Non-destructive testing (NDT) methods are a group of tests allowing one to detect external (surface) as well as internal defects of a structure

The modern commercial vehicle with a weight of more than 3,5 [Mg] is a complex design solution, which contains many of mechatronic systems. The standard equipment are the ability of the driver assistance systems such as ABS (Anti-Lock Braking System), ESP (Electronic Stability Program), ASR (Acceleration Slip Regulation). The technical condition of the modern car's suspension determines the value of the indicators of road safety. An essential element of the suspension system, whose function is to change the mechanical vibration energy into thermal energy, is the shock absorber. Incorrect functioning of shock absorbers affects the quality of the operation of these systems improve safety. In the case of gradually wears of shock absorber even an experienced driver is able to notice this phenomenon. For this reason it becomes necessary the need for regular technical condition monitoring of dampers. Diagnostic dampers on buses and trucks are limited to the organoleptic examination and propose based on intermediate symptoms such as accelerated tire wear. The paper describes the method for estimating the suspension damping characteristics of commercial vehicle in operating conditions.

Radio-over-fiber (RoF) links successfully provide high data rates and bandwidth capacity with a low complexity system architecture, as compared to its counterpart digital-RoF. In addition, the compound of quadrature amplitude modulation (QAM) and orthogonal frequency division multiplexed (OFDM) modulation schemes further enhance the process of these achievements. However, high data rates and bandwidth-capacity-supported RoF links face nonlinearities (NLs), linear distortions (LDs), and phase noise challenges that degrade the reliability of communication networks (CNs). Therefore, in this paper, to suppress NLs, LDs, and phase noise, next generation cloud radio access networks (CRANs) are investigated using RoF links and wavelength division multiplexing (WDM) methodology based on 16, 32, and 64 QAM-OFDM modulation schemes. The receiver of the proposed framework is designed, applying an improved digital signal processing (DSP) system that includes overlap frequency domain equalization (OFDE), a synchronization process, and time domain equalization (TDE). Theoretical and simulation models are organized for estimating the proposed RoF link with the aid of different values of transmission ranges, input power, output power, bit rate, bits per symbol, channel spacing, and the number of users. The fitness of the model matches that of existing approaches.

The optimization of the construction of gears leading to the minimization of dynamic effects and to meet all basic criteria is in many cases only possible by applying numerical methods. The models allow determining the influence of a range of factors on the dynamic phenomena. Proper experimental tests are often not possible because the number of options of influencing factor sets is very large. Using simulation models allows limiting the volume of experimental studies to the necessary minimum, and hence is beneficial from the economic standpoint. The paper describes numerical and laboratory researches on the influence of selected construction, technological and operational factors on the dynamic effects and vibroactivity in gears. Numerical analyses were performed using a custom-developed dynamic model of a test stand with the gears operating in the circulating power system. The models details were presented at the International Congress on Technical Diagnostics in 2008. The idea behind this article is to present selected results of simulation calculations and laboratory tests to determine the possibility of minimizing the noise and vibration of gears. Selected results of the calculations were also compared with the results of laboratory tests to demonstrate the high compatibility of the two test methods.

With the Internet of things and various information and communication technologies, a city can manage its assets in a smarter way, constituting the urban development vision of a smart city

The purpose of the presented research was to determine the suitability of using ultrasonic testing (UT) to inspect heterogeneous, from a material point of view, welded joints on the example of the joints of a ferritic steel element with elements made of an austenitic steel. The echo technique with transverse (SEK) and longitudinal wave heads (SEL) addressed this issue. Due to the widespread use of 13CrMo4-5 and X2CrNiMo17-12-2 steel grades in the energy industry, they were selected as the test materials for the study. The objects of the presented research were welded joint specimens with thicknesses of 8, 12, and 16 mm and dimensions of 300 × 300 mm, made using the 135 metal active gas (MAG) process with the use of the Lincoln 309LSi wire—a ferritic–austenitic filler material. The stages of the research task were (1) making distance–amplitude curve (DAC) patterns from the test materials; (2) preparation of specimens of welded joints with artificial discontinuities in the form of through-holes; (3) performing UT tests on welded joints with artificial discontinuities using heads with 60° and 70° angles for the transverse wave and angle heads for longitudinal waves with similar beam insertion angles; (4) selection, by radiographic testing (RT), of welded joint specimens with natural discontinuities in the form of a lack of sidewall fusion; (5) performing UT tests on welded joints with natural discontinuities, using heads as welded joints with artificial discontinuities. It was found that (1) the highest sensitivity of discontinuity detection was obtained by performing tests on the ferritic steel side, which is due to the lower attenuation of the ultrasonic wave propagating in ferritic steel compared to austenitic steel; (2) the best detection of discontinuities could be obtained using a longitudinal ultrasonic wave; (3) there is a relationship between the thickness of the welded elements, the angle of the ultrasonic beam introduction, and the effectiveness of discontinuity detection.