ode45 求微分方程。

M文件:

function dy=Acable_Fun(t,y)

global ksi w1 a1 a2 a3 a4 OmeggaA

dy = zeros(2,1);

dy(1) = y(2);

dy(2) =-2*ksi*w1*y(2)-(w1^2+a1*sin(OmeggaA*t))*y(1)-3*a2*y(1)^2-a3*y(1)^3-4*a4*sin(OmeggaA*t);

ksi=0.006;

w1=1.8692;

a1=0.1266;

OmeggaA=2*pi*0.2787;

a2=0.0551;

a3=0.0142;

a4=0.1228;

运行

[tA2,yA2]=ode45(@Acable_Fun,[0 500],[0 0]);figure(2),plot(tA2,yA2(:,1));xlabel('时间(s)');ylabel('跨中位移(m)');yAmax2=max(yA2(3500:end,1))

Answer 1

[libamoh]

function dy=Acable_Fun(t,y)

ksi=0.006;

w1=1.8692;

a1=0.1266;

OmeggaA=2*pi*0.2787;

a2=0.0551;

a3=0.0142;

a4=0.1228;

dy = zeros(2,1);

dy(1) = y(2);

dy(2) =-2*ksi*w1*y(2)-(w1^2+a1*sin(OmeggaA*t))*y(1)-3*a2*y(1)^2-a3*y(1)^3-4*a4*sin(OmeggaA*t);

[tA2,yA2]=ode45(@Acable_Fun,[0 500],[0 0]);figure(2),plot(tA2,yA2(:,1));xlabel('时间(s)');ylabel('跨中位移(m)');yAmax2=max(yA2(3500:end,1))