Method formResidAndTangent

SRC/element/shell/ShellDKGT.cpp:1272–1638

form residual and tangent

//form residual and tangent
void  
ShellDKGT::formResidAndTangent( int tang_flag ) 
{
	//
	//six(6) nodal dof's ordered:
	//-----------
	//|    u1    |   <---- plate membrane
	//|    u2    |
	//|----------|
	//|   w = u3 |  <----plate bending
	//|   theta1 |
	//|   theta2 |
	//|----------|
	//|   theta3 |  <- drill (tran from membrane)
	//|----------|
 
	static const int ndf = 6; //two membrane + 3 moment +drill

	static const int nstress = 8; //3 membrane , 3 moment, 2 shear

	static const int ngauss = 4;

	static const int numnodes = 3;

	int i,j,k,p,q;
	int jj,kk;

	int p1,q1;

	int p2,q2;

	int success;

	double volume = 0.0;

	static double xsj; //determinant jacobian matrix

	static double dvol[ngauss]; //volume element

	static Vector strain(nstress); //strain

	static double shp[3][numnodes]; //shape function 2d at a gauss point

	static double shpDrill[4][numnodes]; //shape function drilling dof at a gauss point

	static double shpBend[6][9]; //shape function - bending part at a gauss point

	static Vector residJ(ndf); //nodeJ residual, global coordinates

	static Matrix stiffJK(ndf,ndf);//nodeJK stiffness, global coordinates

	static Vector residJlocal(ndf); //nodeJ residual, local coordinates

	static Matrix stiffJKlocal(ndf,ndf); //nodeJK stiffness, local coordinates

	static Matrix stiffJK1(ndf,ndf);

	static Matrix stiffJK2(ndf,ndf);