Computer program calculates normal vibration modes of complex structures elimating excessively large amounts of input data, run time, and core storage. Provision for accuracy improvement is also included

Jones, C. E.

Kiefling, L.

Whetstone, W. D.

English

NASA Technical Reports Server

June 1972 
•	 NASA TECH BRIEF 
Marshall Space Flight Center 
B72-10265 
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Snap Dynamics 
The problem: 
A fast and economically efficient method was needed 	 printed out for the user. Provision for accuracy improve-
to calculate the normal vibration modes of complex 	 ment is also included. 
structures. Available methods required excessively large 
amounts of input data, run time, or core storage. 	 Notes: 
1. This program was written in FORTRAN V for use on 
The solution:	 the UNIVAC 1108 computer. Program options permit 
A program was developed specifically to eliminate 	 the use of an SC-4020 plotter. 
the problems mentioned above. 	 2. Inquiries concerning this program should be addressed 
to: 
How it's done: 
• Computer run time is minimized by reducing to a 
minimum the number of operations within the machine 
and the amount of data transferred to and from the 
secondary storage. 
Both run times and storage requirements are reduced 
by considering only the non-zero elements of the 
matrices and by taking advantage of all the symmetry 
conditions. Pseudo inverse and iteration are used to find 
only the needed modes. 
The data input is a group of data libraries, and the 
structure is visualized as a structural network. A series of 
accuracy checks are made with each iteration and
COSMIC 
112 Barrow Hall 
University of Georgia 
Athens, Georgia 30601 
Reference: MFS.21531 
Patent status: 
No patent action is contemplated by NASA. 
Source: L. Kiefling, W. D. Whetstone 
and C. E. Jones
Marshall Space Flight Center
(MFS-2 153 1) 
•
Category 09 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States	 will be free from privately owned rights.
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Snap dynamics

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