Abstract: A method of making a three-dimensional fiber preform for fabricating an annular part out of carbon-carbon composite material, the method including stacking layers of a fiber sheet made up of carbon yarns or tows, needling the layers one by one as they are superposed so as to bond them together, and locally modifying the electromagnetic properties of the fiber preform by increasing the fiber density of the layers of the fiber sheet that are situated at half-thickness of the fiber preform.

Abstract: A circular needling machine for needling a textile structure formed from a helical fiber sheet, includes a needling table disposed beneath a feed table for feeding a helical fiber sheet for needling. The feed table includes a circular belt conveyor for receiving thereon a helical fiber sheet for needling, the conveyor being centered on a vertical axis and having a radial slot opening out under the circular conveyor to unwind continuously the fiber sheet received on the conveyor, the slot opening out under the conveyor towards a substantially straight chute that extends vertically between the conveyor and a support tray of the needling table centered on the vertical axis of the conveyor so as to take up the sheet unwound from the conveyor and bring it onto the needling table, the support tray having means for driving the fiber sheet in rotation about the vertical axis.

Abstract: A method of making a three-dimensional fiber preform for fabricating an annular part out of carbon-carbon composite material, the method including stacking layers of a fiber sheet made up of carbon yarns or tows, needling the layers one by one as they are superposed so as to bond them together, and locally modifying the electromagnetic properties of the fiber preform by increasing the fiber density of the layers of the fiber sheet that are situated at half-thickness of the fiber preform.

Abstract: A circular needling table for needling a textile structure made from an annular fiber preform, the table including: a horizontal annular platen for having the annular fiber preform placed thereon; drive means for driving the fiber preform in rotation about the axis of the platen; a needling device having a needling head extending over an angular sector of the platen and driven in vertical motion relative to the platen; and guide means for guiding the fiber preform under the needling head.

Abstract: The present invention provides a method of fabricating an annular fiber structure, the method comprising the steps consisting in: providing a first fiber sheet made up of substantially unidirectional elements; forming a transverse, first annular sheet by laying the first fiber sheet in alternation in one direction and in the opposite direction between coaxial outer and inner circular rings with the sheets being held at said rings; providing a second fiber sheet made up of substantially unidirectional elements; forming a circumferential, second annular sheet by depositing the second fiber sheet in a circumferential direction between said outer and inner rings; bonding the transverse and circumferential annular sheets to each other; and driving the transverse and circumferential annular sheets in rotation about the axis of the outer and inner rings so as to perform a plurality of complete revolutions in order to obtain a thick annular fiber structure having layers made up by the transverse sheet alternating wit

Abstract: The present invention provides a method of fabricating an annular fiber structure, the method comprising the steps consisting in: providing a first fiber sheet made up of substantially unidirectional elements; forming a transverse, first annular sheet by laying the first fiber sheet in alternation in one direction and in the opposite direction between coaxial outer and inner circular rings with the sheets being held at said rings; providing a second fiber sheet made up of substantially unidirectional elements; forming a circumferential, second annular sheet by depositing the second fiber sheet in a circumferential direction between said outer and inner rings; bonding the transverse and circumferential annular sheets to each other; and driving the transverse and circumferential annular sheets in rotation about the axis of the outer and inner rings so as to perform a plurality of complete revolutions in order to obtain a thick annular fiber structure having layers made up by the transverse sheet alternating wit

Abstract: A transverse fiber sheet is lapped by being guided in a substantially radial direction back and forth along a path between circumferentially outer and inner edges of the sheet, with the transverse sheet being reversed at each end of its path, the width of the transverse sheet being narrowed between the outer circumferential edge and the inner circumferential edge, the transverse sheet being held in place as it is lapped. Substantially mutually parallel yarns or tows are pulled to form a helical longitudinal sheet of density per unit area that decreases between its outer edge and its inner edge. The transverse sheet and the helical longitudinal sheet are superposed and advance continuously in flat rotation, and they are assembled together to form a helical sheet which is removed.

Abstract: A transverse fiber sheet is lapped by being guided in a substantially radial direction back and forth along a path between circumferentially outer and inner edges of the sheet, with the transverse sheet being reversed at each end of its path, the width of the transverse sheet being narrowed between the outer circumferential edge and the inner circumferential edge, the transverse sheet being held in place as it is lapped. Substantially mutually parallel yarns or tows are pulled to form a helical longitudinal sheet of density per unit area that decreases between its outer edge and its inner edge. The transverse sheet and the helical longitudinal sheet are superposed and advance continuously in flat rotation, and they are assembled together to form a helical two-dimensional sheet which is removed.

Abstract: A transverse fiber sheet is lapped by being guided in a substantially radial direction back and forth along a path between circumferentially outer and inner edges of the sheet, with the transverse sheet being reversed at each end of its path, the width of the transverse sheet being narrowed between the outer circumferential edge and the inner circumferential edge, the transverse sheet being held in place as it is lapped. Substantially mutually parallel yarns or tows are pulled to form a helical longitudinal sheet of density per unit area that decreases between its outer edge and its inner edge. The transverse sheet and the helical longitudinal sheet are superposed and advance continuously in flat rotation, and they are assembled together to form a helical sheet which is removed.

Abstract: A transverse fiber sheet is lapped by being guided in a substantially radial direction back and forth along a path between circumferentially outer and inner edges of the sheet, with the transverse sheet being reversed at each end of its path, the width of the transverse sheet being narrowed between the outer circumferential edge and the inner circumferential edge, the transverse sheet being held in place as it is lapped. Substantially mutually parallel yarns or tows are pulled to form a helical longitudinal sheet of density per unit area that decreases between its outer edge and its inner edge. The transverse sheet and the helical longitudinal sheet are superposed and advance continuously in flat rotation, and they are assembled together to form a helical two-dimensional sheet which is removed.