Abstract: Method and apparatus to detect and characterize a defect in a fiber preform residing in a preform-receiving cavity of a mold or simulated mold of the type used for liquid composite molding (e.g., resin transfer molding) to make a composite component or structure. The defect may result from fiber preform misplacement in the cavity, accidental inclusions, preform density variations, and/or distortion of the preform. Transient gas or other fluid pressures at multiple locations of the cavity are measured during changing of fluid pressure in the cavity. The measured transient pressures, or data derived therefrom, are analyzed to determine membership of the fiber preform in one of two or more groups that include a standard defect-free group and a defective group, whereby the method determines if the fiber preform or its position in the cavity deviates from the standard defect-free group.

Abstract: A fibrous preform such as a braided or stamped fibrous is inspected for a defect prior to placing the preform in a molding cavity by flowing gas through regions of the preform while it is located outside the molding cavity, measuring gas pressure at the regions, and determining deviations in measured gas parameter among the regions. The deviations of the gas parameter for a particular preform are compared to background data that includes deviations of the gas parameter determined for previously tested performs such that a relatively large deviation for a particular preform is considered to identify that preform as a defective preform as opposed to an acceptable preform.

Abstract: Methods to detect and characterize a defect in a fiber preform residing in a molding cavity for liquid composite molding (e.g. resin transfer molding) to make a composite component or structure. The defect may result from fiber preform misplacement in the molding cavity, accidental inclusions, preform density variations, and/or distortion of the preform. Gas pressures at multiple locations on a mold wall are measured during gas flow through the mold cavity containing the fiber preform. Normalized or measured pressures are analyzed by discriminant analysis to detect and characterize any defect in the tested fiber preform.

Abstract: A fibrous preform such as a braided or stamped fibrous is inspected for a defect prior to placing the preform in a molding cavity by flowing gas through regions of the preform while it is located outside the molding cavity, measuring gas pressure at the regions, and determining deviations in measured gas parameter among the regions. The deviations of the gas parameter for a particular preform are compared to background data that includes deviations of the gas parameter determined for previously tested performs such that a relatively large deviation for a particular preform is considered to identify that preform as a defective preform as opposed to an acceptable preform.

Abstract: Methods to detect and characterize a defect in a fiber preform residing in a molding cavity for liquid composite molding (e.g. resin transfer molding) to make a composite component or structure. The defect may result from fiber preform misplacement in the molding cavity, accidental inclusions, preform density variations, and/or distortion of the preform. Gas pressures at multiple locations on a mold wall are measured during gas flow through the mold cavity containing the fiber preform. Normalized or measured pressures are analyzed by discriminant analysis to detect and characterize any defect in the tested fiber preform.

Abstract: A femoral implant for a hip prosthesis includes a shaft oriented in a longitudinal direction and a neck extending from said shaft at an acute angle .theta. to the longitudinal direction. The implant includes a plurality of layers of fibers in a matrix, wherein the fibers are substantially unidirectional in each respective layer. The implant is made from a stack of layers of the matrix so that the direction of fibers is unbalanced. At least 50% of the fibers are oriented in the .theta. direction and the remainder of said fibers are oriented in directions other than the .theta. angle.