Method getNld_hat

SRC/element/mixedBeamColumn/MixedBeamColumn3d.cpp:1795–1835

}

Matrix MixedBeamColumn3d::getNld_hat(int sec, const Vector &v, double L, bool geomLinear) {
  double xi[MAX_NUM_SECTIONS];
  beamIntegr->getSectionLocations(numSections, L, xi);

  double x, C, E, F;
  Matrix Nld_hat(NDM_SECTION,NDM_NATURAL);
  Nld_hat.Zero();

  x = L*xi[sec];

  C =  1/L;
  E = -4/L + 6*x/(L*L);
  F = -2/L + 6*x/(L*L);

  if (geomLinear) {

    Nld_hat(0,0) = C;
    Nld_hat(1,1) = E;
    Nld_hat(1,3) = F;
    Nld_hat(2,2) = E;
    Nld_hat(2,4) = F;

  } else {

    double A,B;
    A = 1 - 4 * ( x / L ) + 3 * pow ( ( x / L ) , 2 );
    B =   - 2 * ( x / L ) + 3 * pow ( ( x / L ) , 2 );

    Nld_hat(0,0) = C + C*C*v(0);
    Nld_hat(0,1) = A*A*v(1) + A*B*v(3);
    Nld_hat(0,2) = A*A*v(2) + A*B*v(4);
    Nld_hat(0,3) = A*B*v(1) + B*B*v(3);
    Nld_hat(0,4) = A*B*v(2) + B*B*v(4);
    Nld_hat(1,1) = E;
    Nld_hat(1,3) = F;
    Nld_hat(2,2) = E;
    Nld_hat(2,4) = F;
  }

  return Nld_hat;
}

Matrix MixedBeamColumn3d::getNd2(int sec, double P, double L) {
  double xi[MAX_NUM_SECTIONS];