void PLCrackPrescribedDir::propagateInterfaces(EnrichmentDomain &ioEnrDom) {
printf("Entering PLCrackPrescribedDir::propagateInterfaces().\n");
// Fetch crack tip data
std::vector<TipInfo> tipInfo;
ioEnrDom.giveTipInfos(tipInfo);
int tipIndex = 1;
FloatArray dir;
double angleRad = mAngle*M_PI/180.0;
dir.setValues(2, cos(angleRad), sin(angleRad));
dir.normalize();
std::vector<TipPropagation> tipPropagations;
TipPropagation tipProp;
tipProp.mTipIndex = tipIndex;
tipProp.mPropagationDir = dir;
tipProp.mPropagationLength = mIncrementLength;
tipPropagations.push_back(tipProp);
ioEnrDom.propagateTips(tipPropagations);
}
void PLHoopStressCirc :: propagateInterfaces(Domain &iDomain, EnrichmentDomain &ioEnrDom)
{
// Fetch crack tip data
TipInfo tipInfoStart, tipInfoEnd;
ioEnrDom.giveTipInfos(tipInfoStart, tipInfoEnd);
std :: vector< TipInfo >tipInfo = {tipInfoStart, tipInfoEnd};
SpatialLocalizer *localizer = iDomain.giveSpatialLocalizer();
for ( size_t tipIndex = 0; tipIndex < tipInfo.size(); tipIndex++ ) {
// Construct circle points on an arc from -90 to 90 degrees
double angle = -90.0 + mAngleInc;
std :: vector< double >angles;
while ( angle <= ( 90.0 - mAngleInc ) ) {
angles.push_back(angle * M_PI / 180.0);
angle += mAngleInc;
}
const FloatArray &xT = tipInfo [ tipIndex ].mGlobalCoord;
const FloatArray &t = tipInfo [ tipIndex ].mTangDir;
const FloatArray &n = tipInfo [ tipIndex ].mNormalDir;
// It is meaningless to propagate a tip that is not inside any element
Element *el = localizer->giveElementContainingPoint(tipInfo [ tipIndex ].mGlobalCoord);
if ( el != NULL ) {
std :: vector< FloatArray >circPoints;
for ( size_t i = 0; i < angles.size(); i++ ) {
FloatArray tangent(2);
tangent.zero();
tangent.add(cos(angles [ i ]), t);
tangent.add(sin(angles [ i ]), n);
tangent.normalize();
FloatArray x(xT);
x.add(mRadius, tangent);
circPoints.push_back(x);
}
std :: vector< double >sigTTArray, sigRTArray;
// Loop over circle points
for ( size_t pointIndex = 0; pointIndex < circPoints.size(); pointIndex++ ) {
FloatArray stressVec;
if ( mUseRadialBasisFunc ) {
// Interpolate stress with radial basis functions
// Choose a cut-off length l:
// take the distance between two nodes in the element containing the
// crack tip multiplied by a constant factor.
// ( This choice implies that we hope that the element has reasonable
// aspect ratio.)
const FloatArray &x1 = * ( el->giveDofManager(1)->giveCoordinates() );
const FloatArray &x2 = * ( el->giveDofManager(2)->giveCoordinates() );
const double l = 1.0 * x1.distance(x2);
// Use the octree to get all elements that have
// at least one Gauss point in a certain region around the tip.
const double searchRadius = 3.0 * l;
std :: set< int >elIndices;
localizer->giveAllElementsWithIpWithinBox(elIndices, circPoints [ pointIndex ], searchRadius);
// Loop over the elements and Gauss points obtained.
// Evaluate the interpolation.
FloatArray sumQiWiVi;
double sumWiVi = 0.0;
for ( int elIndex: elIndices ) {
Element *gpEl = iDomain.giveElement(elIndex);
IntegrationRule *iRule = gpEl->giveDefaultIntegrationRulePtr();
for ( GaussPoint *gp_i: *iRule ) {
////////////////////////////////////////
// Compute global gp coordinates
FloatArray N;
FEInterpolation *interp = gpEl->giveInterpolation();
interp->evalN( N, * ( gp_i->giveCoordinates() ), FEIElementGeometryWrapper(gpEl) );
// Compute global coordinates of Gauss point
FloatArray globalCoord(2);
globalCoord.zero();
for ( int i = 1; i <= gpEl->giveNumberOfDofManagers(); i++ ) {
DofManager *dMan = gpEl->giveDofManager(i);
globalCoord.at(1) += N.at(i) * dMan->giveCoordinate(1);
globalCoord.at(2) += N.at(i) * dMan->giveCoordinate(2);
}
////////////////////////////////////////
// Compute weight of kernel function
FloatArray tipToGP;
tipToGP.beDifferenceOf(globalCoord, xT);
bool inFrontOfCrack = true;
if ( tipToGP.dotProduct(t) < 0.0 ) {
inFrontOfCrack = false;
}
double r = circPoints [ pointIndex ].distance(globalCoord);
if ( r < l && inFrontOfCrack ) {
double w = ( ( l - r ) / ( pow(2.0 * M_PI, 1.5) * pow(l, 3) ) ) * exp( -0.5 * pow(r, 2) / pow(l, 2) );
// Compute gp volume
double V = gpEl->computeVolumeAround(gp_i);
// Get stress
