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Damper Elements And Node Dampers

Damper elements and node dampers are ‘elements’ with no stiffness but with viscosity, so these do not form stiffness matrices but instead a damping matrix. The general form of the damping matrix is

C=[cx00000−cx00000cy00000−cy0000cz00000−cz000cxx00000−cxx00cyy00000−cyy0czz00000−czzcx00000cy0000cz000cxx00cyy0czz]\mathbf{C} = \begin{bmatrix} c_{x} & 0 & 0 & 0 & 0 & 0 & - c_{x} & 0 & 0 & 0 & 0 & 0 \\ & c_{y} & 0 & 0 & 0 & 0 & 0 & - c_{y} & 0 & 0 & 0 & 0 \\ & & c_{z} & 0 & 0 & 0 & 0 & 0 & - c_{z} & 0 & 0 & 0 \\ & & & c_{xx} & 0 & 0 & 0 & 0 & 0 & - c_{xx} & 0 & 0 \\ & & & & c_{yy} & 0 & 0 & 0 & 0 & 0 & - c_{yy} & 0 \\ & & & & & c_{zz} & 0 & 0 & 0 & 0 & 0 & - c_{zz} \\ & & & & & & c_{x} & 0 & 0 & 0 & 0 & 0 \\ & & & & & & & c_{y} & 0 & 0 & 0 & 0 \\ & & & & & & & & c_{z} & 0 & 0 & 0 \\ & & & & & & & & & c_{xx} & 0 & 0 \\ & & & & & & & & & & c_{yy} & 0 \\ & & & & & & & & & & & c_{zz} \\ \end{bmatrix}

For an axial or torsional damper only the cxc_{x} or cxxc_{xx} terms are specified, the rest are assumed to be zero.

Dampers are assumed to be massless.