Thermal Response Experiments

In each scenario, the specimen was first loaded in a load-control mode to a prescribed level 100%, 75%, 50% of SLS (serviceability limit state) load, see Table 7.3. The load was then kept constant during the subsequent thermal loading process. The SLS-load, Psls determined as follows  

After the load level was reached, water was circulated at the same flow rates as those used in the thermal response experiments, see Table 7.3. Thermal loading was then applied (set as time t = 0) according to the predefined temperature-time curve (see Section 7.6.2) until ultimate failure occurred or the prescribed time duration was reached. 

Water-cooled specimens were subjected to 100% SLS loading in these scenarios, while low (MCI) and high (MC2) flow rates were applied (see Table 7.3). Mechanical 

Specimens were subjected to 75% (MC3) and 50% (MC4) SLS-loads and water cooled at high flow rate, see Table 7.2. After mechanical loading, axial displacements were —2.3 mm (MC3) and —1.6 mm (MC4). The time-dependent axial displacement curves of these two scenarios behaved similarly to those of MCl/2 because of a similar water-cooling effect 

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Figure 7.16 Experimental setup for thermal response experiments (unloaded) and structural endurance experiments (a) noncooled and (b) water-cooled [20]. (With permission from Elsevier.)...

Because the tubes used in the stmctural endurance experiments were not equipped with temperature sensors (see Section 7.6.2), only the chamber temperature was recorded and it was assumed that through-thickness temperature progression was similar to that in the thermal response experiments. The tubes were fully fixed, see Figure 7.16, and therefore exhibited a buckling length of 1/2. Six scenarios were investigated, including different combinations of compressive load levels and water flow rates as summarized in Table 7.3 (two specimens per scenario for scenarios MNl/2 and MCl/2, one specimen for scenarios MC3/4). 

In early research efforts, attention was concentrated on carbonaceous anodes because of the earlier experiences with metallic lithium. Dahn and coworkers studied the thermal response of carbonaceous materials in the presence of electrolytes in an adiabatic environment created in a thermal analysis technique known as accelerating rate calorimetry (ARC). By choosing an arbitrary threshold value for... 

The origin of the deep localized states in the mobility gap that control the dark decay has been attributed to structural native thermodynamic defects [12]. Thermal cycling experiments show that the response of the depletion time to temperature steps is retarded, as would be expected when the structure relaxes toward its metastable liquid-like equilibrium state. As the structure relaxes toward the equilibrium state, t(j decreases further until the structure has reached equilibrium. The only possible inference is that must be controlled by structure-related thermodynamic defects. The generation of such defects is, therefore, thermally activated. We should note that because the depletion discharge mechanism involves the thermal emission of carriers... 

For both experiments extensive instrumentation allowed for monitoring of the hydraulic and mechanical performance of the system before, during and after the test. In the Buffer/Container experiment the thermal response of the system was also measured. 

In this chapter, thermal response results were presented from full-scale experiments on cellular FRP beams and columns with and without liquid-cooling. The structural members were subjected to ISO fire curve and mechanical loading simultaneously until a stop criterion (water leakage or structural failure) or after the planned fire exposure duration. 

Table 7.3 Parameters for thermal response and structural endurance experiments [20],...

An internal liquid cooling system as an active fire protection was implemented in full-scale GFRP panels for beam and column applications, the resulting thermal responses have been introduced and modeled in Chapter 6 and the mechanical responses in Chapter 7. The fire endurance time of each scenario is summarized in Table 9.1 and more details can be found in the previous chapters. It can be concluded that combined mechanical loading and fire experiments on full-scale water-cooled cellular slabs and columns proved the feasibility of an effective fire protection. Fire endurance durations of up to 2 h could be reached at slow water... 

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