42 lines
1.4 KiB
Mathematica
42 lines
1.4 KiB
Mathematica
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function kg = geometricStiffMtxUL(Anl,Elem,U)
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% Element properties
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A = Elem.A;
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I = Elem.I;
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L = elemLength(Elem,U);
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% Internal forces
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P = Elem.fi(4);
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M1 = Elem.fi(3);
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M2 = Elem.fi(6);
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% Simplifications
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L2 = L*L;
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L3 = L2*L;
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PI = P*I;
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AL = A*L;
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AL2 = A*L2;
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AL3 = A*L3;
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% First order terms
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kg1 = P/L *[ 1 0 0 -1 0 0;
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0 6/5 L/10 0 -6/5 L/10;
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0 L/10 2*L2/15 0 -L/10 -L2/30;
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-1 0 0 1 0 0;
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0 -6/5 -L/10 0 6/5 -L/10;
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0 L/10 -L2/30 0 -L/10 2*L2/15 ];
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% Second order terms
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% if (Anl.geom_mtx == 1)
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kg2 = zeros(6,6);
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% elseif (Anl.geom_mtx == 2)
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% kg2 = [ 0 0 -M1/L 0 0 -M2/L;
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% 0 12*PI/AL3 6*PI/AL2 0 -12*PI/AL3 6*PI/AL2;
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% -M1/L 6*PI/AL2 4*PI/AL M1/L -6*PI/AL2 2*PI/AL;
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% 0 0 M1/L 0 0 M2/L;
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% 0 -12*PI/AL3 -6*PI/AL2 0 12*PI/AL3 -6*PI/AL2;
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% -M2/L 6*PI/AL2 2*PI/AL M2/L -6*PI/AL2 4*PI/AL ];
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% end
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% Geometric matrix
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kg = kg1 + kg2;
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end
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