Life Of Components Research Articles

Removing High-Velocity Oxyfuel Coatings Through Electrolytic Dissolution

High-velocity oxyfuel (HVOF) coatings are used to protect components from corrosion and wear at higher temperatures and from wearing out after a certain period of time. Hence, to enhance the life of components, further recoating is required, but removing the older coating is a challenging task due to its high hardness. Thus, this research work studied the electrolytic dissolution process of removing WC-CoCr 86/10/4 HVOF coatings and found that at a voltage of 3 V, the coating was not removed, but at a slightly higher voltage of 6 V, the coating was removed completely. When the voltage was 12 V, the surface was damaged, and corrosion also occurred. A combination of tartaric acid (C4H6O6), sodium bicarbonate (NaHCO3), and water was used as an electrolyte. By using a combination of a voltage of 4.5 V, a current of 1.6 A, and an electrode distance of 55 mm, the coating was completely removed after 10 h, with negligible attacks on the base material. Where the corrosion of the base material is unacceptable, voltages in the range of 4 to 6 V are recommended. If parts have coatings on all surfaces, a voltage within the range of 6 to 12 V can be recommended. The coating from tab SB-002JI-5 TOOLOX-11 and hexagonal mandrel SB-00EA-1 160 TIS was also removed successfully.

Expanding Known Performance Capabilities of Geared Turbofan Engine When Powered by LNG and Methanol

As aviation demand rises, fossil jet fuel consumption follows, thus increasing focus on sustainable aviation fuels to reduce aircraft greenhouse gas emissions. While advanced technologies and optimized operations play a role, alternative fuels, especially non-drop-in options like Liquefied Natural Gas (LNG) and methanol, offer promising potential for significant emission reductions if used in current aero-engines. LNG, a candidate near-term replacement of fossil jet fuel and methanol, even though a less conventional option in aviation, present advantages. Both fuels showcase the ability to generate the same thrust output by also achieving lower post-combustion temperatures, thereby enhancing component life and reducing emissions. Inversely, requesting equal post-combustion temperature as the baseline kerosene operation of the engine can produce greater thrust output, a much needed result for such fuels with low volumetric energy density, which causes greater take-off thrust demand mainly due to their larger tank requirements. This study uses advanced 0-D engine models coupled with detailed chemistry 1-D burner models and mission analysis tools to assess the aforementioned trends of LNG and methanol used to power a current geared turbofan engine. The aim of this work is to provide insights into the advantages, the limitations and the overall viability of the fuels in question as less polluting aviation fuels, addressing both environmental impact and operational feasibility in future aviation applications. According to findings of this article, when compared with Jet-A, LNG can reduce post-combustion temperature by an average of 1% or increase net-thrust by 3% while lowering CO2, NOx and CO emissions by 20%, 46% and 39%, respectively. Adversely, methanol is capable of lessening post-combustion temperature by 3% or enhancing thrust output by 10% while also reducing CO2, NOx and CO emissions by an average of 6%, 60% and 38%, respectively.

Application of Fuzzy Logic to Motorcycle Oil Change Cycle with 10W 30 Oil Viscosity

Oil is a fluid that serves to lubricate the engine, so that friction between engine components is relatively small. Oil changes are based on mileage, oil volume, and oil viscosity levels which usually vary depending on the needs of the vehicle's engine. Most riders are often late and do not even know the routine time of oil changes so that the user's motorcycle engine feels damaged. The application of fuzzy logic has become an important approach in modeling the complex and ambiguous system of motorcycle oil change periods with 10W 30 oil viscosity. The purpose of this study is to determine the application of fuzzy logic in determining the optimal oil. exchange interval. Oil is based on factors such as mileage, oil volume, and oil viscosity when viewed from motorcycle use. To represent these variables using fuzzy sets, a fuzzy logic control system was developed that takes into account oil wear and motorcycle operating conditions which was implemented using the mamdani method and calculated using matlab software. The results showed that oil change intervals tailored to operating conditions and the environment can improve engine performance, reduce maintenance costs and extend component life.

