# $Header: /var/cvs/mbdyn/mbdyn/mbdyn-web/documentation/examples/pendulum,v 1.1 2008/11/12 23:51:46 masarati Exp $
#
# MBDyn (C) is a multibody analysis code. 
# http://www.mbdyn.org
# 
# Copyright (C) 1996-2008
# 
# Pierangelo Masarati	<masarati@aero.polimi.it>
# Paolo Mantegazza	<mantegazza@aero.polimi.it>
# 
# Dipartimento di Ingegneria Aerospaziale - Politecnico di Milano
# via La Masa, 34 - 20156 Milano, Italy
# http://www.aero.polimi.it
# 
# Changing this copyright notice is forbidden.
# 
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation (version 2 of the License).
# 
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
# 

begin: data;
	problem: initial value;
end: data;

begin: initial value;
	initial time: 0.;
	final time: 10.;
	time step: 1.e-2;

	max iterations: 10;
	tolerance: 1.e-6;

	derivatives coefficient: 1.e-6;
end: initial value;

begin: control data;
	structural nodes:
		+1	# ground
		+1	# pendulum
	;
	rigid bodies:
		+1	# pendulum
	;
	joints:
		+1	# clamp
		+1	# revolute hinge
	;
	gravity;
end: control data;

set: integer GROUND = 10;
set: integer PENDULUM = 20;

set: real THETA_0 = 15*deg2rad;		# radian; initial angle
set: real THETA_P_0 = 0.;		# radian/s; initial angular velocity
set: real L = 5.;			# m; length

reference: GROUND,
	null,
	eye,
	null,
	null;

reference: PENDULUM + 1,
	reference, GROUND, null,
	reference, GROUND,
		2, 0., 1., 0.,
		1, cos(THETA_0), 0., sin(THETA_0),
	reference, GROUND, null,
	reference, GROUND, 0., THETA_P_0, 0.;

reference: PENDULUM,
	reference, PENDULUM + 1, 0., 0., -L,
	reference, PENDULUM + 1, eye,
	reference, PENDULUM + 1, null,
	reference, PENDULUM + 1, null;

begin: nodes;
	structural: GROUND, static,
		reference, GROUND, null,
		reference, GROUND, eye,
		reference, GROUND, null,
		reference, GROUND, null,
		output, no;

	structural: PENDULUM, dynamic,
		reference, PENDULUM, null,
		reference, PENDULUM, eye,
		reference, PENDULUM, null,
		reference, PENDULUM, null;
end: nodes;

begin: elements;
	body: PENDULUM,
		PENDULUM,			# node label
		10.,				# mass
		reference, node, null,		# C.M. location
		diag, 1.e-3, 1.e-3, 1.e-3;	# inertia tensor (wrt/ C.M.)

	joint: GROUND, clamp,
		GROUND, node, node;

	joint: PENDULUM, revolute hinge,
		GROUND,
			reference, GROUND, null,
			hinge, reference, GROUND,
				3, 0., 1., 0.,
				1, 1., 0., 0.,
		PENDULUM,
			reference, GROUND, null,
			hinge, reference, GROUND,
				3, 0., 1., 0.,
				1, 1., 0., 0.;

	gravity: 0., 0., -1., const, 9.81;
end: elements;