Wrinkle Reduction in Formed Composite Laminates
First Claim
Patent Images
1. A method of making a composite laminate part exhibiting reduced wrinkling, and having a desired contour along a major axis of loading:
- laying up a substantially flat stack of fiber plies each having a unidirectional fiber orientation, wherein at least some of the plies provide the part with primary axial stiffness along the major axis of loading, including orienting the plies providing the primary axial stiffness at off-angles relative to the major axis of loading;
forming the stack to a desired cross sectional shape; and
,forming the stack to the desired contour along the major axis of loading,wherein during the forming, strain on the plies providing the primary axial stiffness is reduced by their off-angle orientation.
1 Assignment
0 Petitions
Accused Products
Abstract
Wrinkling of a contoured composite laminate part during forming to contour is reduced by using laminate plies having off-angle reinforcing fibers that provide the part with primary axial strength along a major axis of loading.
-
Citations
37 Claims
-
1. A method of making a composite laminate part exhibiting reduced wrinkling, and having a desired contour along a major axis of loading:
-
laying up a substantially flat stack of fiber plies each having a unidirectional fiber orientation, wherein at least some of the plies provide the part with primary axial stiffness along the major axis of loading, including orienting the plies providing the primary axial stiffness at off-angles relative to the major axis of loading; forming the stack to a desired cross sectional shape; and
,forming the stack to the desired contour along the major axis of loading, wherein during the forming, strain on the plies providing the primary axial stiffness is reduced by their off-angle orientation. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A method of making a contoured composite laminate part having a high aspect ratio, a major axis of loading and a plurality of zones along its length respectively having desired stiffnesses, comprising:
-
selecting a set of fiber angles for plies of unidirectional reinforcing fibers; determining, for each of the fiber angles, a number of plies in each of the zones required to provide a desired set of in-plane laminate properties in the zone; determining a shape and stacking sequence of the plies; laying up the plies into a flat stack using the stacking sequence; and forming the flat stack into the shape of the contoured composite laminate part. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
-
-
14. A method of making a composite laminate stiffener having a major axis of loading, and contoured both longitudinally and transversely, comprising:
-
laying up a substantially flat stack of fiber plies each having a unidirectional fiber orientation, wherein at least some of the plies provide the stiffener with primary axial stiffness along the major axis of loading, including orienting the plies providing the primary axial stiffness at off-angles relative to the major axis of loading; forming the stack to desired transverse and longitudinal contours, wherein during the forming the fibers in plies providing the stiffener with primary axial stiffness transition along their lengths from a compression state, to a neutral state, and from the neutral state to a tensile state; and wherein during the forming, strain on the plies providing the primary axial stiffness is reduced by their off-angle orientation. - View Dependent Claims (15, 16, 17, 18, 19, 20)
-
-
21. A method of forming a composite laminate stiffener having a primary axis of loading, comprising:
-
laying up a flat composite laminate stack of plies of reinforcing fibers; forming the composite laminate stack such that the fibers in at least some of the plies are subjected to compression loading; and shortening a length over which the fibers are compressed. - View Dependent Claims (22, 23, 24, 25)
-
-
26. A method of forming a composite laminate stiffener contoured along a primary axis of loading, comprising:
-
laying up a flat stack of plies of reinforcing fibers, some of the plies providing the stiffener with primary axial stiffness; forming the flat stack to a desired contour along the primary axis of loading, wherein the forming places the fibers in the plies providing primary axial stiffness in compression and causes stretching of the fibers; reducing the compression of the fibers in the plies providing primary axial stiffness by reducing a length over which the fibers are compressed during the forming; and converting a portion of the stretching into shear deformation. - View Dependent Claims (27, 28, 29, 30)
-
-
31. A composite laminate stiffener contoured along a major axis of loading, comprising:
a plurality of laminated plies of unidirectional reinforcing fibers held in a plastic matrix, wherein all of the plies have fiber orientations at off-angles relative to the major axis of loading. - View Dependent Claims (32, 33, 34, 35, 36, 37)
Specification