Page 5: IniVel (Initial Velocity)

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  • inivel panel
  • Figure 1 – IniVel Interface

Purpose:

One of the most common initial conditions for crash simulations is some type initial velocity. There are some basic methods of defining initial velocity states in LS_DYNA using *INITIAL_VELOCITY and *INITIAL_VELOCITY_GENERATION, and these methods are effective for simple situations like assigning velocities to all nodes.

In contrast creating initial velocity definitions for directions other than Global XYZ can be more complex and requires additional facilities. This interface allows the flexibility to define velocities in global or local systems, along a vector, in polar coordinates, and even using a combination of angular plus translational. This interface is often used to generate initial velocity conditions for door slam, head impact, and full vehicle crash analysis.

Controls:

  • rbs Show – Show existing *INITIAL_VELOCITY entities
  • rb Modify – Modify *INITIAL_VELOCITY values
  • rb Create – Create new *INITIAL_VELOCITY entities
  • rb Delete – Delete *INITIAL_VELOCITY entities

For Show, Modify, and Delete, the Entity Operation Interface is displayed in the secondary controls area. For Create, the General Selection Interface is displayed in the secondary controls area.

  • Label: Set current entity label type

  • CreateType: Set current inivel create type
  • CreateType: Global

  • Vx: Enter initial velocity in x direction
  • Vy: Enter initial velocity in y direction
  • Vz: Enter initial velocity in z direction
  • Vrx: Enter initial rotational velocity in x direction
  • Vry: Enter initial rotational velocity in y direction
  • Vrz: Enter initial rotational velocity in z direction
  • CreateType: Local

Coordsys

 Popup lind dialog to get coordsys ID

  • Vx: Enter initial velocity in x direction
  • Vy: Enter initial velocity in y direction
  • Vz: Enter initial velocity in z direction
  • CreateType: AlongVect

Direction

 Get Direction

  • Velocity: Enter velocity
  • CreateType: Angular

Rot. Axis

 Get position and direction

  • Omega: Enter omega
  • CreateType: Ang+Tran

Rot. Axis

 Get position and direction

  • Omega: Enter omega

  • Vx: Enter initial velocity in x direction
  • Vy: Enter initial velocity in y direction
  • Vz: Enter initial velocity in z direction

All

 Select all initial velocity entity

None

 Deselect all initial velocity

Rev

 Reverse selection initial velocity

Alist

 Select all entities within the selected range

Apply

 Apply entities for creation/modification

Done

 Exit Initial Velocity Data interface

  • Click item from list to select (1)


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