d) the self assembling long carbon-chain silanes enhance the durability of adhesive joints via the formation of covalent bonds between the adhesive and the activated silane monolayer deposited on the substrate.

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Little, Matthew S. G. "The durability of structural adhesive joints." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417769.

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Sanchez, Francisco Sebastian Rodriguez. "Fracture Behaviour of Automotive Adhesive Joints." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485405.

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Adhesives can enable significant weight reductions in automotive constructions. However, the performance of adhesive joints and the energy absorption of bonded structures needs to be well understood. This thesis describes the perfonnance of a number of automotive adhesive joints using a fracture mechanics approach. The fracture energy, Gc ' was used to characterise the joint perfonnance during different modes of loading at low and high r,ates. A detailed analysis strategy was developed to account for the different types of crack propagatidn observed and the high rate effects encountered. This analysis also included the use of load-independent equations and incorporated the effects of kinetic energy. A high-speed video system was used to study the fracture behaviour and to measure accurately the deformation ofthe joint and the crack growth. During mode I tests the values of Gc decreased as the test rate was increased. The increase in test rate did not induce significant variations in the initiation values of Gc in mode II and mixed-mode VII when load independent methods were used. Delamination of the composite substrates in some tests complicated the interpretation of the results and made some mixed-mode failure criteria difficult to apply. However, an analytical model was introduced to predict the composite delamination observed in the different tests and this showed an excellent agreement with the observed failure paths. The results obtained for mode I demonstrated that neither test velocity nor crack speed was the parameter controlling the toughness. Instead the time parameter rl/2 appeared to describe the variation in G/c more closely. This parameter relates to the adiabatic heating at the crack tip, which causes a material softening. Thermographic measurements were performed to support this proposal. Finally, structural tests on composite crush tubes showed that adhesively bonded structures can indeed be used with confidence in automotive applications.

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Bigwood, David Andrew. "The design of structural adhesive joints." Thesis, University of Surrey, 1990. http://epubs.surrey.ac.uk/770397/.

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This thesis details the work carried out under two research projects at the University of Surrey. The first project titled The Design of Structural Adhesive Joints', was of three years duration from September 1985 to August 1988 and was sponsored by the Science and Engineering Research Council. The second project, sponsored by Ford UK Ltd, and tided 'A General Joint Analysis Facility extended certain aspects of the analysis work initiated In the first period of research. The objective of the work was to address the problem of integrating structural adhesives Into the design process and to provide procedures that would facilitate this integration in a quantitative, rather than the more usual qualitative way. To be effective, such an approach needed to consider not only a means of analyzing a proposed joint but also a way of predicting the actual failure of that joint. An extensive literature survey of analyses available to the design engineer has been completed. The analyses investigated were found to be lacking in several critical respects, and as part of this research, methods of analysis overcoming some of these limitations have been developed. The analyses produced are based on earlier approaches but extended and modified as appropriate. The work on all the analyses produced has been carried out by considering a simple adherend-adhesive sandwich configuration. Five different analyses, considering the sandwich to be modelled with differing degrees of complexity, have been produced. In all of the analyses the adherends are assumed to behave as cylindrically bent plates capable of sustaining both tensile and shear forces and bending moments, with the adhesive transmitting both tensile and/or shear loads. Initially an elastic solution was obtained, adopting a relatively simple approach. This enabled the subsequent enhancement of including non-linear material behaviour to utilize the same governing equations, thus maintaining consistentcy. The General Elastic Analysis (GEA) has been extensively simplified to produce a number of two parameter design formulae suitable for use by an engineer at an early stage in the design process. The two analyses produced by this simplification are called the Simplified Peel Analysis (SPA) and the Simplified Shear Analysis (SSA), so called because they consider the named component of stress in the adhesive layer only. The GEA was then extended to include non-linear material properties in the adhesive layer, and an analysis called the Non-linear Adhesive Analysis (NLAA) was produced. A programme of validation using the NLAA and a non-linear finite element analysis of similar joint configurations was carried out. Additional comparisons with existing analyses have also been undertaken where possible. The NLAA has been shown to produce extremely accurate results for the stresses in the adhesive layer when compared with the component stresses predicted by the finite element method (FEM). The NLAA has been used successfully to determine the spread of yield in a single-lap joint, giving dose agreement with results from analysis using the FEM, but with much reduced computer and operator time. The final stage of the work was concerned with the Inclusion of non-linear adherend material properties, and an analysis called the Full Non-linear Analysis (FNLA) has been produced which Incorporates this refinement to the general model. Again the finite element method has been used to assess the accuracy of this new analysis, and the results from this work are presented here. Derivations of both forms of the elastic analysis and of the non-linear and full non-linear analyses are reported in Chapters 4 and 5 and the software appropriate to each Is described fully. The Initial survey of available literature has shown that there Is considerable lack of knowledge about possible causes of joint failure. Specifically, It Is noted that a criterion by which joint failure can be measured has not been uniquely defined. In an attempt to provide a criterion or criteria to enable the prediction of joint failure a 'Failure Criteria' test and analysis programme has been completed. Joint configurations were manufactured using a range of adhesives with different levels of ductility, and adherends of different stiffnesses. Batches of these test coupons were tested to failure under both predominantly mode I and mode 11ty pes of loading. Both FEM and FNLA analyses of each test configuration have been carried out, and the stress and strain distributions at the levels of failure load were established for each batch and studied to establish any correlation between various proposed failure criteria. Close agreement between certain factors and the equivalent bulk material properties was noted for test batches. The applicability of various failure criteria for both the mode I and mode II test configurations and possible general criteria are discussed. The failure of the mode I test configurations has been shown to be governed by the local level of maximum principal stress at the end of the overlap. The mode II test configurations also show dose agreement in terms of the maximum principal stress, but agreement with bulk data Is poor. Therefore, a further failure criterion is proposed for the mode II joints in terms of the 'global yielding' of the adhesive layer. The bulk property testing of the adherend and adhesive materials to establish their physical properties for use in the finite element analysis of the test programme Is also fully documented.

