# Machine Design

Document Sample

```					  Dynamics System
Modeling- and Controls
-
EGR 345 Lab #3

Introduction to Mechanical
System Modeling

Brian Malkowski
Andrew Edler

9-21-99
Purpose:
Determine the coefficient of kinetic friction between a block sliding on an
inclined surface. This will be done for a block of wood and a block of metal.

Method:
Method 1: A strobe light will be used to generate equal time intervals.
Measurements of the position will be taken at these time intervals to determine the
acceleration of the block.
Method 2: Photo sensors will be placed at equidistant intervals along the inclined
surface. Measurements of the time will be recorded using the LabView program. This
data then will be used to calculate the acceleration of the block.
Method 3: Working Model program will be used to simulate the blocks sliding
down the inclined surface.

Results:
The results that were obtained in this experiment are linked here:
Working Model simulation http://www.eod.gvsu.edu/~edlera/EGR_345/Lab3a.wm
Labview Program data collection http://claymore.engineer.gvsu.edu/~malkowsb/EGR/egr345/lab3a.vi

Discussion of Results:
A Working Model simulation was set up to compare the results that were obtained
experimentally. Coefficients of kinetic friction, which were calculated in Mathcad using
experimental data, were used in Working Model to obtain the acceleration on the blocks.
The following tables show a comparison of the acceleration obtained experimentally

2
Acceleration m/s
Coef. of
Wood           0.083          3.958        3.959
Metal          0.324          7.471        1.882

Table 1. Equal Distance Measurements

2
Acceleration m/s
Coef. of
Wood           0.512          0.265        0.261
Metal           0.53          0.106        0.106

Table 2. Equal Time Measurements

Based on the data from the tables above, it appears that the calculated acceleration
from the equal time measurements were more accurate than the equal distance
measurements calculations.
Possible reasons for the discrepancy of the equal distance calculations could be
inaccurate sensors. In addition the metal block had holes in it, which might have affected