Forced vibration response Ode45

Question

Ryan 2014-4-24

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/127039-forced-vibration-response-ode45

回答： Mohammed Siraj 2021-9-23

I am suck on a question for an assignment. I can not get matlab to work the following function I keep getting error messages.

function f=t

F=940*sin(10*pi*t);

k=50000;

damping=0.05;

r=3.224;

x(1+t)=(F/k)/sqrt((1-R^2)^2+4*(damping^2)*r^2);

t=1/(10*pi);

[x,t]=ode45('f',[T,T*50],0);

plot(x)

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A Jenkins 2014-4-25

编辑：A Jenkins 2014-4-25

Perhaps you should start with an example that works and slowly make modifications to it until you get to your final result?

Then you will know exactly what change you made and therefore only one line will be incorrect at a time.

(We try not to do people's homework for them, so we only answer specific questions here.)

Ryan 2014-4-26

I didn't ask for you to do it for me as you don't have the assignment question. I asked for help with the code I wrote. I have figured out how to do the problem any way.

function [du]=QuestionE(t,u);

du=zeros(2,1);

Damping=0.05;

wn=9.74;

du(1)=-2*Damping*wn*u(1)-u(2)*(wn^2)+(940/530)*sin(10*pi*t);

du(2)=u(1);

end

Damping=0.05;

wn=9.75;

omega=10*pi;

k=50000

m=527.1;

g=9.81;

r=omega/wn;

F=940

wd=wn.*sqrt(1-Damping.^2);

timespan=(50*2*pi)/omega

xst=-(m*g)/k;

v0=0;

A=xst;

B=(v0+Damping*wn*xst)/wd;

[t,u]=ode45(@QuestionE1,[0 timespan],[v0,xst]);

u=exp(-Damping.*wn.*t).*(A.*cos(wd.*t)+B.*sin(wd.*t));

y=(2*Damping*r)/(1-r^2);

fi=atan(y);

X=((F/k)/(sqrt((1-(r^2))^2+4*(Damping^2)*(r^2))))

u1=X.*cos(omega.*t-fi)+u;

plot(t,u,'k')

hold on

plot(t,u1,'b')

title('Forced Vibration Responce')

xlabel('Time')

ylabel('x(t)')

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Answer 1

Mohammed Siraj 2021-9-23

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/127039-forced-vibration-response-ode45#answer_793409

在 MATLAB Online 中打开

 Write the program for the task given: The motion of the forced vibratory system with spring-
mass system is modeled by the following equation, solve the differential equation and find the 
displacement, velocity with respect to time (from 0 to 120 seconds).Analyze the system by 
MATLAB Programming and validate the solution by using SIMULINK. Assume m=1 kg, k=2 
N/m, F=120N and ω=1 rad/sec.