Device and method for testing gas permeability in inner direction of paving layer surface

Abstract

The invention relates to a device for testing the gas permeability in an inner direction of a paving layer surface. The device comprises a die, a loading device, a temperature control device, a vacuumizing device and a flow detection element, wherein the die at least consists of a cavity and a cover board for sealing the cavity; a sealing component is accommodated in the cavity; a test sample to be tested is paved in the sealing component; besides both ends of the test sample to be tested in the inner direction of the paving layer surface, the test sample to be tested is gas-sealed by the sealing component; both ends, corresponding to the non-gas-sealed positions of the test sample to be tested, of the die are provided with a gas inlet and a gas outlet respectively; the flow detection element is communicated with the gas inlet; and the gas outlet is communicated with the vacuumizing device. By the device, test of the gas permeability of prepreg in the inner direction of the paving layer surface is realized by providing power for moving the gas along the inner direction of the prepreg paving layer surface in the vacuum cavity. Due to regulation of pressure and temperature, measurement of the gas permeability of the prepreg in a curing technology can be realized.

Description

technical field [0001] The invention relates to a device and method for testing gas permeability, more specifically, a device and method for testing the permeability of a sample to be tested in the direction of the paving layer using gas as a fluid. Background technique [0002] Permeability is a parameter that characterizes the ease of fluid flow in porous media under pressure. The greater the permeability, the smaller the flow resistance of the porous media to the fluid. In the process of preparing resin-based composite materials by using autoclave or vacuum bag technology, the permeability of prepreg layup is one of the key factors affecting the discharge of air inclusions and volatiles under vacuum, thus affecting the molding of composite components to a certain extent quality. The prepreg system is composed of fiber reinforcement and resin matrix, so the permeability of the prepreg layer is not only determined by the physical properties of the fibers and the fiber netw...

AI Technical Summary

Problems solved by technology

At present, the method of using liquid as fluid to test the permeability of fiber layup tends to be mature, and there are related documents and patents. However, there are great limitations in using liquid to test the permeability of prepreg, for example: (1) Prepreg The impregnation system contains a resin matrix, and liquid is used as the test fluid. It is difficult to judge the flow front, and the permeability cannot be accurately tested; (2) the permeability of the prepreg layer is much smaller than that of the fiber layer, and the liquid passing through the prepreg layer The flow rate is very small. On the one hand, a very small liquid flow between the layup and the mold will cause a huge deviation in the results during the test, and on the other hand, time is wasted; (3) The permeability of the prepreg in the composite material molding process is mainly used for To characterize the ability of gases such as entrained air and volatile matter to be discharged under vacuum, so there are differences between using liquid as the test fluid and the actual situation; (4) The prepreg layup is affected by temperature and pressure during the curing process, and traditional methods are difficult Realize online testing of permeability during curing

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