M. Korzen, R. Schriever, K.-U. Ziener, O. Paetsch, and G. W. Zumbusch.
Real-time 3-d visualization of surface temperature fields measured by
thermocouples on steel structures in fire engineering.
In J. Ziebs, J. Bressers, H. Frenz, D. R. Hayhurst,
H. Klingelhöffer, and S. Forest, editors, Proceedings of
International Symposium Local Strain and Temperature Measurements in
Non-Uniform Fields at Elevated Temperatures, pages 253-262, Camridge, UK,
1996. Woodhead Pub.
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The aim of this paper is to present some advanced techniques for monitoring thermocouples in the field of fire engineering. In a fire test structural elements like columns, beams or slabs, which are insulated by a fire protection material, are subjected to mechanical as well as thermal loadings. Whereas the mechanical loading is constant the mean temperature in the furnace varies - due to oil or gas burners - nearly monotonically as a function of time within 90 minutes between room temperature and 1000 0C. New technical standards as well as research purposes require the monitoring of 30 to 60 thermocouples and more. Although versatile computer based data acquisition systems including necessary signal condition front-ends exist for handling such an amount of data at any required rate, there is a lack in representing these data during the test in their geometrical context, i.e. as a property of the steel surface. The method, which is proposed by the authors, uses some recent developments in computer graphics and numerical mathematics. By this method the monitoring of the thermocouples is understood as a representation of a time-dependent 1-dimensional field, which is based on discrete measured values on a curved surface in 3-D space. For this solution CAD and data visualization tools are under testing, which are originally designed for other purposes. In praxis a geometry file has to be created before the fire test for the structural element under consideration including the information on the position of the thermocouples. This file is used as an appropriate triangulation of the surface of the specimen. The corresponding grid together with the actual temperature readings are the basis for the real time visualization of the temperature field by continuous colors or iso-lines.