elastic_print_eigen.C File Reference

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Functions
void	buildStiffnessMatrix (Eigen::Ref< Eigen::Matrix< double, 6, 6 >> C, const double &G, const double &lambda)
	build a 6x6 representation of the stiffness tensor in C from the shear modulus G and Lame's first parameter lambda. More...
void	umat_ (double *stress, double *statev, double *ddsdde, double *sse, double *spd, double *scd, double *rpl, double *ddsddt, double *drplde, double *drpldt, double *stran, double *dstran, double *time, double *dtime, double *temp, double *dtemp, double *predef, double *dpred, char *cmname, int *ndi, int *nshr, int *ntens, int *nstatv, double *props, int *nprops, double *coords, double *drot, double *pnewdt, double *celent, double *dfgrd0, double *dfgrd1, int *noel, int *npt, int *layer, int *kspt, int *kstep, int *kinc, short cmname_len)

Function Documentation

buildStiffnessMatrix()

void buildStiffnessMatrix	(	Eigen::Ref< Eigen::Matrix< double, 6, 6 >>	C,
		const double &	G,
		const double &	lambda
	)

build a 6x6 representation of the stiffness tensor in C from the shear modulus G and Lame's first parameter lambda.

Definition at line 22 of file elastic_print_eigen.C.

Referenced by FOR_NAME(), and umat_().

{
  C = Eigen::Matrix<double, 6, 6>::Zero();

  for (int i = 0; i < 3; i++)
  {
    C(i, i) += 2 * G;
    C(i + 3, i + 3) += G;
    for (int j = 0; j < 3; j++)
      C(i, j) += lambda;
  }
}

umat_()

void umat_	(	double *	stress,
		double *	statev,
		double *	ddsdde,
		double *	sse,
		double *	spd,
		double *	scd,
		double *	rpl,
		double *	ddsddt,
		double *	drplde,
		double *	drpldt,
		double *	stran,
		double *	dstran,
		double *	time,
		double *	dtime,
		double *	temp,
		double *	dtemp,
		double *	predef,
		double *	dpred,
		char *	cmname,
		int *	ndi,
		int *	nshr,
		int *	ntens,
		int *	nstatv,
		double *	props,
		int *	nprops,
		double *	coords,
		double *	drot,
		double *	pnewdt,
		double *	celent,
		double *	dfgrd0,
		double *	dfgrd1,
		int *	noel,
		int *	npt,
		int *	layer,
		int *	kspt,
		int *	kstep,
		int *	kinc,
		short	cmname_len
	)

Definition at line 38 of file elastic_print_eigen.C.

{

  double E = props[0];
  double nu = props[1];
  double G = E / 2.0 / (1.0 + nu);
  double lambda = 2.0 * G * nu / (1.0 - 2.0 * nu);
  double eps[6];
  double eps_trace;

  for (int i = 0; i < 6; i++)
    eps[i] = stran[i] + dstran[i];

  eps_trace = eps[0] + eps[1] + eps[2];

  for (int i = 0; i < 3; i++)
  {
    stress[i] = lambda * eps_trace + 2.0 * G * eps[i];
    stress[i + 3] = G * eps[i + 3];
  }

  Eigen::Matrix<double, 6, 6> C;
  buildStiffnessMatrix(C, G, lambda);

  for (int i = 0; i < 6; i++)
    for (int j = 0; j < 6; j++)
      ddsdde[6 * i + j] = 0.0;

  for (int i = 0; i < 3; i++)
  {
    ddsdde[6 * i + 0] = C(0, i);
    ddsdde[6 * i + 1] = C(1, i);
    ddsdde[6 * i + 2] = C(2, i);
    ddsdde[6 * (i + 3) + (i + 3)] = C(i + 3, i + 3);
  }

  // Print out eigenvalue using Eigen matrix
  auto eigenvalues = C.eigenvalues();

  if (*npt == 8 && time[0] == 0.0)
    for (int index_i = 0; index_i < *ntens; index_i++)
      Moose::out << "Eigenvalues " << index_i << " " << eigenvalues(index_i).real() << std::endl;
}