StructuralMaterialStatus *ms = dynamic_cast< StructuralMaterialStatus * >( gp_i->giveMaterialStatus() );
if ( ms == NULL ) {
OOFEM_ERROR("failed to fetch MaterialStatus.");
}
FloatArray stressVecGP = ms->giveStressVector();
if ( sumQiWiVi.giveSize() != stressVecGP.giveSize() ) {
sumQiWiVi.resize( stressVecGP.giveSize() );
sumQiWiVi.zero();
}
// Add to numerator
sumQiWiVi.add(w * V, stressVecGP);
// Add to denominator
sumWiVi += w * V;
}
}
}
if ( fabs(sumWiVi) > 1.0e-12 ) {
stressVec.beScaled(1.0 / sumWiVi, sumQiWiVi);
} else {
// Take stress from closest Gauss point
int region = 1;
bool useCZGP = false;
GaussPoint &gp = * ( localizer->giveClosestIP(circPoints [ pointIndex ], region, useCZGP) );
// Compute stresses
StructuralMaterialStatus *ms = dynamic_cast< StructuralMaterialStatus * >( gp.giveMaterialStatus() );
if ( ms == NULL ) {
OOFEM_ERROR("failed to fetch MaterialStatus.");
}
stressVec = ms->giveStressVector();
}
} else {
// Take stress from closest Gauss point
int region = 1;
bool useCZGP = false;
GaussPoint &gp = * ( localizer->giveClosestIP(circPoints [ pointIndex ], region, useCZGP) );
// Compute stresses
StructuralMaterialStatus *ms = dynamic_cast< StructuralMaterialStatus * >( gp.giveMaterialStatus() );
if ( ms == NULL ) {
OOFEM_ERROR("failed to fetch MaterialStatus.");
}
stressVec = ms->giveStressVector();
}
FloatMatrix stress(2, 2);
int shearPos = stressVec.giveSize();
stress.at(1, 1) = stressVec.at(1);
stress.at(1, 2) = stressVec.at(shearPos);
stress.at(2, 1) = stressVec.at(shearPos);
stress.at(2, 2) = stressVec.at(2);
// Rotation matrix
FloatMatrix rot(2, 2);
rot.at(1, 1) = cos(angles [ pointIndex ]);
rot.at(1, 2) = -sin(angles [ pointIndex ]);
rot.at(2, 1) = sin(angles [ pointIndex ]);
rot.at(2, 2) = cos(angles [ pointIndex ]);
FloatArray tRot, nRot;
tRot.beProductOf(rot, t);
nRot.beProductOf(rot, n);
FloatMatrix rotTot(2, 2);
rotTot.setColumn(tRot, 1);
rotTot.setColumn(nRot, 2);
FloatMatrix tmp, stressRot;
tmp.beTProductOf(rotTot, stress);
stressRot.beProductOf(tmp, rotTot);
const double sigThetaTheta = stressRot.at(2, 2);
sigTTArray.push_back(sigThetaTheta);
const double sigRTheta = stressRot.at(1, 2);
sigRTArray.push_back(sigRTheta);
}
//////////////////////////////
// Compute propagation angle
// Find angles that fulfill sigRT = 0
const double stressTol = 1.0e-9;
double maxSigTT = 0.0, maxAngle = 0.0;
bool foundZeroLevel = false;
for ( size_t segIndex = 0; segIndex < ( circPoints.size() - 1 ); segIndex++ ) {
// If the shear stress sigRT changes sign over the segment
if ( sigRTArray [ segIndex ] * sigRTArray [ segIndex + 1 ] < stressTol ) {
// Compute location of zero level
double xi = EnrichmentItem :: calcXiZeroLevel(sigRTArray [ segIndex ], sigRTArray [ segIndex + 1 ]);
double theta = 0.5 * ( 1.0 - xi ) * angles [ segIndex ] + 0.5 * ( 1.0 + xi ) * angles [ segIndex + 1 ];
double sigThetaTheta = 0.5 * ( 1.0 - xi ) * sigTTArray [ segIndex ] + 0.5 * ( 1.0 + xi ) * sigTTArray [ segIndex + 1 ];
// printf("Found candidate: theta: %e sigThetaTheta: %e\n", theta, sigThetaTheta);
if ( sigThetaTheta > maxSigTT ) {
foundZeroLevel = true;
maxSigTT = sigThetaTheta;
maxAngle = theta;
}
}
}
if ( !foundZeroLevel ) {
printf("No zero level was found.\n");
}
if ( iDomain.giveXfemManager()->giveVtkDebug() ) {
XFEMDebugTools :: WriteArrayToMatlab("sigTTvsAngle.m", angles, sigTTArray);
XFEMDebugTools :: WriteArrayToMatlab("sigRTvsAngle.m", angles, sigRTArray);
XFEMDebugTools :: WriteArrayToGnuplot("sigTTvsAngle.dat", angles, sigTTArray);
XFEMDebugTools :: WriteArrayToGnuplot("sigRTvsAngle.dat", angles, sigRTArray);
}
// Compare with threshold
if ( maxSigTT > mHoopStressThreshold && foundZeroLevel ) {
// Rotation matrix
FloatMatrix rot(2, 2);
rot.at(1, 1) = cos(maxAngle);
rot.at(1, 2) = -sin(maxAngle);
rot.at(2, 1) = sin(maxAngle);
rot.at(2, 2) = cos(maxAngle);
FloatArray dir;
dir.beProductOf(rot, tipInfo [ tipIndex ].mTangDir);
// Fill up struct
std :: vector< TipPropagation >tipPropagations;
TipPropagation tipProp;
tipProp.mTipIndex = tipIndex;
tipProp.mPropagationDir = dir;
tipProp.mPropagationLength = mIncrementLength;
tipPropagations.push_back(tipProp);
// Propagate
ioEnrDom.propagateTips(tipPropagations);
}
}
}
}
