Ski boot walking attachment appendix
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- | =Logarithmic Decrement | + | =Code= |
+ | ==Logarithmic Decrement== | ||
+ | ===readenct.m=== | ||
+ | Reads in the text file generated by the MSE Rectilinear apparatus. | ||
+ | <pre> | ||
+ | <nowiki> | ||
+ | function [t,f,val]=readenct(filename,vd,encnum) | ||
+ | |||
+ | a=textread(filename,'','headerlines',23); | ||
+ | if strcmp(vd,'d') | ||
+ | val=-a(:,encnum+1); | ||
+ | end | ||
+ | if strcmp(vd,'v') | ||
+ | val=-a(:,encnum+5); | ||
+ | end | ||
+ | t=a(:,1); | ||
+ | f=a(:,2); | ||
+ | </nowiki> | ||
+ | </pre> | ||
+ | |||
+ | ===num4.m=== | ||
+ | Using the data returned by readenct, allows determination of physical constants using logarithmic decrament analysis. | ||
+ | <pre> | ||
+ | <nowiki> | ||
+ | [time,force,displacement]=readenct('medium_natural.txt','d',1); | ||
+ | figure(1) | ||
+ | plot(time,displacement+0.1198); | ||
+ | axis([10.6 11.4 -4 4.2]) | ||
+ | |||
+ | |||
+ | a=ginput | ||
+ | c=max(a) | ||
+ | |||
+ | figure(2) | ||
+ | plot(time,displacement+0.1198); | ||
+ | axis([10.6 11.4 -4 4.2]) | ||
+ | |||
+ | |||
+ | b=ginput | ||
+ | d=max(b) | ||
+ | |||
+ | prompt={'Number of Peaks in between','X Coordinate First MAX.','X Coordinate Second MAX.'} | ||
+ | name='Get User Input'; | ||
+ | numlines=1; | ||
+ | defaultanswer={'0','0','0'}; | ||
+ | answer=inputdlg(prompt,name,numlines,defaultanswer); | ||
+ | n=str2double(answer{1}); | ||
+ | x1=str2double(answer{2}); | ||
+ | x2=str2double(answer{3}); | ||
+ | |||
+ | T=(x2-x1)/(n); | ||
+ | dampingRatio=((1/(n-1))*(log(c(1,2)/d(1,2))))/sqrt((4*pi^2)+((1/(n-1))*(log(c(1,2)/d(1,2))))^2) | ||
+ | naturalFrequency=((1/(n-1))*log(c(1,2)/d(1,2)))/(dampingRatio*T) | ||
+ | dampedNaturalFrequency=naturalFrequency*sqrt(1-dampingRatio^2) | ||
+ | m=0.79; | ||
+ | k=naturalFrequency^2*m | ||
+ | CoefficientOfDamping=dampingRatio*2*sqrt(k*m) | ||
+ | </nowiki> | ||
+ | </pre> |
Revision as of 20:55, 9 December 2008
Contents |
Code
Logarithmic Decrement
readenct.m
Reads in the text file generated by the MSE Rectilinear apparatus.
function [t,f,val]=readenct(filename,vd,encnum) a=textread(filename,'','headerlines',23); if strcmp(vd,'d') val=-a(:,encnum+1); end if strcmp(vd,'v') val=-a(:,encnum+5); end t=a(:,1); f=a(:,2);
num4.m
Using the data returned by readenct, allows determination of physical constants using logarithmic decrament analysis.
[time,force,displacement]=readenct('medium_natural.txt','d',1); figure(1) plot(time,displacement+0.1198); axis([10.6 11.4 -4 4.2]) a=ginput c=max(a) figure(2) plot(time,displacement+0.1198); axis([10.6 11.4 -4 4.2]) b=ginput d=max(b) prompt={'Number of Peaks in between','X Coordinate First MAX.','X Coordinate Second MAX.'} name='Get User Input'; numlines=1; defaultanswer={'0','0','0'}; answer=inputdlg(prompt,name,numlines,defaultanswer); n=str2double(answer{1}); x1=str2double(answer{2}); x2=str2double(answer{3}); T=(x2-x1)/(n); dampingRatio=((1/(n-1))*(log(c(1,2)/d(1,2))))/sqrt((4*pi^2)+((1/(n-1))*(log(c(1,2)/d(1,2))))^2) naturalFrequency=((1/(n-1))*log(c(1,2)/d(1,2)))/(dampingRatio*T) dampedNaturalFrequency=naturalFrequency*sqrt(1-dampingRatio^2) m=0.79; k=naturalFrequency^2*m CoefficientOfDamping=dampingRatio*2*sqrt(k*m)