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Nagda, Vinit Jethalal. "Virtual Material Testing of Adhesive Joints." Thesis, KTH, Hållfasthetslära, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-284467.

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The automotive industry has shown an increasing interest in adhesive bonding for mixed-material joining. Modern design methods are critically dependent on accurate material models and data for numerical methods to enable the simulation of a design prototype early in the design process. This study proposes a numerical modelling approach to simulate the deformation and failure in adhesive joints subjected to different loading states. The model incorporates the smeared crack method that combines plasticity and damage theories. Linear Drucker-Prager plasticity is coupled with damage formulation for stiffness degradation to model both plasticity and softening. The model validation is performed by comparing the model prediction with experimental test results from Double-Cantilever Beam (DCB) and End Notched Flexure (ENF) fracture tests. The tests have been conducted on adhesive joints with three different adhesive thicknesses. A numerical FE analysis of a Mixed-mode Bending (MMB) test was performed to determine the mixed-mode fracture envelope of the adhesive joint. The path independent J-integral method is used to determine the fracture properties (critical strain energy release rate, Gc) for mixed-mode loading of the adhesive joint. The effect of adhesive thickness on the mixed-mode fracture toughness is investigated. This model complements the existing analytical method used at Volvo Cars to evaluate adhesive strength in CAE as it provides better input data to the existing method without the need for extensive testing.
Bilindustrin visar ett ökande intresse för lim i mixmaterial-fogar. Moderna dimensioneringsmetoder är beroende av noggranna materialmodeller och korrekt materialdata för numeriska metoder för att kunna simulera prototyper tidigt i konstruktionsprocessen. Den här studien föreslår en approach med numerisk modellering för att simulera deformation och brott i limfogar som utsätts för olika laster. Modellen använder smeared crack - metoden som kombinerar plasticitet och skadeteori. Linjär Drucker-Prager plasticitet kopplas med skadeformulering för styvhetsdegradering för att modellera både plasticitet och mjuknande. Modellvalidering sker genom att jämföra predikteringen från modellen med experimentella provresultat från Double-Cantilever Beam (DCB) och End Notched Flexure (ENF) hållfasthetsprov. Provresultat för limfogar med tre olika limtjocklekar används. En numerisk FE analys av ett Mix-Mod Böjningsprov (MMB) görs för att bestämma mix-mod brottenveloppen för limfogen. Den vägoberoende J-integral-metoden används för att bestämma brottegenskaper (kritisk töjningsenergifrigörelse-hastighet, Gc) för mix-mod laster på limfogen. Inverkan av limtjockleken på mix-mod brottstyrkan undersöks. Den här modellen kompletterar en existerande analytisk modell som används på Volvo Cars för att utvärdera limhållfastheten med CAE, eftersom den här modellen ger bättre indata till den existerande modellen, utan omfattande provning.

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Yu, Yang. "Investigation of stresses in adhesive joints." Thesis, Loughborough University, 2005. https://dspace.lboro.ac.uk/2134/35071.

