12.7 Initialization Requests

12.7.1 Initialize Displacement Array(s)

INITIALIZE_D0

INITIALIZE_D0 number_of_load_steps = nstep, etc...

For certain problems, it is required that an initialization takes place (e.g., for pressure dependent materials which require that gravity induced initial stresses be first computed, or for prestressing structural members). In that case nstep load steps are used to establish initial equilibrium conditions. By default, the displacements are thereafter set to zero, e.g. d₀ = 0.

Note	Variable Name	Type	Default	Description
	Stagger_name(s)	list	[all]	Stagger names to be initialized. Name(s) must be enclosed in quotation marks.
	Stagger_number(s)	integer list	[all]	Stagger numbers to be initialized
	Steady_state	list	[on]	Steady state option
	on / off
	Number_of_load_steps	integer	[1]	Number of load steps to be used for initialization
	Reform_lhs_freq	integer	[0]	Number of load steps between stiffness reform
(1)	Clear_array	list	[on]	clear d0 array option.
	on / off
	Clear_stagger_name(s)	list	[all]	Stagger names to be cleared. Name(s) must be enclosed in quotation marks.
	Clear_stagger_number(s)	integer	[all]	Stagger numbers to be cleared.
	Xfem_option on / off	list	[on]	Xfem option flag

Notes/

(1) Not clearing d₀ may affect convergence during the initialization phase.

12.7.2 Initialize Velocity Array(s)

INITIALIZE_V0

INITIALIZE_V0

The default is v₀ = 0. However, for certain problems, it may be required that an initialization takes place for v₀ (Parabolic initial BVP), viz.,

M v₀ = f₀ - K d₀

12.7.3 Initialize Acceleration Array(s)

INITIALIZE_A0

INITIALIZE_A0

The default is a₀ = 0. However, for certain problems, it may be required that an initialization takes place for a₀ (Hyperbolic initial BVP), viz.,

M a₀ = f₀ - C v₀ - K d₀

Notes . .

Notes . .