Code for graphing bending moment is giving the wrong graph and I don't know why, can anyone help?

Question

Tess 2022-11-5

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1844283-code-for-graphing-bending-moment-is-giving-the-wrong-graph-and-i-don-t-know-why-can-anyone-help

编辑： Jan 2022-11-6

采纳的回答： VBBV

在 MATLAB Online 中打开

clear;

range=[0 10];

nweights=3;

w=150;

Wk=[1500 -3000 2500];

p=[3 5 7];

L=max(range);

M=0;

y=0;

M0=0;

sumM=0;

for x=0:L

for k=1:1:nweights

if(x>=0) && (x<=p(k))

M=(Wk(k)*x*(1-(p(k)/L)));

else

if(x>p(k)) && (x<=L)

M=(Wk(k)*x*(1-(p(k)/L))) - (Wk(k)*(x-p(k)));

end

Mt=sumM;

M0=(0.5*w*x*(L-x));

y(x+1)=M0 + Mt;

end

v=0:L;

figure;

plot(v,y);

xlabel('distance x from A (in m)');

ylabel('Bending moment M (in Nm)');

title('A graph showing variation of the bending moment with distance from A');

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Tess 2022-11-5

How would I change it so that Mt changed for each loop?

Torsten 2022-11-5

How should I know how Mt has to change in each iteration ?

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Answer 1

VBBV 2022-11-5

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1844283-code-for-graphing-bending-moment-is-giving-the-wrong-graph-and-i-don-t-know-why-can-anyone-help#answer_1092168

在 MATLAB Online 中打开

Mt=sum(M);

May be by doing this change

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VBBV 2022-11-5

编辑：VBBV 2022-11-5

在 MATLAB Online 中打开

if(x>=0) & (x<=p(k))
          M(k)=(Wk(k)*x*(1-(p(k)/L)));
      else
          if(x>p(k)) & (x<=L) 
              M(k)=(Wk(k)*x*(1-(p(k)/L))) - (Wk(k)*(x-p(k)));
          end 
      end

And this too

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Answer 2

Jan 2022-11-5

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1844283-code-for-graphing-bending-moment-is-giving-the-wrong-graph-and-i-don-t-know-why-can-anyone-help#answer_1092178

编辑：Jan 2022-11-6

在 MATLAB Online 中打开

% sumM=0;    % not here
for x=0:L
    sumM=0;  % but here
    for k = 1:nweights
        if x<=p(k)
            M = Wk(k) * x * (1 - p(k) / L);
        else  % if x>p(k) 
            M = Wk(k) * x * (1 - p(k) / L) - Wk(k) * (x - p(k));
        end
        % Maybe here:
        sumM = sumM + M;
    end 
    Mt = sumM;
    M0 = 0.5 * w * x * (L-x);
    y(x+1) = M0 + Mt;
end