Electric Arc Research Articles

Effect of SiO2 and Al2O3 on the Thermophysical Properties and the Foaming Index of Electric Arc Furnace Slag from the Production of Construction Steel

Viscosity, density, and surface tension of an industrial electric arc furnace (EAF) slag from production of construction steel with varying SiO2 and Al2O3 contents are investigated using a rotating viscometer and the maximum bubble pressure method. In addition, influence of thermophysical properties on foaming index is discussed. To predict the behavior of the solid phase in the slag at different temperatures, thermodynamic calculations are performed using FactSage 8.1 software. The experiments demonstratethat SiO2 and Al2O3 act as network formers in the studied slag systems, resulting in increased viscosity values in the liquid‐dominant region and decreased density of the slag. The presence of alumina and silica altered the behavior of the slag in the liquid‐dominant region, shifting the breaking point of the slags. Furthermore, the addition of silica decreases the surface tension of the slag, confirming its role as a surfactant. However, the addition of Al2O3 increases the surface tension due to the high surface tension of pure alumina. Consequently, the foaming index of the slag can increase by ≈40%, primarily due to the polymerization of the slag.

Investigation of the Effects Caused by Current Interruption Devices of Lithium Cells at High Overvoltages

A faulty voltage measurement can lead to the overcharging of a Li-Ion cell, resulting in gas formation and heating inside the cell, which can trigger thermal runaway. To mitigate this risk, cylindrical cells are equipped with a Current Interrupt Device (CID), which functions as a pressure relief valve, disconnecting the electrical circuit within the cell when internal pressure rises. However, this disconnection causes the cell to suddenly become highly resistant, posing a significant issue in series-connected cells. In such configurations, a portion or even the entire system voltage may drop across the disconnected cell, substantially increasing the likelihood of an electric arc. This arc could ignite any escaping flammable gases, leading to catastrophic failures. In a series of tests conducted on three different cell chemistries—NMC (Nickel Manganese Cobalt), NCA (Nickel Cobalt Aluminum), and LFP (Lithium Iron Phosphate)—it was found that the safe operation of the CID cannot be guaranteed for system voltages exceeding 120 V. Although comparative tests at double the nominal cell voltage did not exhibit the same behavior, these findings suggest that current safety standards, which recommend testing at double the nominal voltage, may not adequately address the risks involved. The tests further revealed that series connections of cells with CIDs are inherently dangerous, as, in the worst-case scenario, the entire system voltage can be concentrated across a single cell, leading to potential system failure.

Research on the anti-ablation performance of TiC particle reinforced aluminum matrix composite coating

During the electromagnetic rail launching process, the severe ablation of the armature caused by the arc can easily lead to launch failure. Therefore, it is necessary to study methods of enhancing the anti-ablation property of the armature. One effective method is to prepare metal-ceramic composite coating on the surface of aluminium alloy armature. This paper conducts molecular dynamics simulation on the ablation protection effect of TiC particle reinforced aluminum matrix composite coatings on the aluminum armature substrate. By applying a surface Gaussian heat source to simulate the arc ablation effect, the micro-enhancement mechanism of TiC particles is analyzed through the depth of ablation craters, material mass loss, and the evolution of TiC particle morphology. The results show that the degree of material ablation intensifies with the increase of arc discharge power. The composite coating helps to improve the anti-ablation performance of the armature, and the anti-ablation performance first increases and then decreases with the increase of TiC mass fraction. The results can provide a theoretical foundation and technical support for optimizing design of anti-ablation performance of armature materials.

Dissolution of EAF slag minerals in aqueous media: Effects of sonication on brownmillerite and gehlenite

