Brno University of Technology

About: Brno University of Technology is a education organization based out in Brno, Czechia. It is known for research contribution in the topics: Computer science & Fracture mechanics. The organization has 6339 authors who have published 15226 publications receiving 194088 citations. The organization is also known as: Vysoké učení technické v Brně & BUT.

Can pure mode III fatigue loading contribute to crack propagation in metallic materials

Abstract: The possibility of pure mode III crack growth is analysed on the background of theoretical and experimental results obtained in the last 20 years. Unlike for modes I and II, there is no plausible micromechanistic model explaining a pure mode III crack growth in ductile metals. In order to realize ‘plain’ mode III fracture surface, we propose the propagation of a series of pure mode II cracks along the crack front. Fractographical observations on crack initiation and propagation in a low alloy steel under cyclic torsion support such a model. The authors have not seen any clear indication of a pure mode III crack growth micromechanism in metals until now.

The influence of structure order on the kinetics of dehydroxylation of kaolinite

Abstract: The structural order of kaolinite is an important factor that shows a substantial effect on the processes which take place during the thermal treatment of kaolin. The influence of structural order on the dehydroxylation process was investigated by simultaneous thermogravimetry and differential thermal analysis (TG-DTA). The thermal analysis was performed on the samples with gradually decreasing structural order prepared by milling procedure. The apparent activation energy of dehydroxylation process decreases with decreasing structural order according to the exponential function. The extrapolation of experimental data leads to the estimation of apparent activation energy of 76.6 kJ mol −1 and of frequency factor of 0.12 × 10 4 s −1 related to completely disordered form of kaolinite, while the ordered form shows the apparent activation energy of 216.17 kJ mol −1 and the frequency factor of 9.26 × 10 4 s −1 . The relationships between features such as the infrared pattern of treated material, the degree of structural order and the apparent activation energy were established.

Utilization of Faraday Mirror in Fiber Optic Current Sensors

Abstract: Fiber optic sensors dispose of some advantages in the field of electrical current and magnetic field meas- urement, like large bandwidth, linearity, light transmission possibilities. Unfortunately, they suffer from some parasitic phenomena. The crucial issue is the presence of induced and latent linear birefringence, which is imposed by the fiber manufacture imperfections as well as mechanical stress by fiber bending. In order to the linear birefringence compensation a promising method was chosen for pulsed current sensor design. The method employs orthogonal polarization conjugation by the back direction propagation of the light wave in the fiber. The Jones calculus analysis presents its propriety. An experimental fiber optic current sensor has been designed and realized. The advantage of the proposed method was proved considering to the sensi- tivity improvement.