Car sliding roof – Thermal expansion issue

During on-road tests, while performing an alternating temperature test, a sliding roof frame suffers from warping and goes out of shape (thermal expansion problem); the sun roof cannot be closed any more.

modlflow analysis fibre orientation plastics engineering
Key points: Thermal expansion, alternating temperature test, filling simulation/moldflow analysis, fibre orientation, cooling simulation, transfer of fibre orientation to finite element analysis

Challenge / task

  • Analysis of the situation and identification of possible ways to reduce component warpage while maintaining component geometry
  • Investigation of how the moldflow process influences the materials' characteristics

Objectives / goal

  • Analyse component warpage using a filling simulation/moldflow analysis to determine fibre orientation
  • Transfer fibre orientation results to ABAQUS simulation software in order to perform a cooling simulation
  • Change fibre orientation within the component by changing the gate position
  • Review results by re-using filling simulation and cooling simulation

Results & benefits

Car sliding roof frame, fibre orientation simulation
Car sliding roof frame, thermal expansion problem: fibre orientation before and after troubleshooting (gate position change)
  • The material's strength along the fibre is much higher than across the fibre. Changing the gate position led to a different fibre orientation (see image) that strenghtened the component's resistance at the right spot against alternating temperatures.
  • By changing the fibre orientation, the component's deformation was reduced substantially and the component's functionality was restored.
  • The component's geometry remained completely unchanged