Abstract In this paper, the fracture properties of a structural adhesive are investigated via the Tapered Double Cantilever Beam (TDCB) and the Mixed Mode Bending (MMB) tests. The experiments were performed at low to fairly low loading rates. The results were analyzed using Linear Elastic Fracture Mechanics (LEFM). It is shown that the testing speed has considerable impact on the fracture behaviour when close to mode II. Nonetheless, TDCB and MMB Load-Unload tests revealed significant non-linearities. Arcan tests demonstrated the important sensibility of the adhesive material properties to the strain rate. Therefore, the relevance of the LEFM approach is also discussed.
Abstract The fracture resistance, Gc, of adhesively bonded joints is known to vary significantly with loading mode and because joints are usually subject to mixed-mode loading in service, it is essential to be able to partition Gc into its I/II components so the appropriate failure criterion can be derived. Various partitioning schemes have been proposed in the literature but they give different results and which is most suitable has been an open question. In this work, joints were tested under ...
#1A.J.S. Leal(ISEP: Instituto Superior de Engenharia do Porto)H-Index: 1
#2Rdsg Campilho(ISEP: Instituto Superior de Engenharia do Porto)H-Index: 11
Abstract Adhesive bonding is widespread in several fields, ranging from construction, packaging, automotive industry, aeronautics and medical applications. As a result, it becomes increasingly necessary to reliably estimate their mechanical behaviour. Modern strength prediction techniques such as Cohesive Zone Modelling (CZM) are based on energetic principles. In the context of CZM, the shear fracture toughness ( G IIC ) is one of the most influential parameters for the strength prediction. This...
Last. Josep Costa(University of Girona)H-Index: 49
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Abstract The definition of the specimen dimensions in mode II fracture tests of bonded joints, where large Fracture Process Zones (FPZ) occur, is still an issue to be solved. Several conditions shall be met in order to obtain propagation values in bonded joints testing; stability of the test, full FPZ formation, and avoidance of large deflections and adherend failure. This work presents a methodology that indicates the specimen dimensions needed to obtain propagation values in End Loaded Split (...
Abstract A novel fracture mechanical test for adhesive joints subjected to pure mode III loading is presented. The experiment uses a modified double cantilever beam specimen, which is loaded out of the plane of crack propagation. The paper presents and discusses first experimental results, applying the new test method on adhesively bonded joints of an elastic-plastic structural adhesive. The tests have been performed under quasi-static load conditions. Beside the critical energy release rate, th...
Abstract This work presents a novel test setup to determine the fracture behavior of adhesive joints subjected to mixed-mode I+III loading. Common mixed-mode tests are mainly focusing on a combination of modes I and II and are limited to approaches derived from linear-elastic fracture mechanics with respect to the test evaluation. The novelty of the here proposed test is based on the principle of superposition of modes I and III, which holds in case of non-linear elastic fracture mechanics as we...
Abstract Adhesive joints are being increasingly used as a good solution to assemble primary structures of metallic and composite materials. Hence, the analysis of the behaviour of adhesively-bonded assemblies under mixed loadings is a critical issue for industry. This article discusses the use of the modified Arcan device to identify the strength of adhesively-bonded metal/metal and metal/composite assemblies. Different assemblies have been tested and their failure envelopes have been determined...
#1A. Ilioni(CNRS: Centre national de la recherche scientifique)H-Index: 1
#2Claudiu Badulescu(CNRS: Centre national de la recherche scientifique)H-Index: 7
Last. David Thevenet(CNRS: Centre national de la recherche scientifique)H-Index: 8
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Abstract Most of the adhesives used in the marine industry are polymers with a mechanical behaviour which is strongly influenced by the strain rate. Therefore, it is important to predict with accuracy their viscous behaviour. To describe their mechanical behaviour in a bonded joint, a viscoelastic-viscoplastic constitutive law is proposed here. The viscous effects on the elastic behaviour are described using a spectral distribution, which divides the viscous strain as the sum of the strains of s...
#1Georgios Stamoulis(CNRS: Centre national de la recherche scientifique)H-Index: 5
#2N. Carrere(CNRS: Centre national de la recherche scientifique)H-Index: 1
Abstract The influence of the mechanical behaviour of a crash optimized adhesive in its fracture properties at different mode ratios in the plane I/II is discussed. The adhesive under investigation has been previously studied by means of standardized TDCB (Tapered Double Cantilever Beam) and MMB (Mixed Mode Bending) tests. In the current study, these tests were modelled numerically considering first the linear elastic case for the adhesive and secondly its non-linear behaviour using a spectral v...
#1Yuki Yamagata(TITech: Tokyo Institute of Technology)H-Index: 2
#2Xi Lu(TITech: Tokyo Institute of Technology)H-Index: 1
Last. Chiaki Sato(TITech: Tokyo Institute of Technology)H-Index: 15
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Double cantilever beam (DCB) tests under impact loading conditions were conducted using a falling-wedge impact test machine and a high-speed camera. The change in mode I fracture energy G IC was investigated in comparison with the results obtained under the quasi-static loading condition. Two types of adhesives with significantly different mechanical properties were used for the DCB tests, and the change in rate dependency of the adhesive types was observed. Adhesively bonded joints have been wi...
Abstract In this paper, a new specimen called mixed mode double cantilever beam (MMDCB) was developed for the mixed mode fracture characterization of adhesives under high displacement rates. The MMDCB specimen was designed using finite elements simulations in order to determine the fracture toughness for a mode mixity in the plane I+II+III. Firstly, results from MMDCB specimens tested under quasi-static loading were experimentally compared to a reference single leg bending test. The test results...
Abstract The pure mode-I, pure mode-II and the mixed-mode I/II fracture behavior of the adhesively-bonded pultruded GFRP/steel joint were experimentally investigated by using double cantilever beam (DCB) test, and four-point end-notched flexure (4ENF) test combined with four-point single leg bending (4SLB) test, respectively. The extended global method (EGM) was employed to obtain closed-form analytical solutions of mode-II fracture toughness for the 4ENF specimen and mixed-mode I/II fracture to...
#1Johnatan Leplat(CNRS: Centre national de la recherche scientifique)
#2Georgios Stamoulis(CNRS: Centre national de la recherche scientifique)H-Index: 5
Last. David Thevenet(CNRS: Centre national de la recherche scientifique)H-Index: 8
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To investigate the mode I fracture properties of adhesively bonded joints after water ageing, the authors reduced here the width of Tapered Double Cantilever Beam (TDCB) specimens to 5 mm (compared...
