Analysis and Detection of Erosion in Wind Turbine Blades

This paper studies erosion at the tip of wind turbine blades by considering aerodynamic analysis, modal analysis and predictive machine learning modeling. Erosion can be caused by several factors and can affect different parts of the blade, reducing its dynamic performance and useful life. The ability to detect and quantify erosion on a blade is an important predictive maintenance task for wind turbines that can have broad repercussions in terms of avoiding serious damage, improving power efficiency and reducing downtimes. This study considers both sides of the leading edge of the blade (top and bottom), evaluating the mechanical imbalance caused by the material loss that induces variations of the power coefficient resulting in a loss in efficiency. The QBlade software is used in our analysis and load calculations are preformed by using blade element momentum theory. Numerical results show the performance of a blade based on the relationship between mechanical damage and aerodynamic behavior, which are then validated on a physical model. Moreover, two machine learning (ML) problems are posed to automatically detect the location of erosion (top of the edge, bottom or both) and to determine erosion levels (from 8% to 18%) present in the blade. The first problem is solved using classification models, while the second is solved using ML regression, achieving accurate results. ML pipelines are automatically designed by using an AutoML system with little human intervention, achieving highly accurate results. This work makes several contributions by developing ML models to both detect the presence and location of erosion on a blade, estimating its level and applying AutoML for the first time in this domain.

Evaluation of Additive Friction Stir Deposition of AISI 316L For Repairing Surface Material Loss in AISI 4340

Additive technologies provide a means for repair of various failure modes associated with material degradation occurring during use in aggressive environments. Possible repair strategies for AISI 4340 steel using AISI 316L deposited by additive friction stir deposition (AFSD) were evaluated under this research by metallography, microhardness, and wear and mechanical testing. Two repair geometries were investigated: groove-filling and surface cladding. The former represents repair of localized grinding to eliminate cracks, while the latter represents material replacement over a larger area, for example to repair general corrosion or wear. The 316L deposited by AFSD exhibited a refined microstructure with decreased grain size and plastic strain, lower strength, and lower hardness than the as-received feedstock. Wear testing by both two-body abrasion and erosion by particle impingement indicated that the wear resistance of the 316L cladding was as good as, or better than, the substrate 4340 material; however, there was some evidence that the resistance to intergranular corrosion was compromised due to the formation of carbides or sigma phase. In both repair geometries, the microstructure of the substrate beneath the deposited material exhibited heat affected zones that appeared to have austenized during the deposition process, and transformed to martensite or bainite during cooling. This report constitutes an initial evaluation of a novel approach to the repair of structural steel components damaged by microcracking, wear or corrosion.

Tribological Properties of Solid Solution Strengthened Laser Cladded NiCrBSi/WC-12Co Metal Matrix Composite Coatings

NiCrBSi, WC-12Co and NiCrBSi with 30, 40 and 50 wt.% WC-12Co coatings were produced on low carbon steel by laser cladding with an Nd:YAG laser with a multi-jet coaxial cladding-nozzle. The microstructure properties after WC-12Co alloying were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), electron backscatter diffraction (EBSD) and Vickers hardness tests. The resulting microstructures consisted of a γ-Ni and Ni3B matrix, strengthened with Co and W, Ni3Si, CrB, Cr7C3, Cr23C6, WC/W2C phases. In coatings with 30, 40 and 50 wt.% WC-12Co, a solid solution, strengthened multi-matrix NiCrWCo phase formed, which yielded a higher matrix hardness. Wear tests that monitored the friction coefficients were performed with a tribometer that contained a ball-on-disc configuration, Al2O3 counter-body and reciprocal sliding mode at room temperature. The major wear mode on the NiCrBSi coatings without the WC-12Co was adhesive with a high wear rate and visible material loss by flaking, delamination and micro-ploughing. The addition of WC-12Co to the NiCrBSi coating significantly increased the wear resistance and changed the major wear mechanism from adhesion to three-body abrasion and fatigue wear.

Research on the use of virtual reality in intervention and rescue activities

In recent years in the virtual reality the developers succeeded in creating an artificial environment that simulates reality so that the user has the impression of an almost real physical presence in the virtual world. By overlapping and synchronizing the projected images with spatial sounds and even forces that interact with the user, there is a detachment of the user from the real environment and an all-encompassing involvement in the virtual world. The virtual reality is present in aviation, medicine, military training and other top fields. The advantages of using the virtual environment are obvious for areas where inexperience can cause very high loss of life and material loss. Although the participants are immersed in the scenario of the virtual environment, the errors produced allow an evaluation of the mistakes made and their correction, the experience gained being then used in professional activity in the real world. Through the experience of the virtual environment, the fear of various dangers can be overcome, so that the objectives of the exercise can be fulfilled. The aim of the paper is to offer to the rescuers opportunities to interact with the elements of the virtual space to fulfill the purpose of the exercise.