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Adhesive joints are widely used as a structural element in automotive and in aerospace applications because of their main advantage of more uniform stress distributions within lap joints relative to conventional bonding for example riveting or bolting. Adhesives can produce a stronger joint and potentially lengthen its service life. However, the stress distribution in the joint is not uniform and stresses are concentrated at the edges of the overlap. This can cause fatigue and reduce the service life of the joint. Therefore, a large number of analytical and numerical studies have been carried out to study this effect. Comparatively speaking, there is lack of experimental data to prove or cast doubt on the theoretical results. One of the main disadvantages of adhesive joints is that they have low durability when exposed to hostile environments. Moisture is the most commonly encountered service environment among various environmental conditions, to be considered a critical factor to affect the service life of adhesive joints. In this thesis, strain gauge, neutron diffraction, and X-ray diffraction methods have been used to directly investigate residual strains and stresses and also strains and stresses under tensile load in the adherends within adhesive joints. The residual strains and stresses have also been studied indirectly by means of a bimaterial method. In addition, the effect of moisture on the joints has been investigated by means of bimaterial and bulk adhesive samples. Neutron diffraction and bimaterial experiment results have been compared to FE predictions and good agreement achieved. The diffraction studies show that residual stress in joints due to manufacture are small and that water diffusion into the joint is a main critical factor affecting the performance of adhesive and adhesive joints.

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13

關健明 and Kin-ming Kwan. "An expert system for adhesive-bonded joints." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31212347.

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Kwan, Kin-ming. "An expert system for adhesive-bonded joints /." Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B14038651.

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15

Zavatta, Nicola. "Influence of adhesive thickness on adhesively bonded joints under fatigue loading." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9713/.

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Research on adhesive joints is arousing increasing interest in aerospace industry. Incomplete knowledge of fatigue in adhesively bonded joints is a major obstacle to their application. The prediction of the disbonding growth is yet an open question. This thesis researches the influence of the adhesive thickness on fatigue disbond growth. Experimental testing on specimens with different thickness has been performed. Both a conventional approach based on the strain energy release rate and an approach based on cyclic strain energy are provided. The inadequacy of the former approach is discussed. Outcomes from tests support the idea of correlating the crack growth rate to the cyclic strain energy. In order to push further the study, a 2D finite element model for the prediction of disbond growth under quasi-static loading has been developed and implemented in Abaqus. Numerical simulations have been conducted with different values of the adhesive thickness. The results from tests and simulations are in accordance with each other. According to them, no dependence of disbonding on the adhesive thickness has been evidenced.

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Butkus, Lawrence M. "Environmental durability of adhesively bonded joints." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/19008.

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Xu, Botao. "Fracture mechanisms and failure criteria of adhesive joints and toughened epoxy adhesives." Thesis, Queen Mary, University of London, 2010. http://qmro.qmul.ac.uk/xmlui/handle/123456789/371.

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Adhesive bonded applications are used widely in industry because of significant advantages such as uniform stress distribution, and the ability to join different materials. However most epoxy structural adhesives are brittle at room temperature and it is required to improve their toughness. The objective of this work was to understand the fracture of adhesive joints, failure criteria and rubber toughening mechanisms via a series of experiments and FEA modelling. Double lap joints (DLJ) bonded by commercial AV119 adhesive were studied. It was found that local strain and failure path were controlled by adhesive thickness. In order to model adhesive joints accurately and efficiently, systematic fracture tests were implemented to determine the fracture criteria. Mode-I, mode-II and mixed mode fracture energy release rates were obtained by Fixed Arm Peel, 4-point End Notched Flexure (ENF) and Mixed Mode Bending (MMB) tests. Numerical analysis was applied to determine the parameters of the Drucker-Prager material model and Cohesive Zone Model (CZM). The 3D FEA results showed good agreement with experimental results of DLJ and MMB. FEA results successfully demonstrated bonding strength, stress and strain distribution and plastic deformation; and further details were found using sub models. The rubber toughening mechanism was studied by modelling different face-centred micromodels. The stress distributions ahead of the crack tip in global DLJ models were extracted and used as the loading condition for the micromodels, so that a relationship between macromodel and micromodel has been established. It is found that Von Mises and hydrostatic stress play very important roles in the toughening mechanisms and also predicted that rubber particles with multi-layer structure have more potential to toughen epoxy resin than simple rubber particles.

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Siu, Frederick Y. K. "Studies of microwaves applications for adhesive, weld joint and NDT technique." Swinburne Research Bank, 2007. http://hdl.handle.net/1959.3/36854.

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Thesis (MEng) - Swinburne University of Technology, Industrial Research Institute Swinburne - 2007.
A thesis submitted for fulfillment of the requirement for the degree of Master of Engineering, Industrial Research Institute, Swinburne University of Technology - 2007. Typescript. Includes bibliographical references (p. 168-193).

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Mubashar, Aamir. "Modelling degradation in adhesive joints subjected to fluctuating service conditions." Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/6336.