The accumulation of electric arc furnace slag (EAFS) in landfills has been causing severe environmental problems. This study examines the dissolution properties of EAFS minerals, including brownmillerite and gehlenite, essential for their possible use in resource recovery. An investigation was conducted to compare the effects of sonication and stirring on mineral dissolution while also assessing the usage of citrate as a complexing agent for gehlenite. Synthetic brownmillerite and gehlenite minerals were dissolved in aqueous solutions at room temperature using a 1:100 g/ml ratio. The dissolved elements were measured using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), while zeta potential and X-ray Photoelectron Spectroscopy (XPS) were used to assess changes in surface chemistry. Brownmillerite had significant dissolution extents, with Al and Ca dissolving up to 16 % and 8 %, respectively, in contrast to gehlenite, which dissolved less than 2 % under similar conditions. Sonication significantly increased the dissolution of brownmillerite by up to 100 %, although its impact on gehlenite dissolution varied depending on the duration of time. Besides, adding citrate enhanced the leaching of Al and Ca from gehlenite by facilitating complexation. XPS data demonstrated differences in elemental ratios on brownmillerite and gehlenite surfaces affected by the method used and the presence of citrate. Lastly, the dissolution extents of Al and Ca from EAFS were up to 12 %, depending on time and mixing method, with a preference for sonication over stirring. In conclusion, this study showed that minerals in EAFS have distinct dissolution characteristics, and sonication and citrate can considerably enhance dissolution.

Designed bimetallic layer-encapsulated tungsten powders for reinforcing tungsten-silver matrix composite electrical contact materials

Electrical contact materials (ECMs) play a pivotal role in maintaining the stability and efficiency of electrical instruments and electronic devices by regulating the current flow. As an essential member of ECMs, W-Ag matrix composite ECMs (W-Ag-MC-ECMs) are integral, demonstrating commendable resistance to welding and arc erosion. However, the limited wettability between the two phases curtails their broader applications. Herein, Ag-Cu and Ag-Ni bimetallic layer-encapsulated tungsten powders were designed and successfully synthesized through a two-step electroless plating process. Subsequently, the W-Ag-MC-ECMs were fabricated following the powder metallurgy route, including the solution ball milling process and the spark plasma sintering technique. The results indicated that Cu-Ag solid solution and Ni with a metal binder effect could strengthen the interface bonding, which can dramatically improve the microhardness (up to 182HV), strength (up to 600 MPa), ductility (up to 24 %) and resistance to arc erosion (nearly two times longer service life). In addition, during the arc erosion, attributed to the Cu-Ag solid solution effect of W@Ag@Cu/Ag-MC-ECMs and solution-strengthening effect of W@Ag@Ni/Ag-MC-ECMs, the work function increases and the arc energy decreases, which reduces mass loss and extends the service life of the contacts.

Contribution of Metastable Oxygen Spectra to Fluctuated Waveform Tails after Breakdown Time in Air under Positive and Negative Impulse Voltages

In this study, we explored the correlation between fluctuated waveform tails under both positive and negative impulse voltages and their corresponding spectral lines during millisecond observations of arc discharge. We examined impulse voltages in ±100, ±125, and ±150 kV across 3, 3.5, and 4 cm gaps using spectroscopic analysis focused on oxygen excitations. Six selected spectra in ±100, ±125, and ±150 kV at 3.5 cm and two negative spectra of −100 kV at 3 and 4 cm were analyzed by identifying spectral lines in the wavelength range of 200–900 nm. The results revealed a correlation between the fluctuated waveform tails and spectral lines in positive voltage discharges, which were almost similar, while in negative voltage discharges, this correlation was found only in −100 kV at 3 and 4 cm. We concluded that during the spark phase for both positive and negative voltage discharges, symmetrical fluctuation in the waveform tails was observed after breakdown time, especially above the voltage level of the recombination phase. This suggested the presence of energetic oxygen excited states in the 200–400 nm range, with higher peak intensity than the O I line at 777.417 nm, observed in most positive impulse voltage discharges and at −100 kV with 3 and 4 cm gaps, contributing to rapid breakdown.

Bifurcation Diagrams of Nonlinear Oscillatory Dynamical Systems: A Brief Review in 1D, 2D and 3D.

