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“An accurate model ensures accurate FEA”. This is the most common misunderstanding while coming up with a model for FEA. As emphasized earlier, the geometry is only a template on which mesh is generated. If the geometry prevents successful mesh generation, model accuracy at that point simply hurts compared to aid analysis process.
Factors that contribute towards successful simulation:
Geometry definitely plays a good role. So its important one gets the concept right before one starts analyzing the designs. The other parameters that play a role are material properties, boundary conditions, and the physics of the problem.
FEA’s comfort zone. What is required ideally?
- All parts are machined.
- Surfaces are polished to take care of the courseness or roughness of the machining.
- All parts are heat treated to remove any residual stress from machining process.
The reason for these being is, it makes results predictable and consistent.
From the above it is obvious we need to have two configurations, one for production, other for analysis. Some general guidelines to simplify your model …
- Suppress any rounds, inside fillets.
- Screw threads or spline features are unnecessary unless they are being specifically studied.
- Small features outside the load patch can be eliminated.
- Decorative features like company logos, part numbers can definitely be ignored.
In essentiality anything that does not directly contribute to the stiffness of the structure can be eliminated.
Plan your Geometry
- Delay including fillets, chamfers and drafts
- Use permanent datums as references to minimize dependencies on other geometries.
- Delete unwanted or incorrect features.
Keep in mind analysis is part of the design cycle. Hence it is very imperative we define goals at the beginning in terms of geometry requirements.
Define successful simulation
- Quickly assess the performance of a new design.
- Evaluate other design options easily.
- Optimize the design for cost / performance.
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