12 March 2018
- Last edited 12 March 2018
Hello my friend José,
What does the wheel roll on? If the wheel rolls on a smooth steel surface then that is simple. If the wheel rolls on the floor and has to roll over bumps, gaps, thresholds, then that is complicated.
What happens at the center of the wheel? Is there a rolling element bearing or does the wheel slip on a smooth fixed shaft?
What is the maximum speed of the wheel? If the wheel rolls very fast and slips on a fixed shaft, then the plastic can heat up and cause problems.
What is the maximum static weight the wheel must support? Is the weight fixed or variable. If the weight is variable, does it spend most of its time unloaded? If the weight is fixed, then you could do a creep analysis.
What temperature does the wheel operate at? If it spends a long time at an elevated temperature under load and requires a long service life, then you must do a creep analysis.
What is the service life expected of the wheel? How many kilometers must it roll before it can be replaced? You could do a wear analysis on the tread and the bearing surface.
Will the wheel be underwater? Nylon is known to absorb moisture and swell up. A tight fit between the shaft and bearing hole could cause a problem when if the wheel has to work under water.
You might have the wheel in CAD, but you have to add a rolling surface and a shaft or bearing to the CAD model. The highest stress will occur when the ground is adjacent to a hole rather than between holes, so place the ground adjacent to a hole.
You should start with a Static Structural system and use an Isotropic Elasticity material for your first model using the properties you found. What you learn there and the answers to the questions above will help to determine which other analyses are worthwhile.