Effect of Gradient Transition Layer on the Cracking Behavior of Ni60B (NiCrBSi) Coatings by Laser Cladding.

Laser cladding technology is an effective method for producing wear-resistant coatings on damaged substrates, improving both wear and corrosion resistance, which extends the service life of components. However, the fabrication of hard and brittle materials is highly susceptible to the problem of cracking. Using gradient transition layers is an effective strategy to mitigate the challenge of achieving crack-free laser-melted wear-resistant coatings. This study presents the cracking issue of laser cladding Ni60B (NiCrBSi) coatings on 38CrMoAl (18CrNiMo7-6) steel by designing a gradient transition layer infused with varying amounts of Ni powder. We examine how different levels of Ni doping in the transition layer influence the fabrication of the Ni60B coating. The results indicate that the cracking mechanism of Ni60B is primarily due to the brittleness and hardness of the fusion cladding layer, which can result in cold cracks under residual tensile stress. Increasing the nickel content in the transition layer reduces the difference in thermal expansion coefficients between the cladding layer and the substrate. Additionally, the nickel in the transition layer permeates the cladding layer due to the laser remelting effect. The physical phase within the cladding layer transitions from the initial CrB, M7C3, and γ-Ni solid solution to γ-Ni solid solution and Ni-B-Si eutectic, with a small amount of boride and carbide hard phases. As the nickel doping in the transition layer increases, the proportion of the toughness phase dominated by Ni elements significantly rises, leading to a decrease in the hardness of the fused cladding layer. However, the average hardness of the fusion cladding layer in crack-free samples was measured at 397.5 ± 5.7 HV0.2, which is 91% higher than that of the substrate.

Cold working technologies for increasing the fatigue life of metal structural components with fastener holes—review and perspectives

Cold working technologies for increasing the fatigue life of metal structural components with fastener holes—review and perspectives

A Novel Mechanism-Equivalence-Based Tweedie Exponential Dispersion Process for Adaptive Degradation Modeling and Life Prediction.

Accurately predicting the remaining useful life (RUL) of critical mechanical components is a central challenge in reliability engineering. Stochastic processes, which are capable of modeling uncertainties, are widely used in RUL prediction. However, conventional stochastic process models face two major limitations: (1) the reliance on strict assumptions during model formulation, restricting their applicability to a narrow range of degradation processes, and (2) the inability to account for potential variations in the degradation mechanism during modeling and prediction. To address these issues, we propose a novel mechanism-equivalence-based Tweedie exponential dispersion process (ME-based TEDP) for adaptive degradation modeling and RUL prediction of mechanical components. The proposed model enhances the original Tweedie exponential dispersion process (TEDP) by incorporating degradation mechanism equivalence, effectively capturing the correlation between model parameters. Furthermore, it improves prediction accuracy and interpretability by employing a dynamic testing-modeling-predicting strategy. Application of the ME-based TEDP model to high-speed rail bogie systems demonstrates its effectiveness and superiority over existing approaches. This study advances the theory of degradation modeling and significantly improves the precision of RUL predictions.

Effect of the Electrogalvanized and Galvannealed Zn Coatings on the Liquid Metal Embrittlement Susceptibility of High Si and Mn Advanced High-Strength Steel

The advanced high-strength steels (AHSSs) with high Si and Mn contents are extensively applied in the automobile manufacturing industry. To improve the corrosion resistance, Zn coatings are generally applied to the steel substrate. However, heat input and tensile stress occur during the resistance spot welding (RSW) process; thus, Zn-induced liquid metal embrittlement (LME) can be produced due to the existence of liquid Zn. Unfortunately, the LME occurrence can trigger the premature failure of welded joints, seriously affecting the service life of vehicle components. In this study, the LME behaviors in high Si and Mn RSW joints with electrogalvanized (EG) and galvannealed (GA) Zn coatings were comparatively investigated. Based on the Auto/Steel Partnership (A/SP) criterion, 16 groups of different welding currents were designed. In particular, four typical groups of RSW joints were selected to reveal the characteristics of the LME behaviors. Moreover, these four typical groups of EG and GA high Si and Mn RSW joints were, respectively, etched to measure their nugget sizes. The results indicated that with the increase in the welding current, more severe LME cracks tended form. As determined during the comprehensive evaluation of the 16 groups of EG and GA welded joints, higher LME susceptibility occurred in the EG high Si and Mn steels. It was concluded that the formation of Fe-Zn intermetallic compounds (IMCs) and internal oxide layers during the annealing process could account for the lower LME susceptibility in the GA welded joints.

