USA flag logo/image

An Official Website of the United States Government

Numerically Efficient Rotorcraft Trim and Transient Response

Award Information

Department of Defense
Award ID:
Program Year/Program:
1996 / SBIR
Agency Tracking Number:
Solicitation Year:
Solicitation Topic Code:
Solicitation Number:
Small Business Information
Advanced Rotorcraft Technology, Inc.
1330 Charleston Rd Mountain View, CA -
View profile »
Woman-Owned: No
Minority-Owned: No
HUBZone-Owned: No
Phase 1
Fiscal Year: 1996
Title: Numerically Efficient Rotorcraft Trim and Transient Response
Agency / Branch: DOD / ARMY
Contract: N/A
Award Amount: $69,965.00


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.

Principal Investigator:

Cheng-jian He Ph.d.

Business Contact:

Small Business Information at Submission:

Advanced Rotorcraft
1685 Plymouth Street, Suite 250 Mountain View, CA 94043

Number of Employees: N/A
Woman-Owned: No
Minority-Owned: No
HUBZone-Owned: No