ReverseLoad Custom Task

A custom task to alter calculations based on crack propagation results.

Introduction

The ReverseLoad custom task monitors crack lengths. Once any crack or a specified crack reaches a specified crack length, the crack propagation of all cracks stops and various actions can be performed.

Task Scheduling

In scripted files, a ReverseLoad custom tasks is scheduled using

CustomTask ReverseLoad
Parameter maxLength,(length))
Parameter crackNumber,(number)
Parameter style,(style)

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

<Schedule name='ReverseLoad'>
   <Parameter name='maxLength'>(length)</Parameter>
   <Parameter name='crackNumber'>(number)</Parameter>
   <Parameter name=style'/>(number)</Parameter>
</Schedule>

where

• (length) - specifies the maximum crack length (in mm). Once this length is reached, all crack propagation will stop.
• (number) - gives the crack number to watch. When that crack reaches the specified maximum length, the task will take effect. Alternatively, (tt)(number) can be zero which causes the task to take effect when any crack reaches the specified maximum length. The default value is 0 or to watch all cracks.
• style - determines what happens after the specified crack length is reached and crack propagation is stopped. The options are:
  • reverse: Reverses all linearly increasing loads (see "linear" style in particle loads) and reverses direction of all rigid particles. This style will unload until the load (on loaded particles) or displacement (on moving rigid particles) returns to zero at which point the analysis will stop.
  • hold: Stops all linearly increasing loads (see "linear" style in particle loads) and stops all rigid particles at their current values. The analysis continues.
  • continue: All loads and rigid particles continue unchanged. Only the crack propagation stops.
  • abort: The analysis terminates.

The default (style) is to reverse all loads to unload the specimen (as implied by the name)