Balázs Czél

Deviation from the Fourier law in room-temperature heat pulse experiments

Abstract We report heat pulse experiments at room temperature that cannot be described by Fouriers law. The experimental data are modeled properly by the Guyer–Krumhansl equation, in its over-diffusion regime. The phenomenon may be due to conduction channels with differing conductivities and parallel to the direction of the heat flux.

Simultaneous Measurement of Temperature Dependent Thermophysical Properties

A new evaluation method for a transient measurement of thermophysical properties is presented in this paper. The aim of the research was to couple a new automatic evaluation procedure to the BICOND thermophysical property measurement method to enhance the simultaneous determination of the temperature dependent thermal conductivity and volumetric heat capacity. The thermophysical properties of two different polymers were measured and compared with the literature data and with the measurement results that were done by well-known, traditional methods. The BICOND method involves a step-down cooling, recording the temperature histories of the inner and the outer surfaces of a hollow cylindrical sample and the thermophysical properties are evaluated from the solution of the corresponding inverse heat conduction using a genetic algorithm-based method (BIGEN) developed by the authors. The BIGEN is able to find the material properties with any kind of temperature dependency, that is illustrated through the measurement results of poly(tetrafluoroethylene) (PTFE) and polyamide (PA) samples. # 2011 The Japan Society of Applied Physics

9.3 – Design of Welded Joints – Determining Stress State

The VDI Richtlinien titled ”Rechnerischer Festigkeitsnachweis fur Maschinenbauteile” was published by Forschungskuratorium Maschinenbau (FKM) in 1998; it provides designers with a design method of a standardized approach on a new basis, even for the stress analysis of welded structures. One of the essential criteria for designing welded seams for static stress and fatigue is knowledge of the stress state in the seam and its surroundings. Erwin Haibach proposes to determine the so-called structural stress characterizing stress state of welded seams along the Haibach line. In our presentation, a brief introduction to the designing of welded structures according to FKM will be followed by a presentation of results of FE analyses to demonstrate the use of stresses interpreted along the Haibach line as structural stresses. Our research and development activities were performed on assignment by and in cooperation with Knorr Bremse Hungaria Kft.