We discuss 1D, 2D and 3D bifurcation diagrams of two nonlinear dynamical systems: an electric arc system having both chaotic and periodic steady-state responses and a cytosolic calcium system with both periodic/chaotic and constant steady-state outputs. The diagrams are mostly obtained by using the 0-1 test for chaos, but other types of diagrams are also mentioned; for example, typical 1D diagrams with local maxiumum values of oscillatory responses (periodic and chaotic), the entropy method and the largest Lyapunov exponent approach. Important features and properties of each of the three classes of diagrams with one, two and three varying parameters in the 1D, 2D and 3D cases, respectively, are presented and illustrated via certain diagrams of the K values, -1≤K≤1, from the 0-1 test and the sample entropy values SaEn>0. The K values close to 0 indicate periodic and quasi-periodic responses, while those close to 1 are for chaotic ones. The sample entropy 3D diagrams for an electric arc system are also provided to illustrate the variety of possible bifurcation diagrams available. We also provide a comparative study of the diagrams obtained using different methods with the goal of obtaining diagrams that appear similar (or close to each other) for the same dynamical system. Three examples of such comparisons are provided, each in the 1D, 2D and 3D cases. Additionally, this paper serves as a brief review of the many possible types of diagrams one can employ to identify and classify time-series obtained either as numerical solutions of models of nonlinear dynamical systems or recorded in a laboratory environment when a mathematical model is unknown. In the concluding section, we present a brief overview of the advantages and disadvantages of using the 1D, 2D and 3D diagrams. Several illustrative examples are included.

Enhanced cyclic oxidation resistance of Metcoloy II coated ASTM A53 Grade B steel by electric arc thermal spray

This study evaluates the enhanced cyclic oxidation resistance of Metcoloy II coatings applied to ASTM A53 Grade B steel substrates using electric arc thermal spray, across temperatures ranging from 500 °C to 700 °C. The research identifies distinct performance differences between coated and uncoated samples under cyclic oxidation conditions. Initially, both sample types exhibited mass increases due to oxide formation. However, uncoated samples developed non-protective iron oxides, while Metcoloy II coatings formed a protective layer of chromium and nickel oxides. During 500 oxidation cycles at 500 °C, uncoated samples showed a rapid mass increase, indicative of accelerated oxidation, whereas Metcoloy II coatings experienced a controlled mass gain, reflecting effective protection by chromium and aluminum oxides. At 700 °C, the mass variation trends were similar for both types initially; however, uncoated samples suffered significant mass loss due to iron oxide volatilization, emphasizing their susceptibility. Conversely, Metcoloy II coatings exhibited a reduced but steady mass increase, indicating their resilience under high-temperature conditions. Microstructural analysis confirmed the presence of a protective oxide layer in the coated samples, which is essential for reducing substrate oxidation. Although challenges such as coating detachment and thinning were observed, particularly at higher temperatures, Metcoloy II coatings maintained their protective role. This study highlights the coating's effectiveness in extending the lifespan of steel substrates subjected to cyclic oxidation, providing valuable insights for optimizing protective coatings in demanding industrial applications and advancing material science strategies for enhanced durability.

Magnetic Sensor Array for Electric Arc Reconstruction in Circuit Breakers.

Noninvasive imaging of circuit breakers under short-circuit testing is addressed by recording the magnetic field produced over an array of external sensors and by solving an inverse problem to identify the causing current distribution. The temporal and spatial resolution of the sensing chain are studied and implemented in a physical set-up. A wire model is adopted to describe electrical current distribution. Additionally, the simpler, more direct approach to evaluating the passage of electric current in front of sensors is proposed. The dynamics of suitable approximating models of the electric arc that forms across contacts is obtained and agrees with multi-physical simulations and with experimental time histories of current and voltage. The two methods are flexible and allow the analysis of different types of circuit breakers.

Effect of Electrodeposition Time on the Growth Rate of Carbon Nanotubes (CNTs)

Carbon Nanotubes (CNTs) are nano-sized carbon that resembles tubes and has the potential to be used in various aspects of applications. Some of the CNT carbon capture methods include arc discharge, lasser ablation, CVD and electrodeposition. The advantage of the electrodeposition method is that the production cost is cheap and the preparation is easy. Electrodeposition is the precipitation of substances by using a direct electric current, with CO2 as the reactant. Factors that affect the growth rate of CNT are voltage, temperature, carbon source, electrode and time. The variation of the electorative time used was 60 minutes, 90 minutes, 120 minutes, 150 minutes, 180 minutes. The data collection process begins by shaping and measuring the weight of the electrode (Ni) with a diameter of 2 cm CNT deposition area. measuring the weight and melting Li2CO3 at a temperature of 750. then the CO2 flow rate setting, voltage setting 5V and time setting were then characterized by SEM-EDX and XRD. The results of the study showed that the optimal time obtained with a time of 120 minutes, the resulting CNT deposition rate was 1,618 g cm-2 h-1. Then based on the characterization of XRD and SEM, it shows that the longer the electrodeposition time, the less impurities are contained in the results obtained.

