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Coupled Thermal-Elastic Response of Structures to Fires.


pdf icon Coupled Thermal-Elastic Response of Structures to Fires. (85 K)
Prasad, K. R.; Baum, H. R.

Poster Session V and Reception;

Combustion Institute/Western States, Central States and Eastern States. Fourth (4th) Joint Meeting of the U.S. Sections. Hosted by The Eastern States Section of the Combustion Institute and Drexel University. Poster Session V and Reception. March 20-23, 2005, Philadelphia, PA, 1-6 pp, 2005.

Keywords:

combustion; structures; equaitons; temperature; stress (mechanics); thermoelasiticity; temperature field

Abstract:

There has been a resurgence of interest in the response of building structures to fires over the past several years. This interest was greatly enhanced by the attack on, and subsequent collapse of, theWorld Trade Center (WTC) towers. Traditional methods of modeling this behavior are based on computing the thermal response of an un-deformed structure and performing structural analysis in a sequential manner. This procedure can lead to significant errors in the thermally induced structural response. While the applications of interest clearly involve highly non-linear calculations, the starting point for most fire scenarios is almost always an undamaged building at room temperature. Since virtually all buildings are designed to keep the stresses well below the elastic limit and the deflections of the load bearing structure reasonably small, the starting point for simulations of fire induced damage must lie within the domain of linear elasticity. Moreover, the difficulties that arise are evident before the temperature rise is large enough to affect the elastic or thermal properties of most structural materials. Under these circumstances the thermally induced stresses are also linear, and the temperature fields can be described by the heat conduction equation for the material(s) of interest.