Author: Publisher:
ISBN:
Category : Aeroelasticity
Languages : en
Pages : 156
Book Description
General Rotorcraft Aeromechanical Stability Program (GRASP): Theory Manual
Author: General Rotorcraft Aeromechanical Stability Program (GRASP) Version 1.03: User's Manual
Author: A. Stewart HopkinsPublisher:
ISBN:
Category :
Languages : en
Pages : 70
Book Description
The Rotorcraft Dynamics Division, Aeroflightdynamics Directorate, U.S. Army Aviation Research and Technology Activity has developed the General Rotorcraft Aeromechanical Stability Program (GRASP) to perform calculations that will assess the stability of rotorcraft in hovering flight and ground contact conditions. This computer program is designed to be a state-of-the-art, hybrid, finite-element/multibody code that can be applied to all existing and future helicopter configurations. While GRASP was specifically designed to solve rotorcraft stability problems, its innovative structure and formulation allow for applications to a wide range of structures. This manual describes the preparation of the input file required by Version 1.03 of GRASP, the procedures used to invoke GRASP on the NASA Ames Research Center Cray X-MP 48 computer, and the interpretation of the output produced by GRASP. The parameters used by the input file are defined, and summaries of the input file and the job control language are included. Keywords: Aeroelasticity; Rotary wings.
Scientific and Technical Aerospace Reports
Author: Integrated Technology Rotor Methodology Assessment Workshop
Author: Michael J. McNultyTechnical Reports Awareness Circular : TRAC.
Author: General Rotorcraft Aeromechanical Stability Program (Grasp)
Author: National Aeronautics and Space Administration (NASA)Publisher: Createspace Independent Publishing Platform
ISBN: 9781723088933
Category :
Languages : en
Pages : 156
Book Description
The general rotorcraft aeromechanical stability program (GRASP) was developed to calculate aeroelastic stability for rotorcraft in hovering flight, vertical flight, and ground contact conditions. GRASP is described in terms of its capabilities and its philosophy of modeling. The equations of motion that govern the physical system are described, as well as the analytical approximations used to derive them. The equations include the kinematical equation, the element equations, and the constraint equations. In addition, the solution procedures used by GRASP are described. GRASP is capable of treating the nonlinear static and linearized dynamic behavior of structures represented by arbitrary collections of rigid-body and beam elements. These elements may be connected in an arbitrary fashion, and are permitted to have large relative motions. The main limitation of this analysis is that periodic coefficient effects are not treated, restricting rotorcraft flight conditions to hover, axial flight, and ground contact. Instead of following the methods employed in other rotorcraft programs. GRASP is designed to be a hybrid of the finite-element method and the multibody methods used in spacecraft analysis. GRASP differs from traditional finite-element programs by allowing multiple levels of substructure 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 the details of the blade/root kinematics for various types. GRASP differs from traditional multibody programs by considering aeroelastic effects, including inflow dynamics (simple unsteady aerodynamics) and nonlinear aerodynamic coefficients. Hodges, Dewey H. and Hopkins, A. Stewart and Kunz, Donald L. and Hinnant, Howard E. Ames Research Center AERODYNAMIC STABILITY; AEROELASTICITY; DYNAMIC STRUCTURAL ANALYSIS; FINITE ELEMENT METHOD; HOVERING; ROTARY WING AIRCR...
Monthly Catalogue, United States Public Documents
Author: Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1644
Book Description
Monthly Catalog of United States Government Publications
Author: Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1200
Book Description
A Collection of Technical Papers
Author: Aeronautical Engineering
Author: Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1036
Book Description
A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).