Vitry-sur-Seine, France
Vitry-sur-Seine, France
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Narynbek Ulu K.,CNRS Research Institute in Civil Engineering and Mechanics | Huneau B.,CNRS Research Institute in Civil Engineering and Mechanics | Verron E.,CNRS Research Institute in Civil Engineering and Mechanics | Beranger A.-S.,LRCCP | Heuillet P.,LRCCP
International Journal of Fatigue | Year: 2017

As of present, fatigue life testing of elastomers in displacement control is extensively utilized in academic research and industry. However, there are limitations to this approach, if the tested elastomer behaves inelastically; it can be shown that the mechanical state parameters of the material, stress or strain, do not remain constant throughout the duration of an experiment carried out in displacement control. As such, application of various fatigue criteria is questionable and, moreover, a valid comparison of fatigue resistances of different materials cannot be carried out. In the present work, a procedure is developed that allows uniaxial fatigue life testing in true stress control and creation of the corresponding Wöhler curve. The procedure allows testing of single specimens and is then extended for several specimens in parallel. The procedure is validated by experiments on a synthetic rubber HNBR for three loading levels of true stress amplitude at a loading ratio R = 0. The results confirm the viability of the procedure for both individual and parallel testing. © 2017 Elsevier Ltd

Labban A.E.,LRCCP | Mousseau P.,OPERP GEPEA ERT 1086 | Bailleul J.L.,French National Center for Scientific Research | Deterre R.,OPERP GEPEA ERT 1086
Inverse Problems in Science and Engineering | Year: 2010

Thick rubber part moulding is a process, during which coupling between heat and chemical kinetic equations is strong. Automatic tooling control, therefore, is the guarantee of achieving proper curing within the mould. This article initially presents a detailed method for curing optimization. With this aim in view, the optimum temperature cycle for the desired curing state is examined. The use, here, of the conjugate gradient method implies to determine the solution of both adjoin and sensitivity equations. A sensitivity study is also conducted in order to improve the kinetic model. Finally, some optimization examples are discussed. © Taylor & Francis.

Marco Y.,Ensta Bretagnelaboratoire Brestois Of Mecanique Et Des Systemes | Masquelier I.,Ensta Bretagnelaboratoire Brestois Of Mecanique Et Des Systemes | Le Saux V.,Ensta Bretagnelaboratoire Brestois Of Mecanique Et Des Systemes | Huneau B.,CNRS Research Institute in Civil Engineering and Mechanics | And 2 more authors.
Constitutive Models for Rubber IX - Proceedings of the 9th European Conference on Constitutive Models for Rubbers, ECCMR | Year: 2015

Because of the heterogeneous nature of these filled materials, the fatigue properties of elastomers are strongly connected to their microstructure. The goal of this study is to characterize the fatigue damage scenario at the inclusions’ scale. In a companion paper (Huneau et al., 2015) SEM techniques were applied to describe the early stages of initiation. Nevertheless, this description remains geometric and provides no local mechanical data. To overcome this limitation, thermal measurements at the microstructure scale are achieved and a specific protocol is applied to infer the dissipation fields from the temperature measurements. Formerly developed on a classical structural sample, this approach is applied to samples with well mastered typical flaws at the microscopic scale and then to samples exhibiting isolated carbon blacks agglomerates. The experimental results obtained are finally correlated to SEM observations, providing a precious database for the understanding and a quantitative evaluation of the initiation mechanisms induced by inclusions. © 2015 Taylor & Francis Group, London, UK.

Omnes B.,Cetim | Heuillet P.,LRCCP
Constitutive Models for Rubber IX - Proceedings of the 9th European Conference on Constitutive Models for Rubbers, ECCMR | Year: 2015

This paper presents the recently studies carried out to improve the knowledge on the tightness of the rubber seal at low temperature, around −50°C. The thermomechanical behaviour, the evolution of the leakage through the temperature glass transition (Tg) and the study of different constitutive equations implemented in the finite element code, are the major items covered by this study. The experimental results obtained on the samples and the O-rings, have been compared to the numerical results. A hyper viscoelastic model with the Prony cells and Time-Temperature dependences has been chosen. The material parameters have been identified on a thermomechanical database. © 2015 Taylor and Francis Group.

Rublon P.,LRCCP | Favier A.,Metravib ACOEM Group
Constitutive Models for Rubber IX - Proceedings of the 9th European Conference on Constitutive Models for Rubbers, ECCMR | Year: 2015

Fatigue crack growth tests consist in measuring the propagation rate of a pre-existing flaw inserted in a sample, in opposition to the crack nucleation approach often studied. Such tests are performed at LRCCP on a DMA+300 fatigue machine developed by ACOEM, on “pure shear” samples. The purpose of this work is thus to evaluate the influence of various experimental parameters on the measured crack growth behaviour of a carbon black filled SBR. It includes the impact of the mechanical loading parameters (frequency, waveform…), and also material parameters (carbon black dispersion, curing system…). However, the only parameter considered in this paper is the effect of the antioxidants addition to the material formulation. Indeed, the comparison of fatigue crack growth rates measured on different samples, with various amounts of 6PPD (acting as antioxidant), before and after a thermal ageing, helps finally to determine how the fatigue crack growth behaviour is affected by this kind of chemical product. © 2015 Taylor & Francis Group, London, UK.

