Rotating machinery facilities have mostly fostered research and development activities related with rotating machines dynamics, but they also allow engineering students, technicians and engineers to get a practical insight, and better understanding, of vibration-related issues in rotating machines, as well as to apply and validate techniques to mitigate the effects due to certain rotor vibration causes. This project pursues to contribute to those latter goals.

The Virtual Rotor Kit (VRK) Project’s proposal arises as an attempt to provide  a stand-alone computational tool to emulate tests carried out in a rotor test rig or rotor kit. The project is under current development, and it is powered by PyChrono, a Python library that wraps a Project Chrono library, which is a robust open source multi-physics simulation engine.

The VRK Project began to be developed in 2021, by Dr. Luis Medina (Universidad Austral de Chile, Valdivia). In 2022, the project gained interest from Dr. Euro Casanova (Universidad del Bío-Bío, Concepción, Chile) and Dr. Carmen Müller-Karger  (Florida International University), who joined Dr. Medina in the work on this project.

Although VRK Project does not pretend to replace any practical experience at a (real) rotating machinery test facility, it aims at complementing understanding of relationship between measuring mechanical vibrations and some of the typical rotordynamic phenomena (e.g. rotor unbalancing, resonant operation, rotor-bearing-support interactions). At the current project’s first stage, a beta demo version of the application is free available, expecting to get some feedback from interested users who may help to evaluate  and improve the feasibility of the VRK Project.

This free available demo version has been developed using reliable, and validated, open source tools. Mainly, PyChrono has been used as core library, alongside other well known python libraries like Numpy, Scipy and Matplotlib, in addition to FreeCAD, PySimpleGUI and Pyinstaller.

By running this stand-alone version, user can be able to conduct tests to balance a rotor by means of a single balancing plane. Since vibration amplitudes measurements and a reference signal are “acquired”, user can decide what rotor balancing method will apply to find the proper solution. For instance, one typical solution method could be based on vibration amplitude and phase measurements (influence coefficient method), or only based on vibration amplitude (i.e. four-run balancing method).

 Similar to an on-site rotor balancing in a lab experience, is up to the user to process the measurements in order to find the rotor balancing solution. Furthermore, for validation purposes, user can implement and hence, verify the calculated solution by running  a verification test using the VRK, addressing constrains to place trial weights at the single plane, and taking into account the available trial weights, in the same way as the balancing tests are conducted in a laboratory's rotor test rig. For more details, please check up the tutorial video, made by Dr. Carmen Müller-Karger, or  the illustrative example, which  describe how VRK works. 

The demo's installation for Windows is quite easy, you just follow these three simple steps:

• Click on following link to download a 322 MB compressed file (.rar)

·         VRK demo version for Windows (September, 2022)

• Once is downloaded in your system, create a new folder to extract the folder that contains the .exe file and data folders. Please, create this new folder  in your  local  drive avoiding a long path to access to it. 

• Run demo.exe file (just by double clicking on it, or typing demo.exe at command promp from the folder where demo.exe is located ). By running the demo with the default inputs you can get a glance of it. 

VRK demo has been bundled in a single executable for an easy distribution. For this reason, it may be little slow (i.e. couple of seconds) to start up.

We would really appreciate if you let us know your thoughts over using this demo, and about what the project is intended to be, by answering a  5-question survey or, if you prefer, reaching me by email. Thanks in advance for your cooperation.

The VRK Project Team

The current VRK demo version was developed thanks to the references mentioned below. For this and similar projects, it must be acknowledged the job done by the open source developer community, who makes possible the availability of the computational tools that are being used in this project.

[1]      “Project Chrono - An Open-Source Physics Engine.” https://projectchrono.org/ (accessed Jan. 07, 2022).

[2]      M. L. Adams, Rotating Machinery Research and Development Test Rigs. CRC Press, 2017.

[3]      Tasora A., “Example: FEA of the Jeffcott rotor passing through resonance.” demo_FEA_beamsIGA.py in pychrono-6.0.0-py38_638/Lib/site-packages/pychrono/demos/fea. 2019.

[4]      A. Alsaleh, H. M. Sedighi, and H. M. Ouakad, “Experimental and theoretical investigations of the lateral vibrations of an unbalanced Jeffcott rotor,” Frontiers of Structural and Civil Engineering, vol. 14, no. 4, pp. 1024–1032, 2020.

[5]      Medina U, Luis U. and Casanova M, Euro L., “Desarrollo de un banco de ensayo virtual para el estudio del desbalanceo de rotores,” in Cuadernos de Mecánica Computacional, Sociedad Chilena de Mecánica Computacional, Aug. 2021, vol. 18, pp. 155–165.

[6]      FreeCAD/FreeCAD. FreeCAD, 2022. Accessed: Jan. 07, 2022. [Online]. Available: https://github.com/FreeCAD/FreeCAD

[7]      Project CHRONO. projectchrono, 2022. Accessed: Jan. 07, 2022. [Online]. Available: https://github.com/projectchrono/chrono

[8]      PySimpleGUI, PySimpleGUI. 2022. Accessed: Jan. 07, 2022. [Online]. Available: https://github.com/PySimpleGUI/PySimpleGUI

[9]      David Cortesi, Giovanni Bajo, William Caban, and Gordon McMillan, PyInstaller. PyInstaller, 2022. Accessed: Jan. 07, 2022. [Online]. Available: https://github.com/pyinstaller/pyinstaller/blob/41842f5ad31dd33d7ba4ae03daace2287c80dcb7/doc/index.rst