Towards green steel-energy and CO2 assessment of low carbon steelmaking via hydrogen based shaft furnace direct reduction process

Under current stringent climate policies, the iron and steel industry, as a major contributor to industrial CO2 emissions, urgently needs the development of low-carbon metallurgical technologies. This work focuses on the hydrogen-based shaft furnace process, which can utilize green energy to significantly reduce CO2 emissions. This work combines the hydrogen-based shaft furnace CFD model, regression equations, and Aspen Plus model to develop a multi-gas source DR (Direct Reduction) plant model. This combination significantly reduces computation time while maintaining predictive accuracy. The transformation from COG (Coke Oven Gas)-DR to H2-DR plant was studied, showing that the top gas circulation process greatly reduces the net carbon input of the entire DR plant. However, the energy consumption of electrolytic hydrogen production limits the transformation of COG-DR plant to H2-DR plant. The process CO2 emissions depend largely on electrical energy footprint. Under traditional electrical energy footprint, the CO2 emissions of H2-DR-EAF (Electric Arc Furnace) route are about four times those of the COG-DR-EAF route. Only when using green source energy does the H2-DR-EAF route achieve the lowest CO2 emissions among all routes, at 344 kg/tls, which is 79 % lower than that of the BF (Blast Furnace)-BOF (Basic Oxygen Furnace) route.

Influence of ultrasonic power modulation on the optimisation of aluminium alloy micro-arc oxidation coating properties

Conventional micro-arc oxidation (MAO) technology, due to the randomness and transient nature of arc discharge, produces coatings with numerous defects, poor abrasion resistance, and inadequate ability to effectively block the intrusion of corrosive media. In this paper, ultrasonic-assisted technology was used to study the effect of different ultrasonic power regulation on the performance optimization of MAO coating on 6061 aluminum alloy. The coating microstructure and elemental composition were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectrometer, and its hardness, wear resistance, corrosion resistance and other properties were tested. The results show that the prepared coating has the characteristics of high hardness, good wear resistance and excellent corrosion resistance under the assistance of ultrasonic power of 50 W. This is mainly attributed to the cavitation effect, mechanical effect and thermal effect generated by the corresponding ultrasonic power, which effectively enhances the surface quality, performance and service life of the coating. This study provides valuable insights into the interaction between ultrasound power and the resulting MAO coatings, and has important implications for optimizing ultrasound-assisted processes and improving coating properties.

INFLUENCE OF GAS ENVIRONMENT OF SPRAYING ON THE PROPERTIES OF GAS-THERMAL METALLIZED COATINGS

This article is devoted to the study of the influence of the technological parameters of spraying, in particular the gaseous medium, on the physical and mechanical properties and corrosion resistance of gas-thermal metallization coatings. To protect the housings of submersible electric motors (PAD) in oil and gas wells, the method of electric arc metallization (EDM) has become widespread, due to the high level of physical and mechanical properties of the resulting gas-thermal metallization coating, high productivity and cost-effectiveness of the process, as well as the mobility of equipment. Despite the effectiveness of this method of protection, it does not exclude the occurrence of corrosion processes in the metal of the PAD body. In this regard, research aimed at increasing the operational life of the metallization coating is relevant and promising.The article considers the theoretical aspects of the influence of the technological parameters of the spraying process on the properties of the metallization coating. The effect of the sputtering gas medium on the physical and mechanical properties and corrosion resistance of metallization coatings has been experimentally investigated. Comparative tests and studies of gas-thermal metallization chromium-nickel coatings applied by the EDM method in an air environment and in an argon environment have been carried out. The main trends and features of the formation of metallization chromium-nickel coatings applied by the EDM method and the effect of the application mode, in particular the technological gas spraying medium on the microstructure studied on metallographic grinds using a scanning electron microscope with an attachment for energy dispersion analysis; microhardness determined by the Vickers method are determined; The wear resistance is determined by abrasive wear during friction against non-rigidly fixed abrasive particles and the corrosion resistance of the resulting coatings, determined by autoclave tests during exposure in a simulated environment containing corrosive components.The study of the influence of certain technological parameters of spraying of gas-thermal metallization coatings, including the gas medium, on the properties of the coatings obtained is a fairly promising task aimed at increasing the operational life of the metallization coating, which in the future will reduce the cases of premature failure of oilfield equipment.