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Adhesive joining is an attractive alternative to conventional joining methods, such as welding and mechanical fastening. The benefits of adhesive bonding include: the ability to form lightweight, high stiffness structures; joining of different types of materials; better fatigue performance, and reduction in the stress concentrations or the effects of the heat associated with welding. However, concerns about the durability of adhesive joints still hinder their widespread use in structural applications. Moisture has been identified as one of the major factors affecting joint durability. This is especially important in applications where joints are exposed to varying moisture conditions throughout their useful life. The aim of this research is to develop models to predict degradation in adhesive joints under varying moisture conditions. This was achieved by a combination of experimental and numerical methods. Experiments were carried out to characterise the moisture uptake and mechanical properties of the single part epoxide adhesive, FM73-M. Single lap joints were manufactured from aluminium alloy 2024 in heat treated (T3) and non heat treated (O) states using the FM73-M, BR127 adhesive-primer system. Tensile testing of the single lap joints was carried out after the joints had been exposed to hot-wet conditioning environments. Models were developed for predicting moisture concentration in the adhesive under cyclic moisture absorption and desorption conditions. A finite element based methodology incorporating moisture history was developed to predict the cyclic moisture concentration. In the next step, a novel finite element based methodology, which was based on moisture history effects, was developed to determine stresses in bonded joints after curing, conditioning and tensile testing. In the final step, a moisture history dependent cohesive zone element based damage and failure criterion was introduced to predict damage initiation, crack growth and failure under variable moisture and temperature conditions. The methodology proposed in this work and its implementation by finite element method provides a systematic approach for determining the degradation in adhesive joints under varying environmental conditions and accomplishes the aim of this research.

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Tu, Yijun. "Water absorption and degradation in adhesive joints." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0002/MQ46087.pdf.

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Adams, Audrey Natasha Natalia. "The durability of organosilane pretreated adhesive joints." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251962.

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Razak, Zeenah. "The durability performance of automotive adhesive joints." Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397238.

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Court, R. S. "The long-term durability of adhesive joints." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598074.

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Hot-wet ageing was performed on three different adhesive joint systems for over 10,000 hours. Joint strengths were found to decrease with ageing time and failure was near-interfacial in the adhesive. There was no evidence of an adhesion type failure mechanism. A novel video imaging system was developed for one of the joint systems which was transparent, and this gave new, in-situ information on damage initiation and propagation in joints. The material properties of the acrylic and epoxy adhesives used for the joints were needed as input for the theoretical studies. Tensile properties were determined for adhesive samples that had been hot-wet aged and which had a range of water contents. Increased water content caused significant reductions in tensile strength and failure strain for both acrylic and epoxy. The reduction in modulus was only significant for the acrylic. A new shear test procedure using a bonded tube-plate sample was developed for adhesives with high failure strains. Accurate and reliable shear properties were measured for the acrylic adhesive. A thickness effect was observed with thin adhesive layers being stronger than thick layers. An analysis was derived, using observations from video images of the fracture process during the shear tests, that helped explain the observed thickness-strength relationship. The theoretical model for adhesive joint durability was developed based on changes to the mechanical properties of the adhesive due to water up-take. The adhesive joints were modelled using crack-bridging concepts not previously applied to this type of problem. The crack-bridging model uses large-scale bridging (LSB) conditions, which requires the material behaviour to be coupled to the component geometry, and this was implemented in a finite element model. The LSB model was found to give accurate results and to give useful predictions of joint performance in response to ageing. The LSB model was able to simulate damage development occurring in joints under load. Failure surfaces for the three joint types were developed and the most appropriate was found to be related to the shear-normal stress ratio in the adhesive.

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Anandarajah, Arumugam. "Fracture mechanics of adhesive joints in shear." Thesis, University of Dundee, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357160.

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Martins, da Silva Lucas Filipe. "Adhesive joints for low and high temperatures." Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400421.

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REZAEI, MOHSEN. "Environmental effects on epoxy adhesive and joints." Doctoral thesis, Politecnico di Torino, 2012. http://hdl.handle.net/11583/2497165.

