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63 lines
1.9 KiB
63 lines
1.9 KiB
3 years ago
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%--------------------------------------------------------------------------
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% Mesh a L-shape using 4 noded Elements
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%--------------------------------------------------------------------------
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function [nodes, eles, eleNum, nodeNum,plotIdx, iK, jK] = GenerateL(nelx, nely)
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% dbstop if error
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% nelx = 20;
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% nely = 20;
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% left - rec
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[nodes1, eles1, eleNum1, nodeNum1] = GenerateMesh(nelx/2, nely, nelx/2, nely);
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% right - square
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[nodes2, eles2, eleNum2, nodeNum2] = GenerateMesh(nelx/2, nely/2, nelx/2, nely/2);
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nodes1(:,3) = 1:nodeNum1;
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borderNodes = nodes1(end-nely:end-nely/2,3); % get border nodes index for eles2
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% offset + nodes2
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nodes2(:,1) = nodes2(:,1)+nelx/2;
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nodes2(:,2) = nodes2(:,2)+nely/2;
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% eles2(1:nely/2+1) -> borderNodes
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[~,cols] = intersect(eles2,1:nely/2+1);
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% offset + eles2
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eles2 = eles2+nodeNum1-(nely/2+1);
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% eles2(1:nely/2+1) -> borderNodes
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tempeles2 = eles2(:);
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tempeles2(cols,1) = borderNodes;
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eles2 = reshape(tempeles2,eleNum2,4);
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nodes = [nodes1;nodes2(nely/2+2:end,:)];
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eles = [eles1;eles2];
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eleNum = eleNum1+eleNum2;
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nodeNum = nodeNum1+nodeNum2-(nely/2+1);
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nodes(:,3) = 1:nodeNum;
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% compute the ele IDX of L shape, include the right-down empty square
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plotIdx = 1:(nely*nelx/2); % left - rec
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for i = 0:(nelx/2-1)
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temp = (i*nely+1) : (nely/2+(i*nely));
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plotIdx = [plotIdx,temp+(nely*nelx/2)];
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end
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edofMat = zeros(eleNum, 8);
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for i = 1:eleNum
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for j = 1:4
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edofMat(i, [2*j-1,2*j]) = [2 * eles(i, j) - 1, 2 * eles(i, j)];
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end
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end
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iK = reshape(kron(edofMat, ones(8, 1)).', 64 * eleNum, 1);
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jK = reshape(kron(edofMat, ones(1, 8)).', 64 * eleNum, 1);
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% test
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% scatter(nodes(:,1),nodes(:,2));
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% figure;
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% for i = 1:eleNum
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% node = eles(i,:);
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% scatter(nodes(node,1),nodes(node,2));hold on;
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% end
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end
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