GLTRS--Glenn
TITLE AND SUBTITLE:
Modified Fully Utilized Design (MFUD) Method for Stress and Displacement Constraints

AUTHOR(S):
Surya Patnaik, Atef Gendy, Laszlo Berke, and Dale Hopkins

REPORT DATE:
August 1997

FUNDING NUMBERS:
WU-505-63-5B

PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES):
National Aeronautics and Space Administration
Lewis Research Center
Cleveland, Ohio 44135-3191

PERFORMING ORGANIZATION REPORT NUMBER:
E-10267

SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES):
National Aeronautics and Space Administration
Washington, D.C. 20546-0001

REPORT TYPE AND DATES COVERED:
Technical Memorandum

SPONSORING/MONITORING AGENCY REPORT NUMBER:
NASA TM-4743

SUPPLEMENTARY NOTES:
Surya N. Patnaik, Ohio Aerospace Institute, 22800 Cedar Point Road, Cleveland, Ohio 44142; Atef Gendy, National Research Council-NASA Research Associate at Lewis Research Center; Laszlo Berke and Dale Hopkins, NASA Lewis Research Center. Responsible person, Laszlo Berke, organization code 5200, (216) 433-5648.

ABSTRACT:
The traditional fully stressed method performs satisfactorily for stress-limited structural design. When this method isextended to include displacement limitations in addition to stress constraints, it is known as the fully utilized design (FUD). Typically, the FUD produces an overdesign, which is the primary limitation of this otherwise elegant method. We have modified FUD in an attempt to alleviate the limitation. This new method, called the modified fully utilized design (MFUD) method, has been tested successfully on a number of designsthat were subjected to multiple loads and had both stress and displacement constraints. The solutions obtained with MFUD compare favorably with the optimum results that can be generated by using nonlinear mathematical programming techniques. The MFUD method appears to have alleviated the overdesign condition and offers the simplicity of a direct, fully stressed type of design method that is distinctly different from optimization and optimality criteria formulations. The MFUD method is being developed for practicing engineers who favor traditional design methods rather than methods based on advanced calculus and nonlinear mathematical programming techniques. The Integrated Force Method (IFM) was found to be the appropriate analysis tool in the development of the MFUD method. In this paper, the MFUD method and its optimality are presented along with a number of illustrative examples.

SUBJECT TERMS:
Fully utilized design; Force method; Optimization techniques

NUMBER OF PAGES:
22

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1997/TM-4743.pdf
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