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.


Name of the equation to be solved.


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

  • Q1-Linear

  • Q2-Quadratic


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


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.


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.


No References.