纤维束交叉起伏对缠绕复合材料刚度的影响

Calculating stiffness of filament winding composite for considering the filament undulation and crossover

纤维缠绕过程会在局部区域形成纤维束的起伏、交织。针对起伏区域纤维束的非正交交织的特点,提出一种缠绕复合材料刚度的计算方法:先通过螺旋缠绕角度和起伏层倾斜角度,将三维刚度进行两次转换,然后将转换后的起伏区域的三维刚度转化成缠绕层面内二维有效刚度;利用二维有效刚度,将缠绕复合材料刚度系数Aij、Bij和Dij各项在起伏区域上进行数值积分取平均值,再利用转换矩阵得到缠绕复合材料的整体刚度矩阵。算例的结果表明,考虑了纤维束的起伏、交织后缠绕复合材料刚度矩阵发生了一些变化,特别是耦合刚度的变化更为明显。

The filament-winding process introduces the fiber undulations and the nonorthogonality of the crossover geometry into thin-shell cylinders.This research identified the micromechanical geometry in the fiber crosserover regions of filament-wound cylinders.A new method for calculating the stiffness of filament winding composites is presented.The calculating process is roughly divided into three steps.First,the 3D stiffness for the undulating layer was converted to a 2D effective stiffness through the two angles,namely the angle of inclination,the out-of-plane angle due to the fiber undulation,and the filament winding angle,the in-plane angle.Next,lamination theory was used to obtain the local laminate stiffness which was functions of the undulation direction,and the stiffness constants were numerically integrated and averaged along the length of the undulation.Third,the whole stiffness of filament winding composites was calculated through the transformed matrix between the principal coordinate axis and the direction of filament-winding.Some important changes exhibited by the stiffness matrices,especially the stiffness coupling effects due to the fiber undulation are obvious.