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Coating–substrate adhesive joints are used in mechanical engineering and automotive vehicle construction. Monitoring their condition, both at the manufacturing and operational stages, is important for durability and extended lifetime. The article proposes a method for continuous monitoring of the state of the coating–substrate joint using ultrasonic surface wave. The waveforms of ultrasonic parameters such as gain of pulse of ultrasonic wave, resonant frequency and bandwidth over the lifetime of the tested joint were determined. The resonant frequency change precedes the final stage of degradation of the coating–substrate connection, which leads to complete detachment of the coating from the body sheet. Both, during the period of constitution and degradation, rapid changes in the pulse gain of the ultrasonic surface wave were recorded. The knowledge about the waveforms of the selected ultrasonic wave parameters makes it possible to assess the condition of the joint and is the basis for deciding on its further operation or repair.

Adhesive bonds, including car putty coatings, are used in the construction of modern motor vehicles. Therefore, it is important to improve methods that allow nondestructive evaluation of the properties of these joints. The main objective of this study was to evaluate selected properties of putty coatings such as the width of the applied coating and adhesion to the substrate based on changes in ultrasonic wave parameters. The research was carried out in two stages. In the first, the values of the surface wave amplitude were determined as a function of the width of the coating to the substrate. It was found that as the width of the coating increases, the amplitude of the surface wave pulse decreases. The second stage involved correlation studies to relate the reflection coefficient |r| to the adhesion of the coating to the substrate. Based on the results, it was found that as the value of the reflection coefficient decreases, the value of the coating's adhesion to the substrate increases. The determined values of this parameter range from 0.30 to 0.86, which correspond to the adhesion of the range 1.51 to 18.97 MPa. The obtained test results have practical significance and can be used in evaluating the condition of coatings in vehicle body repair shops. [ABSTRACT FROM AUTHOR]

The article presents a study of the tribocorrosion phenomenon and its effects on Inconel 718 alloy produced conventionally by extrusion and additively manufactured using the laser powder bed fusion method. In addition, the samples were subjected to a heat treatment process to change their properties. The research was carried out using the pin-on-disk method in 3.5% NaCl. Based on the study, it was found that the material made with additive technology is more resistant to tribocorrosion phenomenon, and the difference from conventionally made material is about 50%. The synergistic effect between friction and corrosion (ΔZ) occurred. However, heat treatment in the AA-2 variant ensures higher hardness and reduces purely mechanical wear (ZM) and the synergy effect (ΔZ). [ABSTRACT FROM AUTHOR]

Renovation of dirt roads requires a reliable and durable work tool. This article includes the methodology of field and bench tests as well as the results of these tests and conclusions for cutters used for dirt road renovation. The main novelty of the research presented in this article was to determine the wear mechanisms occurring during field and laboratory tests, to determine the differences in wear levels and the cost of renovation of one kilometer of dirt road. Calculations of the efficiency of replacing these working elements and the cost of operating various cutters per km are also presented. The lowest mass loss was characterized by milling cutters Ø25 mm mounted on an expansion sleeve and amounted to 130 g. The dominant wear mechanism that was observed after the renovation of dirt roads was micro-scraping and micro-bruising. For this variant, the cost per 1 km of road renovation was also the lowest and amounted to about PLN 2. [ABSTRACT FROM AUTHOR]

The paper presents the results of research aimed at the verification of the existing design solutions of four example sowing units for agricultural seed drills with the most frequently used types of sowing wheels. The research was conducted with the use of modern computer simulation systems based on the discrete element method (DEM) with the evaluation of the efficiency of selected design solutions in terms of achieved performance and metering uniformity. The paper includes a description of virtual research models and the employed mathematical models used for mirroring contact between seeds. Moreover, for the purpose of verification of the obtained results, bench tests were conducted using actual models of selected design solutions.

In the article design of a self-propelled vehicle for inspecting ventilation ducts and ceiling structures in buildings equipped with omni wheels was presented. Such vehicles are used in places that are hard to reach for people. The vehicle was designed using the vehicle control system – ARDUINO. For this system dedicated program was written, which is used to operate it. The vehicle is remotely controlled by radio waves. Its range is about 100 meters and the power supply is a 12 V battery. The vehicle operator has joysticks (controllers) modelled on those used in game controllers that are used for precise vehicle control. The vehicle is equipped with cameras that allow to view the image in real time. The omni wheels have also been tested for strength by the finite element method (FEM). Carried out FEM analysis as part of the work allowed to determine the strength of omni wheels on the acting forces during vehicle movement.

Cultivators are machines used among others to open and smooth out the surface of the ploughland and to mix mineral fertilizers with soil. The article presents a design of a cultivator mounted on an agricultural tractor with a power of up to 20 kW. The main design assumption mainly focuses on keeping the weight of the device low, while ensuring the required durability. Moreover, the design makes it possible to attach it to the three-point linkage in a category 1 tractor. The drafted design was subjected to the MES analysis, according to which, the maximum travel of the cultivator frame does not exceed 1.3 mm, and the stress typically reaches the level of 40 MPa and does not exceed the stress permissible for the E295 steel. An analysis of the costs of manufacturing the cultivator was also performed and on its basis, it was found that the price should not exceed PLN 1,800.

The main purpose of the performed works was to develop a concept of a bulldozer blade mounted to the road roller. The paper presents the main assumptions, design stages, results of strength analyses of the blade, which can be used in a road roller. Because the elements that push the components of machines operating on construction sites, in mines and in the agricultural environment, the elaborated element would enable wider use of the roller. Based on the FEM analyses, it has been confirmed that the developed load bearing structure is characterized by full operating strength. The designed blade meets the initial assumptions and can be used as equipment of heavy machines.

The article presents results of experimental studies on mechanical properties of the polymer-composite material used in manufacturing firefighting helmets. Conducted studies included static and impact strength tests, as well as a shock absorption test of glass fiber-reinforced polyamide 66 (PA66) samples and firefighting helmets. Samples were subject to the impact of thermal shocks before or during being placed under a mechanical load. A significant influence of thermal shocks on mechanical properties of glass fiber-reinforced PA66 was shown. The decrease in strength and elastic properties after cyclic heat shocks ranged from a few to several dozen percent. The average bending strength and modulus during the 170 degree Celsius shock dropped to several dozen percent from the room temperature strength. Under these thermal conditions, the impact strength was lost, and the lateral deflection of the helmet shells increased by approximately 300%. Moreover, while forcing a thermal shock occurring during the heat load, it was noticed that the character of a composite damage changes from the elasto-brittle type into the elasto-plastic one. It was also proved that changes in mechanical and elastic properties of the material used in a helmet shell can affect the protective abilities of a helmet. [ABSTRACT FROM AUTHOR]