stiffnessmatrix.m

是个好东西

function k= StiffnessMatrix( ie ) % (定义单刚计算函数)
      global node element material K
      k = zeros( 6, 6 ) ;  % (零矩阵)
      E = material( element(ie, 3), 1 ) ; %(弹性模量)
      A = material( element(ie, 3), 2 ) ; %(截面积) 
      I=material(element(ie,3),3);        %惯性据
      xi = node( element( ie, 1 ), 1 ) ;  %(两端座标)
      yi = node( element( ie, 1 ), 2 ) ;  %(两端座标)
      xj = node( element( ie, 2 ), 1 ) ;  %(两端座标)
      yj = node( element( ie, 2 ), 2 ) ;  %(两端座标)
      L = ( (xj-xi)^2 + (yj-yi)^2)^(1/2) ;  %(单元长度)
      k = [ E*A/L            0              0                 -E*A/L          0               0
             0          12*E*I/L^3         6*E*I/L^2            0        -12*E*I/L^3     6*E*I/L^2
             0           6*E*I/L^2         4*E*I/L              0          -6*E*I/L^2       2*E*I/L
            -E*A/L            0              0                E*A/L            0             0
             0          -12*E*I/L^3      -6*E*I/L^2             0       12*E*I/L^3       -6*E*I/L^2
             0           6*E*I/L^2        2*E*I/L                0           -6*E*I/L^2   4*E*I/L  ];
      t=trans(ie);
      k = t*k*transpose(t) ;   %(坐标转换)
      return