shell_angle#

EQ =shell_angle{1 | 2} {Galerkin_wt} {SH_ANG1 | SH_ANG2} {Interpol_fnc}

Description / Usage#

This card provides information for solving a definition equation for the surface orientation angle in a 2-dimensional bar element. It applies only to shell element blocks. Note that this equation is available in three-dimensional problems but is in fact untested at this time.. The shell angle equation(s) determine the components of the normal vector to the shell surface; since its magnitude is 1 by definition, one less degree of freedom is required tha the number of coordinates. The Galerkin weight and the interpolation function must be the same for the code to work properly.

shell_angle{1|2}

Name of the equation to be solved.

{Galerkin_wt}

Two- or four-character value that defines the type of weighting function for this equation, where:

  • Q1-Linear

  • Q2-Quadratic

SH_ANG{1|2}

SH_ANG{1|2} Name of the variable associated with the shell angle equation.

{Interpol_fnc}

Two- or four-character value that defines the interpolation function used to represent the variable SH_ANG where:

  • Q1-Linear Continuous

  • Q2-Quadratic Continuous

This equation requires no equation term multiplier entries.

Examples#

The following are sample cards that use linear continuous curvature interpolation and weight function:

EQ = shell_angle1 Q1 SH_ANG1 Q1

EQ = shell_angle2 Q1 SH_ANG2 Q2

The second card applies only to 3D problems.

Technical Discussion#

For 2D problems, the defining equation is: \(\Theta\) = atan[ \(n_x\), \(n_y\)] where Q is shell_angle1 and \(n_x\) and \(n_y\) are the components of the normal vector to the shell surface. There is an analogous definition for shell_angle2.

References#

No References.