Operation Order and Matrix Agreement Not working

Question

Lawson Hoover 2012-11-30

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/55235-operation-order-and-matrix-agreement-not-working

This code will not run with the error "inner matrix dimensions must agree".I am not sure is the fomulas are written out completely. This utilizes the Deflection equations found here (It is a pdf of multiple deflection equations):

https://encrypted.google.com/url?sa=t&rct=j&q=deflection%20equations&source=web&cd=4&ved=0CD8QFjAD&url=http%3A%2F%2Fcourses.arch.ntua.gr%2Ffsr%2F141842%2FElastiki%2520grammi.pdf&ei=_hC4UIr4NIS_2QX67IG4Bw&usg=AFQjCNHCQ_6BZkPTCDDLyTkMIWagEd9xVA

I used the formulas on: 2, 3, 7, 8

I is the moment of Inertia L is the actual Length of the beam b is the width of the beam x is the points to test on a beam // this is saved a a vector 0 is omega which is the Force(Magnitude) divided by the Length of the beam

Please help if you can understand this or know what is wrong.

 I = z.Inertia;
  L = z.Length;
  b = z.Width;
  x = linspace(0,z.Length);
  o = z.Magnitude/z.Length;   % Magnitude is them same as the force
if z.Load == 1
    if z.Support == 1 
        Beam.y1 = (F*x.^2/6*E*I)*(3*a-x);  % 0<x<a
        Beam.y2 = (F*a^2/6*E*I)*(3*x-a);   % a<x<L
    else  % x.Support == 2
        Beam.y1 = (F*b*x/6*L*E*I)*(L^2-x.^2-b^2);                  % 0<x<a
        Beam.y2 = (F*b/6*E*L*I)*((L/b)*(x-a)^3+(L^2-b^2)*x-x.^3);  % a<x<L
    end
else    % x.Load == 2
    if z.Support == 1
        Beam.y1 = (o*x.^2/24*E*I)*(x.^2+6*L^2-4*L*x);
    else % x.Support == 2 
        Beam.y1 = (o*x.^2/24*E*I)*((L^3-2*L*x.^2)+x.^3);
    end
end

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Walter Roberson 2012-11-30

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/55235-operation-order-and-matrix-agreement-not-working#answer_67016

在 MATLAB Online 中打开

Several parts of your code have expressions of the general form

f(x) * g(x)

where x is a row vector and f and g transform row vectors to row vectors. Therefore the multiplication you are requesting by the "*" operator is matrix multiplication between two row vectors. Matrix multiplication requires columns to match with rows, not rows to match with rows.

What you probably want is the .* operator

f(x) .* g(x)

which does element-by-element multiplication.