Typical Engineering Research Articles

Gas turbine aero engine fault detection using Geo-TLSVM and digital twin with multimodal data analysis

DT is the digital representation of physical systems to simulate real situations in a digital version. Here, the DT of the GaT-AE is created for the Fault Detection (FD) process. The GaT is a type of internal combustion engine that uses the air as the working fluid to propel the flight. However, the incorporation of big data analysis in the DT model is challenging in previous works. So, a multimodal GaT-AE fault identification system is proposed. First, the 3D print of the GaT-AE is created. Then, the data is collected from both built-in sensors and DT. Afterward, the multimodal data is pre-processed and balanced by using HT-QNN and QADASYN, respectively. Next, the features are processed by GT-PFS, and finally, the faults are detected by Geo-TLSVM. The analysis proved that the developed model outperformed the other state-of-the-art model with its effective FD rate of 97.24%.

Seismic fragility analysis of high‐strength concrete frame structures reinforced with high‐strength steel bars

SummaryTo investigate the influence of using high‐strength steel bars in columns on the seismic resistance capacity and seismic resilience of frame structures, seismic fragility evaluation of three 8‐story reinforced concrete (RC) frame structures was conducted based on the incremental dynamic analysis (IDA) using 11 ground motion records. The main parameter is the longitudinal reinforcement configuration in the frame columns, where the first structure is reinforced with HRB 600 grade steel bars in the columns, the second structure is replaced with equal area ultra‐high‐strength (UHS) steel bars (i.e., with a yield strength of approximately 1425 MPa), and the third structure is replaced with equal strength UHS steel bars. A numerical model of the RC frame structure was developed and then validated using previous experimental results. The exceeding probabilities at various performance limit states were calculated based on two typical engineering demand parameters (EDPs) of maximum interstory drift and residual interstory drift. The results showed that using UHS longitudinal steel bars instead of HRB 600 grade steel bars in frame columns could reduce the energy dissipation capacity of the structure, inevitably leading to an increase in the maximum interstory response of the frame. However, much lower exceedance probability was observed in the UHS‐enhanced frame under the repair available limit state based on the residual interstory drift, indicating that the UHS‐enhanced RC frame had higher seismic resilience. In addition, compared to equal area substitution, equal strength substitution is a more ideal design method that can use fewer UHS steel bars to achieve comparable reparability and a smaller increase in maximum interstory drift.

The University Sector is Converging on Manufacturing in UK

Many UK inhabitants now adopt careers working in both university and manufacturing sectors. In a typical engineering career, a young student may now start at university, spend time in factories, often in research and development, and then return to university in later life to teach evolving innovation principles of industry. It is clear to such people that universities are expanding rapidly whereas manufacturing has declined and reached an equilibrium of output but with lower job numbers due to robotics. Manufacturing in 2022 was approximately 8% of British GDP whereas the university sector was only about 2%. This paper analyses the growing connections and co-locations with numerous universities/manufacturing companies, predicting that convergence in both jobs and GDP contribution will occur around 2050.

Are front crash prevention systems less effective at preventing rear-end crashes where trucks and motorcycles are struck?

Objective Automatic emergency braking (AEB) and forward collision warning (FCW) are effective at preventing rear-end crashes, but they may perform better in some rear-end crash scenarios than others. The goal of this study was to estimate the effects of front crash prevention systems equipped to passenger vehicles in crashes where another passenger vehicle, a medium/heavy truck, or a motorcycle is struck and compare effectiveness by struck vehicle type. Methods More than 160,000 two-vehicle rear-end crashes were identified where a passenger vehicle with or without FCW and AEB was the striking vehicle and another passenger vehicle, medium/heavy truck, or motorcycle was the struck vehicle. Poisson regression was used to estimate the effect of front crash prevention by struck vehicle type on rear-end crash rates per registered vehicle year, accounting for the state and year of the crash and the make, model year, class, and engine type of the striking vehicle. Results Front crash prevention was associated with a 53% reduction in rear-end crash rates when striking another passenger vehicle, which was significantly larger than the reductions of 38% when striking a medium/heavy truck and 41% when striking a motorcycle. Reductions in rear-end injury crash rates when striking a passenger vehicle also were larger than when striking a medium/heavy truck and when striking a motorcycle. Discussion If all passenger vehicles were equipped with FCW and AEB that were as effective in crashes striking a truck or motorcycle as they are in crashes with another passenger vehicle, over 5,500 additional crashes with medium/heavy trucks and 500 with motorcycles could potentially be prevented annually in the United States above what would be expected from current front crash prevention systems. Extending front crash prevention testing in consumer information programs to include motorcycle and truck targets could encourage auto manufacturers to improve performance in these crash scenarios.

