Online Documentation

# Page 5: IniVel (Initial Velocity)

• 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:

• Show - Show existing *INITIAL_VELOCITY entities
• Modify - Modify *INITIAL_VELOCITY values
• Create - Create new *INITIAL_VELOCITY entities
• 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

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

Get Direction

• Velocity: Enter velocity
• CreateType: Angular

Get position and direction

• Omega: Enter omega
• CreateType: Ang+Tran

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

Select all initial velocity entity
Deselect all initial velocity
Reverse selection initial velocity
Select all entities within the selected range
Apply entities for creation/modification
Exit Initial Velocity Data interface

• Click item from list to select

© 2012 Livermore Software Technology Corporation