Bilateral submerged abrasive waterjet peening improved high-temperature fatigue strength of titanium alloy thin-walled simplified blades

Waterjet peening has exhibited excellent performance in improving the surface integrity and fatigue life of metal components. This paper proposes a novel and efficient thin-walled simplified-blade-surface full-coverage strengthening method, namely the bilateral submerged abrasive waterjet peening process (BSA-WJP), to improve the surface integrity and fatigue strength of simplified aeroengine blades. First, the surface integrity of simplified titanium alloy TA19 blades treated with BSA-WJP at different abrasive flow rates (100, 175, and 250 g/min) was investigated. The results revealed that the lowest surface roughness value of Ra = 0.329 μm was obtained. Compressive residual stress (CRS) layers of 111–128 μm with a maximum CRS of 738 MPa were introduced to the simplified blade surface. Plastic deformation layers of 15–32 μm were formed on the simplified blade surface after BSA-WJP treatment. The microstructure of the BSA-WJP-treated simplified blade was further examined using transmission electron microscopy. It was found that ultrafine grains with an average size of 107 nm and dense dislocations were induced on the topmost surface and subsurface. Finally, the high-cycle vibration fatigue performance of the simplified TA19 blade at 450 °C was verified. The result revealed that a 13.6 % increase in the high-temperature fatigue limit of the simplified TA19 blade was achieved after BSA-WJP treatment. The fracture morphology revealed that the considerable CRS, grain refinement layer, and optimized surface morphology played significant roles in inhibiting the initiation and propagation of cracks. This study provides an effective method for improving the fatigue strength of titanium alloy thin-walled blades and has promising engineering application prospects.

Machinability and surface integrity analysis of Ti-17 alloy using WEDC for advanced aero-engine application.

Recent advancements in aerospace industry demand intricate aero-engine parts, leading to the increased use of titanium alloys, particularly Ti-17, due to its high strength, thermal stability, and corrosion resistance. However, its low thermal conductivity and tool wear tendency pose significant machining challenges, impacting surface integrity, fatigue life, and overall component performance. This study investigates the Wire Electrical Discharge Cutting (WEDC) process, revealing that the mechanism behind improved surface integrity lies in the controlled thermal input, which minimizes phase transformations and reduces residual stresses. Experimental results reveal that rough-cutting Ti-17 yields higher surface roughness of ∼2.68μm than that of finish cutting of ∼1.01μm, with increased microhardness up to 80μm depth. Further, rough cutting leads to a thicker recast layer of ∼10-15μm, and higher residual stresses of ∼540MPa, while finish cutting achieves a thinner recast layer of ∼2-5μm and reduced stresses of ∼304MPa. The innovation of this study is the investigation of WEDC behavior in Ti-17 alloy, addressing a gap in understanding its surface integrity features to improve the performance, durability, and service life of aero-engine components, advancing next-generation aerospace manufacturing.

Influence of Low-Temperature Stress-Relieving Treatment in the Fatigue Life of Components Produced by Laser Powder Bed Fusion in AlSi10Mg

This study investigates the impact of low-temperature stress-relieving treatment on the fatigue life of AlSi10Mg components produced by Laser Powder Bed Fusion (L-PBF). The research focuses on a bicycle crank arm, comparing its performance in as-built and heat-treated conditions. The heat treatment involved stress-relieving at 250 °C for 2 h, followed by water quenching. The study found that the as-built condition exhibited a supersaturated Si cellular-dendritic microstructure, while the heat-treated condition showed coarsening of β-Mg2Si phases and Si precipitates. This morphological change led to a decrease in hardness and an increase in ductility. Fatigue tests demonstrated that the heat-treated crank arms achieved the target of 100,000 cycles without failure, unlike the as-built samples, which failed prematurely. The fractography analysis identified surface porosity as the primary crack initiation site. The findings suggest that low-temperature stress-relieving treatment can enhance the fatigue performance of L-PBF AlSi10Mg components by reducing residual stresses and improving defect tolerance.

