Ejemplo n.º 1
0
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);
}
Ejemplo n.º 2
0
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);
            }
        }
    }
}