**WARNING MINIMUM TIME STEP

kotian

Hi everyone ,

i am new user for radioos solver , as i am working on crash analysis,   i am getting error of minimum time step,  why ?

please correct my doubt and error ,

<?xml version="1.0" encoding="UTF-8"?>

 

interface parameter

 

<?xml version="1.0" encoding="UTF-8"?>

 

engine file 

 

<?xml version="1.0" encoding="UTF-8"?>

please help me out in above error 

Simon Križnik

Hi,

 

the minimum timestep warning in the interface is due to the kinematic time step of the interface. It is because the node is penetrating too far into the gap. You can try increasing the Gapmin in your TYPE7 interface which will allow the contact to work sooner and prevent node from penetrating so far.  Or you could try making the interface stiffer, Istf=3 which uses the maximum stiffness of the slave and master. 

 

First check for initial penetrations and intersections:
-in Hypercrash: Quality>Check all Solver Contact Interfaces
-in Hypermesh: Tool>penetration check

 

Check the gap that is used for this interface.The value must be physically realistic and based on shell thicknesses in case of contact between shells. In case of constant gap (Igap =0) with no input gap (Gapmin=0), RADIOSS determines a default value for Gapmin and you can check this value in the starter out file. Gapmin=1mm usually works in most simulations.

 

If some elements fail on the master side or on the slave side of the interface, it is important to set Idel =2 (or Idel =1) for this interface. This will prevent nodes connected to deleted elements whose stresses are released to impact with a possible high velocity.