Contributions to Proceedings:
"Parametric Identification of Thermal Deformations Using Adaptive Kalman-Filtering Techniques";
in: "Proceedings of the 1st FIG International Symposium on Engineering Surveys for Construction Works and Structural Eingineering",
1st FIG International Symposium on Engineering Surveys for Construction Works and Structural Engineering , 2004,
The investigation of the progress of thermal deformations as consequence of dynamic temperature loads is an important task in civil and in mechanical engineering. Typical fields of interest are slim buildings under sun exposure and the computational compensation of thermal influences in the heating and cooling phases of machine tools. Within these applications, the determination of the thermal bend resulting of only one-sided influencing heat sources is of central importance. Its quantification with a physically justified structural model enables the prediction and close-to-reality simulation of bending procedures under time-variable loads.
Using a structural model the description of thermal deformations requires the knowledge of the progress of the spatial temperature distribution inside the regarded object. Consequently the collection of representative temperature data can be considered as a central task. In many cases the sensors can only be placed at the objects surface or in its outside layers. The high-grade nonlinearly spatial temperature gradient is then supposed to be linear which causes significant model errors. The minimization of these errors requires the modelling of the heat flow inside the object.
In this paper a dynamic temperature deformation model based on non-stationary temperature processes is presented. The model was developed for the investigation of the effect of one-sided thermal loads on bar-shaped bodies (i.e. slim towers in civil engineering and robot arms in industrial manufacturing). Using additional temperature measurements the experimental identification of the material parameters is realised by means of adaptive KALMAN-filtering. In lab tests with an aluminium column the estimation of thermal diffusivity suceeds with a deviation of only 0,2%. Control measurements are showing that the identified model can be used to predict the columns thermal bend with a mean deviation smaller than 10 mgon. Consequently the deformation model is suitable for the precise prediction and close-to-reality simulation of thermal deformations under variable loads. Future activities are especially planned for industrial applications.
Key words: Dynamic temperature loads, thermal bend, non-stationary heat flow, adaptive KALMAN-filtering, identification of "white box"-model
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