Research and development of fully enclosed wire-shell support structure technology for deep soft rock roadway based on TRIZ theory

The TRIZ theory was used to accurately discover the problems to be solved in the design of roadway surrounding rock control technology. This paper tried to solve the complex issue of surrounding rock control in deep roadways from a new perspective. Based on the functional component analysis and causal axis analysis of the problem’s primary reason, simultaneously, the surrounding rock control technology was optimized through technical contradiction analysis, physical contradiction analysis, and substance and field model analysis. As a result, a fully enclosed wire-shell support technology was proposed. Finally, taking the typical soft rock roadway engineering of Pansan Coal Mine in Huainan Mining Area, Anhui Province, China, as the engineering background, the engineering application and effect evaluation were completed. This paper provides a reference for controlling the instability of deep soft rock roadways in coal mines. A new idea of optimizing roadway support engineering based on TRIZ theory was proposed.

Optimization for diffusion-type oxygen supply nearby working face of railway tunnel in plateau

During the construction of railway tunnels in plateau environment regions, ensuring adequate oxygen supply is crucial for both worker health and safety, and tunnelling progress. Existing diffusion-type oxygen supply enrichments for plateau regions lack quantitative conclusions and have not been implemented systematically in actual engineering. To refine the design parameters of the required method, this study utilized computational fluid dynamics (CFD) to examine the optimal design parameters for oxygen supply equipment in a typical engineering project. The optimal scheme consisted of three rows of oxygen diffusion apparatuses with 0.07 m inlet diameter, 0.4 m lateral spacing and 60° tilt that maintain a constant oxygen supply rate. This configuration maximized oxygen concentration enrichment in workers’ breathing zones, with oxygen partial pressure in most target zones remaining below 3000 m altitude, except for the ventilation side where it was 3360 m. This study elucidated the effects of various design parameters on oxygen distribution and proposed the optimal combination for a typical tunnel engineering project. The findings provide a guidance for implementing diffusion-type oxygen enrichment in high-altitude tunnel construction, aiding both worker safety and project efficiency.

Reduction of GHG Emissions: Air Quality Improvement in Urban Areas

This paper focuses on the impact that urban traffic has on the environment. The study characterizes the global effect of GHG emissions, including the ecologic evaluation and the characterization, normalization, and evaluation factor. The work makes a detailed survey of the different modes of driving and their influence on engine performance as one of the principal causes of gas emissions during the combustion process. The article analyzes six types of vehicles equipped with different engine configurations: diesel and gasoline, GLP and GNC, hybrid electric, and plug-in hybrid electric. Simulation of the driving mode under various operational conditions for every type of engine result in energy consumption, thus, in GHG emissions, carbon dioxide and monoxide, nitrogen oxides, and Sulphur dioxide. The study concludes that a reduction in vehicle speed, thus in the engine revolutions, has positive effects on engine combustion and gasses emissions, which is reduced by 27.5%. The study also concludes that the limitation in driving mode, avoiding sharp and sudden acceleration, may reduce up to 45% of GHG emissions. The changes applied in the driving mode improve the air quality in the urban environment, reducing the content of GHG from 39% to 61%.

EFFECT OF CYLINDER HEAD GASKET ADDITION AND VARYING OCTANE NUMBER GASOLINE TO INTERNAL COMBUSTION ENGINE PERFORMANCE

The aim of this research was to investigate the different impacts of compression pressure on power and torque outputs using gasoline RON 92, RON 95, and RON 100. The study involved experiments using a single-cylinder motorcycle engine with a capacity of 125 cm. The selection of this type of engine is based on the popularity of vehicles in Indonesia that use a single-cylinder engine with a capacity of 125 cm. To modify the compression pressure, variations in the number of gaskets were applied to the cylinder head, with quantities of 1 and 3 gaskets. Dynamometer tests were conducted to measure the engine's performance differences. Throughout the testing, the settings for the main jet, pilot jet, and the number of idle screw rotations on the carburetor remain constant. The findings indicate that the engine with the highest compression pressure of 11.8 Kg/cm, using RON 100 gasoline, produces the highest power output at 7.9 kW, with the highest torque at 10 Nm.

Karakteristik Semburan Bahan Bakar Aviation Gasoline dengan Nozzle Pesawat Cessna 172S

Avgas fuel is fuel from aviation engines, namely piston engine type aircraft, where the spray of this fuel is very influential on the life of a piston type aircraft engine. The characteristics of avgas fuel bursts, namely the distance, temperature and shape of the spray, are rarely studied in Indonesia, so with using experimental and varied data collection techniques, we obtained the characteristic results of the avgas type fuel spray and its mixture, where the mixture of 20% ethanol with a distance of 21 cm at a pressure of 3 bar is the lowest point of the fuel mixture spray temperature, namely reaching 15oC, the effect of The mixture of fuel with ethanol means spots on the walls and combustion chamber due to the mixture of alcohol containing water so that traces and water spots can become crust on the combustion chamber.

