/FAIL/VISUAL

Block Format Keyword The purpose of this failure criteria is to record the maximum tensile 1st principal stress or maximum tensile 1st principal strain in a simulation. The maximum value of all the cycles in a simulation is used to compute the damage output.

The failure model is only for visualization and does not cause element failure. It is compatible with shells and solids elements and can be used with elastic, visco-elastic and elasto-plastic materials.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/FAIL/VISUAL/mat_ID/unit_ID
Type C_min C_max F-coefficient F-flag   Strdef
Optional Line
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
fail_ID                  

Definition

Field Contents SI Unit Example
mat_ID Material identifier.

(Integer, maximum 10 digits)

  
unit_ID Unit Identifier.

(Integer, maximum 10 digits)

  
Type Selector type.
=0
Set to 1.
= 1 (Default)
Maximum 1st principal stress is recorded.
= 2
Maximum 1st principal strain is recorded.

(Integer)

  
C_min Lower limit for stress or strain that defines when the maximum value starts to be recorded. Below this value Damage = 0.
Note: C_min ≥ 0.

Default = 0.0 (Real)

 [Pa] or None
C_max Maximum limit for stress or strain. Values larger than this will have Damage = 1.
Note: C_max ≥ 0 .

(Real)

 [Pa] or None
F-coefficient Filter coefficient value. 1
If F-Flag =1, Exponential moving average,
= 0
Set to 1.
= 1 (Default)
No filtering.

(Real)

  
If F-Flag = 2, Cutoff frequency

Default = 0.0 (Real)

 [Hz]
F-flag Filter flag. 1
= 0
Set to 1.
= 1 (Default)
Exponential moving average filter.
= 2
4-Pole Butterworth filter.
  
Strdef Strain measure definition used in failure criterion.
= 1 (Default)
Strain defined by Ismstr flag in property.
= 2
Engineering strain.
= 3
True strain.

(Integer)

  
fail_ID Failure criteria identifier.

(Integer, maximum 10 digits)

  

▸Example (Steel)

Comments

  1. Filtering option, F-Flag:

    If F-flag=1, an exponential moving average filter is used for filtering the stress or strain. Assuming stress is being filtered.

    (1)
    σf(t)=ασ(t)+(1−α)σ(t−Δt) MathType@MTEF@5@5@+=feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeq4Wdm3aaSbaaSqaaiaadAgaaeqaaOWaaeWaaeaacaWG0baacaGLOaGaayzkaaGaeyypa0JaeqySdeMaeq4Wdm3aaeWaaeaacaWG0baacaGLOaGaayzkaaGaey4kaSYaaeWaaeaacaaIXaGaeyOeI0IaeqySdegacaGLOaGaayzkaaGaeq4Wdm3aaeWaaeaacaWG0bGaeyOeI0IaeyiLdqKaamiDaaGaayjkaiaawMcaaaaa@4F8A@
    Where,
    σf MathType@MTEF@5@5@+=feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeq4Wdm3aaSbaaSqaaiaadAgaaeqaaaaa@38D0@
    Filtered stress
    α MathType@MTEF@5@5@+=feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqySdegaaa@3795@
    The degree of weighting decrease, which is a constant smoothing factor between 0 and 1.
    A higher α MathType@MTEF@5@5@+=feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqySdegaaa@3795@ value discounts previous values faster, which means there is less filtering.

    If F-Flag=2, a 4-Pole-Butterworth filter is used where the F-coefficient defines the cut-off frequency. This is the same filter used in /ACCEL.

  2. Damage is output as:(2)
    D=max(0,min[1,σmajor−CminCmax−Cmin]) MathType@MTEF@5@5@+=feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiraiabg2da9iGac2gacaGGHbGaaiiEamaabmaabaGaaGimaiaacYcaciGGTbGaaiyAaiaac6gadaWadaqaaiaaigdacaGGSaWaaSaaaeaacqaHdpWCdaWgaaWcbaGaamyBaiaadggacaWGQbGaam4BaiaadkhaaeqaaOGaeyOeI0Iaam4qaiaad2gacaWGPbGaamOBaaqaaiaadoeacaWGTbGaamyyaiaadIhacqGHsislcaWGdbGaamyBaiaadMgacaWGUbaaaaGaay5waiaaw2faaaGaayjkaiaawMcaaaaa@5724@

    Which means, D MathType@MTEF@5@5@+=feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKfMBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhiov2DaebbnrfifHhDYfgasaacH8srps0lbbf9q8WrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbba9q8WqFfea0=yr0RYxir=Jbba9q8aq0=yq=He9q8qqQ8frFve9Fve9Ff0dmeaacaGacmGadaWaaiqacaabaiaafaaakeaacaWGebaaaa@39A0@ is always 0 ≤ D MathType@MTEF@5@5@+=feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbwvMCKfMBHbqefqvATv2CG4uz3bIuV1wyUbqedmvETj2BSbqefm0B1jxALjhiov2DaebbnrfifHhDYfgasaacH8srps0lbbf9q8WrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbba9q8WqFfea0=yr0RYxir=Jbba9q8aq0=yq=He9q8qqQ8frFve9Fve9Ff0dmeaacaGacmGadaWaaiqacaabaiaafaaakeaacaWGebaaaa@39A0@ ≤ 1.

  3. Advanced math in HyperView can be used to calculate the maximum value:(3)
    σmajor=D(Cmax−Cmin)+Cmin MathType@MTEF@5@5@+=feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeq4Wdm3aaSbaaSqaaiaad2gacaWGHbGaamOAaiaad+gacaWGYbaabeaakiabg2da9iaadseadaqadaqaaiaadoeacaWGTbGaamyyaiaadIhacqGHsislcaWGdbGaamyBaiaadMgacaWGUbaacaGLOaGaayzkaaGaey4kaSIaam4qaiaad2gacaWGPbGaamOBaaaa@4C9C@
  4. When maximum 1st principal strain TYPE=2 is recorded, replace stress in the previous equations with strain.
  5. For shell elements with /MAT/LAW1, only /PROP/SHELL N=1 is supported.