Challenges in Damage Detection for Real-time Monitoring and Predictive Maintenance Methodology

Damage detection techniques offer a sophisticated and effective way to monitor and assess the health of engineering systems, but they come with challenges related to model accuracy, sensor data quality, and the detection of subtle or distributed damage. Advances in computational methods, sensor technology, and hybrid techniques continue to improve the practical application of these methods, making them increasingly relevant in real-time condition monitoring and predictive maintenance systems. The proposed methodology aims to develop damage detection systems that play a key role in enabling real-time monitoring and early identification of potential problems. This approach significantly reduces the need for conventional checks, leading to time and cost savings. By predicting the remaining service life of components, the methodology helps optimize maintenance schedules and prevent unexpected failures. Additionally, the use of smart materials and sensors enhances the accuracy and efficiency of damage detection, allowing more proactive, data-driven damage detection and monitoring systems.

Process Research of Surface Laser Phase Transformation Hardening for 42CrMo Material

42CrMo is an ultra-high-strength, low-alloy structural steel. To enhance its surface wear resistance and prolong the service life of components, surface strengthening techniques are commonly applied. In this study, a numerical model for the laser phase transformation hardening of 42CrMo was established. The temperature field and metallurgical transformations during the laser phase transformation hardening process were investigated through numerical simulation, and the morphology of the hardened layer after laser surface treatment was predicted. The effects of key process parameters on the temperature field and the characteristics of the hardened layer were identified. The optimal parameters for single-pass laser phase transformation hardening were found to be a laser power of 1200 W, a scanning speed of 20 mm/s, and a spot diameter of 6 mm. The accuracy of the simulation results was validated through laser phase transformation hardening experiments. The results indicate that under these optimal conditions—laser power of 1200 W and a scanning speed of 20 mm/s—the hardening effect is maximized. The surface hardness reaches a maximum of 782 HV0.2, with a cross-sectional hardness peaking at 875 HV0.2, which is three to four times higher than the base material’s hardness, with an average surface hardness of 745 HV0.2.

Propagation of a Fatigue Crack Through a Hole.

The stop-hole technique is a well-known strategy to extend the fatigue life of cracked components. The ability to estimate fatigue life after the hole is important for safety reasons. The objective here is to develop strategies for the accurate prediction of initiation and propagation life ahead of the stop-hole. Experimental work was developed in a Compact-Tension (CT) specimen made of 7050-T7451 aluminium alloy and with a 3 mm diameter hole. A total number of 625,000 load cycles were required to re-initiate the crack after the hole. Crack initiation life after the hole was estimated using the Theory of Critical Distances combined with the Smith-Watson-Topper parameter. A value of a0 = 31.83 µm was obtained for El Haddad parameter, which was used to define the critical distance. The predicted life was found to be only 4% lower than the experimental value. The fatigue crack growth (FCG) rate was calculated using a node release strategy, assuming that cyclic plastic deformation is the main damage mechanism and that cumulative plastic strain is the crack driving parameter. A good agreement was found between the numerical predictions of da/dN and the experimental results. The main result, however, is the proposed methodology, which allows predicting the initiation and propagation lives in notched components.

A Contribution to the Study of the Integrity Surface of the IC10 Ni3Al-Based Alloy After Creep-Feed Grinding with a Focus on High-Temperature Fatigue Life

