Anisotropic viscous behavior of sheet molding compounds (SMC) during compression molding

Dumont, Pierre; Orgéas, Laurent; Corre, Steven Le; Favier, Denis

doi:10.1016/s0749-6419(01)00077-8

Cited by 67 publications

(79 citation statements)

References 21 publications

(32 reference statements)

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“…The first apparatus is the simple compression rheometer initially developed for the rheology of sheet moulding compounds [20,34,41]. Tests consist in compressing lubricated cylindrical samples (initial radii R 0 = 35 mm and 55 mm, initial height h 0 = 20 mm) at constant axial average strain rates D 33 =ḣ/ h (compression direction given by the unit vector e 3 ) between two horizontal platens parallel to the (e 1 , e 2 ) plane, (e 1 , e 2 , e 3 ) being the usual orthogonal reference frame.…”

Section: Rheometersmentioning

confidence: 99%

“…when the suspending fluid is also a concentrated granular suspension [15]. For example, some studies were carried out to understand the rheology of Sheet Moulding Compounds (SMC), a fibre-bundle reinforced thermoset polymer composites with a matrix, which is similar to that of the BMC [1,14,20,30,[34][35][36]50].…”

Section: Introductionmentioning

confidence: 99%

“…More recently, Orgéas et al [41] performed an extensive experimental study of the rheology of a BMC. BMC samples were deformed using lubricated simple compression experiments, similar to those initially proposed for SMC or other planar fibre or fibre-bundle reinforced polymer composites [20,21,34]. Provided both a good lubrication and samples with large dimensions (with respect to the fibre length), these tests allow the analysis of the rheology of compounds with reduced discrepancy and without any a priori constitutive assumptions.…”

Section: Introductionmentioning

confidence: 99%

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Towards the simulation of mould filling with polymer composites reinforced with mineral fillers and short fibres

et al. 2009

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Bulk Moulding Compounds (BMC's) are short fibre reinforced polymer composites that behave, during their forming, as concentrated fibre suspensions. Their suspending fluid is also a concentrated granular suspension made up of the polymer filled with mineral fillers. In this work, a method is proposed to model their flow. Firstly, the rheology of an industrial BMC was analysed by performing two types of mechanical tests, i.e. lubricated simple and plane strain compression experiments. Experimental results underline the roles of the current strain, the strain rate as well as the mechanical loading on the rheology of the BMC. Secondly, a 3D tensorial rheological model is proposed to reproduce the simple and plane strain compression experiments. Then this model is implemented into a Finite Element code dedicated to the simulation of The 'Pôle de Compétitivité Plastipolis' (Région Rhône-Alpes -France) supports this research. compression moulding. Simulation results are finally compared with experiments achieved with rather complex flow situations.

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Section: Rheometersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Towards the simulation of mould filling with polymer composites reinforced with mineral fillers and short fibres

et al. 2009

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“…These are much less prone to segregation [11]. Flow models based on flow of concentrated suspensions, as proposed in [17,18] could thus be applied to model TP-P4 flow in the future. Since each material has specific mechanical properties and flow characteristics, they could be used together to take the best advantage of their respective properties.…”

Section: Tp-p4 Burn Offmentioning

confidence: 99%

Flow Properties of Tailored Net-Shape Thermoplastic Composite Preforms

et al. 2009

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A novel thermoplastic programmable preforming process, TP-P4, has been used to manufacture preforms for non-isothermal compression molding. Commingled glass and polypropylene yarns are deposited by robot onto a vacuum screen, followed by a heatsetting operation to stabilize the as-placed yarns for subsequent handling. After an optional additional preconsolidation stage, the preforms are molded by preheating and subsequent press forming in a shear edge tool. The in-and out-of-plane flow capabilities of the material were investigated, and compared to those of 40 wt % Glass Mat Thermoplastics (GMTs). Although the TP-P4 material has a fiber fraction of 60 wt %, the material could be processed to fill 77 mm deep ribs with a thickness of 3 mm, indicative of complex part production. The pressure requirements for out-of-plane flow were shown to depend on the fiber length and fiber alignment. Segregation phenomena were found to be less severe with TP-P4 than with GMT material.

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“…However, those theories cannot account properly for the e ects of local interactions between ÿbers, that may be due to dry friction e ects or localized viscous forces (Toll and Manson, 1994), and their validity is therefore limited to quite dilute suspensions, which is not the case of many industrial processes such as compression of Sheet Molding Compounds (SMC) or Glass Mat Transfer (GMT), or injection of Bulk Molding Compounds (BMC) (Dumont et al, 2003;Le Corre et al, 2002). Moreover, the complete solving of theoretical problems often requires further statistical assumptions that make the e ective calculation of the behavior possible only in the case of perfectly unidirectional or perfectly isotropic orientations of ÿbers (Fredrickson and Shaqfeh, 1989;Shaqfeh and Fredrickson, 1990).…”

Section: Introductionmentioning

confidence: 99%

Behavior of a net of fibers linked by viscous interactions: theory and mechanical properties

Corre

Caillerie

Orgéas

et al. 2004

Journal of the Mechanics and Physics of Solids

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International audienceThis paper presents an investigation of the macroscopic mechanical behavior of highly concentrated fiber suspensions for which the mechanical behavior is governed by local fiber-fiber interactions. The problem is approached by considering the case of a net of rigid fibers of uniform length, linked by viscous point interactions of power-law type. Those interactions may result in local forces and moments located at the contacting point between two fibers, and respectively power-law functions of the local linear and angular velocity at this point. Assuming the existence of an elementary representative volume which size is small compared to the size of the whole structure, the fiber net is regarded as a periodic assembly of identical cells. Macroscopic equilibrium and constitutive equations of the equivalent continuum are then obtained by the discrete and periodic media homogenization method, based on the use of asymptotic expansions. Depending on the order of magnitude of local translational viscosities and rotational viscosities, three types of the equivalent continua are proved to be possible. One of them leads to an effective Cosserat medium, the other ones being usual Cauchy media. Lastly, formulations that enable an effective computation of constitutive equations are detailed. They show that the equivalent continuum behaves like an anisotropic power-law fluid

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Anisotropic viscous behavior of sheet molding compounds (SMC) during compression molding

Cited by 67 publications

References 21 publications

Towards the simulation of mould filling with polymer composites reinforced with mineral fillers and short fibres

Towards the simulation of mould filling with polymer composites reinforced with mineral fillers and short fibres

Flow Properties of Tailored Net-Shape Thermoplastic Composite Preforms

Behavior of a net of fibers linked by viscous interactions: theory and mechanical properties

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