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The use of adhesive joining in mechanical structures, especially in industrial usage, is rapidly increasing. However, to be confident in their use it is essential to evaluate the performance of the joints, especially when their strength tends to decrease upon exposure to warm and humid conditions that cause degradation. Since degradation is a long time process and evaluating the degradation of adhesive joints in normal condition needs several months or years tests, accelerated test under controlled environment is unavoidable. Water can affect both the physical and mechanical properties of the adhesive itself and also the nature of the interface or interphase that exists between it and the substrate. The aim of this thesis is considering both aspects, including also other factors that can affect the durability of bonded joints. To obtain in short time experimental data on the degradation of adhesives exposed to moisture or immersed in water, a valuable technique is represented by the open-face configuration. Apart from the acceleration of moisture uptake which is obtained due to the larger area exposed, a further advantage is the uniformity of degradation. A further acceleration can be obtained by adding a hygroscopic contaminant at the adhesive/adherend interface, which speeds up moisture uptake and accentuates the interfacial nature of the failure. The decay of the mechanical strength in absence or presence of a contaminating agent was evaluated. The effects of a humid and warm environment and also immersion in water on tensile strength, Young’s modulus and Poisson’s ratio of a twocomponent epoxy adhesive, Henkel Hysol 3425, were evaluated using bulk specimens,. To relate the exposure time to the moisture uptake, measurements were performed for both bulk adhesive specimens and bonded open face joint, in periods of time between 1 and 3 months depending on the type of test, exposure to warm moisture or immersion in water. In a further part of the work, the performance of different surface pretreatment techniques of aluminum open-faced single lap joints was evaluated. Four different surface treatment processes were tested, namely: Degreasing and Roughening, treating with Picklex 20, Phosphoric Acid Anodizing (PAA) without and with contamination. Finally, the effect of warm moisture on the fracture energy of an epoxy-based adhesives was measured. To evaluate the effect on fracture energy and other related parameters, open-faced double cantilever beam (DCB) specimens of epoxy-steel adhesive system were exposed to warm moisture, at 100 % relative humidity and 50 °C. The methodology introduced in this thesis leads to further investigation on the durability of the considered adhesive (in terms of joint strength, water uptake measurements, fracture energy, etc) under different environmental conditions. The methods adopted to accelerate the degradation process (open face and contamination) revealed an interesting reduction in duration of degradation process. Surface preparation methods to protect aluminum bonded joints against severe environmental condition were evaluated and the most suitable one (PAA process) was identified.

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Puthenparambil, Abhilash. "Effect of bonding pressure on reliability of anisotropic conductive adhesives [sic] joints in a silicon-to-flex-substrate interconnction." Diss., Online access via UMI:, 2006.

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Lefebvre, Didier R. "The durability of adhesive joints: an engineering study." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/52325.

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Water diffusion through the adhesive is the rate controlling factor for the durability of many metal-to-polymer bonds exposed to moist environments. A methodology is proposed, to relate the diffusion coefficient of water in polymers to temperature, strain and penetrant concentration. The approach used is based on well known free volume theories. In the rubbery state, it is assumed that the transport kinetics is governed by the constant redistribution of the free volume, caused by the segmental motions of the polymeric chains. An expression for the diffusion coefficient is inferred from the temperature, strain and penetrant concentration of the free volume. lt is shown that the free volume treatment can be extended to the glassy range by introducing a few additional features in the model. The stress dependence of solubility as well as the non-fickian driving forces contributing to mass transport are predicted from the Flory-Huggins theory. Experimental validation of the concentration dependence and temperature dependence of the diffusion coefficient is shown. The effect of mechanical strain on diffusivity and solubility in the glassy state is also investigated experimentally, using both the permeation and sorption techniques. Good agreement with theory is generally found. The coupling mechanisms between the diffusion process and the viscoelastic response of the adhesive are explained. A numerical scheme for fully coupled solutions is implemented in a two- dimensional finite element code. A few numerical solutions are shown. In the case of bonds undergoing unusually harsh environmental exposure however, alternative methods must be sought for durability characterization and prediction. This is illustrated with the case of rubber-to-steel joints exposed to a cathodic potential in seawater. The mechanical analysis of a durability specimen is presented and a procedure for debond prediction is suggested.
Ph. D.

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Richardson, Guy. "An investigation of interfacial failure of adhesive joints." Thesis, University of Surrey, 1993. http://epubs.surrey.ac.uk/843357/.

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Interfacial failure in adhesive joints has been studied. It has been shown by previous researchers that adhesive joints often contain bi-material geometric features that give rise to theoretically singular stress/strain fields even when there are no flaws present. It is reasonable to expect that failure occurs at, or close to, these points. To investigate failure under these conditions and to relate it to well understood failure mechanisms, tests were undertaken on uncracked joints (containing a bi-material singularity) and joint geometries with interfacial cracks of varying lengths. To provide comparative data under different conditions the joint tests were carried out under both mode I and mixed mode loading. The bulk properties of the adhesive used for the joint tests were also assessed. The rate dependent stress-strain behaviour was determined from a range of flat tensile tests. Similar tests were used to determine Poisson's ratio and to investigate the sensitivity of the adhesive to temperature variations. Four point bend tests on the adhesive were also carried out. A new method of processing the data obtained during such a test was developed and this was used to determine the ratio of the yield stress in compression to the yield stress in tension as a function of hardening. The results of these experimental programmes were then used as the basis for a series of finite element analyses. Firstly three-dimensional elastic analyses of the joint used in the experimental programme were carried out. As well as providing information on the stresses in the adhesive, these analyses showed that there was considerable variation across the width of the joint in the effective two-dimensional loading. A method of determining the correct loading was therefore developed and used for subsequent two-dimensional analyses. Three types of detailed two-dimensional analyses were carried out: elastic, elasto-plastic and a group of stress controlled separation analyses in which the material in front of the point of failure was allowed to separate under controlled conditions, thus simulating rupture. The results from these detailed two-dimensional analyses were used to assess the stresses in the joints at the failure loads and to determine the applicability of various failure criteria. Although no failure criterion was found to be universally applicable the results have indicated, clearly, possible directions for future development.

