Transactions on Transport Sciences, 2010 (vol. 3), issue 1
Study of the Development of Cracks Accompanying Mechanical Loading of Solids
P. Koktavý, B. Koktavý
Transactions on Transport Sciences 2010, 3(1):1-8 | DOI: 10.2478/v10158-010-0001-5
The formation of cracks in mechanically loaded insulators is accompanied by the generation of an electromagnetic field. Four basic processes of the crack's growth have been suggested based on the dipole model of a crack. A differential equation describing the transformation of the crack's primary parameters into a measurable electric signal has been derived for each of the four cases. Thus obtained theoretical curves have been compared with the experimental ones. Based on the comparison, some primary parameters of the crack have been determined.
The Problem of Testing the Grouting of Prestressing Reinforcement Use of Radiography
Transactions on Transport Sciences 2010, 3(1):9-16 | DOI: 10.2478/v10158-010-0002-4
One of the less frequent requirements from real world condition is to verify the correctness of the grouting of prestressed reinforcement. The experiment described in this paper aims at examining the possibilities of Co-60 radiography in solving this problem, depending on the thickness of the concrete, the form of defect, and the space configuration of the radiography of this defect.
Non-linear Ultrasonic Spectroscopy as an Assessment Tool for the Structure Integrity of Concrete Specimens
M. Korenska, M. Matysik
Transactions on Transport Sciences 2010, 3(1):17-22 | DOI: 10.2478/v10158-010-0003-3
On the basis of non-linear effect studies, new diagnostic and defectoscopic methods have been designed which are based on the elastic wave non-linear spectroscopy. The non-linear ultrasonic spectroscopy brings new prospects into the acoustic non-destructive testing of material degradation. Poor material homogeneity and, in some cases, the shape complexity of some units used in the building industry, are heavily restricting the applicability of "classical" ultrasonic methods. These linear acoustic methods focus on the energy of waves, which are reflected by structural defects, variations of the wave propagation velocity, or changes in the wave amplitude....
Optimizing the Location of Piezoelectric Sensors
I. Pląková, Z. Chobola, M. Matysík
Transactions on Transport Sciences 2010, 3(1):23-28 | DOI: 10.2478/v10158-010-0004-2
Piezoelectric sensors appear to be best suited for picking up acoustic signals thanks to their high sensitivity over a wide frequency range, frequency response stability, design compactness, and reliability. Their design differs from sensor to sensor, depending on the type of the measurement to be carried out. Piezoelectric sensors are manufactured on the basis of crystals and polarized dielectrics. They feature, above all, a very good signalto-noise ratio, a fast response to the load change and a wide range of operating temperatures. Along with the measurements of the noise voltage spectral density, the sensor sensitivity measurements are of high...
Fast Impedance Spectroscopy Method for Insulating Layers with Very High Impedance
Transactions on Transport Sciences 2010, 3(1):29-38 | DOI: 10.2478/v10158-010-0005-1
This paper presents the fast impedance spectroscopy method for objects with a very high impedance |Zx| ≥ 1GΩ modeled by RC networks. The method is suitable for predicting the lifetime and reliability of insulating materials. The fast impedance spectroscopy method was tested on insulating layers which were part of the system metalinsulator-metal (MIM). The method is based on measurements of the power loss and phase shift in the AC voltage divider, which consists of the measured system MIM and of the known impedance. Computer controlled instruments measure the gain and phase shift between the two outputs of alternating electrical circuit and...
Influences of Utility Networks on Measuring
Transactions on Transport Sciences 2010, 3(1):39-44 | DOI: 10.2478/v10158-010-0006-0
The measuring of any quantities is always encumbered with inaccuracy. To attain the best results it is necessary to restrict these errors. The exactness of measuring depends on the quality of the measuring equipment, the lay-out of the equipment, and on external influences. The goal of this paper is to draw attention to those external influences that are rare or are not supposed to be present.
Pedestrian Model for Injury Prediction for Lateral Impact
H. Čechová, L. Hynčík
Transactions on Transport Sciences 2010, 3(1):45-52 | DOI: 10.2478/v10158-0007-z
World-wide statistics still reflect a high percentage of seriously injured pedestrians in the urban areas. The lateral impact is the most common type of traffic accident in towns. This paper describes the validation of a pedestrian model that will be able to assess the type and level of injury. The human model used is rigid body based with realistic biomechanical joints. The human body model is validated for the case of a lateral pedestrian impact using published experimental cadaveric data. Particular body segment trajectories fit into given kinematic corridors. Based on the standard injury criteria the pedestrian model is able to predict life threatening...