Phenolics are widely used for over a century in different industries due to their chemical resistance and thermomechanical properties. However, the presence of voids in phenolic resins has negative effects on the mechanical properties and a conventional approach is to avoid these by utilizing very long cure cycles. Our alternative approach investigates the tailoring of void size and distribution to achieve a better balance between processing time and mechanical properties. Therefore, we produced phenolic resin with a void-free microstructure by a long cure cycle as a reference. To alter the void size and distributions, we utilized different catalysts and a short cure cycle to obtain phenolic resins and test their flexural properties with respect to the reference. We investigated the fracture surfaces of all materials by SEM, FTIR and compared results to finite element modeling that confirmed the effects of different void size and distributions on the mechanical properties.
A proper orthogonal decomposition (POD) reduced-order finite difference (FD) extrapolating model is established for the channel flow with local expansion denoted by non-stationary Stokes equations. The POD-based reduced-order numerical model to produce the solutions on the time span [T 0 , T] (T 0 T) are obtained by extrapolation and iteration from the very short time span [0, T 0 ] information. The guides to choose the number of POD basis and renew POD basis are provided, and an implementation for solving the POD-based reduced-order FD extrapolating model is given. Some numerical experiments are used to show that the POD-based reduced-order FD extrapolating model is feasible and efficient for simulating the channel flow with local expansion.
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