DeleteDamaged Custom Task

A custom task to delete failed particles or to remove unneeded particles after a specified time.

Introduction

The main use of a DeleteDamage custom task is to delete particles from a simulation after then undergo decohesion. This function is only useful for softening materials. Some simulations work better if failure particles are removed. This tasks works best when failure particles are confined to small regions of the object.

A second use of this task is to delete particles after a certain time. This function work best for rigid particles and provides one way to create transient boundary conditions in a problem (i.e., boundary conditions that disappear after a while).

Task Scheduling

In scripted files, a DeleteDamage is scheduled with the following block:

CustomTask DeleteDamaged
Parameter material,(matID)
Parameter matname,(matname)
Parameter store_x,(xloc)
Parameter store_y,(yloc)
Parameter store_z,(zloc)
Parameter minCOD,(cod)
Parameter direction,(dir)
Parameter deleteTime,(time)

In XML files, this task is created using a <Schedule> element, which must be within the single <CustomTasks> block:

<Schedule name='DeleteDamaged'>
   <Parameter name='material'>(matID)</Parameter>
   <Parameter name='matname'>(matname)</Parameter>
   <Parameter name='store_x'>(xloc)</Parameter>
   <Parameter name='store_y'>(yloc)</Parameter>
   <Parameter name='store_z'>(zloc)</Parameter>
   <Parameter name='minCOD'>(cod)</Parameter>
   <Parameter name='direction'>(dir)</Parameter>
   <Parameter name='deleteTime'>(time)</Parameter>
</Schedule>

The parameters are

• (matID) or (matname) - specifies material type by number or name.
• (xloc),(yloc),(zloc) - deleted particles are moved to this location on the background grid. This location must be empty such that particles will not interact with active particles.
• (minCOD) - normally particles are deleted right after they fail. Alternatively, you can require the implied crack in the particle to open further before deletion by enter that crack opening displacement (cod) in
• (dir) -
• (time) -