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Ficarra, Christina Helene. "ANALYSIS OF ADHESIVE BONDED FIBER-REINFORCED COMPOSITE JOINTS." NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20010626-155040.

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The work presented in this thesis involved the analysis of adhesive bonded joints for composite bridge decks and was divided into three phases. The first phase involved a parametric study on a single lap joint using ANSYS finite element analysis software. The purpose of the parametric study was to alter the geometry and material properties of the joint and study their effects on the stress distribution in both the adherends and adhesive. The four different cases studied included adding a taper to the adherends, different edge shapes on the adhesive layer, a material stiffness imbalance and a geometric stiffness imbalance. It was found that for the taper case and the edge shape case, the stress field in the joint was affected slightly. The material and geometric stiffness imbalance cases had the most drastic affect on the stress field of both the adhesive and adherend. Phase two of this study involved physical tests on single lap joints pulled in uniaxial tension. Tests were performed on three different types of laminates in order to study the interfacial effects these laminates had on the adhesive bond. It was found that by changing the surface of the composite, the mode of failure changed significantly.Phase three of this research involved a study on surface preparation. Three different surface preparations were conducted on the adherends of a butt-strap joint. The first included an acetone wipe. The second involved sanding the adherends. The third surface preparation involved adding APRIME-2, a secondary bonding agent, to the adherends before adding the strap. By simply sanding the adherends, the load to failure was increased by 350% compared to an acetone wipe. The ATPRIME-2 improved the load to failure by an additional 60% as well as improved the failure mode to a fiber tear. It was concluded that surface preparation has a major impact on the behavior of adhesively bonded joints.

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31

Korin, Christer. "Fracture Behaviour of adhesive Joints in carton board." Licentiate thesis, Karlstad : Faculty of Technology and Science, Chemical Engineering, Karlstad University, 2007. http://www.diva-portal.org/kau/abstract.xsql?dbid=1191.

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32

Steidler, Silvana M. "Structural modelling of adhesive joints in automotive bodies." Thesis, Oxford Brookes University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323906.

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33

李雁婷 and Ralphaelynne Cochingyan Lee. "Investigation of epoxy and polychloroprene adhesive bonded joints." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1987. http://hub.hku.hk/bib/B3120823X.

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34

Webb, Peter W. "Investigation of the interphasial behaviour of adhesive joints." Thesis, Loughborough University, 2004. https://dspace.lboro.ac.uk/2134/14470.

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The theme of this report is the examination of the interphase. Three different aspects of the interphase have been examined. Firstly, the detrimental effects of contamination upon the interphase were examined. Substrates were contaminated with quantified levels of PDMS (polydimethylsiloxane) in an attempt to create weak boundary layers, and the resulting performance of joints manufactured from these substrates was evaluated. A notable reduction in bond strength was observed with specimens prepared from two different toughened adhesive systems whilst a similar system formulated without any toughener remained comparatively unaffected, demonstrating the capability of the epoxide adhesive to accommodate several monolayers of this contaminant. The second aspect of the interphasial region studied was the chemical heterogeneity within the bondlines of adhesive joints. An excess of unreacted curing agent as discovered in the lower interphasial regions of tensile test specimens coupled with a tendency for near interfacial failure within this region. The curing reagent was found to be settling out of the adhesive during cure. Significant differences were also observed in the interphasial polymer compared to the bulk on samples taken from annular joints that had undergone premature failure. Thirdly, the effects of the deliberate creation of an interphase for the enhancement of the bondabiIity on steel substrates was examined. In this aspect of the work, a new adhesive and novel surface treatments have been identified as providing potential improvements in performllnce over the current bonding system. Of particular importance was the performance of a phosphate-based treatment Bonderite 9Ol/Pyrene 8-90, which gave demonstrable improvements over the existing strip laminate bonding system. The improved performance was attributed to a very stable phosphate layer deposited on the steel substrate from the chemical treatment,providing a wettable, uniform, micro-rough, corrosion resistant surface ideal for adhesive bonding.

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35

Mays, Geoffrey Charles. "Fatigue performance and durability of structural adhesive joints." Thesis, University of Dundee, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334180.

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36

Morshed, Syed Ahnaf. "Durability Properties of Nanomodified FRP-Concrete Adhesive Joints." Thesis, University of Louisiana at Lafayette, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=10844250.

