FABRICATING PROCESS AND MECHANICAL PROPERTY RESEARCH OF STITCHED COMPOSITE STRUCTURES

Fabricating processand mechanical property research of stitched composite materialsand their development are discussed, including stitched compositeapplications, process, mechanical properties and analysis methods.The mechanical properties and the strength analysis model ofstitched composites are illustrated emphatically. The concepts ofelasticity matrix field function and strength field of stitchedcomposites are put forward firstly in the strength analysis model.There are obvious advantages with stitched composites, such asstructure integrate, great interface mechanical properties,compressive properties after low velocity impact and so on, andthus they have attracted much attention in Europe and America andother advanced countries. However, the processing technologies ofstitched composites are relatively more complicated. Stitching hasnegetive effect on some inplane mechanical properties, and theadvantage of great interface mechanical properties cannot bebrought into play under hygrothermal conditions. Therefore, theengineering application of stitched composites is affected tocertain degree. Laminate sequences, applied environmentconditions, and stitching effect on in-plane lamina mechanicalproperties should be studied systematically when the decisionwhether stitched structures are adopted is made. Stitchedcomposites have been used in missile structures where thehygrothermal properties are not so much required.