The rise in prices of traditional energy sources, the high dependence of many countries on their import, and the associated need for security of supply have led to large investments in new capacity of wind power plants. Although wind power generation is a mature technology and levelized cost of electricity low, there is still room for its improvement. A review of available literature has indicated that wind turbine development in the coming decade will be based on upscaling wind turbines and minor design improvements. These include further improvements in rotor blade aerodynamics, active control of the rotor blade rotation system, and aerodynamic brakes that will lead to increased power generation efficiency. Improvements in system maintenance and early diagnosis of transmission and power-related faults and blade surface damage will reduce wind turbine downtime and increase system reliability and availability. The manufacture of wind turbines with larger dimensions presents problems of transportation and assembly, which are being addressed by manufacturing the blades from segments. Numerical analysis is increasingly being used both in wind turbine efficiency analysis and in stress and vibration analysis. Direct drive is becoming more competitive with traditional power transmission through a gearbox. The trend in offshore wind farms is to increase the size of wind turbines and to place them farther from the coast and in deeper water, which requires new forms of floating foundations. Due to the different work requirements and more difficult conditions of the marine environment, optimization methods for the construction of offshore substructures are currently being developed. There are plans to use 66-kV cables for power transmission from offshore wind farms instead of the current 33-kV cables. Offshore wind farms can play an important role in the transition to a hydrogen economy. In this context, significant capacity is planned for the production of “green” hydrogen by electrolysis from water. First-generation wind turbines are nearing the end of their service life, so strategies are being developed to repower them, extend their life or dismantle and recycle them.

Using vehicles and other mobile systems to transport passengers and goods, approximately 25% of Europe's greenhouse gases are generated. At the same time, many research papers, published by researchers and students, promote the use of electric vehicl...

During the manufacturing of welded structures, some degree of residual stresses occurs. The classic approach to residual stress reduction is Post-Weld Heat Treatment (PWHT). In the case of structural grade mild steels, the thermal process is well established. In case of S690QL1 High Strength Steel (HSS), which is manufactured using the Quenching and Tempering (QT) process considered in this paper, only limited PWHT treatment is possible without deterioration of mechanical properties. Since this steel grade is susceptible to subsequent heat input, the challenge is to establish adequate PWHT parameters, achieving residual stress reduction while retaining sufficiently high mechanical properties. The paper considers X joint welded HSS steel plates with slightly overmatching filler metal. The welded coupon is prepared and subjected to PWHT treatment. The research on the influence of heat treatment was performed using the four different PWHT cycles and initial As-Welded (AW) material condition. The authors proposed those PWHT cycles based on available resources and the literature. Process holding temperature is considered the variable parameter directly related to the behaviors of material properties. The methodology of welded joint analysis includes experimental testing of mechanical properties, metallographic examination, and residual stress quantification. Testing of mechanical properties includes tensile testing, Charpy V-notch impact testing, and hardness testing in scope of complete welded joint (BM + HAZ + WM). Metallographic examination is performed in order to characterize the welded joint material in relation to applied PWHT cycles. In order to quantify residual stresses, all heat-treated samples were examined via the X-ray diffraction method. Mechanical properties testing determined that an increase in PWHT cycle holding temperature leads to degradation of tested mechanical properties. For specific zones of the welded joint, the decreasing trend from AW condition to Cycle D (max. 600 °C) can be quantified. Based on representative specimens comparison, strength values (BM ≤ 5.7%, WM ≤ 12.1%, HAZ ≤ 20%), impact testing absorbed energy (BM = 17.1%, WM = 25.8%, FL = 12.5%, HAZ = 0.6%), and hardness values (BM = 4.1%, WM = 3.2%, CGHAZ = 16.6%, HAZ = 24.2%) are all exhibiting decrease. Metallographic examination, using the light microscopy, after the exposure to PWHT thermal cycles, did not reveal significant changes in the material throughout all specific welded joint segments. Average relative reduction in residual stress in correlation with PWHT temperature can be observed (AW = 0%, Cycle A (max. 400 °C) = 72%, Cycle B (max. 530 °C) = 81%, Cycle C (max. 550 °C) = 93% and Cycle D (max. 600 °C) = 100% stress reduction). It can be concluded that S690QL1 HSS welded joints can generally be subjected to PWHT, while adhering to the limits of the material and process. In the authors’ shared opinion, it is advisable to use the PWHT Cycle C (max. 550 °C) with 93% RS reduction, while mechanical properties retain high values.

In this paper the impact of square opening, as a source of stress concentration, on the distribution of stress in parts of machines and devices is considered. The fact is that these forms of the openings occur less in practice, but the knowledge of t...

Applying new technologies to reduce friction and wear in vehicles and equipment can minimize mechanical losses. This reduces power loss in internal combustion engines and reduces fuel consumption and emissions. Consumption of fuel energy...

The development of corrosion mechanisms is a major issue that industrial experts are faced with while dealing with all phases of metal exploitation. Damage caused by corrosion affects the increase in both direct and indirect costs of manufacture. With adequate surface protection technology, it is possible to lessen the intensity of corrosion mechanisms’ development. In order for the selected surface protection technology to provide its full protective action, it is necessary to be familiar with its process parameters. This paper deals with a surface protection system that creates a barrier between the aggressive environment and the base material. The tested barrier was created on a base material surface by electrostatic powder spraying. In this experiment, three types of base material (carbon steel, aluminum and galvanized steel) were coated by applying different combinations of operating parameters. Operating parameters, i.e., the voltage and strength of the electric current, were taken as numerical input variables in the experiment. Each experiment design was focused on measuring the thickness of the protective layer. Analysis of the obtained results and statistical data processing confirmed that appropriate parameters (input variables) provided the target thickness of the protective coating on each of the tested materials. Optimization of parameters contributes to the efficiency of production, shortens the processing time and ensures that coating thickness stays within the limits defined either by the manufacturer or the end user.