Plotting for loop values
显示 更早的评论
Hello! I am trying to plot values using a for loop but everytime I run the code I get a figure with nothing on it except for axis values. I am not sure how to fix this.
EA=30000;
alpha=30;
beta=30;
gamma=180-(alpha+beta);
a=20;
n=6;
L_ab=a;
L_bc=(a*sind(alpha))/(sind(beta));
L_ac=(a*sind(alpha+beta))/(sind(beta));
for h = 0.1:0.1:1
syms r phi
U=((n*EA)/2)*(L_ab*((2*(r/L_ab)*sin(pi/n)-1)^2)+L_bc*(((sind(beta)/sind(alpha))*sqrt(((h/L_ab)^2)...
-(2*((r/L_ab)^2)*cos(phi))+2*((r/L_ab)^2)))-1)^2+L_ac*((sind(beta)/sind(alpha+beta))*sqrt(((h/L_ab)^2)...
-(2*((r/L_ab)^2)*cos(phi+(2*pi/n)))+(2*((r/L_ab)^2)))-1)^2);
assume(phi>=0 & phi<=2*pi)
assumeAlso(r<=2)
assumeAlso(r,'positive')
eqns=[diff(U,r)==0,diff(U,phi)==0]
sol=vpasolve(eqns,[r,phi])
sol1=sol.r
sol2=sol.phi
plot(h,sol1,'r'); hold on
plot(h,sol2,'b')
end
回答（1 个）
David Hill
2021-3-11
编辑：David Hill
2021-3-11
Try indexing
h=.1:.1:1;
for H = 1:length(h)
syms r phi
U=((n*EA)/2)*(L_ab*((2*(r/L_ab)*sin(pi/n)-1)^2)+L_bc*(((sind(beta)/sind(alpha))*sqrt(((h(H)/L_ab)^2)...
-(2*((r/L_ab)^2)*cos(phi))+2*((r/L_ab)^2)))-1)^2+L_ac*((sind(beta)/sind(alpha+beta))*sqrt(((h(H)/L_ab)^2)...
-(2*((r/L_ab)^2)*cos(phi+(2*pi/n)))+(2*((r/L_ab)^2)))-1)^2);
assume(phi>=0 & phi<=2*pi)
assumeAlso(r<=2)
assumeAlso(r,'positive')
eqns=[diff(U,r)==0,diff(U,phi)==0]
sol=vpasolve(eqns,[r,phi])
sol1(H)=sol.r
sol2(H)=sol.phi
end
plot(h,sol1,'r',h,sol2,'b');
3 个评论
Ashmika Gupta
2021-3-11
David Hill
2021-3-11
Are you getting a solution?
sol=vpasolve(eqns,[r,phi]);
Is the above line passing?
Ashmika Gupta
2021-3-12
类别
在 帮助中心 和 File Exchange 中查找有关 Programming 的更多信息
2021-3-11
2021-3-12
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