Roche N.,LRCCP | Perier L.,Metravib ACOEM Group
Procedia Engineering | Year: 2013

Elastomers exhibit complex fracture mechanical properties. The crack growth rate depends on various factors such as polymer type, fillers, curing state. For numerous applications elastomeric parts often work under complex periodic loadings. The new Fatigue Test Analysers of Metravib ACOEM allows performing fatigue crack growth tests at controlled tearing energy in pure shear samples. This method of loading is strongly recommended to compare dynamic fatigue properties of elastomers. This study deals with crack growth rate measurements and performance comparison of several rubber compounds. The influence of the formulation and mixing parameters of formulation and mixing would be presented on an SBR compound: the dispersion of filler, the antioxidant quantity, and the curing system. All compounds are characterized with normalized mechanical tests such as uniaxial tensile, monotonic tearing, hardness; one is also tested with normalized fatigue tests as FTFT (Fatigue To Failure Tensile), DeMattia Flexing Fatigue Tester (in initiation and propagation). © 2013 The Authors.

Rouillard F.,LRCCP | Heuillet P.,LRCCP | Omnes B.,CETIM
Constitutive Models for Rubber VIII - Proceedings of the 8th European Conference on Constitutive Models for Rubbers, ECCMR 2013 | Year: 2013

Rubber compounds exhibit non linear viscoelastic mechanical behavior, stress-strain response strongly depends on time and temperature parameters. For numerous applications and mainly for sealing applications, rubber parts often work under a given displacement. This type of loading, named stress relaxation, leads to a load decrease versus time due to viscoelastic effects. In case of sealing applications, contact pressure developed by a seal decreases and in extreme situations leaks occur in case of unsatisfactory design and/or non applicable material. This presentation deals with stress relaxation phenomena for sealing applications at low temperatures, for temperatures nearly or inferior to glass transition temperature (Tg) of the polymer(s) retained for the rubber compound. In this domain, between the rubbery state and the glassy state, the final behavior of the seal will depend on the whole loading history applied to the material combined with dilation phenomena given small strain variations of the material. © 2013 Taylor & Francis Group.

Bruno F.,LRCCP | Deme F.,LRCCP | Pineau Q.,Arkema | D'Herbecourt B.,Arkema
Rubber World | Year: 2014

Two different grades of Platamid film, M 1943 and M 1276, were tested to bond a cured nitrile rubber formula on itself. These Platamid compounds were compared to industrial methods, namely the use of a nitrile rubber dissolution and the Chemosil X6025 available bonding agent. The use of Platamid film produces higher levels of peel strength in comparison with those obtained by conventional methods. The adhesion performance was strongly influenced by the acrylonitrile content of the NBR grade tested. Using thin Platamid films represents a promising and interesting solution to replace actual dissolutions used in rubber work rooms and plants. This new method produces no volatile solvents harmful to the health and the environment. Platamid films, due to the presence of amide groups in their chemical structure, showed a specific affinity to polar groups. After thermal aging in air and oil, nitrile bond strengths of 28% and 18% ACN NBR remained at a low level versus the 45% ACN reference NBR.

Ait Hocine N.,University of Tours | Hamdi A.,LRCCP | Nait Abdelaziz M.,Lille University of Science and Technology | Heuillet P.,LRCCP | Zairi F.,Lille University of Science and Technology
International Journal of Solids and Structures | Year: 2011

This work deals with fracture of elastomers by cavitation. So, tension tests were achieved on specific volumetric specimens, the shape of which should induce void nucleation in the bulk of the material. Macroscopic behaviour of this material was related to the cavitation phenomenon. It was particularly proved that the slope break of the stress-strain curves coincides with the apparition of voids. Then, all experimental tests were numerically modelled using Finite Element Method (FEM) and results were analysed. Numerical study highlighted, among others, effects of specimen shape factor and those of filler volume fraction on the nucleation and growth of cavities. © 2011 Elsevier Ltd. All rights reserved.

Roche N.,LRCCP | Heuillet P.,LRCCP | Janin C.,LRCCP | Jacquot P.,Bodycote
Surface and Coatings Technology | Year: 2012

Industrial use of rubber ranges a broad field of applications, which many of them would require better surface characteristics such as a lower friction coefficient, improved wear resistance or low permeability. Ion bombardment of polymers has proven to have a great potential for improving polymers' surface mechanical and tribological properties.In this work, a HNBR surface was subjected to nitrogen plasma source ion implantation (PSII). In order to evaluate the influence of aging on the surface treatment, tensile mechanical fatigue and thermal aging were performed. Surface characterization by SEM showed that the HNBR surface aspect was greatly modified by ion bombardment. Tensile mechanical testing showed no major modifications of the tensile properties. The tribological behavior was tested with a high load (250. N) tribometer. Results showed that the CoF (Coefficient of friction) can be divided by a factor up to 3 for treated HNBR. Wear resistance of the treated surfaces was characterized by multiple consecutive tribotests. SEM assisted surface analysis after testing shows that the morphology has been greatly altered. The results obtained also shows little influence of thermal aging and tensile mechanical fatigue on the tribological properties. © 2012 Elsevier B.V.

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