The Apparatus Of Split Hopkinson Tensile/Pressure Bar And Strain Rate Effects On Tensile And Compress For Fiber Reinforced Composites

The bar-bar impact apparatus of split Hopkinson tensile/pressure bar for high strain rate tests of fiber reinforced composites is developed. The components of this apparatus, the data sampling method and software are introduced in details. This SHT/PB apparatus can be used for both compress tests and tensile tests of materials at high strain rate.Tensile tests of carbon filament yarn shows at high strain rate that the mechanical behavior of carbon fiber bundles are insensitive to strain rate, i.e., the failure stress strain and elastic modulus are not increased with the rising of strain-rate. However, the fractograph of carbon fiber is rate-dependent. The fractograph of carbon will become smooth from coarse as the strain rate increases.The compress tests on 3D woven glass-fiber composite have been carried out at high strain rates. The test results show that the out-of-plane compressive property of 3D woven composite are rate sensitive. The elastic modulus isn't increased with the rising of strain-rate, however, the maximum compress stress and strain of 3D woven composite increase from 228Mpa to 272Mpa,from 15% to 20% as the strain rate increases from 2000/s to 3000/s. 3D woven glass-fiber composite is sensitive to strain rate.The compress tests on multiaxial multi-layer warp knit glass-fiber composite (MMWK) have also been carried out at high strain rates. The out-of-plane compressive property of multiaxial multi-layer warp knitglass-fiber composite are also rate sensitive. The maximum stress strain and elastic modulus of MMWK composite increase with the rising of strain rate. This shows that MMWK glass-fiber composite is sensitive to strain rate.