Patent EP-1932653-A1 (EP)
Inventor: LALANDE JOELLE
IPC: B29C70/24
Filed: 2007-11-16
Abstract: The process of manufacturing a crankcase-nozzle set to constitute components for a rocket exhaust pipe or outlet cone, comprises forming a fibrous reinforcement (150), maintaining the fibrous reinforcement in a form same as crankcase-nozzle set to be prepared, and impregnating the fibrous reinforcements with a thermohardening resin and polymerization of the resin. The step of forming the fibrous reinforcement comprises preparing a first fibrous preform (50) with a first fiber and a second fibrous preform (100) with a second fiber. The process of manufacturing a crankcase-nozzle set to constitute components for a rocket exhaust pipe or outlet cone, comprises forming a fibrous reinforcement (150), maintaining the fibrous reinforcement in a form same as crankcase-nozzle set to be prepared, and impregnating the fibrous reinforcements with a thermohardening resin and polymerization of the resin. The step of forming the fibrous reinforcement comprises preparing a first fibrous preform (50) with a first fiber and a second fibrous preform (100) with a second fiber. The first preform is corresponding to nozzle part of crankcase-nozzle set. The second preform is corresponding to the crankcase part of crankcase-nozzle set, and is placed on the first preform. The first fibrous preform is made of fibers having a thermal conductivity of less than 50 W.m -> 1>.K -> 1>, and is made of pitch precursor carbon fibers, polyacrylonitrile carbon precursor fiber or carbon fiber with rayon precursor. The second fibrous preform is made of fibers having a tensile strength of 3000 MPa and a Young's modulus of 200 Gpa, and of polyacrylonitrile carbon precursor fiber or carbon fiber with pitch precursor. The thermosetting resin is a polyaddition resin having structural characteristics and coke-metal ratio of 50%. The first fibrous preform is made of annular fibrous layers having a first series of directed fibers in an angle alpha and a second series of directed fibers at an angle -alpha . The first fibrous preform is made by stack of annular fibrous layers on an egg cup or conical shaped tool, where each layer is placed on the tools at an angle beta with respect to an axis of the tool. The first and second series of fibers having annular fibrous layer are produced by placing and automatic sewing of fibers between two frameworks defining an annular space, where each layer is extracted from the frameworks by cutting after making a circular link in the layer. The second preform is made from first and second fibrous superimposed layers. The first fibrous superimposed layer having fibers is oriented in a determined direction. The second fibrous superimposed layer is made of a fiber layer, which is placed on the first layer, and is made by filament winding on the first layer maintained as a conical tool. The second preform is placed on the first preform to form the fibrous reinforcements. The fibrous reinforcement made of first and second superimposed fibrous preforms is placed in a tool, which is heated by circulating a thermal control fluid. The tool comprises a mold, a counter-mold defining an internal space in which the reinforcement is maintained, and heating units to maintain the fibrous reinforcement at substantially uniform temperature. The thermohardening resin is injected at a base of reinforcement, and a pressure gradient is established in the internal space of the counter-mold to circulate the resin injected at the base of reinforcement towards a tip of the reinforcement.