RESEARCH
Introduction
Carbon fiber composite materials are lightweight, excellent in specific strength and specific rigidity, and demand is expanding now as a substitute for existing metal materials in a wide range of fields such as aerospace and automotive industries. At present, carbon fiber which is a reinforcing material is excellent in mechanical properties, but it is known that it is expensive and impregnation of resin is bad. According to the air spreading technology developed by Fukui Prefectural Industrial Technology Center, carbon fiber spreads thinly so the price can be made cheap and impregnation of resin can be made better. In this research, we aimed to fabricate fabric from thermoplastic thin layer semi-prepreg sheet using polyamide 6 resin as thermoplastic resin and to investigate the resin impregnation degree, crimp ratio, basic physical properties of the fabric.
Materials and Method
Carbon fiber and a PA6 resin matrix are used in this experiment. A semi-prepreg sheet was produced by tow spreading technology at Industrial Technology Center of Fukui Prefecture. Here, a CF tow was spread by air, and then attached by heat to a thin resin film to produce a 0.04mm-thick sheet with the fiber volume fraction (Vf) of 50%.This material was woven as a base yarn. A woven fabric laminate A in which the woven fabrics were laminated in the same direction, and a fabric laminate B in which the woven fabric was alternately arranged at 45 ° and 0 ° and symmetrically were obtained. As a comparison object, a semi-prepreg sheet was laminated in a laminated configuration[0/90]12s,[45/-45/90/0]6s.The fineness angle was measured from the sectional view of the laminated plate, and the crimp ratio of the weaving yarn was calculated. Further, a test piece was cut out from the laminate, and subjected to a tensile test and a bending test.
Results
Since voids were almost not confirmed by visual observation, it was judged that impregnation was done sufficiently. The difference in maximum stress between the fabric laminates A and B and the semi-prepreg sheet laminate was about 32% and 15%, but the elastic modulus was almost the same. Since the fabric laminate A had a high crimp ratio, stress concentration occurred more than the fabric laminate B. However, it is considered that the modulus of elasticity of the fabric laminate is hardly affected by the crimp ratio. Compared with [45/-45/90/0]6s the board, the difference in the 0 ° and 90 ° direction of the fabric laminate B became smaller.
The strength of the laminated woven fabric made from the semi-prepreg sheet is lower than that of the semi-prepreg sheet laminate, and the elastic modulus is retained and the material is highly isotropic to bending. Therefore, it can be expected for structural materials of automobiles.
Carbon fiber composite materials are lightweight, excellent in specific strength and specific rigidity, and demand is expanding now as a substitute for existing metal materials in a wide range of fields such as aerospace and automotive industries. At present, carbon fiber which is a reinforcing material is excellent in mechanical properties, but it is known that it is expensive and impregnation of resin is bad. According to the air spreading technology developed by Fukui Prefectural Industrial Technology Center, carbon fiber spreads thinly so the price can be made cheap and impregnation of resin can be made better. In this research, we aimed to fabricate fabric from thermoplastic thin layer semi-prepreg sheet using polyamide 6 resin as thermoplastic resin and to investigate the resin impregnation degree, crimp ratio, basic physical properties of the fabric.
Materials and Method
Carbon fiber and a PA6 resin matrix are used in this experiment. A semi-prepreg sheet was produced by tow spreading technology at Industrial Technology Center of Fukui Prefecture. Here, a CF tow was spread by air, and then attached by heat to a thin resin film to produce a 0.04mm-thick sheet with the fiber volume fraction (Vf) of 50%.This material was woven as a base yarn. A woven fabric laminate A in which the woven fabrics were laminated in the same direction, and a fabric laminate B in which the woven fabric was alternately arranged at 45 ° and 0 ° and symmetrically were obtained. As a comparison object, a semi-prepreg sheet was laminated in a laminated configuration[0/90]12s,[45/-45/90/0]6s.The fineness angle was measured from the sectional view of the laminated plate, and the crimp ratio of the weaving yarn was calculated. Further, a test piece was cut out from the laminate, and subjected to a tensile test and a bending test.
Results
Since voids were almost not confirmed by visual observation, it was judged that impregnation was done sufficiently. The difference in maximum stress between the fabric laminates A and B and the semi-prepreg sheet laminate was about 32% and 15%, but the elastic modulus was almost the same. Since the fabric laminate A had a high crimp ratio, stress concentration occurred more than the fabric laminate B. However, it is considered that the modulus of elasticity of the fabric laminate is hardly affected by the crimp ratio. Compared with [45/-45/90/0]6s the board, the difference in the 0 ° and 90 ° direction of the fabric laminate B became smaller.
The strength of the laminated woven fabric made from the semi-prepreg sheet is lower than that of the semi-prepreg sheet laminate, and the elastic modulus is retained and the material is highly isotropic to bending. Therefore, it can be expected for structural materials of automobiles.