Study On The Mechanical Properties Of Three Dimensional Angle-Interlock Architecture Composites

In the thesis, the mechanical properties of 3D angle-interlock architecture composites were studied experimentally, and the equivalent engineering elastic constants were predicted theoretically using the mechanical analyzing method of textile composites.Based on researching various weave structures of angle-interlock architecture, evolvement rule of angle-interlock architecture is presented firstly. The structures of angle-interlock architecture are classified into two kinds, one is regular angle-interlock architectures, and the other is irregular angle-interlock architectures. Among all regular angle-interlock weave structures there are 12 different kinds of weaves which are used in making composites widely.The four preforms with different weave structures were woven using T700 12K carbon fiber on the loom designed and manufactured by our institute, they are orthogonal angle-interlock weave, orthogonal angle-interlock weave with stuffer warp, orthogonal angle-interlock weave with stuffer weft, orthogonal angle-interlock weave with both, which were made into composites by means of Resin Transfer Molding.Based on observing and analyzing the photo images of composites architecture manufactured by us, it is affirmed that the cross section of weft in composites is close to convex and the cross section of warp in composites is close to rectangle, and stuffer warp,stuffer weft and weft are linear, but stitching warp is curve. The curve is consisted of two sections, one is linear and the other is arc that equal to contour line of the cross section of weft. The brand new geometric models are set.Tensile, compress and bend properties of the composites along 0°,30°,45°,60°,90°directions were measured on Shimadzu Material Equipment manufactured by Japan, which was equipped with a set of resistance stress measuring system built by ourselves.It is deduced and presented firstly that the numerical relationship between preform design parameters and elastic constants predicting equations.The computer predicting system software is programmed based on orientation averaging model theory and five mechanical analyzing models.Based on studying and analyzing experiment data, it is affirmed that there are orthogonal anisotropy with the four angle-interlock weave preform composites, and stuffer yarn plays an important part to increasing strength and modulus, especially when applying force is along stuffer yarn direction.Based on comparing theory prediction values of equivalent engineering elastic constants and experiments data, it is affirmed that the predicting system of equivalent engineering elastic constants programmed by the author is actual, reliable and practical, and the proximal mechanical analyzing model is equi-strain model. Both values of theory prediction of equivalent engineering elastic constants and experiments data are accordant.