Beam thermal response modeling

Different thermophysical property models were developed and introduced in Chapter 4. Furthermore, full-scale experimental comparative studies were conducted on cellular beams and columns of glass fiber-reinforced polymer (GFRP) composites, especially for civil engineering apphcations [21, 22]. The experimental procedures and results will be introduced in this chapter and the thermophysical property models from Chapter 4 will be assembled in the final governing equation to predict the thermal responses. The results obtained from the mathematical models will be compared to experimental results in this chapter. 

Temperature-dependant material property models were implemented into stmc-tural theory to establish a mechanical response model for FRP composites under elevated temperatures and fire in this chapter. On the basis of the finite difference method, the modeling mechanical responses were calculated and further vaUdated through experimental results obtained from the exposure of full-scale FRP beam and column elements to mechanical loading and fire for up to 2 h. Because of the revealed vulnerabihty of thermal exposed FRP components in compression, compact and slender specimens were further examined and their mechanical responses and time-to-failure were well predicted by the proposed models. 

In this chapter, the post-fire behavior of FRP composites was evaluated and modeled on the stmctural level. Results from the models compared well with results from fuU-scale post-fire experiments on cellular GFRP beam and column specimens that had been subjected to mechanical and thermal loading up to 120 min with inclusion of different thermal boundary conditions. On the basis of the previously proposed thermal and mechanical response models, existing approaches for post-fire evaluation can be applied. Predicted temperature profiles and the conversion degrees of decomposition can be used to estimate the post-fire stiHhess from existing two- and three-layer models. The borders between different layers can be determined either by a temperature criterion or a RRC criterion. 

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... 

In 1964 a brief description of the ECD kinetic model was presented in Nature. This occurred in response to criticism of the use of ECD data to measure the affinity of biological molecules for free electrons. A new procedure for studying electron attachment in swarms and beams had been applied to chlorobenzene. Since the ECD response was originally referenced to that of chlorobenzene, critics emphasized the distinction between dissociative capture and nondissociative capture. They noted that dissociative capture can take place with thermal electrons. This was not disputed. It was realized that certain molecules could undergo dissociative electron capture and that the kinetic model would have to be expanded to include these types of compounds. 

If the width of the irradiating beam is greater than the thicknesses of the layers probed and the variation of sample properties with distance is slow, the measured photothermal response data may be interpreted, in simple cases, by a theory derived by Rosencwaig and Gersho. In this case, the system is modeled as one-dimensional in optical absorbance and heat transport profiles. In this case, theoretical approaches for multiple layers are to be found in the literature. Continuous profiles of optical absorption or thermal diffusivity may be recovered from photothermal data by means of inversion methods. 

Each of these steps depends on the process before. The software suite starts with the material selection, in which also an individual material can be dehned. Fiber orientations and the number of plies can be selected in a following step. All material parameters must be chosen before the analysis can start. Six structural analysis modules can be differentiated with the CDS software suite. These solid mechanic modules are thick-walled cylinder, thin plate, thin plate impact-fastener modeling, thick plate, discontinuous tile modeling and compliant beam interlayer analysis. The CDS software suite allows changing the parameters of the manufacturing process or the laminate structure in real time. Four result sections for those parameter changes are provided by the software the effective properties, thermal-processing response, stress-strain results and the failure response. The CDS software suite is a complete analysis tool kit which is easy to use for the client. The software also allows export into an external simulation tool. 

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