带负扭转的复合材料桨叶蒙皮分层裂纹尖端场分析

蒙皮分层是复合材料浆叶疲劳破坏的主要形式.本文采用非线性桨叶结构模型,推导广义二雏下带负扭转的直升机菜叶蒙皮的位移方程及应力一应变关系;在此基础上,基于Stroh理论,采用各向异性界面断裂力学分析了蒙皮存在分层裂纹时裂尖应力场和位移场的渐近解.通过数值算例分析了离心力作用下带不同负扭转桨叶蒙皮分层裂尖的振荡系数、应力场及应力强度因子,所得结果合理,表明本文方法可以为复合材料菜叶蒙皮分层破坏提供分析依据.

Analysis of Delamination Crack Tip Fields for Composite Blade Skins with Untwist

The delamination of skins is the main fatigue failure type for composite blades. The generalized two-dimensional displacement equations and stress-strain relationships of blade skins of the helicopter with untwist are derived by the nonlinear structural model for blades. Based on the Stroh formal-ism, the asymptotic solutions of stress fields and the displacement at the delamination crack tip are obtained by applying the interracial fracture mechanics for anisotropic bimaterials. The oscillatory indexes, stress fields and stress intensity factors are numerically researched for the delamination crack tip of blade skins with initial twist on the centrifugal forces. The reasonable results indicate that the method can be used as the basis for analyzing the delamination failure of composite blade skins.