Description

The page will document the process and results of conducting Quasi-Static, Modal, and Random Vibration analyses on FINCH V2.

Outline

• [x] Defeaturing
• [x] Literature Review & Research
• [x] Model Set Up
  • [x] Material Assignment
  • [x] Contact Definitions (Bonded, Frictionless, etc.)
• [ ] Quasi-Static Analysis
• [ ] Modal Analysis
• [ ] Random Vibration Analysis

Model Set Up

Overview

This stage involves importing the model into Ansys Workbench as a STEP file, assigning materials to each of the components, defining contact types, generating a mesh, and finally running a simple uniaxial Quasi-Static simulation. In this way, we ensure that there are no issues such as overconstraint, which would prevent us from obtaining accurate results in the following Quasi-Static, Modal, and Random Vibration simulations.

Notes

• Solved geometry issues with GNSS receiver which was causing its mesh to fail
• Used three different body sizings to increase mesh quality above 0.7
• Switched from mostly fictionless contacts to all bonded due to unresolvable contact separation issues
  • Solved but very inaccurate results (deformation in metres)
  • Got warning about overconstraint
    • Used Status under Contact Tool to find areas of overconstraint and set these contacts to frictionless
• Got warning about underconstraint
  • Identified “Far” contacts using Status under Contact Tool between payload housing and lens. To resolve, suppressed the lens object.
  • Warning was unresolved
    • Set all contacts back to bonded and reintroduced X-direction displacement support (compression-only support still applied)
    • Solved but very inaccurate results (deformation in metres)
      • Suppressed the offending bodies (two bodies within payload subassembly)
• After suppressing the two offending bodies, reasonable stress and deformation results were achieved, thus concluding the model set up.

+X Acceleration

Below are the stress and deformation results for the +X acceleration case. The payload exhibited less deformation than expected. However, since we expect -X deformation for a +X acceleration, this could be explained by the compression-only support preventing deformation of the payload. To ensure that the lack of deformation is not due to overconstraint, a -X acceleration will also be applied.