% cantbeamanimation.m Last modified 7/29/2008 % Uniform cantilever beam animation via the steady state solution to % the Bernoulli_Euler beam equation. The beam is driven by a sinusiodal % motion of amplitude Y0 to the root of the beam. % Input is the ratio of driving freq. to the first natural freq. % This m-file was written at the University of Wyoming in the Electrical % and Computer Engineering Department and is to be distributed without % cost. clear all set(0,'DefaultAxesFontSize',12); set(0,'DefaultTextFontSize',12); fratio=-1; disp(' ') while fratio<=0|fratio==1 string1=' The ratio of excitation freq. to first natural freq. = '; fratio=input(string1); if fratio==1 disp(' ') disp(' This is the resonant case choose another freq. ratio'); disp(' ') end end xoverL=linspace(0,1,201); betaL=sqrt(fratio)*1.8751041; betax=betaL*xoverL; cL=cos(betaL); sL=sin(betaL); chL=cosh(betaL); shL=sinh(betaL); c1=cos(betax); s1=sin(betax); ch1=cosh(betax); sh1=sinh(betax); delta=-2*(1+chL*cL); A=(-1-chL*cL-sL*shL)/delta; C=(-sL*chL-shL*cL)/delta; amplitude=ch1+A*(c1-ch1)+C*(s1-sh1); lim=max(abs(amplitude)); figure(1);clf; plot(xoverL,abs(amplitude)) hold on plot([0 1],[0 0]); axis([0 1 -.2*lim 1.2*lim]); text(.8,1.1*lim,['f/f_1 = ',num2str(fratio)]) xlabel('Dimensionless distance from the fixed end, x/L') ylabel('Dimensionless Amplitude, |y(x)/Y_0|') text(.1,1.1*lim,'Press Enter to Continue') xp1=[0 -.1 -.1 0 0]; yp1=[-.2*lim -.2*lim .2*lim .2*lim -.2*lim]; amplitude=[1 amplitude]; xoverL=[-.07 xoverL]; pause figure(2);clf; set(gca,'Box','on') axis([-.3 1.3 -2*lim 2*lim]); xlabel('Distance, x/L') ylabel('Displacement, y(x,t)/Y_0') hold on texthandle2=text(-.1,-1.6*lim,['f/f_1 = ',num2str(fratio)]); ys=amplitude*0; plot(xoverL,ys,'k','LineWidth',[1.5]); hold on ydata=[ys]; texthandle2=text(0,1.5*lim,'Press Enter to Animate one Frame at a Time'); xlabel('Distance , x/L'); pause t=linspace(0,8*pi,257); sine=sin(t); for k=1:2:65 ys=amplitude*sine(1,k); plot(xoverL, ys,'k','LineWidth',[2.5]); hold on set(texthandle2,'String', 'Press Enter to Animate One Frame at a Time'); pause end set(texthandle2,'String','Press Enter to Continue'); pause figure(3);clf; axis([-.3 1.3 -2*lim 2*lim]); hold on set(gca,'Box','on') hold on P=plot(xp1,yp1,'EraseMode','xor'); xlabel('Distance, x/L') ylabel('Displacement, y(x,t)/Y_0') hold on x1=[-.3 1.3];y1=[0 0]; plot(x1,y1) hold on texthandle2=text(-.1,-1.6*lim,['f/f_1 = ',num2str(fratio)]); ys=amplitude*0; L=plot(xoverL,ys,'k','EraseMode','xor','LineWidth',[3.5]); ydata=[ys(1,2:202)]; texthandl=text(0,1.5*lim,'Press Enter to Animate'); xlabel('Distance , x/L') ylabel('Displacement, y(x,t)/Y_0') pause set(texthandl,'String',' '); t=linspace(0,8*pi,257); sine=sin(t); for k=2:257 ys=amplitude*sine(1,k);; yp2=yp1+ones(1,5)*sine(1,k); set(L,'Ydata',ys); set(P,'Ydata',yp2); pause(.05) ydata=[ydata ;ys(1,2:202)]; end set(texthandl,'String','Press Enter to Continue'); pause figure(4);clf; [X,T]=meshgrid(xoverL(1,2:202),t); mesh(X,T,ydata) axis([0 1 0 30 -1.2*lim 1.2*lim]); text(1,5,-lim,'Dimensionless Time, \omegat','Rotation',-10) text(1,30,-lim,'Dimensionless Distance, x/L','Rotation',32) zlabel('Displacement, y(x,t)/Y_0') view(120,30) text(0,10,1.1*lim,'Press Enter to Continue','Rotation',-10); pause