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| Stamoulis, Georgios; Carrere, Nicolas; Cognard, J. Y.; Davies, Peter; Badulescu, Claudiu. |
| The use of adhesively bonded structures is widespread in various engineering fields, as they provide many advantages over other conventional types of mechanical joints. In this study, we use a crash optimized, single-component epoxy adhesive (SikaPower®-498 made of a rigid epoxy matrix containing soft, tough polymer inclusions that provide additional ductility to the adhesive layer) at a constant layer thickness of 0.5 mm to bond metallic substrates. We investigate its fracture properties under mode I and mixed-mode I/II loadings, in order to obtain the full fracture envelope. Mode I loading has been performed using the ISO 25217 standard: the substrates were designed according to the TDCB (Tapered Double Cantilever Beam) geometry, and the fracture... |
| Tipo: Text |
Palavras-chave: Fracture toughness; Linear Elastic Fracture Mechanics (LEFM); Adhesive bonding; Finite Element Analysis (FEA); Failure criterion. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00181/29273/27685.pdf |
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| Cognard, J. Y.; Sohier, L.; Davies, Peter. |
| Composite materials are a key element in weight reduction strategies, so the analysis of the mechanical behavior of assemblies of composite modules is of great importance. Failure initiation in bonded assemblies involving composites is often associated with crack initiation in the adhesive or delamination of the composite plies close to the adhesive joint, caused by interlaminar or through-thickness stresses. Thus, the analysis of the behavior of composites and their assemblies under out-of-plane loadings is necessary in order to optimize such structures. However, few experimental devices are proposed in the literature and they often require thick composite specimens which are not representative of most industrial applications. This paper describes the use... |
| Tipo: Text |
Palavras-chave: Laminates; Adhesion; Stress concentrations; Mechanical testing. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00026/13740/11039.pdf |
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| Cognard, J. Y.; Creac'Hcadec, R.; Da Silva, L. F. M.; Teixeira, F. G.; Davies, Peter; Peleau, Michel. |
| The modelling of the non-linear behaviour of ductile adhesives requires a large experimental database in order to represent accurately the strains which are strongly dependent on the tensile-shear loading combination. Various pressure-dependent constitutive models can be found in the literature, but only a few experimental results are available, for instance, to represent accurately the initial yield surface taking into account the two stress invariants, hydrostatic stress, and von Mises equivalent stress. This paper presents the possibility of combining the use of tests on bulk specimens and tests on bonded assemblies, which strongly limit the influence of the edge effects, with a pressure vessel especially designed to study the influence of hydrostatic... |
| Tipo: Text |
Palavras-chave: Adhesive testing; Finite element analysis; Hydrostatic stress; Modelling; Non-linear behaviour; Yield surface. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00048/15917/13374.pdf |
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| Cognard, J. Y.; Creac'Hcadec, R.; Maurice, J.; Davies, Peter; Peleau, Michel; Da Silva, L. F. M.. |
| Generally, adhesives are viscoelastic-plastic materials, for which the development of viscosity and plasticity varies depending on the type of adhesive and the stress state. Various models exist to represent the yield surface, or the so-called elastic limit, taking into account the two stress invariants, hydrostatic stress and von Mises equivalent stress. Moreover, to develop precise pressure-dependent constitutive models, it is necessary to have a large experimental database in order to accurately represent the adhesive strains which are strongly dependent on the tensile-shear loading combination. Under quasi-static loadings, for a given strain rate range viscous effects can be neglected, but only a few experimental results are available to model the... |
| Tipo: Text |
Palavras-chave: Adhesive testing; Non-linear behaviour; Modelling; Hydrostatic stress; Finite element analysis. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00018/12903/10396.pdf |
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