Attention

The ShARC HPC cluster was decommissioned on the 30th of November 2023 at 17:00. It is no longer possible for users to access that cluster.

Mechanical / MAPDL

Ansys Mechanical is a finite element analysis (FEA) tool that enables you to analyze complex product architectures and solve difficult mechanical problems. You can use Ansys Mechanical to simulate real world behavior of components and sub-systems, and customize it to test design variations quickly and accurately. ANSYS Mechanical has interfaces to other pre and post processing packages supplied by ANSYS and can make use of built in MPI to utilize multiple cross node CPUs and can scale to hundreds of cores.

Caution

ANSYS users can now use a maximum of 400 concurrent cores, across all devices on campus, including personal machines and HPC clusters, and regardless of the number of ANSYS applications they have open. Please see ANSYS license restrictions for more detail.

Module loading

After connecting to ShARC (see Establishing a SSH connection), you can start an interactive graphical session or submit a batch job using ANSYS programs by activating them and making them available with one of the module load commands below:

module load apps/ansys/15.0
module load apps/ansys/16.1
module load apps/ansys/17.2
module load apps/ansys/18.0/binary
module load apps/ansys/18.2/binary
module load apps/ansys/19.0/binary
module load apps/ansys/19.1/binary
module load apps/ansys/19.2/binary
module load apps/ansys/19.3/binary
module load apps/ansys/19.4/binary
module load apps/ansys/20.1/binary
module load apps/ansys/20.2/binary
module load apps/ansys/21.1/binary
module load apps/ansys/21.2/binary
module load apps/ansys/22.2/binary

Interactive jobs

While using a X11 GUI forwarding supported SSH client, an interactive session can be started on ShARC with the qrshx command which supports graphical applications. You can load an ANSYS module above and then start the ANSYS mechanical launcher program by running the launcher command.

If desired, the ANSYS Workbench GUI executable can be launched with the runwb2 command. To use more than a single core, you should write a batch job script and ANSYS mechanical APDL script file for submission to the batch queues.

Batch jobs

MAPDL is capable of running in both MPI and SMP parallel environments but will use its in-build MPI communications for both. This necessitates the use of either the smp (up to 16 cores on a single node only) or mpi (as many cores as desired across many nodes) parallel processing environments.

Sample MPI MAPDL Scheduler Job Script

Error

  • Please use ANSYS versions 19.4 and above to avoid errors which result in MAPDL falling back to using SMP rather than MPI mode.

The following is an example batch submission script, mech_job.sh, to run the mechanical executable mapdl with input file CrankSlot_Flexible.inp, and carry out a mechanical simulation. The script requests 4 cores using the MPI parallel environment with a runtime of 10 mins and 2 GB of real memory per core:

Hint

  • The #$ -V SGE option can be used to instruct SGE to import your current terminal environment variables. CAUTION - this may not be desirable and can break job submission if jobs are submitted from an existing interactive job.

  • Use of the mpi parallel environment to run MPI parallel jobs for Ansys is required if using more than 16 cores on ShARC.

  • The argument $NSLOTS is a Sun of Grid Engine variable which will return the requested number of cores.

  • The argument -mpi=INTELMPI instructs MAPDL to use the in-built Intel MPI communications - important for using the high performance Omnipath networking between nodes.

  • The exported I_MPI_FABRICS and I_MPI_FALLBACK variables instruct MAPDL to use the high performance Omnipath networking.

#!/bin/bash
#$ -cwd
#$ -N JobName
#$ -M a.person@sheffield.ac.uk
#$ -m abe
#$ -l h_rt=00:10:00
#$ -l rmem=2G
#$ -pe mpi 4
module load apps/ansys/22.2/binary

MACHINEFILE="machinefile.$JOB_ID"

for host in `cat $PE_HOSTFILE | awk '{print $1}'`; do
    num=`grep $host $PE_HOSTFILE | awk '{print $2}'`
    for i in `seq 1 $num`; do
    echo $host >> $MACHINEFILE
    done
done

MACHINELIST=""
for host in $(cat $MACHINEFILE)
do
    MACHINELIST+="${host}:1:"
done

export I_MPI_FABRICS=shm:ofi    #Set Omnipath.
export I_MPI_FALLBACK=no        #You may wish to allow fallback to ethernet.

mapdl -b -np $NSLOTS -machines $MACHINELIST -mpi=INTELMPI -i CrankSlot_Flexible.inp

Sample SMP MAPDL Scheduler Job Script

The following is an example batch submission script, mech_job.sh, to run the mechanical executable mapdl with input file CrankSlot_Flexible.inp, and carry out a mechanical simulation. The script requests 4 cores using the SMP (single node shared memory) parallel environment with a runtime of 10 mins and 2 GB of real memory per core:

#!/bin/bash
#$ -cwd
#$ -N JobName
#$ -M a.person@sheffield.ac.uk
#$ -m abe
#$ -l h_rt=00:10:00
#$ -l rmem=2G
#$ -pe smp 4
module load apps/ansys/22.2/binary
mapdl -b -np $NSLOTS -smp -i CrankSlot_Flexible.inp

Further details about how to construct batch jobs can be found on the batch submission guide page

The job is submitted to the queue by typing:

qsub mech_job.sh

ANSYS Mechnical training and help resources

Important

Academic support requests should be directed to the IT Services’ Research and Innovation team or the ANSYS Learning Forum (ensure you register with your University email for priority support).

ANSYS provides numerous academic training and help resources including tutorials, video lectures and examples for for structural and mechnical products. A short list of the resources ANSYS maintains is summarised below: