Method formResidAndTangent

SRC/element/shell/ShellNLDKGQ.cpp:1411–1869

form residual and tangent

//form residual and tangent
void  
ShellNLDKGQ::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)
	//|----------|
  // membrane strains ordered :
  //
  //            strain(0) =   eps00     i.e.   (11)-strain
  //            strain(1) =   eps11     i.e.   (22)-strain
  //            strain(2) =   gamma01   i.e.   (12)-shear
  //
  // curvatures and shear strains ordered  :
  //
  //            strain(3) =     kappa00  i.e.   (11)-curvature
  //            strain(4) =     kappa11  i.e.   (22)-curvature
  //            strain(5) =   2*kappa01  i.e. 2*(12)-curvature 
  //
  //            strain(6) =     gamma02  i.e.   (13)-shear
  //            strain(7) =     gamma12  i.e.   (23)-shear
  //
  //  same ordering for moments/shears but no 2 
  //  
  //  Then, 
  //              epsilon00 = -z * kappa00      +    eps00_membrane
  //              epsilon11 = -z * kappa11      +    eps11_membrane
  //  gamma01 = 2*epsilon01 = -z * (2*kappa01)  +  gamma01_membrane 
  //
  //  Shear strains gamma02, gamma12 constant through cross section
  //     neglected in this shell element   Zero();
  //
	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 = 4;

	int i,j,k,p,q;
	int jj,kk;
	int jlast,jnew; //add for geometric nonlinearity

	int p1,q1;

	int p2,q2;

	int p3,q3;