Tensile and compressive tests of textile composites and results analysis

Abstract

The presented work is focused on an experimental investigation of the behavior of six types of textile composites subjected to pure tensile, cyclic tensile and compressive loading according to ASTM standards. Each type was loaded in directions forming angles between 0°and 90°, with a step of 15°with respect to the reference directions of the weaves. Two types of woven fabrics were tested (plain and quasi-unidirectional plain-woven fabric). Images of specimens taken during the tests were subsequently used for the calculation of the so-called locking angle of yarns (bundles) just before failure. Force-displacement dependencies were recorded during the tensile tests. Ultimate forces were obtained from the compressive tests. The second half of the article is dedicated to the analysis of the experimental data gathered with nearly 1000 experiments. Special software for automatic calculation of averaged dependencies, maximum forces and maximum displacements was created. Furthermore, the methodology for calculating the locking angle was proposed and tested. The obtained results will be used for the identification of the material parameters of the proposed material model in the following research. Keywords: textile composites, woven fabric, tensile test, compressive test, result analysis, weave locking Prispevek je usmerjen v eksperimentalno preiskavo obna{anja {estih vrst tekstilnih kompozitov, obremenjenih z natezno, cikli~no-natezno in tla~no obremenitvijo skladno z ASTM standardi. Vsaka vrsta je bila obremenjena v smeri, ki je tvorila kot med 0°in 90°, s koraki po 15°, glede na smer tkanja. Preizku{eni sta bili dve vrsti tkanin (obi~ajna in kvazi enosmerna obi~ajna tkanina). Posnetki vzorcev med preizkusi so bili uporabljeni za izra~un zapornega kota preje (sve`njev) tik pred poru{itvijo. Odvisnosti sila-raztezek so bile posnete med nateznimi preizkusi. Kon~ne sile so bile dobljene iz tla~nih preizkusov. Naslednji del prispevka je bil posve~en analizi eksperimentalnih podatkov iz skoraj 1000 preizkusov. Kreirana je bila posebna programska oprema za avtomatsko ra~unanje povpre~nih odvisnosti: maksimalnih sil in maksimalnih raztezkov. Poleg tega je bila predlagana in preizku{ena metodologija za izra~un zapornega kota. Dobljeni rezultati bodo uporabljeni pri nadaljevanju raziskav za dolo~anje parametrov materiala v predlaganem modelu materiala.