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Modeling of the deformation of resin bonded foundry sand core during casting

Abstract : The inner cavities of aluminum cylinder heads are made using sand cores, which are made of silica sand and of a polyurethane resin binder. The cores are placed in the metallic mold just before casting. During this stage, the cores are submitted to the metallo-static pressure and high temperatures. Under these extreme loading conditions, with the development of thinner and thinner walls with complex designs, the cores exhibit significant deformation causing dimensional defects in the final cast.To control the deformation of the sand core, it is necessary to possess a robust characterization of their thermal and mechanical properties, that could be introduced in structural computations simulating the flow of the liquid metal, the solidification and the thermal fields. This approach is still not fully in use in the industry. A review of the literature confirms that this knowledge is incomplete for the moment.The work was therefore concentrated on the experimental characterization of the thermomechanical behavior and the thermophysical properties of the foundry cores and Polyurethane resin binder.Then, a behavior model capable of taking into account the viscosity of the material, damage development, and especially its evolution as a function of time and temperature because of the thermal degradation of the binder resin was developed.A technological specimen was finally designed and an experimental protocol has been established to measure the deformation of a core during casting and numerically validate the constitutive equations under complex thermal and mechanical loadings.
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Submitted on : Tuesday, January 14, 2020 - 2:36:29 PM
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2019PSLEM004_archivage.pdf
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  • HAL Id : tel-02439083, version 1

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Hiba Bargaoui. Modeling of the deformation of resin bonded foundry sand core during casting. Mechanics [physics.med-ph]. PSL Research University, 2019. English. ⟨NNT : 2019PSLEM004⟩. ⟨tel-02439083⟩

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