METHOD OF MANUFACTURING PIPES FROM FIBROUS COMPOSITE MATERIALS WITH LONGITUDINAL REINFORCEMENT Russian patent published in 1997 - IPC

FIELD: composite materials. SUBSTANCE: invention concerns pressure treatment of fibrous composite materials and may be, in particular, applied in aerospace industry. Pipes with longitudinal reinforcement are manufactured by way of assembling stock directly on holder-adapter, to which stock is rigidly fastened, and drawing the both through draw ring. In this operation, stock is rendered compact under isothermal conditions. Length of working zone of draw ring is chosen in the range between minimum and maximum length. The former is determined from equation: l_min= 2•Δr/2tgα, and the latter from equation: , where Δr is required absolute squeezing of stock in respect to wall thickness, α taper angle of draw ring, D_p and d_p, respectively, outer and inner diameters of pipe, σ_r ultimate resistance of fibrous composite material on stretching, and σ*sav

is average flow stress of matrix constituent when compacting fibrous composite material. EFFECT: considerably increased productivity and reduced cost because of less expensive equipment. 1 dwg