RE: Absorbing Boundary: PML

[James Kennedy]

Dear Sina,

 

Update group  to the Yahoo Group of :LS-DYNA

 

'LS-DYNA2' ls-d...@googlegroups.com

 

PML Absorbing Boundary

 

https://lsdyna.ansys.com/pml/#examples

 

Examples

 

MAT_­PML_­ELAS­TIC for quar­ter mesh mod­el of elas­tic half-space

MAT_­PML_­ELAS­TIC_­FLU­ID for se­mi-in­fi­nite chan­nel

MAT_­PML_­ACOUSTIC for acoustic wave­guide

MAT_­PML_­OR­THOTROP­IC for half-space

MAT_­PML_­ANISOTROP­IC for half-space

  

References

 

U. Ba­su and A. K. Chopra. Per­fect­ly matched lay­ers for
time-har­mon­ic elas­to­dy­nam­ics of un­bound­ed do­mains: the­o­ry and
fi­nite-el­e­ment im­ple­men­ta­tion. Com­put­er Meth­ods in Ap­plied
Me­chan­ics and En­gi­neer­ing, 192(11–12):1337–1375, March 2003.

U. Ba­su and A. K. Chopra. Per­fect­ly matched lay­ers for tran­sient
elas­to­dy­nam­ics of un­bound­ed do­mains. In­ter­na­tion­al Jour­nal for
Nu­mer­i­cal Meth­ods in En­gi­neer­ing, 59(8):1039–1074, Feb­ru­ary
2004. Er­ra­tum: Ibid. 61(1):156–157, Sep­tem­ber 2004.

U. Ba­su. Ex­plic­it fi­nite el­e­ment per­fect­ly matched lay­er for
tran­sient three-di­men­sion­al elas­tic waves. In­ter­na­tion­al
Jour­nal for Nu­mer­i­cal Meth­ods in En­gi­neer­ing, 77(2):151–176,
Jan­u­ary 2009.

 

Sincerely,

James M. Kennedy

KBS2 Inc.

January 18, 2024

 

From: Sina Zolfaghary [mailto:sina...@gmail.com]
Sent: Thursday, January 18, 2024 11:11 AM
To: James Kennedy <j...@kbs2.com>
Subject: Absorbing Boundary: PML

 

Dear Dr. Kennedy

Hope you are doing well.

 

I am writing to ask a question about the Absorbing boundaries for Wave Propagation studies in LSDyna. I am so sorry for writing directly to your address. In the past (2020), I could message you in the Yahoo Group of LSDyna, however, it seems that the group is out of access these days.

 

I am trying to model the wave propagation into an Isotropic Plate, and I wanted to apply the non-reflecting boundaries using Perfectly Matched Layers in LSDyna to avoid the effects of reflecting energy. I have seen some simple examples on the LSDyna tutorial website and have tried to apply the PML to my model. However, the following error appears: 

 

 *** Warning 10668 (KEY+668)
     no interior plane for exterior plane at x1 = -5.0000E+00
     ==> exterior plane ignored, no damping in direction -x1
 
 *** Warning 10668 (KEY+668)
     no interior plane for exterior plane at x2 = -5.0000E+00
     ==> exterior plane ignored, no damping in direction -x2
 
 *** Warning 10668 (KEY+668)
     no interior plane for exterior plane at x3 = -5.0000E+00
     ==> exterior plane ignored, no damping in direction -x3

 

 *** Error 10678 (KEY+678)
     element 30001 not found in any PML block

...

 

Could you please kindly help me understand what should I do? Attached please kindly find the *.k file and a schematic of the model.

Thanks in advance for your help. 

Kind regards,

 

--

Sina Zolfagharysaravi
Research Fellow
Department of Civil Engineering
University of Bologna
Bologna, Italy

[Yahia Halabi]

Dear  Sina

I have the same errors you had when modelling PML, could you please help me how could you solve the problem?