How can I create FEA colour plots?

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Tamas Lanci 2020-3-6

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编辑： Tamas Lanci 2020-4-16

Hi Everyone,

I have an array of dataset containing X,Y coordinates and their corresponding FEA results (Von Mises, Displacement, Strain).

What is the easiest way to plot this data on coloured contour plots?

Thank you for your help.

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Tamas Lanci 2020-4-3

Can you be a bit more specific?

I have tried to fiddle with the commands you recommended but I couldn't work out how to create the plot.

darova 2020-4-3

Please show your attempts. Attach the data

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回答（1 个）

Lubos Smolik 2020-4-3

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Assuning that you have a planar rectangular geometry and coordinates and results are stored in vectors x, y and vonMises, you can use the following code:

% x - vector of x coordinates
% y - vector of y coordinates
% vonMises - nodal von Mises stress
n = 50; % number of levels
contourf(x, y, vonMises, n);
xlim([min(x) max(x)]);
ylim([min(y) max(y)]);
xlabel("X coordinate")
ylabel("Y coordinate")
bar = colorbar;
title(bar, "Von Mises stress")

If your geometry is not rectangular, then you also need some information about connections between individual nodes as J. Alex Lee has already noted.

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Lubos Smolik 2020-4-3

编辑：Lubos Smolik 2020-4-3

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Do you still think ContourF function is the applicable in this case?

Definitely yes!

You can take full advantage of a fact that contourf does not fill areas with NaN values. The idea comes from this Matlab answer.

In your case, you need to create ghost nodes in the hollow area. The following code should do the trick.

% Import input data
% x - vector of x coordinates
% y - vector of y coordinates
% vonMises - nodal von Mises stress
% Create "ghost points"
r   = 10;   % radius of the hollow area
            % I am assunming that the centre of the area is in x = 0, y = 0.
pts = 60;   % number of the ghost points
phi  = linspace(0, 2*pi, pts + 1)';
ptsX = 0.999 * r * cos(phi(1:end-1));
ptsY = 0.999 * r * sin(phi(1:end-1));
% Add the ghost points to your input data
x = [x; ptsX]; % I am assuming that x is a column vector
y = [y; ptsY];
vonMises = [vonMises; nan(size(ptsX))];
% Plot countour diagram
n = 50; % number of levels
contourf(x, y, vonMises, n);
xlim([min(x) max(x)]);
ylim([min(y) max(y)]);
xlabel("X coordinate")
ylabel("Y coordinate")
bar = colorbar;
title(bar, "Von Mises stress")

Alternatively, you can use your input data and just draw a white circle in the hollow area.

EDIT: Typo corrected.

Lubos Smolik 2020-4-4

https://www.mathworks.com/matlabcentral/answers/509490-how-can-i-create-fea-colour-plots#comment_820886

Tamas, have you checked comment https://www.mathworks.com/matlabcentral/answers/509490-how-can-i-create-fea-colour-plots#comment_820742 ? I used scatteredInterpolant there and than visualised data using surface function.

Tamas Lanci 2020-4-10

编辑：Tamas Lanci 2020-4-16

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Thank you for everybody's help.

I used the TriScatteredInterp method with the ghost nodes as suggested:

clear all
clc
M=readmatrix("DIC_PLATE_COPY.csv");
%Mu=M(1:2:end,:);
px=(M(:,1));
py=(M(:,2));
pz=(M(:,10));
r   = 6;   % radius of the hollow area
% I am assunming that the centre of the area is in x = 0, y = 0.
pts = 500;   % number of the ghost points
phi  = linspace(0, 2*pi, pts + 1)';
ptsX = 0.999 * r * cos(phi(1:end-1));
ptsY = 0.999 * r * sin(phi(1:end-1));
% Add the ghost points to your input data
px = [px; ptsX]; % I am assuming that x is a column vector
py = [py; ptsY];
pz = [pz; nan(size(ptsX))];
x=linspace(min(px(:,1)),max(px(:,1)),1000);
y=linspace(min(py(:,1)),max(py(:,1)),1000);
[X,Y]=meshgrid(x,y);
F=TriScatteredInterp(px(:,1),py(:,1),pz(:,1));
[M c]=contourf(X,Y,F(X,Y),40,'LineColor','none');
daspect([1 1 1])
colormap(jet)
colorbar 