Plotting a multivariable function

Question

Akshay Pratap Singh 2019-2-20

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/445944-plotting-a-multivariable-function

评论： Akshay Pratap Singh 2019-2-20

采纳的回答： KSSV

在 MATLAB Online 中打开

I wrote a code for plotting a mutivariable function but getting error like "Error using fplot (line 136)

Invalid parameter '0 ...'.

Error in SFDBMDNLK (line 83)

fplot(SF,x,SF1,x).

How can I resolve it?

code:

clear all
clc
format longEng
syms  y1 y2 x
phi=(pi/180)*39;
delta=(pi/180)*26;
gma=18.4;
h=4;
h1=1.91;
h2=0.088;
L=h+h1+h2;
q=0;
beta=1;
alfa=1;
Ra1=-1; 
Ra2=-(alfa*(y2))^0.5;
Rp1=3*(beta*(1-y1))^0.5;
Rp2=3*(alfa*(y2))^0.5;
delma1=0.5*(1-Ra1)*delta;
delma2=-0.5*(1-Ra2)*delta;
delmp1=0.5*(Rp1-1)*delta;
delmp2=0.5*(Rp2-1)*delta;
ka1=(2*cos(phi)^2)/(cos(phi)^2*(1+Ra1)+cos(delma1)*(1-Ra1)*(1+sqrt((sin(phi+delma1)*sin(phi))/cos(delma1)))^2);
ka2=(2*cos(phi)^2)/(cos(phi)^2*(1+Ra2)+cos(delma2)*(1-Ra2)*(1+sqrt((sin(phi+delma2)*sin(phi))/cos(delma2)))^2);
kp1=1+0.5*(Rp1-1)*((cos(phi)^2/(cos(delmp1)*(-sqrt((sin(phi+delmp1)*sin(phi))/cos(delmp1))+1)^2))-1);
kp2=1+0.5*(Rp2-1)*((cos(phi)^2/(cos(delmp2)*(-sqrt((sin(phi+delmp2)*sin(phi))/cos(delmp2))+1)^2))-1);
fup1=matlabFunction(kp1*y1*cos(delmp1));
Final_result_p1=gma*(x-h)^2*integral(fup1,0,1);
M21=matlabFunction(kp1*cos(delmp1)*y1);
Final_result_m21=gma*h1*(x-h)^2*integral(M21,0,1);
M22=matlabFunction(kp1*cos(delmp1)*y1^2);
Final_result_m22=gma*(x-h)^3*integral(M22,0,1);
Final_result_m2=Final_result_m21+Final_result_m22;
Hfup1=matlabFunction(kp1*y1*cos(delmp1));
HFinal_result_p1=gma*h1^2*integral(Hfup1,0,1);
T31=matlabFunction(kp2*cos(delmp2));
HFinal_result_T31=gma*(h+h1)*(x-h-h1)*integral(T31,0,1);
T32=matlabFunction(ka2*cos(delma2));
HFinal_result_T32=gma*h1*(x-h-h1)*integral(T32,0,1);
T33=matlabFunction(kp2*cos(delmp2)*y2-ka2*cos(delma2)*y2);
HFinal_result_T33=gma*(x-h-h1)^2*integral(T33,0,1);
T3=HFinal_result_T31+HFinal_result_T32+HFinal_result_T33;
M21=matlabFunction(kp1*cos(delmp1)*y1);
Result_M21=gma*h1*(x-h)^2*integral(M21,0,1);
M22=matlabFunction(kp1*cos(delmp1)*y1^2);
Result_M22=gma*(x-h)^3*integral(M22,0,1);
M23=matlabFunction(kp1*y1*cos(delmp1));
Result_M23=gma*(x-h-h1)*(x-h)^2*integral(M23,0,1);
M31=matlabFunction(kp2*cos(delmp2)*y2);
Result_M31=gma*(h+h1)*0.5*(x-h-h1)^2*integral(M31,0,1);
M32=matlabFunction(ka2*cos(delma2)*y2);
Result_M32=gma*h1*0.5*(x-h-h1)^2*integral(M32,0,1);
M3=Result_M31-Result_M32;
M4=matlabFunction((kp2*cos(delmp2)-ka2*cos(delma2))*y2*(1-y2));
Result_M4=gma*(x-h-h1)^3*integral(M4,0,1);
MT1=-0.5*ka1*gma*x^2*cos(delma1);
MM1=-(1/6)*ka1*gma*x^3*cos(delma1);
MT2=-0.5*ka1*gma*x^2*cos(delma1);
MM2=-(1/6)*ka1*gma*x^3*cos(delma1);
i=0;
for x=0:0.02:L
    i=i+1;
    if(x<h)
        SF(i)=MT1;
        SF1(i)=0;
        BM(i)=MM1;
        BM1(i)=0;
    elseif(x>=h && x<(h+h1))
        SF(i)=MT2+Final_result_p1;
        SF1(i)=0;
        BM(i)=MM2+Final_result_m2;
        BM1(i)=0;
    else
        SF(i)=-0.5*ka1*gma*(h+h1)^2*cos(delma1) + HFinal_result_p1 - T3;
        SF1(i)=0;
        BM(i)=-0.5*ka1*gma*(h+h1)^2*(((h+h1)/3)+(x-h-h1))*cos(delma1)+ M3 - Result_M4; %0.5*kp1*gma*h1^2*((h1/3)+(x-h-h1))*cos(delmp1)-0.5*gma*(x-h-h1)^2*(kp2*(h+h1)*cos(delmp2)-ka2*h1*cos(delma2))-(1/6)*(kp2*cos(delmp2)-ka2*cos(delma2))*(x-h-h1)^3;
        BM1(i)=0;  
    end
end
x=0:0.02:L;
subplot(2,1,1);
fplot(SF,x,SF1,x)
xlabel('Length of the beam in m')
ylabel('Shear Force in KN')
title('Shear force diagram')
col_header={'x',SF};
xlswrite('data.xlsx',[x(:),SF(:)],'Sheet1','A2');
xlswrite('data.xlsx',col_header,'Sheet1','A1');
subplot(2,1,2)
fplot(BM,x,BM1,x)
xlabel('Length of the beam in m')
ylabel('Bending Moment in KN-m')
title('Bending Moment diagram')
col_header={'x',BM};
xlswrite('data.xlsx',[x(:),BM(:)],'Sheet1','A2');
xlswrite('data.xlsx',col_header,'Sheet1','A1');