Modal Analysis of Lenses Used in Automotive Lighting Industry and Obtaining MAC Matrix

Year 2019, , 401 - 413, 25.07.2019

Erhan Ay , Barış Ediz , Birhat Sönmezay , Sevda Telli Çetin

https://doi.org/10.24107/ijeas.571192

Abstract

In this study, 4 different pieces of automotive
rear lamp lenses which are made of Polymethylmethacrylate (PMMA)
and have different geometries have been inspected. Free-free natural
frequencies and mode shapes of lenses have been estimated by the help of ANSYS
WB® Finite Element Analysis (FEA) software. Meanwhile, by the help of Experimental
Modal Analysis (EMA) methods; natural frequencies, damping ratios and mode
shapes of the lenses have been determined. Finally, mode shapes calculated by
FE and measured by EMA were compared and Modal Assurance Criteria matrix (MAC)
was determined. After experimental modal tests, FRF’s were calculated by
DEWESoft® X3 software then natural frequencies, damping ratios and mode shapes
were calculated by the use of ME’scope® VESVT-570 Visual Modal software. In
addition, MAC was calculated by the help of MEScope® software. The main reason
for the use of such experimental methods was to understand if the assumptions
made before theoretical analysis were satisfied in reality or not.

Keywords

Auotomotive Lighting, Polymethylmethacrylate, Finite Element Modal Analysis, Experimental Modal Analysis, Modal Assurance Criteria

References

• Selman Tümer, T., Uçak kanadında titreşim analizi (Y. Lisans Tezi), CBÜ, Makine Mühendisliği Anabilim Dalı, Manisa, 2016.
• Altunel F., Modal updating of a helicopter structure using a newly developed correlation improvement technique (Y. Lisans Tezi), ODTÜ, Makine Mühendisliği Anabilim Dalı, Ankara, 2009.
• Gündoğan, M., Çelik model köprünün yapı sağlığının gözlenmesi (Y. Lisans Tezi), DEÜ, İnşaat Mühendisliği Anabilim Dalı, İzmir, 2012.
• Ay, E., Ediz, B., Çal, T., Telli Çetin, S., Modal analysis of automotive rear lamp lens produced from plastic material. International Journal of Automotive Science and Technology, (under review), 2019.
• Ay, E., Ediz, B., Çal, T., Telli Çetin, S. ,Calculation of the modulus of elasticity with using natural frequency formula and updated finite element analysis of automotive rear lamp lens. International Journal of Automotive Science and Technology, 3 (2): 27-31, 2019.
• Anonymous, Modal assurance criterion (MAC). https://community.plm.automation.siemens.com/t5/Testing-Knowledge-Base/Modal-Assurance-Criterion-MAC/ta-p/368008, 2016.
• Pastor, M., Binda, M., Harčarik, T. 2012. Modal assurance criterion. Science Direct.