Carbon Emission Analysis of RC Core Wall-Steel Frame Structures

The development of super high-rise building projects has become crucial for mitigating land shortages in rapidly growing urban areas. Super high-rise steel structures, particularly RC core wall-steel frame systems, have become the preferred choice due to their superior performance, high prefabrication level, and construction efficiency. Despite their benefits, super high-rise buildings face challenges related to higher energy consumption and carbon emissions. Consequently, it is important to analyze the carbon emissions of these buildings throughout their lifecycle and propose low-carbon construction strategies. A carbon emission analysis focused on super high-rise buildings with RC core wall-steel frame structures is conducted in this study. A carbon emission analysis model is constructed based on BIM-enabled LCA through a real-world case study. The emission factor method is combined with the BIM model to calculate carbon emission. Furthermore, carbon emissions across various construction strategies are compared, with a particular focus on the manufacturing processes of the main materials. The results indicate that incorporating admixtures in concrete, along with adopting the electric arc furnace (EAF) method and utilizing recycled scrap steel in steel manufacturing, significantly reduces the carbon emissions of the buildings. Lastly, effective low-carbon approaches for these buildings are proposed.

Electrosurgery: heating, sparking and electrical arcs.

The translation of impedance (R), current (I), and voltage (V) into tissue effects and the understanding of the settings of electrosurgical units is not obvious if judged by the many questions during live surgery. Below 200 V, the current heats the tissue until the steam of boiling stops the current. Thus, slower heating, because of less energy or a larger contact area, results in deeper coagulation. Above 200 V and a duty cycle (per cent of time electricity is delivered) of >50% (yellow pedal), sparks become electric arcs, and the heat causes the explosion of superficial cells, i.e. cutting. With higher voltages, cutting is associated with coagulation, i.e. blended current. With even higher voltages and a duty cycle <10% preventing arching, only coagulation occurs (blue pedal; forced coagulation). Voltage being crucially important for tissue effects, newer electrosurgical units deliver a constant voltage and limit the energy output (Maximal Watts: W=I*V= joules/sec). Unfortunately, the electrosurgical units indicate the combination of voltage and duty cycles as a force of cutting (pure cutting or blended) or coagulation (soft, forced or spray) current. It is important that the surgeon understands whether electrosurgical units control voltages or output, as well as the electrical basics of the different settings and programs used.

Automated process control in electric arc furnaces in the aspect of digital twin technology

An approach to managing the main modes of smelting steel in heavy-duty electric arc furnaces (EAF) using digital twin technology was defined and formulated. It was noted, that the existing power regulators do not have the function of balancing the effective power of phases and, accordingly, electric arcs because they are focused on working with a certain average value of the signal. It is proposed to use the analysis of dynamic characteristics based on instantaneous values of input parameters instead of operating ones, as it’s usually implemented in most devices. This allows us to obtain more accurate data on the arc state and reduce the amount of time and computing power required to obtain a result and form recommendations. Based on the data obtained as a result of long - term observations of the heavy-duty EAF-135 operation, the relationship of the constant component of the arc voltage (CCAV) with the metal oxidation is shown. An example of its use as a criterion for controlling the melting oxidative stage is given. This reduces the consumption of electrochemical sensors for each melting in the case of serial metal production. Based on the recorded data, it is possible to timely determine the unevenness of the arc power release between the furnace electrodes and issue recommendations on gas burners operation regulating to equalize the rate of scrap melting at electrodes with less power release. The authors propose the idea of using digital twins based on models of the active power distribution across the melting bath zones and dependence of metal oxidation on oxygen blowing for monitoring and controlling the electric mode and the oxygen blast mode at the oxidative stage of the melting process. Simplified schemes of these twins are given.

Machine Learning Approach for Predicting Bead Geometry of Stainless Steel in Wire arc Additive Manufacturing

Wire arc additive manufacturing (WAAM) employs an electric arc to melt wire feedstock, making it a method within additive manufacturing (AM). It deposits material layer by layer to build up a part. The present study investigated the application of machine learning classification-based models for estimating bead width and bead height of stainless-steel parts fabricated using WAAM. The input parameters (voltage, current, wire feed rate, and travel speed) were considered as input to algorithms. Training and testing were performed for 98 experimental data sets from peer-reviewed literature. The machine learning classification models, K-nearest neighbors, decision tree with gini index as criteria, and random forest were evaluated. The ML model performance was evaluated utilizing statistical metrics, including accuracy, F1 score, precision, and recall. The decision tree classifier exhibited the highest accuracy of 87.8% for bead width and 84.7% for bead height. The findings offer valuable insights into leveraging ML techniques to enhance the performance and accuracy of predictive models within WAAM-based AM.

