62 3-D textile reinforcements in composite materials multi-layer weavings multiaxial warp knittings technical embrolderies textiles for knot elements braidings integral knittings SuuO 2.13 Braided,knitted and stitched knot elements for spaceframe WV St:6t structures. 2102 would therefore be very effective.Nevertheless,the manufacturing of con- ventional sandwich structures based on foam or honeycomb cores is time consuming and expensive.Additionally,the poor damage tolerance prevents these structures from being used intensively in transportation applications. angh An interesting new design and manufacturing concept is feasible by using integrally woven sandwich structures.The integral structure combining the two skins and the 'core'during the textile process offers a high potential for automated,cost-effective manufacturing of sandwich structures with a high damage tolerance because of the 3-D fibre reinforcement. An exemplary demonstrator component is shown in Fig.2.14.A hood for a passenger car has been made by using a glass fibre weaving in one shot. After impregnation in an epoxy resin bath and pressing to adjust the resin content,the wet preform was placed in a negative mould and pressed in the area of the structure borders by a frame.Owing to the sandwich design,the 3-D fibre reinforcement and the ability to realize very effective load intro- ductions,the weight-saving potential of this structure is very high.Even compared with an aluminium sheet hood a weight reduction of nearly 50% is possible.Nevertheless,an important development goal for exterior applications is to improve the surface quality of textile-based composite materials. The goals,typical structural components and possible applications of tex- tiles are summarized in Fig.2.15.would therefore be very effective. Nevertheless, the manufacturing of con￾ventional sandwich structures based on foam or honeycomb cores is time consuming and expensive. Additionally, the poor damage tolerance prevents these structures from being used intensively in transportation applications. An interesting new design and manufacturing concept is feasible by using integrally woven sandwich structures. The integral structure combining the two skins and the ‘core’ during the textile process offers a high potential for automated, cost-effective manufacturing of sandwich structures with a high damage tolerance because of the 3-D fibre reinforcement. An exemplary demonstrator component is shown in Fig. 2.14. A hood for a passenger car has been made by using a glass fibre weaving in one shot. After impregnation in an epoxy resin bath and pressing to adjust the resin content, the wet preform was placed in a negative mould and pressed in the area of the structure borders by a frame. Owing to the sandwich design, the 3-D fibre reinforcement and the ability to realize very effective load intro￾ductions, the weight-saving potential of this structure is very high. Even compared with an aluminium sheet hood a weight reduction of nearly 50% is possible. Nevertheless, an important development goal for exterior applications is to improve the surface quality of textile-based composite materials. The goals, typical structural components and possible applications of tex￾tiles are summarized in Fig. 2.15. 62 3-D textile reinforcements in composite materials 2.13 Braided, knitted and stitched knot elements for spaceframe structures. RIC2 7/10/99 7:26 PM Page 62 Copyrighted Material downloaded from Woodhead Publishing Online Delivered by http://woodhead.metapress.com Hong Kong Polytechnic University (714-57-975) Saturday, January 22, 2011 12:29:45 AM IP Address: 158.132.122.9