Linear structural time integration

Functions
c_structural_integrator	c_create_dense_generalized_alpha_integrator (int n, const double *m, int ldm, const double *c, int ldc, const double *k, int ldk, double rho_infinity)
	Create a dense generalized-alpha integrator for M*a + C*v + K*u = f.
void	c_free_structural_integrator (c_structural_integrator obj)
	Release a structural integrator handle.
void	c_structural_integrator_step (c_structural_integrator obj, int n, const double *force_current, const double *force_next, double dt, double *displacement, double *velocity, double *acceleration)
	Advance the state by one time step.
void	c_structural_integrator_solve (c_structural_integrator obj, int n, int npts, const double *forces, int ldf, double dt, double *displacement, double *velocity, double *acceleration)
	Advance the state through a force history using npts - 1 constant steps.

Detailed Description

Function Documentation

c_create_dense_generalized_alpha_integrator()

c_structural_integrator c_create_dense_generalized_alpha_integrator	(	int	n,
		const double *	m,
		int	ldm,
		const double *	c,
		int	ldc,
		const double *	k,
		int	ldk,
		double	rho_infinity
	)

Create a dense generalized-alpha integrator for M*a + C*v + K*u = f.

The matrices must already reflect any boundary conditions.

Parameters

n	Number of degrees of freedom.
m	n-by-n mass matrix.
ldm	Leading dimension of m.
c	n-by-n damping matrix.
ldc	Leading dimension of c.
k	n-by-n stiffness matrix.
ldk	Leading dimension of k.
rho_infinity	High-frequency spectral radius in [0, 1]. A value of 1 gives the average-acceleration (trapezoidal) scheme.

Returns

Integrator handle; release with c_free_structural_integrator.

c_free_structural_integrator()

void c_free_structural_integrator

(

c_structural_integrator

obj

)

Release a structural integrator handle.

Parameters

obj	Integrator handle; NULL is ignored.

c_structural_integrator_step()

void c_structural_integrator_step	(	c_structural_integrator	obj,
		int	n,
		const double *	force_current,
		const double *	force_next,
		double	dt,
		double *	displacement,
		double *	velocity,
		double *	acceleration
	)

Advance the state by one time step.

Parameters

obj	Integrator handle.
n	Number of degrees of freedom.
force_current	n-element external force at the start of the step.
force_next	n-element external force at the end of the step.
dt	Positive time step.
displacement	n-element displacement; updated to the end state.
velocity	n-element velocity; updated to the end state.
acceleration	n-element acceleration; updated to the end state. On the first step this must be consistent with the initial conditions.

c_structural_integrator_solve()

void c_structural_integrator_solve	(	c_structural_integrator	obj,
		int	n,
		int	npts,
		const double *	forces,
		int	ldf,
		double	dt,
		double *	displacement,
		double *	velocity,
		double *	acceleration
	)

Advance the state through a force history using npts - 1 constant steps.

Only the final state is returned.

Parameters

obj	Integrator handle.
n	Number of degrees of freedom.
npts	Number of force samples (time points); at least 2.
forces	n-by-npts matrix whose columns are the external force at each time point.
ldf	Leading dimension of forces.
dt	Positive time step.
displacement	n-element displacement; initial state on input, final state on output.
velocity	n-element velocity; initial state on input, final state on output.
acceleration	n-element acceleration; initial state on input, final state on output.