LOAD-BEARING PIPE-SHELL IN THE FORM OF BODY OF REVOLUTION OF COMPOSITE MATERIAL, METHOD AND FORMER FOR ITS MANUFACTURE Russian patent published in 1998 - IPC

FIELD: shell structure of fuselage- mounted engines used in flying vehicles, operating in conditions of high loads. SUBSTANCE: load-bearing pipe-shell in the form of a body of revolution uses a load-bearing framework of a cellular structure, and an external protective coating. The load-bearing framework is furnished with layers of systems of crossing helical bands of different length with unidirectional threads. The longer layers of systems of crossing helical bands coat the entire surface of the load- bearing pipe-shell. The shorter layers of systems of crossing helical bands coat part of the surface of the pipe-shell so that the bands of the shorter layers are arranged in the middle between the bands of the longer layers and form with them a structure in this shell section with smaller cells. The loops of helical bands of the shorter layers are arranged in cells of the longer layers and fastened to them by ring bands of unidirectional threads. The structural depth of ribs of helical bands of the shorter layers is equal to or less than the structural depth of ribs of helical bands of the longer layers. At manufacture of pipes-shells the former is coated with rubber-like material with intercrossing grooves, helical and ring bands are laid in the grooves, stiffening ribs are formed, forming elements are applied onto them, and heat treatment is performed with subsequent extraction of the former and rubber-like coating. Ring bands laid with a tension proportional to radial compliance of the rubber-like coating are used as forming elements. A higher tension of the ring band is preset in shell sections with a more frequent arrangement of stiffening ribs. The former for manufacture of pipes-shells has a core coated with rubber-like material with intercrossing grooves for laying helical and ring bands of unidirectional threads in them to form stiffening ribs of the framework of the pipe-shell. The former rubber-like material has several systems of crossing helical grooves of different length; one of them is made over the entire surface of rubber-like material, and the rest - on part of its surface. Their helical grooves are arranged in the middle between the helical grooves made on the entire surface or part of it of rubber-like material, and their ends in the points of transition from one direction to another one are in tetragonal shoulders formed by helical grooves made with large intervals between them. The depth of these grooves is equal to or less than the depth of helical grooves arranged with a large interval. EFFECT: enhanced reliability. 3 cl, 6 dwg