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Ideas for smoothing solid-flex contacts (PSHELL)?

erik_spe
Attached model drags a simple block across a simple flexible plate's surface. Force is too unsteady to be of any use. Even with flexbody rigid, force is unsteady.
 
I've noticed using SI2 solver dramatically helps, but hoping someone out there has other tricks up their sleeve (other than just softening the contact parameters).
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    In your approach you have a sim/sta statement and you try to change ERROR & HMAX in order to improve "convergence".
    Unfortunately it's as helpful as filling up your wiper reservoir when the dashboard shows low engine oil.
    (Both parameters only influence dynamic solution, but the "convergence" message is from the static solver)
     
    In a nutshell: Static and dynamic solver are two different things.
    By sim/sta you order ADAMS to first find a static solution which is always VERY tricky with contacts. Almost none of my models find equilibrium when contacts are active.
    My usual approach is to skip the sim/sta command and let an initial dynamic phase with very small tome steps do the "equillibrium".
    The other method would be first to use "very small steps for static solution" by limiting TLIM/ALIM to small values and increase MAXIT.
    An additional trick is to stage multiple static commands one after another ("funneling") until an equilibrium could be found. Something like:
    EQUILIBRIUM/tlim=1,alim=1,maxit=100
    ! Funneling fuer Statik
    EQUILIBRIUM/error=10,stability=5,imbalance=10
    sim/stat
    EQUILIBRIUM/error=1,stability=1,imbalance=1
    sim/stat
    EQUILIBRIUM/error=0.1,stability=0.1,imbalance=0.1
    sim/stat
    EQUILIBRIUM/error=0.01,stability=0.01,imbalance=0.01
    sim/stat
    ! Start the dynamic analysis
    Activate/MOTION,ID= 3
    simulate/dynamics, END=3.0, dtout=5E-03
     
     
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  • 0
    In your approach you have a sim/sta statement and you try to change ERROR & HMAX in order to improve "convergence".
    Unfortunately it's as helpful as filling up your wiper reservoir when the dashboard shows low engine oil.
    (Both parameters only influence dynamic solution, but the "convergence" message is from the static solver)
     
    In a nutshell: Static and dynamic solver are two different things.
    By sim/sta you order ADAMS to first find a static solution which is always VERY tricky with contacts. Almost none of my models find equilibrium when contacts are active.
    My usual approach is to skip the sim/sta command and let an initial dynamic phase with very small tome steps do the "equillibrium".
    The other method would be first to use "very small steps for static solution" by limiting TLIM/ALIM to small values and increase MAXIT.
    An additional trick is to stage multiple static commands one after another ("funneling") until an equilibrium could be found. Something like:
    EQUILIBRIUM/tlim=1,alim=1,maxit=100
    ! Funneling fuer Statik
    EQUILIBRIUM/error=10,stability=5,imbalance=10
    sim/stat
    EQUILIBRIUM/error=1,stability=1,imbalance=1
    sim/stat
    EQUILIBRIUM/error=0.1,stability=0.1,imbalance=0.1
    sim/stat
    EQUILIBRIUM/error=0.01,stability=0.01,imbalance=0.01
    sim/stat
    ! Start the dynamic analysis
    Activate/MOTION,ID= 3
    simulate/dynamics, END=3.0, dtout=5E-03
     
     
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