Abstract
Abstract This paper discusses the effect of pressure on the content of microvoids and defects inside laminates fabricated under different pressures, by vacuum methods. Two basic vacuum methods resin transfer molding (RTM) and vacuum bag method were used in this paper. A glass mat with an alignment angle of (0□/90□) and a mass of 450 g/cm2 was used to produce the laminate, and a polymer resin was used as the matrix. Special attention was paid to the technological parameters of both processes. A mathematical analysis of the most important parameters which include flow rate, permeability, and gelation temperature has been carried out. In addition, the resin temperature is used to reduce the viscosity of the resin to facilitate its flow through the reinforcement, and in the final stage of production to control the chemical reactions occurring in the mold. The pressure is chosen so that the resin flow is continuous. The synchronization of these two parameters and the measurement of the time in which they occur are called the “cure cycle”. In the final step of the study, the composite was subjected to a static tensile test, using specimens of two different dimensions (scale effect) to evaluate the effect of microvoids and microcracks created by the processes on the strength of the material.
Highlights
Two basic vacuum methods resin transfer molding (RTM) and vacuum bag method were used in this paper
The Resin transfer molding (RTM) process has many advantages, and the most important of which are low mold production costs, simple curing cycles compared to the vacuum bag method, low styrene emission, and high quality of components
There is no consensus in the literature as to which is the best model for determining flow and the most commonly used based on Darcy’s law; this model describes the flow of Newtonian fluids in porous media [3, 4]
Summary
The Resin transfer molding (RTM) process has many advantages, and the most important of which are low mold production costs, simple curing cycles compared to the vacuum bag method (because the process takes place in two solid closed molds), low styrene emission, and high quality of components. The fibers are fully impregnated in the radial direction so the flow is divided between the two macro and micro scales. The third model is the pressure-dependent drive phenomenon occurs micro impregnation along the fiber direction and at the same time transverse flow to macropores. There is no consensus in the literature as to which is the best model for determining flow and the most commonly used based on Darcy’s law; this model describes the flow of Newtonian fluids in porous media [3, 4].
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