Experimental Investigations on the Fabrication of Low Alloy Steels Using Wire Arc Additive Method

Wire arc additive manufacturing (WAAM) has emerged as a transformational technology with the capacity to redefine the landscape of alloy steel component production. This method utilizes an electric arc to selectively fuse a continuous wire feed, progressively constructing intricate metal structures layer by layer. GMAW-based WAAM adaptability enables the creation of complex geometries and customized part designs, making it applicable across diverse industrial sectors. This paper investigates WAAM-specific applications in alloy steel fabrication, focusing on key process variables such as voltage, travel speed, and Gas mixture ratio. The experimental parameters for a single layer are examined with voltage ranging from 20 to 22, travel speed from 23, 25, and 27 mm/min, and Gas mixture ratio 1,5,9 mm/min. It utilizes materials like TM B9, a 1.2- diameter flux-cored wire. Additionally, the study considers the nominal composition (wt-%) of 9 Chromium, and 1 Molybdenum, with small additions of nitrogen and niobium to improve the creep resistance. Furthermore, the final findings of the study suggest that the optimal combination of process variables for achieving highquality weld beads in WAAM of alloy steel components can be determined through Response Surface Methodology (RSM). RSM is a statistical method for analysing and modeling the relationship between the response of interest and some independent variables. In this case, the response variable would be the quality of the weld bead, which encompasses factors such as bead geometry, integrity, and absence of defects.

Microstructural and mechanical characteristics of alkali-activated green concrete using slag from electric arc furnaces as precursor and aggregate

Abstract Alkali-activated materials (AAM) have gained popularity in research because of their lower carbon dioxide emissions than Portland cement. Electric arc furnace slag (EAFS) exceeds landfills. Moreover, electric arc furnaces emit less CO2 than oxygen-blast furnaces. This research is the first to suggest that mixing EAFS and metakaolin (MK) as AAM precursors could compensate for the deficiency of SiO2 and Al2O3 in the EAFS and CaO in the MK, which would produce better AAM properties than using either of them singularly. Furthermore, the utilization of EAFS aggregate instead of natural aggregate in alkali-activated concrete (AAC) reduces waste materials, consumes fewer natural resources, and solves the problem of natural aggregate scarcity. This study’s main objectives were to evaluate the effects of varying ratios of EAFS and MK as precursors and EAFS aggregate to natural aggregate ratios on the AAC’s fresh and hardened properties. The properties under consideration are workability and cube compressive strength. The outcomes showed that increasing EAFS with decreasing MK content increased AAC workability and cube compressive strength while increasing EAFS aggregate over natural aggregate improved AAC workability and decreased cube compressive strength.

Prediction of Failure Due to Fatigue of Wire Arc Additive Manufacturing-Manufactured Product

Currently, the focus of production is shifting towards the use of innovative manufacturing techniques and away from traditional methods. Additive manufacturing technologies hold great promise for creating industrial products. The industry aims to enhance the reliability of individual components and structural elements, as well as the ability to accurately anticipate component failure, particularly due to fatigue. This paper explores the possibility of predicting component failure in parts produced using the WAAM (wire arc additive manufacturing) method by employing fractal dimension analysis. Additionally, the impact of manufacturing imperfections and various heat treatment processes on the fatigue resistance of 30CrMnSi steel has been investigated. Fatigue testing of samples and actual components fabricated via the WAAM process was conducted in this study. The destruction of the examined specimens and products was predicted by evaluating the fractal dimensions of micrographs acquired at different stages of fatigue testing. It has been established that technological defects are more dangerous in terms of fatigue failure than microstructural ones. The correctly selected mode of heat treatment for metal after electric arc welding allows for a more homogeneous microstructure with a near-complete absence of microstructural defects. A comparison of the fractal dimension method with other damage assessment methods shows that it has high accuracy in predicting part failure and is less labor-intensive than other methods.