Applied Mechanics and Materials Vol. 838

Abstract: In this paper new kinematics systems were studied for a single lapping process. In order to ensure the constant profile wear of the tool a standard kinematic system can be changed. Lapping is carried out by applying loose abrasive grains between two surfaces and causes a relative motion between them. The result is a finish of multi-directional lay. During process, the mechanism of surface formation are decisively affected by a pressure force, a process time and a motion type of grains. It has been proven, that providing the additional movements of the conditioning ring affects the profile wear of the lapping plate. First of all, the kinematics equations of the lapping process have been developed and the process has been simulated. A type of the abrasive particle trajectories in standard single-disk lapping depends on rotational speed ratio of a tool and a conditioning ring. In addition, two new kinematic systems were presented: with radial and secant movement of the conditioning ring. Finally, comparison and analysis of abrasive trajectories were carried out.

Abstract: The paper presents experimental evaluation of susceptibility of the high strength S460ML steel to cold cracking in the conditions of wet welding with the use of covered electrodes. From the results of Tekken tests it was found out that the investigated steel was characterised, in the conditions of the carried out experiments (underwater wet welding and air welding with rutile electrodes), of high susceptibility to cold cracking. Maximum hardness of HAZ in most cases do not fulfill criterion of PN-EN ISO 15614-1 standard: exceeds 380HV10.

Abstract: In this paper results of comparison of characteristic resonant frequencies of circular saw blades as a function of the saw clamping diameter from the impact test are presented. Obtained results revealed that proportionally with the increase of the saw clamping diameter also the dynamical stiffness of the saw blade increased. As a consequence of that the resonant frequencies of the saw blade move to higher values. Moreover, with the increase of the saw blade clamping diameter for higher frequencies of forcing vibrations of the saw blade the amplitude of vibration are expected to be decreased.

Abstract: Flexural strength and low velocity impact properties were investigated in terms of possibile improvements due to epoxy matrix modification by SiO₂ nanoparticles (1%, 2%, 3%, 5%, 7%wt.) in glass/epoxy laminates formed using hand lay-up method. The matrix resin was Hexion L285 (DGEBA) with Nanopox A410 - SiO₂ (20 nm) nanoparticle suspension in the base epoxy resin (DGEBA) supplied by Evonic. Modification of epoxy matrix by variable concentrations of nanoSiO₂ does not offer significant improvements in the flexural strength σ_g, Young’s modulus E and interlaminar shear strength for 1% 3% and 5% nanoSiO₂ and for 7% a slight drop (up to ca. 15-20%) was found. Low energy (1J) impact resistance of nanocomposites represented by peak load in dynamic impact characteristics was not changed for nanocompoosites compared to the unmodified material. However at higher impact energy (3J) nanoparticles appear to slightly improve the impact energy absorption for 3% and 5%. The absence or minor improvements in the mechanical behaviour of nanocomposites is due to the failure mechanisms associated with hand layup fabrication technique: (i.e. rapid crack propagation across the extensive resin pockets and numerous pores and voids) which dominate the nanoparticle-dependent crack energy absorption mechanisms (microvoids formation and deformation).

Abstract: In the article application of queuing systems model in the field of operation of motor transport is presented. The system of maintenance service (MS) and operating repair (OR) of the cars on technological base is considered as multichannel multiphase queuing system. The mathematical model allows to receive necessary parameters of system MS and OR and to optimize them on technical-economic criterion.

Abstract: Discussed are the design features of exhaust systems of cars and the factors influencing the formation of condensation in them.

Abstract: The article discusses the causes of humidification of engine oil from vehicles and provides quantitative estimates of transferring of water into oil.

Abstract: The article reviews issues of training process effectiveness increase by means of implementation and adaptation of the simulator of gas injection control system for petrol engine performed by applying LPG TECH Co technologies, when technical training relates to the use of alternative fuels on the motor transport.

Abstract: This paper gives a study of working oil with the dielectric parameters determining device. The correlation analysis of the dielectric and the physicochemical properties of motor oils was carried out.