Four Ultra-High Molecular Weight Polyethylene (UHMWPE) materials were evaluated after various irradiation crosslinking processes to determine the effects of the materials and processes on their properties for orthopaedic applications. The materials and processes included two molecular weight materials (GUR 1020 and GUR 1050), two fabricated forms (ram extruded bar and compression-molded sheet), two irradiation sources (gamma and e-beam) and multiple irradiation doses ranging from 30–120 kGy. Increasing irradiation dose led to increased crosslinking, decreased wear, and decreased toughness. The molecular weight of the starting material and the irradiation source both had effects on the final properties while the fabricated form did not. Wear testing of selected groups indicated that there was a direct correlation with irradiation dose but not with the crosslink density (as calculated from the swell ratio).

Four Ultra-High Molecular Weight Polyethylene (UHMWPE) materials were evaluated after various irradiation crosslinking processes to determine the effects of the materials and processes on their properties for orthopaedic applications. The materials and processes included two molecular weight materials (GUR 1020 and GUR 1050), two fabricated forms (ram extruded bar and compression-molded sheet), two irradiation sources (gamma and e-beam) and multiple irradiation doses ranging from 30–120 kGy. Increasing irradiation dose led to increased crosslinking, decreased wear, and decreased toughness. The molecular weight of the starting material and the irradiation source both had effects on the final properties while the fabricated form did not. Wear testing of selected groups indicated that there was a direct correlation with irradiation dose but not with the crosslink density (as calculated from the swell ratio).

This paper presents a study into the influence of the Through-The-Thickness (T-T-T) binder yarn count on the fibre volume fraction (Vf), crimp and damage tolerance within 3D woven carbon fibre composites. Three fabrics were woven with varying binder yarn counts; the first had 1x12k binders, the second had 2x6k binders (two individual 6k tows laid on top of one another into the structure to form one tow) and the third had 1x6k binder tows. Dry fabric compress tests conducted on the three 3D woven fabrics showed that a power law can be successful utilised to predict Vf and identify the required pressure to achieve a specific Vf. All three fabrics achieved Vf‘s in the range of 45–47% however the 2x6k binder fabric had higher %CV's compared to the other fabrics. The degree of crimp within the three 3D woven fabrics was shown to be highest within the 1x12k binder fabric followed by the 1x6k binder fabric with the 2x6k binder fabric having the lowest percentage crimp. Compression after Impact (CAI) tests were conducted and showed that impact depth was significantly influenced by impact location on the T-T-T binders with impact depth differences up to 97% observed. It was shown that impact location and depth played no major role in the CAI strength of the composite. CAI strength was observed to be highest within the 2x6 k binder composite followed by the 1x6k binder composite with the 1x12k composite having the lowest CAI values.

This paper describes a feasibility study to assess the viability and potential benefit of 3D woven textile reinforcements with metallic yarns integrated into the structure. It reports the results from a study of the manufacture and mechanical testing of hybrid 3D woven composite materials. The hybrid structures were manufactured using carbon fibre and aluminium wire, and subsequently impregnated with a two-part aerospace resin system. Details are given concerning the manufacturing issues with hybrid materials, and the results from mechanical testing of the first of these novel hybrid structures are examined. In addition there is a discussion of possible future developments in this area. Some preliminary data within this paper was used in a presentation at TexComp-8 Nottingham, October 2006.

The compression molding process is known to produce UHMWPE components of improved oxidation resistance [1] and quality surface finish. Induction of molecular orientation in non-crosslinked UHMWPE was demonstrated by using a slot drawing process [2]. The objective of this study was to assess the effect of flow ratio on wear and mechanical properties of crosslinked UHMPWE. Pre-irradiated GUR 1020 preforms, corresponding to flow ratios from 1.06 to 1.40, were evaluated in this study. Molecular orientation was shown by Thermal Mechanical Analysis and crossed polarizer microphotographs. Tensile (Type V), double notched Izod and pin on disk wear data were generated. The degree of molecular orientation was correlated with the flow ratio and was reflected by the enhancement of the mechanical properties. Pin on disk wear data show that there was no significant difference in wear resistance between oriented, crosslinked UHMWPE and its machined counterpart.