Download or read book General Rotorcraft Aeromechanical Stability Program GRASP Theory Manual written by and published by . This book was released on 1990 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book General Rotorcraft Aeromechanical Stability Program Grasp Theory Manual written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-11-18 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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...
Download or read book General Rotorcraft Aeromechanical Stability Program GRASP Version 1 03 User s Manual written by A. Stewart Hopkins and published by . This book was released on 1988 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book General Rotorcraft Aeromechanical Stability Program Grasp Version 1 03 written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-07 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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. The program is designed to be 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 application 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. Hopkins, A. Stewart and Kunz, Donald L. Ames Research Center...
Download or read book Introduction to GRASP General Rotorcraft Aeromechanical Stability Program A Modern Approach to Rotorcraft Modeling written by Dewey H. Hodges and published by . This book was released on 1986 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Reports Awareness Circular TRAC written by and published by . This book was released on 1987 with total page 746 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Application of GRASP General Rotorcraft Aeromechanical Stability Program to Nonlinear Analysis of a Cantilever Beam written by Howard E. Hinnant and published by . This book was released on 1987 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The General Rotorcraft Aeromechanical Stability Program (GRASP) was developed to analyse the steady-state and linearized dynamic behavior of rotorcraft in hovering and axial flight conditions. Because of the nature of problems GRASP was created to solve, the geometrically nonlinear behavior of beams is one area in which the program must perform well in order to be of any value. Numerical results obtained from GRASP are compared to both static and dynamic experimental data obtained for a cantilever beam undergoing large displacements and rotations caused by deformations. The correlation is excellent in all cases.
Download or read book Integrated Technology Rotor Methodology Assessment Workshop written by Michael J. McNulty and published by . This book was released on 1988 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Correlation of Analytical Calculations from GRASP General Rotorcraft Aeromechanical Stability Program with Torsionally Soft Rotor Data written by Donald L. Kunz and published by . This book was released on 1987 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: As a part of the continuing effort to develop and validate the General Rotorcraft Aeromechanical Stability Program (GRASP), a correlation study is presented to compare the frequency, moment, and stability data for a model-scale, torsionally-soft, helicoptor rotor with GRASP numerical calculations. The hierarchical representation of the model rotor is discussed along with the calculations of the vacuum frequencies, the steady-state blade moments in air, and the aeroelastic stability. Correlation is generally quite good. The GRASP predictions of the first vacuum flap frequencies are outstanding and the first vacuum lag and torsion frequencies correlate reasonably well with the experimental data. Consistently outstanding results are obtained for all of the steady blade moments. The calculations of stability data are in general as good as those made by other programs, but are not quite as good as anticipated.
Download or read book Monthly Catalogue United States Public Documents written by and published by . This book was released on 1991 with total page 1644 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on with total page 1200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Collection of Technical Papers written by and published by . This book was released on 1987 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aeronautical Engineering written by and published by . This book was released on 1991 with total page 1036 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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).
Download or read book NASA Army Rotorcraft Technology Volume 1 Aerodynamics and Dynamics and Aeroelasticity written by and published by . This book was released on 1988 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA SP written by and published by . This book was released on 1991 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Conference Publication written by and published by . This book was released on 1988 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:
