Published: June 25, 2018
Matthew S. Hoehler, Christopher M. Smith
The behavior of engineering structures in fire is commonly studied through large-scale experiments. Full-field, noncontact measurement techniques such as Digital Image Correlation (DIC) are potentially ideal for such experiments; however, the presence of light emitted by the flames, thermal radiation from the heated structure, and convective thermal gradients in the air make this a challenging application for DIC. A simple method has been developed to enable the use of DIC in large, low-soot, fires using narrow-spectrum blue light and spectrally- matched bandpass optical filters to increase signal-to-noise ratio and filter undesired radiant energy before it reaches the camera. The method is applied to full-scale experiments in which a 6 m long W16x26 steel beam is supported over a 700 kW fire from a natural gas diffusion burner. The resulting images are temporally and spatially averaged during post-processing to smooth out false distortions of the images caused by the thermal gradients in and around the flames before DIC techniques are applied to resolve strain.
Pub Type: Talks
digital image correlation, DIC, fire, narrow-spectrum illumination, blue light
Created June 25, 2018, Updated July 24, 2018