The initial version of the General Rotorcraft Aeromechanical Stability Program (GRASP) was developed for analysis of rotorcraft in steady, axial flight and ground contact conditions. In these flight regimes, the material continua of the rotorcraft may experience deformations which are independent of time. GRASP can obtain this steady-state solution and can solve the eigenproblem associated with perturbations about such a steady-state solution. GRASP is the first program implementing a new method for dynamic analysis of structures, parts of which may be experiencing discrete motion relative to other parts. Application of this new method to GRASP, including substructuring, frames of reference, nodes, finite elements and constraints, is described in the paper. The library of finite elements includes a powerful nonlinear beam element that incorporates aeroelastic effects based on a simple nonlinear, aerodynamic theory with unsteady induced inflow.
Analysis of Structures with Rotating, Flexible Substructures Applied to Rotorcraft Aeroelasticity in GRASP (General Rotorcraft Aeromechanical Stability Program)
1987
11 pages
Report
No indication
English
Aircraft , Aeroelasticity , Rotary wing aircraft , Motion , Flight envelope , Nonlinear systems , Rotation , Structures , Deformation , Finite element analysis , Perturbations , Aerodynamics , Theory , Structural analysis , Computer programs , Stiffness , Beams(Structural) , Nodes , Eigenvalues , Axes , Solutions(General) , Steady state , Nonlinear analysis , GRASP computer program , Aeromechanical stability