Lifecycle

A DT lifecycle consists of explore, create, execute, save, analyse, evolve and terminate phases.

Phase	Main Activities
explore	selection of suitable assets based on the user needs and checking their compatibility for the purposes of creating a DT.
create	specification of DT configuration. If DT already exists, there is no creation phase at the time of reuse.
execute	automated / manual execution of a DT based on its configuration. The DT configuration must checked before starting the execution phase.
analyse	checking the outputs of a DT and making a decision. The outputs can be text files, or visual dashboards.
evolve	reconfigure DT primarily based on analysis.
save	involves saving the state of DT to enable future recovery.
terminate	stop the execution of DT.

A complete digital twin will support all the phases but it is not mandatory.

Even though not mandatory, having a coding structure makes it easy to manage DT lifecycle phases. It is recommended to have the following structure

workspace/
  digital twins/
    digital-twin-1/
      lifecycle/
        analyze
        clean
        evolve
        execute
        save
        terminate

A dedicated program exists for each phase of DT lifecycle. Each program can be as simple as a script that launches other programs or sends messages to a live digital twin.

Examples

Here are the programs / scripts to manage three phases in the lifecycle of mass-spring-damper DT.

#!/bin/bash
mkdir -p /workspace/data/mass-spring-damper/output
#cd ..
java -jar /workspace/common/tools/maestro-2.3.0-jar-with-dependencies.jar \
    import -output /workspace/data/mass-spring-damper/output \
    --dump-intermediate sg1 cosim.json time.json -i -vi FMI2 \
    output-dir>debug.log 2>&1

The execute phases uses the DT configuration, FMU models and Maestro tool to execute the digital twin. The script also stores the output of cosimulation in /workspace/data/mass-spring-damper/output.

It is possible for a DT not to support a specific lifecycle phase. This intention can be specified with an empty script and a helpful message if deemed necessary.

#!/bin/bash
printf "operation is not supported on this digital twin"

The lifecycle programs can call other programs in the code base. In the case of lifecycle/terminate program, it is calling another script to do the necessary job.

#!/bin/bash
lifecycle/clean