Issue 39

M. Romano et alii, Frattura ed Integrità Strutturale, 39 (2016) 226-247; DOI: 10.3221/IGF-ESIS.39.22 237 Reinforcement fibers HT-Carbon Polymeric matrix Epoxy resin Structural mechanic material property Value Structural mechanic material property Value Young’s modulus E f,1 230 GPa Young’s modulus E m 3.3 GPa Young’s modulus E f,2 28 GPa Shear modulus G m * 1.22 GPa* Shear modulus G f,12 50 GPa Poisson’s ratio ν m 0.35 Shear modulus G f,23 * 11.4 GPa* Poisson’s ratio ν f,12 0.230 Poisson’s ratio ν f,21 ** 0.028** Poisson’s ratio ν f,23 0.225 * no independent structural mechanic material property, determined because of presumed (quasi-)isotropy ** no independent structural mechanic material property, determined by relation according to Maxwell-Betti Table 1 : Structural mechanic material properties of the single components according to [30-33]: Left: HT-carbon as reinforcement fibers. Right: Epoxy resin as polymeric thermoset matrix system. Kind of fiber reinforcement: HT-carbon fiber reinforced epoxy Region of plane rep. sequence Longitudinally cut (warp yarn) Micromechanic homogenization Transversally cut (fill yarn) Young’s modulus E 1 150.7 GPa weighted average stiff 11.4 GPa Young’s modulus E 2 11.4 GPa Chamis 1983/84 [37], [38] 11.4 GPa Young’s modulus E 3 11.4 GPa Chamis 1983/84 [37], [38] 150.7 GPa Shear modulus G 12 5.7 GPa Chamis 1983/84 [37], [38] 3.7 GPa* Shear modulus G 23 3,7 GPa* Tsai 1980 [39] 5.7 GPa Shear modulus G 13 5.7 GPa Chamis 1983/84 [37], [38] 5.7 GPa Poisson’s ratio ν 12 0.272 weighted average Poisson 0.333 Poisson’s ratio ν 23 0.333 Foye 1972 [40] 0.021* Poisson’s ratio ν 13 0.272 weighted average Poisson 0.021* * no independent structural mechanic material property for transversally isotropic material behavior Table 2 : Homogenized structural mechanic material properties of the 0°-unidirectionally reinforced single layer of HT-carbon fiber reinforced epoxy resin in the local 1-2-3-coordinate system of the respective region of the warp and fill yarn at the presumed fiber volume content of %65 Rf,   as the input values for the input mask of the FE-preprocessor of ANSYS [34] Homogenized structural mechanic material properties of the 0°-unidirectionally reinforced single layer The fiber reinforced regions (warp and fill yarns) are considered as 0°-unidirectionally reinforced, having the same (local) fiber volume content. Because of the transversally isotropic material behavior to the fiber direction, there are five independent structural mechanic material properties in the local 1-2-3-coordinate system. Tab. 2 contains the homogenized structural mechanic material properties of the 0°-unidirectionally reinforced single layer of HT-carbon fiber reinforced epoxy resin in the local 1-2-3-coordinate system of the respective region of the warp and fill yarn. Thereby, an achievable and technically reasonable local fiber volume content of f,R 65 %   is presumed. The applied rules of mixtures are referenced. The density of the composite material ρ c is calculated as a weighted average of the densities of the single components based on the fiber volume content. The physical material property for HT-carbon fiber reinforced epoxy at f,R 65 %   is 3 c,HT Carbon-EP 1.55 g/cm    .