Added "fluid moving frame" body force.

FEBioFluid/FEBioFluid.cpp

@@ -83,6 +83,7 @@ SOFTWARE.*/
 
 #include "FEConstFluidBodyForce.h"
 #include "FECentrifugalFluidBodyForce.h"
+#include "FEFluidMovingFrameLoad.h"
 
 #include "FEFluidModule.h"
 
@@ -171,6 +172,7 @@ REGISTER_FECORE_CLASS(FEFluidRCLoad                , "fluid RC"
 // body loads
 REGISTER_FECORE_CLASS(FEConstFluidBodyForce      , "fluid body force");
 REGISTER_FECORE_CLASS(FECentrifugalFluidBodyForce, "fluid centrifugal force");
+REGISTER_FECORE_CLASS(FEFluidMovingFrameLoad     , "fluid moving frame");
 
 //-----------------------------------------------------------------------------
 // boundary conditions

FEBioFluid/FEFluidMovingFrameLoad.cpp

@@ -0,0 +1,106 @@
+/*This file is part of the FEBio source code and is licensed under the MIT license
+listed below.
+
+See Copyright-FEBio.txt for details.
+
+Copyright (c) 2021 University of Utah, The Trustees of Columbia University in
+the City of New York, and others.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.*/
+#include "stdafx.h"
+#include "FEFluidMovingFrameLoad.h"
+#include "FEFluidMaterialPoint.h"
+#include <FECore/log.h>
+
+BEGIN_FECORE_CLASS(FEFluidMovingFrameLoad, FEBodyForce)
+	ADD_PARAMETER(m_w.x, "wx")->setLongName("x-angular velocity")->setUnits(UNIT_ANGULAR_VELOCITY);
+	ADD_PARAMETER(m_w.y, "wy")->setLongName("y-angular velocity")->setUnits(UNIT_ANGULAR_VELOCITY);
+	ADD_PARAMETER(m_w.z, "wz")->setLongName("z-angular velocity")->setUnits(UNIT_ANGULAR_VELOCITY);
+	ADD_PARAMETER(m_a.x, "ax")->setLongName("x-linear acceleration")->setUnits(UNIT_ACCELERATION);
+	ADD_PARAMETER(m_a.y, "ay")->setLongName("y-linear acceleration")->setUnits(UNIT_ACCELERATION);
+	ADD_PARAMETER(m_a.z, "az")->setLongName("z-linear acceleration")->setUnits(UNIT_ACCELERATION);
+END_FECORE_CLASS();
+
+FEFluidMovingFrameLoad::FEFluidMovingFrameLoad(FEModel* fem) : FEBodyForce(fem)
+{
+	m_w = vec3d(0, 0, 0);
+	m_al = vec3d(0, 0, 0);
+	m_q = quatd(0, vec3d(0, 0, 1));
+}
+
+void FEFluidMovingFrameLoad::Activate()
+{
+	m_wp = m_w;
+	FEBodyForce::Activate();
+}
+
+void FEFluidMovingFrameLoad::PrepStep()
+{
+	double dt = GetTimeInfo().timeIncrement;
+	m_al = (m_w - m_wp) / dt;
+
+	vec3d wa = (m_w + m_wp) * 0.5;
+
+	quatd qn = m_q;
+	quatd wn(wa.x, wa.y, wa.z, 0.0);
+	m_q = qn + (wn * qn) * (0.5 * dt);
+	m_q.MakeUnit();
+	m_wp = m_w;
+
+	vec3d R = m_q.GetRotationVector();
+
+	feLogDebug("al : %lg, %lg, %lg\n", m_al.x, m_al.y, m_al.z);
+	feLogDebug("R : %lg, %lg, %lg\n", R.x, R.y, R.z);
+}
+
+vec3d FEFluidMovingFrameLoad::force(FEMaterialPoint& pt)
+{
+	FEFluidMaterialPoint& fp = *pt.ExtractData<FEFluidMaterialPoint>();
+
+	quatd qi = m_q.Inverse();
+
+	vec3d r = pt.m_rt;
+	vec3d v = fp.m_vft;
+	vec3d w = qi * m_w;
+	vec3d al = qi * m_al;
+	vec3d f = qi*m_a + (al ^ r) + (w ^ (w ^ r)) + (w ^ v) * 2.0;
+	return f;
+}
+
+mat3d FEFluidMovingFrameLoad::stiffness(FEMaterialPoint& pt)
+{
+	FEFluidMaterialPoint& fp = *pt.ExtractData<FEFluidMaterialPoint>();
+	vec3d v = fp.m_vft;
+
+	const FETimeInfo& tp = GetTimeInfo();
+	double gamma = tp.gamma;
+	double dt = tp.timeIncrement;
+
+	quatd qi = m_q.Inverse();
+	vec3d w = qi * m_w;
+	vec3d al = qi * m_al;
+
+	mat3da Sw(w);
+	mat3da A(al);
+	mat3d S2 = Sw * Sw;
+	mat3d K = S2 + A + Sw * (4.0 * gamma / dt);
+
+	// NOTE: we need a negative sign, since the external load stiffness needs to be subtracted from the global stiffness
+	return -K;
+}

FEBioFluid/FEFluidMovingFrameLoad.h

@@ -0,0 +1,52 @@
+/*This file is part of the FEBio source code and is licensed under the MIT license
+listed below.
+
+See Copyright-FEBio.txt for details.
+
+Copyright (c) 2021 University of Utah, The Trustees of Columbia University in
+the City of New York, and others.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.*/
+#pragma once
+#include <FEBioMech/FEBodyForce.h>
+
+//! This body load emulates the effect of a moving frame
+class FEFluidMovingFrameLoad : public FEBodyForce
+{
+public:
+	FEFluidMovingFrameLoad(FEModel* fem);
+
+	void Activate() override;
+
+	void PrepStep() override;
+
+	vec3d force(FEMaterialPoint& pt) override;
+
+	mat3d stiffness(FEMaterialPoint& pt) override;
+
+private:
+	vec3d	m_w;	// angular velocity of frame
+	vec3d	m_a;	// linear acceleration of frame
+
+	quatd	m_q;
+	vec3d	m_wp;
+	vec3d	m_al;
+
+	DECLARE_FECORE_CLASS();
+};