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R. Burdzik, Z. Stanik and J. Warczek

Method of Assessing the Impact of Material Properties on the Propagation of Vibrations Excited with a Single Force Impulse

The article provides a discussion on the studies comprising active experiments conducted on selected structural components, the purpose of which was to analyse the impact of properties of the material used on the dynamic state form. The vibration excitation was achieved by applying a force impulse of a specific value. The studies were conducted on excitations acting perpendicularly to the surface of the component being examined in strictly established geometric arrangements. Consequently, signals were obtained to be subsequently applied for the sake of analysis of the impact of material properties on the manner of the vibration energy propagation in the machine components examined. The signal processing method used was based on application of a time and frequency transformation which enables obtaining the information the signals carry in two domains simultaneously, namely those of time and frequency. The results provided and discussed evidence the applicability of the method described in the analysis of the material impact on dynamic properties of the given structural component.

Open access

R. Burdzik, P. Folęga, B. Łazarz, Z. Stanik and J. Warczek

The study discussed in the paper consisted in testing the impact of surface layer parameters on wear intensity of friction pair components. The study was conducted having taken additional operational factors into consideration, namely the friction conditions (presence of lubricant) and the value of loads affecting the contact zone of the samples being tested. The study constituted laboratory tests of wear and were conducted by means of a T-01M type laboratory test stand used to experimentally analyse frictional cooperation of various materials used in structural components of motor vehicles. The friction pairs examined were previously operating in a pin-on-disk system under various conditions. The materials of the friction pairs tested at the stand were subjected to heat treatment and chemical processing in order to attain specific parameters of their surface layers. The studies conducted enabled determination of the abrasive wear values for the material samples tested having entailed the surface layer parameters and the factors related to operation of actual structural components used in automotive engineering. An additional advantage of the studies conducted was the possibility to establish actual coefficients of friction occurring in specific friction pairs. Establishing the actual values of friction coefficients for the materials of friction pairs under specific conditions and having taken the impact of the surface layer parameters into consideration enabled identification of the reasons for excessive surface wear. Hence a reference can be made between the stationary tests undertaken and actual components cooperating with one another in kinematic pairs of machines. The utilitarian premise resulting from the studies conducted is the necessity of paying particular attention to surface layer parameters while designing friction pairs for machines.

Open access

R. Burdzik, A. Lisiecki, J. Warczek, Ł. Konieczny, P. Folęga, A. Szkliniarz and G. Siwiec

The article addresses a method proposed for comprehensive research of vibration properties dedicated to new structural materials. The method in question comprises three-stage studies, thus enabling the related costs to be reduced on each stage of the process. Subjects of identification and assessment are both the properties and the material structure as well as numerically determined dynamic characteristics and actual vibration characteristics of materials. The article provides preliminary research results obtained for Cu-2Ti-1Co and Cu-6Ti-1Co alloys, the mechanical properties of which are very prospective. An additional advantage of the method proposed is the capability of identifying alloy types by application of non-destructive vibratory methods.

Open access

A. Lisiecki, R. Burdzik, G. Siwiec, Ł. Konieczny, J. Warczek, P. Folęga and B. Oleksiak

Autogenous laser welding of 0.8 mm thick butt joints of car body electro-galvanized steel sheet DC04 was investigated. The Yb:YAG disk laser TruDisk 3302 with the beam spot diameter of 200 μm was used. The effect of laser welding parameters and technological conditions on weld shape, penetration depth, process stability, microstructure and mechanical performance was determined. It was found that the laser beam spot focused on the top surface of a butt joint tends to pass through the gap, especially in the low range of heat input and high welding speed. All test welds were welded at a keyhole mode, and the weld metal was free of porosity. Thus, the keyhole laser welding of zinc coated steel sheets in butt configuration provides excellent conditions to escape for zinc vapours, with no risk of porosity. Microstructure, microhardness and mechanical performance of the butt joints depend on laser welding conditions thus cooling rate and cooling times. The shortest cooling time t8/5 was calculated for 0.29 s.