MODELING OF MECHANICAL SYSTEMS BY ANSYS

m

k

m

kExample:2.1

k=35000 N/mm=100 kg

ω=18.71 rad/s=2.98 Hz

* Run ANSYS Interactive

* Set Working Directory

* Run Notepad text editor and write the following commands below.

/prep7et,1,mass21et,2,combin14r,1,0,100r,2,35000,0n,1,0,0n,2,0,0.25type,1real,1e,2type,2real,2e,1,2

1

2

/solud,all,ux,0d,all,uz,0

antype,2modopt,lanb,1solve finish

Save as e01.txt

Write e01.txt in ANSYS Command Window

General Postproc > Results Summary

d,1,uy,0

eplot

File>Clear&Start New...>OK>YES

In Example 2.1,* The command file is prepared with a text editor. (Notepad)* The file is run in ANSYS

GUI can used by clicking ANSYS menu without preparing a command file.

et,1,mass21

Main Menu>Preprocessor>Element Type>Add/Edit/Delete>Add...>

Help>Help on can be used for more information abut the ANSYS commnads.

The commands are recorded in a file with an extension of “.log” The “.log” file can be examined in a text editor.

Structural Mass>3D mass 21

* Programs establish a mathematical model of a system, solve it and give results

In CAD/CAE programs like ANSYS:

* System elements and connections are defined in programs with commands

Gy2y1

k c k c

L1 L2

m,IyA yB

Homework 01C - Problem 4:m=1050 kg, I=670 kg-m2 k=35300 N/m, c=2000 Ns/m L1=1.7 m, L2=1.4 m

yA and yB are the inputs, y1 ve y2 generalized coordinates.f1=1.2968 Hz, f2=2.5483 Hz

Soluiton by ANSYS:/prep7et,1,beam3et,2,mass21et,3,combin14r,1,0.2,7e-4,0.1r,2,0,1050,0,0,0,670r,3,35300,2000mp,ex,1,200e9

1 23

4 5

type,1real,1mat,1e,1,3e,3,2

n,1,0,0n,2,3.1,0n,3,1.7,0n,4,0,-0.25n,5,3.1,-0.25

type,2real,2e,3type,3real,3e,1,4e,2,5

d,all,ux,0d,all,uz,0

d,4,uy,0d,5,uy,0antype,2modopt,lanb,2solve finish

General Postprocessing> Results Summary

/solu

eplot