Créé le : 09/06/2015
Aimé H., Comas-Cardona S., Bintruy C., Schell J., Lacrampe MF, Lagardère M. - fin 2014 - Revue International journal of material forming, springer…
The construction of mesoscopic models of washing eects during the RTM process with thermoplastic polymers requires the knowledge of the limit of adhesion coecients between dry and impregnated fabric reinforcement plies and the mold. To measure these coecients a new method is described. During RTM process, a preform is placed in the cavity. The mold is closed to reach a given cavity thickness. Therefore the normal stress applied to the preform can be relaxed prior to injection. In order to comply with these RTM specicities, the limit of adhesion coecients are measured on relaxed preforms at given thicknesses. Hence, a rst set of compression tests followed by a relaxation step are performed in order to measure the normal stresses the preforms undergo. The relaxation can reduce compression normal stress by 30%. The relaxation is taken into account for the limit of adhesion calculation. Then a second setup has been built in order to measure forces during pull-out of fabric plies inserted between other plies or metallic plates. This method provides mean values of coecients of limit of adhesion for dry and lubricated preforms and various stacking sequences. These coecients can be rened so as to take into account the real area of the contact interface for ply/ply and ply/mold congurations.
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Julia Schell
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