%***********************************************************************
%  function define_elements
%
%  define particulars of each element type
%***********************************************************************
function [ETags, ElemType] = define_elements

% tags used to identify element types
ETags.spring1d = 1; 
ETags.truss2d  = 2;
ETags.pBar2 = 5;  % 1-D linear bar element, 2 nodes
ETags.pBar3 = 6;  % 1-D quadratic Lagrangean bar element, 3 nodes
ETags.pBar4 = 7;  % 1-D cubic Lagrangean bar element, 4 nodes
ETags.pBar5 = 8;  % 1-D quartic Lagrangean bar element, 5 nodes


% define parameters for each element type
% assuming that all nodes have the same number of dofs.

% 1D spring element
ElemType(ETags.spring1d).nnodes     = 2;   % num. nodes for spring element
ElemType(ETags.spring1d).ndofs_node = 1;   % num. dofs per node for spring element

% 2D truss element
ElemType(ETags.truss2d).nnodes     = 2;   % num. nodes for 2D truss element
ElemType(ETags.truss2d).ndofs_node = 2;   % num. dofs per node for 2D truss element

% 1-D linear bar element, 2 nodes
ElemType(ETags.pBar2).nnodes     = 2;   % num. nodes 
ElemType(ETags.pBar2).ndofs_node = 1;   % num. dofs per node (longitudinal displacement)

% 1-D quadratic Lagrangean bar element, 3 nodes
ElemType(ETags.pBar3).nnodes     = 3;   % num. nodes 
ElemType(ETags.pBar3).ndofs_node = 1;   % num. dofs per node (longitudinal displacement)

% 1-D cubic Lagrangean bar element, 4 nodes
ElemType(ETags.pBar4).nnodes     = 4;   % num. nodes 
ElemType(ETags.pBar4).ndofs_node = 1;   % num. dofs per node (longitudinal displacement)

% 1-D quartic Lagrangean bar element, 5 nodes
ElemType(ETags.pBar5).nnodes     = 5;   % num. nodes 
ElemType(ETags.pBar5).ndofs_node = 1;   % num. dofs per node (longitudinal displacement)