The purpose of this study is to clarif シ effects of fabrication condition on fiber orientation state and mechanical properties of braided CFRP pipcs ． Two types of braided CFRP pipes， cylinder pipes and reCtangular pipes were fabricated ． And the braided CFRP pipes with longitUdinal fibers and those without longitudinal fibers were also fabricated by changing braiding angle ． Four − point bending test was performed for each specimen ． The bending modulus ofboth of cylinder pipes and rectangular pipes was increased with a decrease in the braiding angle． The bending st1 ℃ ngth of cylinder pipes was inoreased with a decrease in the braiding angle ， but that ofrectangular pipes with longitudinal 且bers was decreased with a decrease in the braiding angle ． By measuring the strains and observe the cross section of the sp imens ， the f( ) 110Wing factors tO decrease the bending strength were clarified ， The factors were stress con 。entration caused by localized deformation and Performance decline offiber strength caused by the crimps ofthe middle − end −fiber ．

The purpose of this study is to clarify the effect of the fiber crimps in braided carbon fiber reinforced plastics pipe (Braid pipe). Braid pipes with different crimp angles were fabricated by using carbon fiber with different fineness for the braiding yarn and different 0° fiber contents. Larger fineness of carbon fiber and/or more content of 0° fiber made the crimp angle larger. The braiding angle was ±45°and 0°fiber (MEY) was inserted between braiding yarns. 0° fiber content was changed as, 0%, 15% and 29%. The effects of crimp on the bending property and the torsion property were investigated comparing with SW pipes with non-crimp structure made by Sheet Winding method. As regarding bending property, Braid pipe performed 75% to 95% of the bending modulus of the SW pipe. With the increase in the crimp angle, the bending modulus was linearly decreased. The longitudinal yarn in Braid pipe with gap between braiding yarns had crimp and bending strength was decreased. The Poisson's ratio of Braid pipe was smaller by 67% than that of SW pipe. The crimp in longitudinal yarn and Poisson's ratio had greater effect on the bending strength than the crimp of braiding yarn. As regarding torsion property, both of the torsion modulus and strength were decreased with the increase in the crimp angle at braiding yarn. The crimp had 2.5 times greater effect on torsion strength than torsion modulus. It was clarified that the effect of crimp at braiding yarn on the mechanical properties depended on the angle between fiber orientation and the principal stress directions.