78 lines
2.9 KiB
78 lines
2.9 KiB
function [nodes, eles, eleNum, nodeNum] = GenerateMesh(lx, ly, numx, numy, removedE)
|
|
% To Mesh a membrane using 4 noded Elements
|
|
%--------------------------------------------------------------------------
|
|
%--------------------------------------------------------------------------
|
|
% Purpose:
|
|
% To Mesh a square/rectangular membrane to use in FEM Analysis
|
|
% Synopsis :
|
|
% [coordinates,nodes,nel,nnode] = GenerateMesh(lx,ly,numx,numy)
|
|
% Variable Description:
|
|
% Input :
|
|
% lx - length of the membrane along X-axes
|
|
% ly - breadth of the membrane along Y-axes
|
|
% numx - number of Elements along X-axes
|
|
% numy - number of Elements along Y-axes
|
|
% Output :
|
|
% nodes - The nodal coordinates of the mesh
|
|
% -----> nodes = [node X Y]
|
|
% arranged by cols: x = 0,y = 10:0 ...
|
|
% eles - The nodal connectivity of the elements
|
|
% arranged by cols: ex = 0,ey = 10:0 ...
|
|
% Nodes sequence in one element:
|
|
% _______ 0 _____ x
|
|
% | 1 2 | |
|
|
% | | |
|
|
% |_4___3_| y
|
|
% -----> nodes = [node1 node2......]
|
|
% nel- total number of elements
|
|
% nnodes- total number of nodes
|
|
%--------------------------------------------------------------------------
|
|
% lx = numx;
|
|
% ly = numy;
|
|
|
|
eleNum = numx * numy; % Total Number of Elements in the Mesh
|
|
nnel = 4; % Number of nodes per Element
|
|
% Number of points on the Length and Breadth
|
|
npx = numx + 1;
|
|
npy = numy + 1;
|
|
nodeNum = npx * npy; % Total Number of Nodes in the Mesh
|
|
% Discretizing the Length and Breadth of the membrane
|
|
nx = linspace(0, lx, npx);
|
|
ny = linspace(0, ly, npy);
|
|
[xx, yy] = meshgrid(nx, fliplr(ny));
|
|
XX = xx; YY = yy;
|
|
|
|
nodes = zeros(nodeNum, 2);
|
|
nodes(:, [1, 2]) = [XX(:) YY(:)];
|
|
|
|
% To get the Nodal Connectivity Matrix
|
|
NodeNo = 1:nodeNum;
|
|
eles = zeros(eleNum, nnel);
|
|
|
|
% small code for selecting nodal point number for specific element
|
|
NodeNo = reshape(NodeNo, npy, npx);
|
|
eles(:, 4) = reshape(NodeNo(1:npy - 1, 1:npx - 1), eleNum, 1);
|
|
eles(:, 3) = reshape(NodeNo(1:npy - 1, 2:npx), eleNum, 1);
|
|
eles(:, 2) = reshape(NodeNo(2:npy, 2:npx), eleNum, 1);
|
|
eles(:, 1) = reshape(NodeNo(2:npy, 1:npx - 1), eleNum, 1);
|
|
|
|
% if have removedE
|
|
if nargin > 4
|
|
removedN1 = eles(removedE, :);
|
|
eles(removedE, :) = [];
|
|
removedNodes = setdiff(removedN1(:), eles(:));
|
|
nodes(:, 3) = 1:nodeNum;
|
|
nodes(removedNodes, :) = [];
|
|
|
|
nodeNum = size(nodes, 1);
|
|
eleNum = size(eles, 1);
|
|
|
|
% eles still save old nodes idx, repair it
|
|
for i = 1:4
|
|
[~, r] = intersect(nodes(:, 3), eles(:, i));
|
|
eles(:, i) = r;
|
|
end
|
|
end
|
|
|
|
% figure;
|
|
% scatter(nodes(:,1),nodes(:,2),'filled');
|