/INTER/TYPE8

Block Format Keyword This interface is used to simulate drawbeads. It is mainly used in the process industry to model metal forming.

Drawbeads are used to prevent the metal strip from sliding during the stamping process. Normals of the main segments must be oriented toward the secondary nodes (unsorted group).

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/INTER/TYPE8/inter_ID/unit_ID
inter_title
grnd_IDs surf_IDm Iform
Fn_first Ft_first DEPTH Tstart Tstop
Fn_last Ft_last

Definition

Field Contents SI Unit Example
inter_ID Interface identifier.

(Integer, maximum 10 digits)

unit_ID Unit Identifier.

(Integer, maximum 10 digits)

inter_title Interface title.

(Character, maximum 100 characters)

grnd_IDs Secondary unsorted node group identifier.

(Integer)

surf_IDm Main surface identifier.

(Integer)

Iform Friction penalty formulation type.
= 1
Viscous (total) formulation.
= 2 (Default)
Stiffness (incremental) formulation. Recommended when the loading speed is low.

(Integer)

Fn_first Drawbead normal force per unit length at the first node defined in grnd_IDs.

(Real)

[ N m ]
Ft_first Drawbead restraining force per unit length at the first node defined in grnd_IDs.

(Real)

[ N m ]
DEPTH The drawbead depth.

(Real)

[ m ]
Tstart Start time for contact impact computation.

(Real)

[ s ]
Tstop Temporary deactivation time.

(Real)

[ s ]
Fn_last Drawbead normal force per unit length at the last node defined in grnd_IDs.

Default = 0 (Real)

[ N m ]
Ft_last Drawbead restraining force per unit length at the last node defined in grnd_IDs.

Default = 0 (Real)

[ N m ]

Comments

  1. The node group for secondary surface must be an unsorted group (/GRNOD).
  2. Iform =1 is not available when using Idt =1 in option /ADMESH/GLOBAL.
  3. When Fn_first0, normal force is computed. The normal force is due to the bending of the blank into the drawbead as the binder closes on the die. The total contact force is the sum of the restraining force and normal force.
  4. Fn represents a limiting value. The normal force begins to develop when the distance d between the blank and drawbead line is less than the drawbead depth (DEPTH). When the drawbead is close to blank (distance equal to depth), this normal force reaches a plateau Fn. The value of normal force depends on the penetration as described here:
    Figure 1.

    inter_type8

    Where, δ = DEPTH d + Thickness Blank 2 .

  5. If Fn_last0, the limit value Fn varies linearly between the value Fn_first and Fn_last from the first node defined in the set grnd_IDs to the last node, according to the curvilinear distance between nodes. Otherwise, the limit value Fn is constant and equal to Fn_first.
  6. If Ft_last0, the limit value Ft varies linearly between the value Ft_first and Ft_last from the first node defined in the set grnd_IDs to the last node, according to the curvilinear distance between nodes. Otherwise, the limit value Fn is constant and equal to Ft_first.
  7. If DEPTH = 0 or F n D E P T H > S t i f f n e s s B l a n k MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbbG8FasPYRqj0=yi0dXdbba9pGe9xq=JbbG8A8frFve9 Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaeaaeaaakeaadaWcaaqaai aadAeadaWgaaWcbaGaamOBaaqabaaakeaacaWGebGaamyraiaadcfa caWGubGaamisaaaacqGH+aGpcaWGtbGaamiDaiaadMgacaWGMbGaam Ozaiaad6gacaWGLbGaam4CaiaadohadaWgaaWcbaGaamOqaiaadYga caWGHbGaamOBaiaadUgaaeqaaaaa@4A85@ , the slope of the linear part of the curve is reset to the stiffness of the blank, so that the same time step as the one without normal force is used to guarantee the stability.