ANALYSIS OF A LAMINATED BLADE RETENTION SYSTEM

Design of a helicopter main rotor blade retention system is a challenging problem. This critical system must reliably carry large blade loads while allowing extreme blade motions. Several different methods for blade retention systems are currently in service including laminated metallic stacks (LMS). Due to the lack of precise analytic methods laminated metallic stack systems have historically been developed through test. A methodology, developed by the authors, is presented herein to accurately predict the behavior of a LMS blade retention system. This method uses nonlinear finite element (FE) analysis to predict LMS motions and stresses. Finite element results are interrogated to obtain damage and fatigue life predictions. The analytical results are compared to test data with excellent agreement thus verifying the methodology.