基于悬臂梁位移模型的直升机桨叶损伤检测

从悬臂梁位移模型出发,建立桨叶结构损伤检测的位移残差范数准则,通过桨叶实测位移残差的范数分析结构是否存在局部裂纹损伤,研究一种基于悬臂梁位移模型的桨叶结构损伤检测方法.桨叶结构损伤用裂纹大小或刚度下降等参数指标表示.采用能量方法分析裂纹对梁元弯曲刚度的影响,建立裂纹梁有限元模型,根据桨叶有限元模型构造一种节点力残差向量,利用该力残差向量可确定损伤位置和损伤程度.最后,通过实例验证方法的可行性和有效性.

DAMAGE ASSESSMENT OF HELICOPTER BLADE BASED ON CANTILEVER BEAM DISPLACEMENT MODEL

Cantilever beam displacement model was used to establish the damage criterion for helicopter blade which is defined as the modulus of residual displacement vector from the measured displacement data. Fail in meeting the criterion indicated presence of some damage. Such a structure damage assessment method based on cantilever beam displacement model was developed. The damage of blade structure was quantified in terms of stiffness change and crack size. The stiffness matrix for the crack element was derived using energy approach to take account of bending stiffness degeneration. Residual nodal force vector was obtained for the blade finite element method (FEM) model, which was used to indicate the location and extent of the damage. Experiments on a sample blade verified the effectiveness of proposed method.