The IC10 directionally solidified superalloy is a nickel-based alloy with high temperature resistance, and its surface integrity has a significant impact on the fatigue life of critical hot-end components in aerospace engines. This paper investigates the influence of creep-feed grinding surface integrity (surface roughness and surface hardness) on the high-temperature fatigue life of IC10 directionally solidified superalloy. High-temperature fatigue life tests were conducted on IC10 directionally solidified superalloy, and a method for evaluating the high-temperature fatigue life of the IC10 directionally solidified superalloy using surface integrity is proposed. The results indicate that as the surface roughness Ra increases from 0.60 μm to 2.15 μm, the maximum valley depth Rv of the grinding surface profile and the stress concentration factor increase, leading to more scratches and wider grooves. The fatigue fracture of IC10 consists of a fatigue source zone, a fatigue propagation zone, and an instantaneous fracture zone. With increasing surface roughness, the number of fatigue sources also increases, and the stress concentration on the grinding surface intensifies. Under the action of multiple fatigue propagation sources, the sample structure is more likely to reach a critical value and lose stability, leading to fracture and thus reducing the high-temperature fatigue life. When the surface hardness increases from 387.11 HV to 393.60 HV, the high-temperature fatigue life of IC10 improves by 68.13%; when the surface hardness increases from 401.62 HV to 418.13 HV, the high-temperature fatigue life of IC10 decreases by 73.12%. The surface integrity of the IC10 directionally solidified superalloy has a notable impact on its high-temperature fatigue life.

Assessment of the Influence of the Life Cycle of Solar Power Plant Materials and Components on Ecosystem Quality.

Currently, silicon is the most often utilized material for photovoltaic cell manufacturing, as it has the potential to convert solar energy directly into electricity. The silicon used in photovoltaic solutions must be highly pure. Large amounts of power, raw materials, and fossil fuels are consumed in the production process. Post-consumer treatment of polymers, materials, and components also requires energy and matter. These processes have a significant influence on the environment. As a result, the primary purpose of this article is to evaluate the influence of a photovoltaic power plant's material and component life cycle on ecosystem quality. The research focuses on an actual photovoltaic power plant with a capacity of 2 MW located in northern Poland. According to the findings, photovoltaic modules are the part that has the most negative environmental impact, since their manufacturing requires a substantial amount of materials and energy (primarily from conventional sources). Post-consumer management, in the form of recycling after use, would provide major environmental advantages and reduce detrimental environmental consequences throughout the course of the solar power plant's full life cycle.

Materials and Structures Used in Aeronautics: Present and Future Perspectives

In recent years, significant advancements have been made in the development of novel materials for aeronautic applications. This effort aims to reduce costs by extending the operational life of structural and engine components, improving fuel economy, load capacity, and flight range. This paper investigates metallic materials such as aluminum alloys, titanium alloys, magnesium alloys, steels, nickel superalloys, and metal matrix composites (MMCs), providing an overview of recent advancements and highlighting current challenges and future perspectives in aeronautic metals. Several crucial factors are considered when selecting materials for aviation applications. These materials must withstand various environmental conditions, including humidity and temperature, as well as mechanical stresses such as tension, compression, bending, cyclic loads, creep, and torsion. The selection process is complicated by the wide range of available materials and the numerous variables involved, with cost being a critical factor in making an informed decision. In aviation, the most significant material characteristics are strength combined with lightness and stability in the operating environment. Trial and error can be costly in this context, necessitating well-planned design and engineering to ensure resistance to aerodynamic forces during flight. This approach has drawn the interest of aircraft designers since the inception of the Boeing 747, which utilized 1.3% composite materials. Modern aircraft, such as the Airbus A380 and Boeing 787, now incorporate 25% and 50% composite structures, respectively. Research has increasingly focused on enhancing the efficiency of structural engineering and material development through the use of sandwich structures. These structures are valued for their excellent stiffness-to-weight ratios and impact energy absorption properties. A typical sandwich structure consists of two thin, rigid face layers bonded to a core material. While various core materials like balsa and foam have been used in aviation, the honeycomb structure is the most prevalent. Honeycomb core configurations, including hexagon, reinforced hexagon, rectangle, flex-core, and square cell, primarily serve to support normal loads in the longitudinal direction and shear loads along the transverse axis.

