pygritbx 0.1.0

Python-based Gearbox Reliability and Integrity Tool

Python-based Gearbox Reliability and Integrity Tool (PyGRIT)

PyGrit is a python-based tool born thanks to a project in the course "Fundamentals of Machine Design" at Politecnico di Torino. Students following 3rd year of the Mechanical Engineering bachelor's degree are required to submit a report for this project. The tool helps students define the components that constitute the gearbox in the given project, in order to then verify their design.

What does it do?

Given a gearbox configuration and an operating point, the tool is able to:

1. Calculate all the forces exchanged between gears and reactions on bearings.
2. Calculate internal loads and stresses on shafts.
3. Perform static and fatigue verification on shafts by calculating the corresponding safety factors.
4. Gear tooth verification in terms of bending and pitting (wear).
5. SKF bearing life analysis.

How does it do it?

Thanks to Python Object-Oriented Programming (POOP), the tool is able to define the components of the gearbox as objects as well as account for their specific geometries and interactions to perform the necessary calculations.

Components

The tool supports the following components:

1. Input Motor
2. Helical Gear (can be used as spur gear by settin helix angle to 0)
3. Shaft
4. SKF Bearings This structure allows the user to define the components based on their given characteristics.

Interactions and Geometries

The tool supports other classes that the user needs in order to define the interactions between different components as well as their geometry:

1. Mesh: to define the meshing between two gears
2. Material: to define the material properties for a certain component (yield strength, ultimate tensile strength, etc.)
3. Force/Torque: to define any external forces or torques acting on a certain component
4. Shaft Profile: to define the external profile of a shaft component
5. Shaft Section: to define a section of a shaft whose profile has already been defined to analyze it

The tool accounts for stress concentration factors, notch sensitivity factor, and fatigue limit correction factors to accurately perform the analysis. The user must define the geomtry of the shaf(s) properly so that the tool can account for all these factors accurately.

Examples

I. Normal Internal Load

II. Bending Stress

II. Haigh Diagram