计及纤维交叉起伏影响的缠绕复合材料刚度分析

针对缠绕复合材料交叉起伏区域的细观结构,建立了一种细观分析模型。首先,将纤维交叉起伏区域划分为环向交叉起伏区和螺旋交叉起伏区2种类型;然后,以缠绕面为基准,用平行横截面将起伏区域空间结构模型离散化为多个子模型,运用纤维束起伏角、富树脂区域尺寸、纤维束的体积分数、纤维束的横截面形状及尺寸等细观参数来描述缠绕复合材料交叉起伏区域的细观结构。基于所建立的细观模型及层合板理论,提出了缠绕复合材料交叉起伏区域的等效刚度计算方法。通过算例研究了纤维束截面、纤维束起伏角以及富树脂区体积分数等细观参数对局部区域等效刚度的影响。结果表明:环向交叉起伏区的弹性模量比螺旋交叉起伏区下降得更为明显;在富树脂区域,弹性模量和剪切模量降低较为明显,而泊松比则有所增大。纤维束厚度增加及纤维束截面变化对交叉起伏区域等效刚度会产生明显影响。 

Stiffness analysis of filament wound composites considering filament crossover and undulation

Aimed at the meso-structure of crossover and undulation region in filament wound composites, a meso-scale analytical model is proposed. First, the crossover and undulation region are classified to two types, i.e. the circumferential crossover and undulation region, and the helical crossover and undulation region. Next, based on the filament wound surface, parallel cross-section was used to discrete spatial structure model of undulation region, which will be discretized to numbers of sub-models to describe the meso-structure of crossover and undulation region of filament wound composites by using meso-parameters such as fiber bundle inclination angle, size of resin rich area, volume fraction, cross-section shape and size of fiber bundle. With this meso-scale model and the laminate theory, a method for calculating the equivalent stiffness of crossover and undulation region of filament wound composites is eventually established. The effects of cross-section, inclination angle of fiber bundle and the volume fraction of resin rich area on local area equivalent stiffness were studied. The results show that the elastic modulus for circumferential crossover and undulation region decreases to greater extent as compared that of the helical crossover and undulation region. Significant decrease in elastic modulus and shear modulus and increase in Poisson's ratio are found for resin rich area. Thickness increase and cross-section change of fiber bundle have evident effects on the equivalent stiffness of crossover and undulation region.