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36 lines
933 B
36 lines
933 B
3 years ago
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%--------------------------
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% @Author: Jingqiao Hu
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% @Date: 2020-10-29 15:04:18
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% @LastEditors: Please set LastEditors
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% @LastEditTime: 2020-11-28 21:49:16
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%--------------------------
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function f = elastic_force(F, dF, nodeNum, edofMat, lx, u, l)
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f = zeros(nodeNum*2, 1);
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jac = lx^2/4;
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eleNum = size(edofMat,1);
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for gp = 1:4
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dFe = dF{gp}; % 4 * 8 * m
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Fe = F{gp, 1}; % 4 * m
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P2(1, :, :) = PK1_fast(u, l, Fe); % 4 * m
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fe = squeeze(mtimesx(P2, dFe)) * jac; % 8*m
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for ele = 1:eleNum
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edof = edofMat(ele, :);
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f(edof) = f(edof) - fe(:, ele); % NOTE: MINUS!
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end
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end
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end
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function PP = PK1(u,l,F)
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% Neo hookean
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JJ = log(det(F));
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Finv = inv(F)';
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PP = u*(F-Finv) + l*JJ*Finv;
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% Linear
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% I = eye(3,3);
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% PP = u*(F + F'-2*I) + l * (trace(F)-3) * I;
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end
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