contact::PairForce Class Reference

#include <pairForce.h>

Inheritance diagram for contact::PairForce:

Collaboration diagram for contact::PairForce:

Public Member Functions
virtual	~PairForce ()=default
virtual void	beginStep ()
virtual void	endStep ()
virtual util::Point	springForce (const Pair &p)
virtual util::Point	nodeDampingForce (const Pair &p)
virtual util::Point	force (const Pair &p)

Detailed Description

Node-node contact law (same role as material::Material for PD bonds).

Spring force density uses neighbor volume Vj (optionally partial-volume corrected by assembly). Default friction is coulomb_simple (mu * |Fn| along tangential velocity).

Definition at line 57 of file pairForce.h.

Constructor & Destructor Documentation

~PairForce()

virtual contact::PairForce::~PairForce ( )

virtualdefault

Member Function Documentation

beginStep()

virtual void contact::PairForce::beginStep ( )

inlinevirtual

Reimplemented in contact::StickSlipPairForce.

Definition at line 61 of file pairForce.h.

{}

endStep()

virtual void contact::PairForce::endStep ( )

inlinevirtual

Reimplemented in contact::StickSlipPairForce.

Definition at line 62 of file pairForce.h.

{}

force()

util::Point contact::PairForce::force ( const Pair &  p )

virtual

Default: spring + node damping (used by tests / simple callers).

Definition at line 82 of file pairForce.cpp.

                                               {
  return springForce(p) + nodeDampingForce(p);
}

nodeDampingForce()

util::Point contact::PairForce::nodeDampingForce ( const Pair &  p )

virtual

Node-level normal damping (density form).

Definition at line 59 of file pairForce.cpp.

                                                          {
  const auto yji = p.yj - p.yi;
  const auto Rji = yji.length();
  if (!(Rji > 0.) || !util::isLess(Rji, p.deck.d_contactR))
    return {};
 
  if (!p.deck.d_dampingOn || !(p.voli > 0.) || !(p.deck.d_K > 0.) ||
      !(p.deck.d_contactR > 0.))
    return {};
 
  const auto vji = p.vj - p.vi;
  auto en = yji / Rji;
  auto vn_mag = vji * en;
  if (!util::isLess(vn_mag, 0.))
    return {};
 
  const double meq =
      util::equivalentMass(p.rhoi * p.voli, p.rhoj * p.volj);
  const double beta_n =
      p.deck.d_betan * std::sqrt(p.deck.d_K * p.deck.d_contactR * meq);
  return (beta_n * vn_mag / p.voli) * en;
}

References inp::ContactPairDeck::d_betan, inp::ContactPairDeck::d_contactR, inp::ContactPairDeck::d_dampingOn, inp::ContactPairDeck::d_K, contact::Pair::deck, util::equivalentMass(), util::isLess(), util::Point::length(), contact::Pair::rhoi, contact::Pair::rhoj, contact::Pair::vi, contact::Pair::vj, contact::Pair::voli, contact::Pair::volj, contact::Pair::yi, and contact::Pair::yj.

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springForce()

util::Point contact::PairForce::springForce ( const Pair &  p )

virtual

Spring + friction contribution (force density ∝ volj).

Reimplemented in contact::StickSlipPairForce.

Definition at line 34 of file pairForce.cpp.

                                                     {
  const auto yji = p.yj - p.yi;
  const auto Rji = yji.length();
  if (!(Rji > 0.) || !util::isLess(Rji, p.deck.d_contactR))
    return {};
 
  const auto vji = p.vj - p.vi;
  auto en = yji / Rji;
  auto vn_mag = vji * en;
  auto et = vji - vn_mag * en;
  if (util::isGreater(et.length(), 0.))
    et = et / et.length();
  else
    et = util::Point();
 
  auto scalar_f = p.deck.d_Kn * (Rji - p.deck.d_contactR) * p.volj;
  if (scalar_f > 0.)
    scalar_f = 0.;
 
  util::Point f = scalar_f * en;
  if (p.deck.d_frictionOn)
    f += p.deck.d_mu * scalar_f * et;
  return f;
}

References inp::ContactPairDeck::d_contactR, inp::ContactPairDeck::d_frictionOn, inp::ContactPairDeck::d_Kn, inp::ContactPairDeck::d_mu, contact::Pair::deck, util::isGreater(), util::isLess(), util::Point::length(), contact::Pair::vi, contact::Pair::vj, contact::Pair::volj, contact::Pair::yi, and contact::Pair::yj.

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The documentation for this class was generated from the following files:

• /home/user/project/src/contact/pairForce.h
• /home/user/project/src/contact/pairForce.cpp