| With the development of the technology of low temperature superconducting and the demand of aerospace field, composite materials are more and more widely used in low temperature areas. There are all specific requirements for the structure and support about its low temperature mechanical properties. The performance of materials will been quite changed in low temperature, this makes that it is necessary to research on the low temperature mechanical properties.Unidirectional fiber composite intensity and rigidity is higher in fiber direction, and is very lower in vertical to fiber direction. It is appeared in the form of the laminated plates in the practical application. But there is more complex, changeable and difficult on the analysis of micromechanics structure. Researching on fabric composite material mechanics performance will be a complex and the practical significance job. At present, research on the performance of orthogonal layer of the composite material is still rare in low temperature. The paper will study on mechanical properties of the carbon fiber fabric enhanced epoxy resin composite material in room temperature and low temperature.Therefore, this paper will carry on the following aspects research:1. First, research on the process performance of the low temperature epoxy resin system; Second, studying on DSC thermal analysis, gel time, curing degree analysis, we have established the formula for curing system:100℃2h/+130℃/4h+150℃/4h;2. Analyzing of the RTM mold design and the process parameters, establish the formula of the molding process:Room temperature perfusion, Vacuum degree:0.08-0.09MPa, Injection pressure:0.02-0.03MPa;3. From the test of resin casting body performance, the novel epoxy resin casting body system has good performances. Tensile strength at room temperature is99MPa, bending strength is2.6GPa;4. By researching and analyzing the mechanics experimental, we found that the strength of stitched fabric reinforced composites has more or less reduced by comparing with others, the tensile strength has reduced41%, bending strength18%; Fiber arrangement of composite has a significant impact on bending strength,0/90fiber layer can improve the strength of the materials (at room temperature from167MPa to530MPa); Carbon fiber surface bonding strength state have influenced the mechanical properties of materials, the tensile strength of T300epoxy composites is583.1MPa, bending strength is505MPa, Impact toughness is95.4KJ/m. The tensile strength of T700epoxy composites is693.14MPa, bending strength530MPa.T700composites is281KJ/m2.5. Compared with room temperature, tensile strength at low temperature has increased and the growth rate is about20%. Bending strength has also improved. Among of all, the strength of ChanXiangBu orthogonal layer fiber reinforced materials and T700pane cloth reinforced materials at low temperature is bigger, respectively for1157.80MPa and1168.60MPa. Impact toughness as the temperature decrease. Based on this topic found that (±45°seam fiber composite material impact toughness at room temperature and low temperature is best, respectively for347KJ/m2and151.61KJ/m2. we have also found that composite material damage is severe at low temperature, and interface unglued area is bigger by the SEM images.6. Finally, the low temperature toughening mechanism is discussed. Micro cracks theory have been adopt to research the interface fracture performance.2D finite element method is used to analysis in order to forecast the performance of composites. |
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