Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

% calculations of envelope from vehicle uniformly distributed load
Max = zeros(n,n);
Min = zeros(n,n);
for j = 1:n
    for i = 1:n
        if Im(i,j)>= 0
            Max(i,j) = Im(i,j)*q_max*dx;
            Min(i,j) = 0;
        end
        if Im(i,j)<0
            Max(i,j) = 0;
            Min(i,j) = Im(i,j)*q_max*dx;
        end
    end
end
for i = 1:n
    EnvQ(i,1) = sum(Min(:,i));
    EnvQ(i,2) = sum(Max(:,i));
end
% calculations of envelope from vehicle passage
temp = [zeros(36,n);Im]
+ [zeros(24,n);Im;zeros(12,n)] 
+ [zeros(12,n);Im;zeros(24,n)] 
+ [Im;zeros(36,n)];
for i = 1:n
    EnvV(i,1) = min(temp(:,i))*V_max;
    EnvV(i,2) = max(temp(:,i))*V_max;
end
% calculations of total envelope
Env = EnvG + EnvQ + EnvV;
% preparation of figures and saving of envelopes
figure('WindowState','maximized')
x = 0:dx:sum(L);
plot(x,EnvG(:,1),'b',x,EnvG(:,2),'r',
'LineWidth',1.5)
xlim([0 sum(L)])
set(gca,'ydir','reverse','FontSize',14)
xlabel('x [m]')
ylabel('M [kNm]')
title('Env M(G)')
grid
saveas(gcf,'Env_M(G).fig')
saveas(gcf,'Env_M(G).bmp')
figure('WindowState','maximized')
x = 0:dx:sum(L);
plot(x,EnvQ(:,1),'b',x,EnvQ(:,2),'r',
'LineWidth',1.5)
xlim([0 sum(L)])
set(gca,'ydir','reverse','FontSize',14)
xlabel('x [m]')
ylabel('M [kNm]')
title('Env M(Q)')
grid
saveas(gcf,'Env_M(Q).fig')
saveas(gcf,'Env_M(Q).bmp')
figure('WindowState','maximized')
x = 0:dx:sum(l);
plot(x,EnvV(:,1),'b',x,EnvV(:,2),'r',
'LineWidth',1.5)
xlim([0 sum(L)])
set(gca,'ydir','reverse','FontSize',14)
xlabel('x [m]')
ylabel('M [kNm]')
title('Env M(V)')
grid
saveas(gcf,'Env_M(V).fig')
saveas(gcf,'Env_M(V).bmp')
figure('WindowState','maximized')
x = 0:dx:sum(L);
plot(x,Env(:,1),'b',x,Env(:,2),'r',
'LineWidth',1.5)
xlim([0 sum(L)])
set(gca,'ydir','reverse','FontSize',14)
xlabel('x [m]')
ylabel('M [kNm]')
title('Env M(G,Q,V)')
grid
saveas(gcf,'Env_M.fig')
saveas(gcf,'Env_M.bmp')
plot(x,EnvG(:,1),'b',x,EnvG(:,2),'r',

↑

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for

mismatched delimiters.

[Walter Roberson]

This appears to be from the paper

Application of Matlab software in static calculations of bridge structures

by Paweł Hawryszków, Bronisław Czaplewski

[Norma]

yes, can u solve my problem. because the code from paper i think stil incorrect

[Walter Roberson]

Everything before the final line you posted is part of table 2, ending at the bottom of the second last panel of table 2 right above the MATLAB logo.

The final line you posted is a partial line from roughly 1/2 way down on the final panel of table 2, posted missing some of the lines above it. The line got truncated by whoever copied it. The actual line is

plot(x,EnvQ(:,1),’b’,x,EnvQ(:,2),’r’, ’LineWidth’,1.5)

but you need the other lines from the last panel of table 2.

Answer 1

[madhan ravi]

 plot(x,Env(:,1),'b',x,Env(:,2),'r')

Note: just responding to the error message, assuming rest of the code works fine.

[Norma]

how?

[Dyuman Joshi]

@Norma, It's not clear (atleast to me) what you are asking about in the comment above.

Please be more specific.

[Image Analyst]

What is n and Im in your code? We can't run it.