Page 534 - Thomson, William Tyrrell-Theory of Vibration with Applications-Taylor _ Francis (2010)

Computer Programs

This appendix contains the flow diagram s for the four com puter program s in the
software accom panying the test. The background discussions for these programs
are presented in Chapter 4 for the R unge-K utta calculations, and in Chapter 8 for
the Polynom ial, the Iteration, and the Cholesky-Jacobi calculations.
Each flow diagram is preceded by a brief statement describing the course of
the calculation. For the more detailed steps of the calculations, the complete
program can be printed out by typing the pro g ra m n am e followed by .for.

RUNGA

Program R U N G A solves the differential equation

m x -t- c i + /cx = / ( r )
described in Sec. 4.8 of Chapter 4 and follows the same pattern of com putation.
See Fig. F -1. W ith y = i, the equation is written as

y = f i t ) - cy - k x ] = F { x , y , t )

The user inputs values for m, c, and /c, and up to 20 pairs of t and f i t ) to
describe the forcing function. Function f i t ) is linearly interpolated between input
points.
The output is given for about 2.5 (30 /4 = 2.39) periods with increm ents of
about 1 / 1 2 ( 1 / 1 2 = 0.08) period. The output can be num erical an d /o r a rough
graph.

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