Numerically Efficient Rotorcraft Trim and Transient Response

Award Information
Agency: Department of Defense
Branch: Army
Contract: N/A
Agency Tracking Number: 32853
Amount: $749,338.00
Phase: Phase II
Program: SBIR
Awards Year: 1998
Solicitation Year: N/A
Solicitation Topic Code: N/A
Solicitation Number: N/A
Small Business Information
Advanced Rotorcraft
1685 Plymouth St. Suite 250, 250, Mountain View, CA, 94043
DUNS: N/A
HUBZone Owned: N
Woman Owned: N
Socially and Economically Disadvantaged: N
Principal Investigator
 Cheng-jian He Ph.d.
 (415) 968-1464
Business Contact
Phone: () -
Research Institution
N/A
Abstract
We propose to develo a numerically efficient rotorcraft trim and transient response algorithm. The algorithm is intended for application in a periodic dynamic system with a large number of degrees of freedom as is commonly the case in current comprehensive rotorcraft analysis codes (such as 2GCHAS). The innovation of this proposal can be summarized as follows: 1) Utilizing Model Order Reduction to establish a sufficiently accurate reduced order model based on model reduction from finite elements to find the rotorcraft trim. The transient of the full finite element dynamic equations are solved using the solution from the reduced order model as an initial estimation to reduce the runtimes to reach steady state. 2) Taking advantage of periodicity of a multi-bladed rotor to reduce the size of rotor system equations by a factor of the number of blades. 3) Applying the Quasi-Newton method for the solution of nonlinear equations to overcome the disadvantage of computing and inverting the Jacobian matrix as required in the Newton-Raphson method. Utilization of Broyden-Fletcher-Shanno Rank Two algorithm, one of the most successful algorithm of the Quasi-Newton method in nonlinear equation solutions, will allow the aerodynamic effects to be included in the solution iteration. Thus, the solution convergence speed will be improved.

* information listed above is at the time of submission.

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