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Externally bonded fiber-reinforced polymer (FRP) composites represent a simple and economical solution for many repair and strengthening applications in concrete structures. However, the potential occurrence of sudden and brittle debonding failure in such repairs becomes prominent when FRP-concrete bond undergoes environmental degradation induced by moisture. Ambient-cured low-viscosity Bisphenol A epoxy adhesives are most commonly utilized in the engineering practice to bond wet-layup FRP to the concrete substrate. This study aims to elucidate the effects of Bisphenol A-based epoxy modified with commercial surface-modified nanosilica (SMNS), core-shell rubber (CSR) nanoparticles and multi-walled carbon nanotubes (MWCNT) on the improvement of mechanical properties of the epoxy adhesives, and strength and durability of FRP-concrete adhesively bonded joints. Moisture ingress in epoxy, DSC, tensile test on epoxy and three-point bending beam bond tests were performed. To determine the effects of environmental degradation, all specimens were subjected to the following environments: control—23 °C at RH 50 ± 10% for 18 weeks; and accelerated conditioning protocol (ACP)—water immersion at 45 ± 1 °C for 18 weeks. Improvement in mechanical properties were observed in dogbone specimens modified with nanoparticles without any reduction in glass transition temperature (Tg). In control conditions, nanomodified epoxy groups exhibited enhanced mechanical properties compared to the neat epoxy. Following ACP, strength, elongation and modulus of elasticity of neat epoxy deteriorated significantly, while no significant deterioration was observed in the nanomodified group of adhesives. Among all the nanomodified adhesive groups CSR Type-1 showed most improvement in mechanical properties over neat epoxy group both in control condition and in ACP. CSR-modified adhesive joints experienced practically no degradation when subjected to ACP and showed the highest maximum bond strength retention of 100% among all the adhesive groups. The bond strength of neat epoxy adhesive joints degraded most dramatically (15%) following ACP.

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37

O'Brien, Emmett P. "Durability of Adhesive Joints Subjected to Environemntal Stress." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/29139.

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Environmental stresses arising from temperature and moisture changes, and/or other aggressive fluid ingressions can degrade the mechanical properties of the adhesive, as well as the integrity of an adhesive interface with a substrate. Therefore such disruptions can significantly reduce the lifetime and durability of an adhesive joint.1-4 In this research, the durability of certain epoxy adhesive joints and coatings were characterized using a fracture mechanics approach and also by constant frequency impedance spectroscopy. The shaft-loaded blister test (SLBT) was utilized to measure the strain energy release rate (G) or adhesive fracture energy of a pressure sensitive adhesive tape. In this study, support for the value of the SLBT fracture mechanics approach was obtained. The SLBT was then used to investigate the effects of relative humidity on a model epoxy bonded to silicon oxide. Lastly, the effects of water and temperature on the adhesion of a commercial filled epoxy bonded to silicon oxide was characterized and interpreted. A novel impedance sensor for investigating adhesion was developed in a collaborative effort between Virginia Tech and Hewlett-Packard. Utilizing the technique of constant frequency impedance spectroscopy, the distribution and transport of fluids at the interface of adhesive joints was measured. A broad spectrum of adhesives was tested. In addition, the effects of hygroscopic cycling on the durability of adhesive coatings were measured for the commercial filled epoxy using the device. Lastly, recommended modifications of the experimental set-up with the new sensor are proposed to improve the technique.
Ph. D.

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38

Lee, Ralphaelynne Cochingyan. "Investigation of epoxy and polychloroprene adhesive bonded joints /." [Hong Kong] : University of Hong Kong, 1987. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12359506.

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39

McGovern, Scott. "The development of embedded sensors to assess the fatigue response of adhesive joints in marine environments." Access electronically, 2007. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20080911.154008/index.html.

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40

Malladi, Sailaja. "Parametric modeling and analysis of structural bonded joints." Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=80.

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Thesis (M.S.)--West Virginia University, 2004.
Title from document title page. Document formatted into pages; contains x, 56 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 52-53).

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41

Rider, A. N. Parslow D. "Progress report on activities in support of composite repair engineering development program tasks AF, AH and AI." Fishermans Bend, Victoria : Defence Science and Technology Organisation, 2006. http://hdl.handle.net/1947/4682.

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42

蘇慶華 and Hing-wa So. "Strength of adhesive-bonded joints immersed in different solutions." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1992. http://hub.hku.hk/bib/B3121096X.

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43

Yen, Hsin-Yi. "NEW ANALYSIS AND DESIGN PROCEDURES FOR ENSURING GAS TURBINE BLADES AND ADHESIVE BONDED JOINTS STRUCTURAL INTEGRITY AND DURABILITY." [Columbus, Ohio] : Ohio State University, 2000. http://www.ohiolink.edu/etd/send-pdf.cgi?osu967666610.

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Thesis (Ph. D.)--Ohio State University, 2000.
Includes vita. Title from title page display. Abstract. Advisor: M.-H. Herman Shen, Dept. of Aerospace Engineering, Applied Mechanics, and Aviation. Includes bibliographical references (p. 152-154).

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44

Li, Shi. "Modeling of active crack damage control and the active fatique damage control of adhesive joint." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-08222009-040330/.

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45

Korin, Christer. "Mechanical Behaviour of Adhesive Joints in Cartonboard for Packaging." Doctoral thesis, Karlstads universitet, Avdelningen för kemiteknik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-4731.

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A cartonboard package is often sealed and closed with an adhesive – either a hot-melt adhesive (adhesives that are applied in a molten state on the cartonboard) or a dispersion adhesive (adhesives that are applied as water-based dispersions). This thesis focuses on the process of hot-melt gluing, and how material properties and process conditions affect the performance of the adhesive joint. Requirements vary depending on how the package is to be used. A package that is only supposed to protect the product during transport differs from one that is supposed to attract consumers and facilitate their use of the product. If a package has been opened, due to external or internal forces that cause a fracture in the adhesive joint, the consumer may choose another package instead. A fracture of the adhesive joint may occur in several different ways; for example, a cohesive fracture in the adhesive, an interfacial fracture between the adhesive and one of the cartonboard surfaces, and a cohesive fracture in the cartonboard. The traditional way of testing the adhesive joint is to subjectively evaluate the fibre tear after manually tearing the joint apart. The primary interest of this study has been to find an objective method that can characterise the adhesive joint – that is, its strength and joint characteristics. The work has principally concentrated on physical experiments where the Y-peel method has been evaluated and further developed, including the construction of a laboratory adhesive applicator. Adhesive joint failure is analysed and correlated to the force-elongation curve during Y-peel testing in order to explore various mechanisms of the failure. The force versus elongation curves are transformed into a force versus inelastic deformation curve for the adhesive joint. The inelastic deformation of the adhesive joint is defined as the inelastic opening of the adhesive joint perpendicular to the cartonboard surface. The dissipative descending energy has been used to characterise the adhesive joint. High descending dissipative energy showed high resistance against final failure of the joint. This correlates very well with the manual fibre-tear test. Characteristic force-elongation curves in Y-peel testing – that is, the shape of the curve – have been analysed, and four main failure modes have been identified. The finite element method has been used to predict mechanical behaviour in the ascending part of the force-elongation curve. When it comes to local behaviour, a high stiffness adhesive results in bending behaviour while a low results in shearing, but on a global scale, no big difference was detected on the ascending part of the force-elongation curve. The new laboratory adhesive applicator and finite element method can be used to objectively design the interaction between the adhesive and the cartonboard for a specific application. This can be achieved by modifying the cartonboard, the adhesive or the process parameters.

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46

Log, Audun Reinsborg. "Fatigue properties of adhesive joints in composite patch repair." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for produktutvikling og materialer, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19034.

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This paper is a master thesis written at NTNU for the Co-Patch project. The Co-Patch project is an EU-funded consortium of 15 organizations from 8 different countries, developing a standard for composite patch repair of steel structures in fire hazard areas. The standard includes methods for dimensioning against delamination. This thesis looks at the fatigue properties in delamination of patches from their substrates. By testing Double Cantilever Beam and End-Notched Flexure specimens in fatigue loading, G-N curves were made for Mode I and Mode II fatigue fracture. This gives an indication of the lifetime of a patch given a specific cyclic load condition and a pre-existing crack. The longest cycle life recorded was 4.35E5 cycles at 104 J/m2 for Mode I and 1.23E5 cycles at 122 J/m2 for Mode II.Furthermore, a relation for crack propagation rate and energy release rate in Mode I was found for low cycle life estimation. From this relation, the crack front position may be estimated for a given set of cycles through calculations using Paris’ law. Based on the quasi-static data of a previous report, and the fatigue data found in this thesis, a numerical simulation procedure for crack propagation was proposed. Using direct cyclic fatigue analysis and Virtual Crack Closure Technique based on linear elastic fracture modelling, the crack propagation may be estimated for patches exposed to combined conditions, such as plane strain/plane stress and different fracture modes, as well as on advanced geometries. The procedure was validated as a viable simulation, but more work needs to be done on the model for accurate estimates. 

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47

Vintilescu, Ion Virgil. "Mixed-mode I-II-III fracture of adhesive joints." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ28870.pdf.

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48

Safavi-Ardebili, Vahid. "Micromechanical characterization of the interphase zone in adhesive joints." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0009/NQ35308.pdf.

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49

Allin, Jonathan Mark. "Disbond detection in adhesive joints using low frequency ultrasound." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270834.

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50

Frantzis, Panagiotis Thesi. "Environmental attack on adhesive joints : a fracture mechanics approach." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47440.

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Dissertations / Theses on the topic 'Adhesive joints'

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