Verbesserte Tribokorrosionsbeständigkeit des martensitischen Stahls X54CrMoVN17-1 durch die Erzeugung von expanded martensite

Seal-free, media-lubricated rolling bearings have a high-energy efficiency as the absence of the seal minimizes frictional loss and increases the efficiency of the driven machine. In addition, the environment is protected by the absence of hazardous lubricants. However, media-lubrication increases tribocorrosive attack on the bearing surface. Therefore, the tribocorrosion resistance of the bearing surface can be increased by a thermal surface treatment called low-temperature plasma nitriding. The produced “expanded martensite” in martensitic steels features a high hardness with comparatively good corrosion resistance. Tribocorrosion tests in 0.9 % NaCl-solution show that the material loss could be reduced by 70 % due to expanded martensite compared to the initial state of the steel.

SITUATION WITH FIRES CAUSED BY ELECTRICAL PRODUCTS AND DEVICES AT DIFFERENT OBJECTS IN THE RUSSIAN FEDERATION IN 2011-2020

Представлены результаты статистического анализа показателей обстановки с пожарами, произошедшими в Российской Федерации в 2011-2020 гг. от электрооборудования. Рассчитаны значения как абсолютных, так и долевых показателей данных пожаров в общих значениях по России. Приведены распределения показателей пожаров от электрических изделий и устройств по различным объектам пожаров. По результатам исследования установлено, что наибольшее число пожаров от электрооборудования произошло на трех группах объектов: здания, сооружения жилого сектора; транспортные средства; общественные здания, сооружения. Основная часть погибших и травмированных людей, а также наибольший прямой ущерб соответствуют группе объектов «здания, сооружения жилого назначения, надворные постройки». There are presented the results of statistical analysis of parameters characterizing situation with fires caused by electrical equipment that occurred in the Russian Federation in 2011-2020. Both absolute and shared parameters of these fires in general values among Russia are calculated. The distributions of parameters of fires caused by electrical products and devices on different objects of fires are sited. According to the results of the study it was found that the largest number of fires caused by electrical equipment occurred on three main groups of objects: buildings and structures of residential sector; vehicles; public buildings and structures. The major part of fire deaths, fire injures and also the largest direct material loss from fires corresponds to the group of object “residential buildings and structures, outbuildings”.

Efficient Way for Chemicals Identification Using Hexagonal Fiber with the Terahertz (THz) Band

To detect chemicals, we proposed a photonic crystal fiber (PCF) with hexagonal cladding and a hexahedron core (THz). Circular air holes (CAHs) in the vestibule provide the basis of the suggested sensor. To develop and evaluate our suggested hexahedron PCF sensor, we employed the finite element (FEM) technique and perfectly matched layers (PML), which utilized the optical parameters numerically. Here, 92.65%, 95.25%, and 90.70% are relatively sensitive, and confining losses are low. the value 5.40×10− 08, 6.70×10− 08 dB/m, and 5.75×10− 08 dB/m for three chemicals such as Ethanol (n = 1.354), Benzene (n = 1.366) and Water (n = 1.330) and effective material loss (EML) of 0.00694 cm− 1. The suggested Hx-PCF sensor has been successfully tested at 1 THz. We are certain that the suggested sensor's optimal geometric structure can be manufactured and that it can contribute to real-world applications in biomedicine and industry. In terahertz areas, our suggested PCF fiber is also suited for a wide range of medical signals and applications (THz).

Effect of Corrosion Pit on the Structural Characteristics of Foil Journal Bearings

Due to corrosive environment, material loss in a localized area leads to formation of a corrosion pit. It diminishes the structural integrity and performance of product. To predict and analyze the effect of corrosion pit on the performance of gas foil bearings (GFBs), FEM analysis of bump-type GFBs is carried out. The effect of corrosion pit is investigated for three different shapes: circular, square and triangular. In this study, the FEM analysis of bump-type GFBs is performed in ANSYS software. Firstly, the influence of a corrosion pit is analyzed for various shapes under different pressure loading. These results show that the presence of a corrosion pit developed high-stress crack intensity, which can result in crack initiation in foil bearings. As pressure loading increased, the stress crack intensity in foil bearings increased. Among different pit shapes, the circular pit shape induces the maximum stress crack intensity in foil bearings, which shows that the crack initiation in foil bearings is observed for a circular pit. Then, the influence of a corrosion pit on the structural stiffness of foil bearings is evaluated for various foil materials under different friction coefficients. These results show that the influence of friction coefficient in foil bearings is increased within the presence of a corrosion pit.