Esempio n. 1
0
int
SSPquad::update(void)
// this function updates variables for an incremental step n to n+1
{
	// get trial displacement
	const Vector &mDisp_1 = theNodes[0]->getTrialDisp();
	const Vector &mDisp_2 = theNodes[1]->getTrialDisp();
	const Vector &mDisp_3 = theNodes[2]->getTrialDisp();
	const Vector &mDisp_4 = theNodes[3]->getTrialDisp();
	
	// assemble displacement vector
	Vector u(8);
	u(0) = mDisp_1(0);
	u(1) = mDisp_1(1);
	u(2) = mDisp_2(0);
	u(3) = mDisp_2(1);
	u(4) = mDisp_3(0);
	u(5) = mDisp_3(1);
	u(6) = mDisp_4(0);
	u(7) = mDisp_4(1);

	Vector strain(3);
	strain = Mmem*u;
	theMaterial->setTrialStrain(strain);

	return 0;
}
Esempio n. 2
0
const Vector &
SSPquad::getResistingForce(void)
// this function computes the resisting force vector for the element
{
    // get stress from the material
    mStress = theMaterial->getStress();

    // get trial displacement
    const Vector &mDisp_1 = theNodes[0]->getTrialDisp();
    const Vector &mDisp_2 = theNodes[1]->getTrialDisp();
    const Vector &mDisp_3 = theNodes[2]->getTrialDisp();
    const Vector &mDisp_4 = theNodes[3]->getTrialDisp();

    Vector d(8);
    d(0) = mDisp_1(0);
    d(1) = mDisp_1(1);
    d(2) = mDisp_2(0);
    d(3) = mDisp_2(1);
    d(4) = mDisp_3(0);
    d(5) = mDisp_3(1);
    d(6) = mDisp_4(0);
    d(7) = mDisp_4(1);

    // add stabilization force to internal force vector
    mInternalForces = Kstab*d;

    // add internal force from the stress  ->  fint = Kstab*d + 4*t*Jo*Mmem'*stress
    mInternalForces.addMatrixTransposeVector(1.0, Mmem, mStress, 4.0*mThickness*J0);

    // subtract body forces from internal force vector
    double xi[4];
    double eta[4];
    xi[0]  = -1.0;
    xi[1]  =  1.0;
    xi[2]  = 1.0;
    xi[3]  = -1.0;
    eta[0] = -1.0;
    eta[1] = -1.0;
    eta[2] = 1.0;
    eta[3] =  1.0;

    if (applyLoad == 0) {
        for (int i = 0; i < 4; i++) {
            mInternalForces(2*i)   -= b[0]*mThickness*(J0 + J1*xi[i] + J2*eta[i]);
            mInternalForces(2*i+1) -= b[1]*mThickness*(J0 + J1*xi[i] + J2*eta[i]);
        }
    } else {
        for (int i = 0; i < 4; i++) {
            mInternalForces(2*i)   -= appliedB[0]*mThickness*(J0 + J1*xi[i] + J2*eta[i]);
            mInternalForces(2*i+1) -= appliedB[1]*mThickness*(J0 + J1*xi[i] + J2*eta[i]);
        }
    }

    // inertial unbalance load
    mInternalForces.addVector(1.0, Q, -1.0);

    return mInternalForces;
}
Esempio n. 3
0
const Vector &
SSPquadUP::getResistingForce(void)
// this function computes the resisting force vector for the element
{
	Vector f1(8);
	Vector f2(4);
	Vector mStress(3); 
	
	// get stress from the material
	mStress = theMaterial->getStress();

	// get trial displacement
	const Vector &mDisp_1 = theNodes[0]->getTrialDisp();
	const Vector &mDisp_2 = theNodes[1]->getTrialDisp();
	const Vector &mDisp_3 = theNodes[2]->getTrialDisp();
	const Vector &mDisp_4 = theNodes[3]->getTrialDisp();

	Vector d(8);
	d(0) = mDisp_1(0);
	d(1) = mDisp_1(1);
	d(2) = mDisp_2(0);
	d(3) = mDisp_2(1);
	d(4) = mDisp_3(0);
	d(5) = mDisp_3(1);
	d(6) = mDisp_4(0);
	d(7) = mDisp_4(1);

	// add stabilization force to internal force vector 
	f1 = Kstab*d;

	// add internal force from the stress
	f1.addMatrixTransposeVector(1.0, Mmem, mStress, 4.0*mThickness*J0);

	// get mass density from the material
	double density = theMaterial->getRho();

	// subtract body forces from internal force vector 
	double xi[4];
	double eta[4];
	xi[0]  = -1.0; xi[1]  =  1.0; xi[2]  = 1.0; xi[3]  = -1.0;
	eta[0] = -1.0; eta[1] = -1.0; eta[2] = 1.0; eta[3] =  1.0;

	if (applyLoad == 0) {
		for (int i = 0; i < 4; i++) {
			f1(2*i)   -= density*b[0]*mThickness*(J0 + J1*xi[i] + J2*eta[i]);
			f1(2*i+1) -= density*b[1]*mThickness*(J0 + J1*xi[i] + J2*eta[i]);
		}
	} else {
		for (int i = 0; i < 4; i++) {
			f1(2*i)   -= density*appliedB[0]*mThickness*(J0 + J1*xi[i] + J2*eta[i]);
			f1(2*i+1) -= density*appliedB[1]*mThickness*(J0 + J1*xi[i] + J2*eta[i]);
		}
	}

	// account for fluid body forces
	Matrix k(2,2);
	Vector body(2);
	// permeability tensor
	k(0,0) = perm[0];
	k(1,1) = perm[1];
	// body force vector
	if (applyLoad == 0) {
		body(0) = b[0];
		body(1) = b[1];
	} else {
		body(0) = appliedB[0];
		body(1) = appliedB[1];
	}
	f2 = 4.0*J0*mThickness*fDens*dN*k*body;

	// assemble full internal force vector for the element
	mInternalForces(0)  = f1(0);
	mInternalForces(1)  = f1(1);
	mInternalForces(2)  = f2(0);
	mInternalForces(3)  = f1(2);
	mInternalForces(4)  = f1(3);
	mInternalForces(5)  = f2(1);
	mInternalForces(6)  = f1(4);
	mInternalForces(7)  = f1(5);
	mInternalForces(8)  = f2(2);
	mInternalForces(9)  = f1(6);
	mInternalForces(10) = f1(7);
	mInternalForces(11) = f2(3);

	// inertial unbalance load
	mInternalForces.addVector(1.0, Q, -1.0);

	return mInternalForces;
}