FKFS Veranstaltungen

2025 Stuttgart International Symposium
on Automotive and Engine Technology

3. - 4. Juli 2025

Session: Development Methods II | | 17:35 - 18:05

Fiber Segment Interferometry for Automotive Strain, Shape, and EV Battery Temperature Testing

Marian Gragert, Kistler Instrumente GmbH

It is essential for Research and Development teams to have access to the most appropriate and capable tools and measurement technologies. Fiber Segment Interferometry (FSI) is a measurement technique with potential applications across automotive engineering. It combines the precision and speed of response of laser interferometry, but contained within optical fiber. The dielectric construction of optical fiber sensors also make them particularly well suited to high-voltage environments. This allows it to extend the capability of test stands to address challenging applications such as monitoring conditions inside EV battery packs and e-motors. This approach differs from a more conventional optical Fiber Bragg Grating (FBG) approach where diffraction gratings that reflect specific wavelengths of light are fabricated in optical fiber. Instead, FSI directly detects the change in length between points in the fiber to provide segment-wise distributed measurement along the entire sensor. In the case of temperature sensing, the fiber is encased in a low-friction polymer tube that is bonded to the device under test. For strain measurements, the fiber is bonded directly to the surface (as with a conventional strain gauge) to ensure transfer of mechanical strain. This paper will evaluate the performance of the technology for distributed strain, deformation, and temperature measurements for real-world automotive applications.