The files are infrared measurement files, which can be opened by the Altair Software of FLIR Systems. 
The evaluated results (phase images) are published in QIRT journal 2021 (https://www.tandfonline.com/toc/TQRT20/current):

B.Oswald-Tranta: Detection and characterization of short fatigue cracks by inductive thermography

- GT_PD_100ms_100Pz_1.ptw: the phase image is shown in Fig.19a
- Kalib_A_St_300ms_60Pz_0Gr_1.ptw: the phase image is shown in Fig.20b
- Kalib_A_St_300ms_60Pz_45Gr_1.ptw: the phase image is shown in Fig.20c