solving coupled differential system

Question

0 个投票

Hello. I am trying to solve two coupled differential equation as below:

m1x"+m2ry"=-k1(2x1-x2-x0)

m2x"+Ay"=-k2x1+Ky-f

Note: m1,m2,k1,k2,x2,x0,A,k2,K,f are known

thanks alot

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John D'Errico 2020-4-25

编辑：John D'Errico 2020-4-25

Why was it necessaryu to ask this question twice? I've closed the other one you asked.

Answer 1

Radu Trimbitas 2020-4-25

0 个投票

Dear Saman,

If set x=u(1), x'=u(2), y=u(3), y'=u(4) and

M=[1,0,0,0; 0, m1,0,m2; 0,0,1,0; 0, m2,0,A], then the system becomes

[u(2); -k1*(2*x1-x2-x0); u(4);-k2*x1+K*u(3)-f];

M could be seen as a mass matrix and can be introduced using option Mass in odeset function, see the attachment.

saman ahmadi 2020-4-25

thanks alot Dear Radu Trimbitas

saman ahmadi 2020-4-30

dear Dear Radu

Hi. i can solve this problem using your guidenc, now,how can i plot frequency graph for this problem?(i change primary equations to ode)

thanks alots