Скачать или смотреть Fluid Pressure Penetration in Abaqus/Explicit with a User-Defined VDLOAD Subroutine

This video is an extension of the simulation in Abaqus/Standard here:   • Pressure Penetration of a Bonded Compressi...  .

Abaqus/Explicit does not have a built-in pressure penetration capability, so a subroutine was used to apply pressure to nodes that are exposed to the fluid region. The mass (weight) of the seal is scaled by a factor of 100,000,000 which leads to significant inertia waves as the seal deforms. At times, you can see these disrupt the sealing front (which is the interface between the seal, the fluid, and the top contact surface).

For more information, review this:

T. Hohenberger, (2022). Prediction of Leakage in Elastomeric Seals for High Pressure Applications. PhD Thesis. Queen Mary University of London. (planned release in Q2 2022).

Here is the VDLOAD subroutine code:

C **********************************************************************
C Author: Travis Hohenberger
C Date: 2021-10-07
C E-mail: [email protected]
C Version: 0
C **********************************************************************
C
C This subroutine is built from the template in Simulia (2020) (see re-
C ference below). It has been developed to apply fluid pressure penetr-
C ation to the surface of an axisymmetric seal that is compressed betw-
C een two plates. A bonded interface is used to fix the seal to the bo-
C ttom plate. A frictional interface is used with the top plate. When
C developed, the plates were assumed to be rigid bodies, so plate defl-
C ection is not accounted for. The geometry used when developing this
C code is in Schematic 1. Some important notes:
C
C 1. Pressure of magnitude “F_Lim” is applied to the left surface of
C the seal.
C
C 2. As the seal deforms under pressure, nodes on the seal that init-
C ially contact the top plate may be pulled out of contact. If th-
C ese nodes fall below the user-defined y-coordinate “y_Lim”, pre-
C ssure propagates to that node. Therefore, this code uses a kine-
C matic definition to propagate pressure, as opposed to the built-
C in pressure penetration schemes in Abaqus/Standard which use n
C odal contact pressure. The different solutions have similar res-
C ults when a sufficiently small mesh is used.
C
C 3. For the problems tested, a kinematic contact definition (as opp-
C osed to the penalty option that is also available in Abaqus/Exp-
C licit) was used at the top interface. To prevent premature seal
C leakage, it was found necessary to set “y_Lim” slightly below t-
C he y-coordinate of the top plate in some cases. As one example,
C when the compressed seal height was 10.619 mm, y_Lim=10.6185 was
C used. The lower value is required because elastic waves due to
C inertia can cause the sealing front to be unstable.
C
C REFERENCE:
C ---------
C SIMULIA, (2020). “VDLOAD”. In: Abaqus R2020 User Subroutines Manu-
C al. Dassault Systèmes Simulia Corp. Providence, Rhode Island, USA.
C
C **********************************************************************
SUBROUTINE VDLOAD(nBlock, ndim, stepTime, totalTime, amplitude,
1 curCoords, velocity, dirCos, jltyp, sname, value)
C
INCLUDE 'vaba_param.inc'
C
DIMENSION curCoords(nBlock,ndim) , velocity(nBlock,ndim),
1 dirCos(nBlock,ndim,ndim) , value(nBlock)
CHARACTER*80 sname
C
C LOCAL VARIABLES
C ---------------
INTEGER km
REAL*8 y_Lim , F_Lim , y
C
C ******************************************************************
C ---------------- USER INPUTS (SEE SCHEMATIC 1) -----------------
C ******************************************************************
y_Lim = 10.6185
F_Lim = 17.
C
C ******************************************************************
C --------- APPLY PRESSURE TO THE ELEMENTS IN THE MODEL ----------
C ******************************************************************

DO 100 km = 1,nBlock
IF (curCoords(km,2).LT.y_Lim) THEN
value(km) = amplitude * F_Lim
END IF
100 CONTINUE
C
RETURN
END SUBROUTINE VDLOAD