The mechanical properties of 3D thermoplastic composites knitted by micro-braiding yarns

• Main Authors: Yu-Ting Wei, 魏妤庭
• Other Authors: 李春穎
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/kz4cxk

碩士 === 國立臺北科技大學 === 製造科技研究所 === 104 === The study on thermoplastic composites has been an important subject for ac-ademic research. Nowadays, the development of thermoplastic composite prod-ucts becomes focus of industrial applications. In this study, micro-braiding yarns were first prepared with the braiding of nylon and glass fiber filaments. The well mixing of the nylon and glass fibers shortens the distance between reinforcement fibers and the nylon melt matrix during the thermoforming. Therefore, the wetting on the glass fibers can be improved. Usually, for the manufacturing of the high performance composite structure, laminates are made with hand lay-up technique. Without the reinforcement fibers in the thickness direction, the shortcoming of low interlaminar strength can be expected. Thus, the fabrication of 3-D thermo-plastic composite structure using the micro-braiding yarns was proposed to in-crease the interlaminar strength of composite in applications. The results showed that the resin content of the fabricated 3-D composite structure was able to reduce to 35%. Furthermore, the test results in the mechanical properties of the 3-D wo-ven composites were compared with those of 2-D laminates. Apparently, the kink formed at the node of the 3-D woven composites and caused the stress concentra-tion in glass fiber, the tensile and flexural bending strength were inferior to their 2-D laminate counterpart. However, in the short-beam bend test for the interlami-nar shear strength, the proposed 3-D structure demonstrated the superior im-provement in interlaminar shear strength with no delamination before flexural fail-ure.