The Analytical Characterization of Nonlinear Strain Rate Dependent Triazial Braided Composite
With the increasing application of fibre reinforced polymer matrix composites in the aerospace industry, a composite model that has the capability to capture the nonlinear, strain rate dependent deformation behaviour of the material is desired for analysis. Due to their low cost and high impact resistance, textile composites are gaining more favour in aerospace industry nowadays. Under circumstances where the strain rate is high, such as in an impact problem, the nonlinear, strain rate dependent deformation behaviour of composites becomes important for a proper simulation.Polymers are believed to be the major contributors to the nonlinearity and rate dependence of the composites. In this study, the nonlinear, strain rate dependent constitutive polymer model developed by modified Goldberg to incorporate the rate dependence of the elastic modulus and a simple damage model were proposed to improve its unloading prediction. The polymer constitutive equations were then implemented within strength of material based micromechanics method in order to predict the nonlinear, strain rate dependent deformation of the composite.Triaxial braided composite with through-thickness integration method was proposed with example to simulate the deformation behaviour. The basic idea in the braiding methodology is first to select the unit cell representing the fibre architecture in the lamina. Unit cell is defined as the smallest repeating fibre architecture in the triaxial textile composites. The axis 1 is the fibre direction, the axis 2 is the transverse direction and the axis 3 is the thickness direction. The unit cell is then divided into four sub-cells. For one layer, each sub-cell is divided into 2 or 3 slices of equal thickness in the thickness direction. Each of the slices represents a fibre bundle in 0, or direction respectively. Equally spaced integration points are assigned to each of the slices in the sub-cells.The triaxial braided (T300/QY9512 carbon fibre/epoxy) composite of fibre architecture (00±45o) was examined with the method. The deformation behaviour of the coupon tensile specimen were successfully predicted, especially the nonlinear deformation behaviour in the matrix dominated transverse system.
Zhao Yong-Li
Tianjin Polytechnic University
国际会议
南京
英文
1
2009-10-18（万方平台首次上网日期，不代表论文的发表时间）