Introduction to GRASP - General Rotorcraft Aeromechanical Stability Program - A Modern Approach to Rotorcraft Modeling,

Abstract

The General Rotorcraft Aeromechanical Stability Program (GRASP) is described in terms of its capabilities and development philosophy. The program is capable of treating the nonlinear static and linearized dynamic behavior of structures represented by arbitrary collections of rigid-body and beam elements that may be connected in an arbitrary fashion and are permitted to have large relative motions. The main limitation is that periodic coefficient effects are not treated, restricting the solutions to rotorcraft in axial flight and ground contact conditions. Rather than following in the footsteps of other rotorcraft programs, GRASP is more of a hybrid between finite element programs and spacecraft-oriented multibody programs. GRASP differs from standard finite-element programs by allowing multiple levels of substructures in which the substructures can move and/or rotate relative to others with no small-angle approximations. This capability facilitates the modeling of rotorcraft structures, including the rotating/nonrotating interface and details of the blade/root kinematics for various rotor types.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1986
Accession Number
ADA174161

Entities

People

  • A. S. Hopkins
  • Dewey H. Hodges
  • Donald L. Kunz
  • Howard E. Hinnant

Tags

DTIC Thesaurus Topics

  • Air Masses
  • Aircrafts
  • Airframes
  • Composite Materials
  • Computational Science
  • Elastic Properties
  • Equations
  • Equations Of Motion
  • Experimental Data
  • Finite Element Analysis
  • Flow Fields
  • Frequency
  • Helicopters
  • Mechanics
  • Modulus Of Elasticity
  • Relative Motion
  • Rotary Wing Aircraft

Fields of Study

  • Physics

Readers

  • Aerospace Engineering
  • Robotics and Automation.
  • Structural Dynamics.

Technology Areas

  • Space
  • Space - Spacecraft Maneuvers