Video records used in the paper "Damage identification in beams using burst video-records during free-vibration"

Abstract

The beam specimen under test consisted of a 1 m long straight beam made of polypropylene with a 25.4 × 25.4 mm squared cross-section. The beam was free in the left end and fixed at the right end. The resulting free span was 0.8 m long and the FNP was 0.13 s (no cracks condition). The free vibration was produced by imposing an initial displacement of between 4 and 5 centimetres at the beam tip. Videos were recorded with a Chronos 2.1-HD high-speed camera, with a total duration of 2.7 s (≈20 FNPs), at a frame rate of 1000 fps, with an exposure time of 100% (1/1000 s), and a resolution of 1280 × 1024 px, of which 1200 px were considered for the ROI. The optical setup resulted in a pixel scale of ≈0.6 mm/px. The beam was artificially damaged by producing vertical and rectangular Mode I (opening) cracks on its upper face using a steel saw. The actual widths of the cracks were between 0.5 and 1 mm, so it were small enough to be considered infinitesimal and large enough to avoid crack breathing. As a combination of crack locations and depths, eight successive damage scenarios could be defined; which are summarised in Table 1. Cracks were produced at 100, 200 and 300 mm from the fixed end; and their depths were measured using a Vernier caliper.