Simulating hydrogen-controlled crack growth kinetics in Al-alloys using a coupled chemo-mechanical phase-field damage model

Environmentally Assisted Cracking (EAC) of 7xxx series aluminium alloys involves interactions between multiple physical phenomena, which ultimately influence the in-service life of critical components. In this work, we present a new model to study EAC in 7xxx series alloys, which is implemented in the multiphysics simulation framework, DAMASK. The chemo-mechanical model couples crack tip hydrogen generation, resulting from surface oxidation, and transport, with crystal-plasticity-governed intergranular crack propagation, through the microstructural trapping of hydrogen at dislocations, grain boundaries (GB), and crack tip stress fields. Large-scale simulations with realistic grain structures have been performed to provide novel insight into the dominant rate-controlling processes associated with intergranular EAC in 7xxx series aluminium alloys. The model was able to reproduce experimentally measured crack velocities under different loading conditions. Parametric studies indicate that, in addition to the GB network morphology, the crack growth rate was controlled by hydrogen generation at the crack tip with long-range diffusion having negligible influence. Additionally, the total hydrogen generated through crack tip oxidation appears to be more significant than the peak generation rate.

Topology Optmization Applied to Problems with Local Fatigue Constraints Based on Augmented Lagrangian Method

Fatigue is the most usual failure mode of any mechanical structure subject to loading. There are several methods to predict the structure life, and different approaches can be applied to extend this life. From the point of view of materials engineering, new materials can be proposed to deal with this issue. However, developing and producing these materials can be expensive. A different approach consists of optimizing the design using some optimization algorithm, determining the optimized material distribution that ensures a higher fatigue life. This work proposes to use topology optimization to design structures subjected to permanent loads to increase the component life. The objective is to minimize the volume, considering fatigue constraints. The works in the literature deal with fatigue constraints using aggregate methods, which are common in problems considering stress constraints. Our proposed approach uses a norm of the stress field to represent the stress constraint. However, stress and fatigue are local phenomena. Thus, in this work, the Augmented Lagrangian method is used to deal with the large number of constraints in the problem. This approach, previously used in stress-constraints problems, makes treating fatigue as a local phenomenon. The Modified Goodman method is used to measure local fatigue. This method considers a sensitivity factor that accurately estimates fatigue life. Numerical examples show the efficiency of the proposed method.

Numerical Investigation of Heat Transfer Characteristics for Various CPU Designs

Abstract Due to the rise in demand of computers with high computing power, there is significant advancement in electronic components inside the CPU cabinet every 6 months. The life of these electronic components is greatly affected by their working temperatures. Therefore, it is necessary to maintain the temperature of these devices within acceptable limits. Forced air cooling inside the CPU cabinet is a widely used technique for this purpose. Heat sinks are another way of increasing the heat transfer rate. The present study analyses the effect of different probable improvement cases implemented in the basic CPU cabinet. These improvement cases include changing the position and number of fans, changing the type of heat sink, and changing the inlet cross section. By making use of commercially available CFD softwares like Ansys Fluent and Icepak, the cooling effect in the CPU cabinet is analysed.

Influence of water-repellent admixtures ( Sitren and Stearate materials) on the microstructure and mechanical performance of conventional Portland cement paste and mortar

The longevity of mortar and concrete structures can be compromised by the absorption of water and other fluids, leading to deterioration and aesthetic issues. To address this, water-repellent admixtures are employed to enhance the service life of mortar and concrete components by improving their mechanical and microstructural characteristics. This study focus on the effects of incorporating Sitren P 750 and various stearate materials (calcium, zinc, aluminum, and barium) as admixtures with ordinary Portland cement at mortar and paste dosages of 0.5%, 1.0%, and 1.5% of the cement content. We found that mortars with water-repellent admixtures exhibited competitive mechanical properties at all curing ages. Additionally, the study confirmed the contribution of these admixtures to the production of hydration products and the structural development of the mortars, as investigated through scanning electron microscopy, thermogravimetric–derivative thermogravimetric, and X-ray diffraction analyses. Despite alterations in several physical properties and hydration kinetics due to the water-repellent compounds and their dosages, all admixtures provided effective water-repellent protection. This was further corroborated by water contact angle tests and the measurement of the capillary water absorption coefficient for all samples. Identifying the optimal mixture ratio for construction technology and effectively incorporating repellence features is a crucial aspect of this research.