Study on the Emission Characteristics of Typical City Buses under Actual Road Conditions

Five typical in-use city buses in Tangshan with different emission standards, fuel power types, and emission control technology routes were selected as the research objects. PEMSs (Portable Emissions Measurement Systems) and OBD (On-Board Diagnostic) remote monitoring technologies were used to conduct research on actual road conditions and emission characteristics. The research aimed to analyze the driving characteristics of different power types of bus engines and after-treatment systems, as well as their impact on emissions. The results indicated that the actual road driving is mainly in the urban and suburban areas of the local region. Additionally, the VSP (Vehicle Specific Power) was found to be distributed in the low- and medium-speed range of mode Bin0~Bin24. The emission rates of each pollutant showed an increasing trend with the increase in VSP. THC and NOx emissions of CNG and LNG buses are significantly higher than those of gas–electric hybrid buses. However, the PM emissions are lower. Therefore, it is necessary to strengthen the NOx emission control of CNG and LNG buses. With the improvement in emission standards and the use of hybrid technology, CO2 and NOx emissions of China IV buses can be reduced by 13% and 53.5% compared with China III buses of the same tonnage. The CO2 and NOx emissions of China V buses using natural gas combustion and an electric mixture are 20% and 18.8% lower than those of China V buses of the same tonnage using only natural gas. In the actual operation of the diesel–electric hybrid bus equipped with the SCR (Selective Catalytic Reduction) system, the working time of the engine is about 35.5 ± 5%, and the working time of the SCR system only accounts for 65.5 ± 12%. The low working conditions of the SCR system and the low temperature of SCR system are the reasons for the high NOx concentration at the rear end of the SCR system when the hybrid electric bus is running at low speeds.

Buckling Analysis for Carbon and Glass Fibre Reinforced Hybrid Composite Stiffened Panels

Composite laminated structural panels are widely used in various industries such as aerospace and machinery because of their light weight, large specific stiffness, and strong fatigue resistance. As a typical engineering structure, the composite stiffened plate is designed to enhance the bearing capacity of the laminated plate. In this study, composite stiffened panels reinforced by carbon and/or E-glass fibres are modelled by finite element analysis (FEA) using Ansys. Nonlinear structural analysis is employed to find the critical buckling load. Three different skin layups, i.e., [45°/−45°/90°/0°]S, [90°/0°/90°/0°]S, and [60°/−30°/90°/0°]S, are studied. For each ply angle combination, different ply material combinations are studied. The cost and weight of each combination formed by applying different ply materials to the skin and stiffeners are studied. The results show that hybrid reinforcement in the stiffened panels reduces costs and maintains high buckling loads. Carbon/epoxy composites as the outer layers also reduce costs and maintain acceptable buckling loads without compromising the overall performance. Customized composite designs in terms of cost and weight can be achieved while maintaining critical buckling loads.

Residual impact resistance behavior of PVA fiber reinforced cement mortar containing Nano-SiO2 after exposure to chloride erosion

High-performance cement-based composite materials are commonly employed in marine structural engineering. However, the deterioration of mechanical and durability properties of composite structures caused by chloride erosion in marine environments is a typical engineering problem. This study aims to assess the impact of NS and PVA fibers on the strength, chloride resistance, and impact resistance of NS-PVA fiber mortar. The impact frequency distribution of NS-PVA fiber mortar was analyzed under two conditions: natural environment and after chloride erosion, utilizing both log-normal and two-parameter Weibull distribution models. The findings indicate that the impact energy consumption of NS-PVA fiber mortar increases after 28 days of chloride erosion compared to the natural environment, primarily due to the formation of a compact pore structure attributed to the reaction product Friedel's salt. The optimal composite dosage is determined to be 1.8% for NS and 1 vol% for PVA fiber. At this dosage, the PS18 mortar exhibits a 44.8% and 53.7% increase in initial cracking and failure impact energy, respectively, compared to conventional mortar in the natural environment. Furthermore, these enhancements are further amplified to 53.4% and 64.6% after chloride erosion. Concurrently, a negative correlation is observed between accelerated impact energy consumption and chloride diffusion depth in NS-PVA fiber mortar. A predictive model for impact energy consumption of NS-PVA fiber mortar following chloride erosion, considering various failure probabilities, is established, offering valuable insights for the practical application of NS-PVA fiber mortar in marine engineering.

Numerical simulation of charged characteristics of scramjet combustion products

The combustion of the engine in the air vehicle causes the presence of charged particles in the jet stream, and the electric field displayed varies with engine type and fuel characteristics. In order to show the magnitude and distribution of charged particles in combustion products during scramjet operation, we constructed microphysical model and fluid calculation model based on the physical characteristics of supersonic combustion to simulate the variation of charged particles concentration in the scramjet combustion chamber and the charge density distribution outside the combustion chamber. The obtained results show that the charged particles in combustion products are mainly composed of ions, electrons, ion clusters, and charged soot particles. The electron concentration can be almost negligible at the exit of the combustion chamber. The other charged particles in the combustion products are ejected into the atmosphere with the jet. The charge density distribution of the jet has a certain symmetry in a short time due to the influence of the flow field. It is found that the type of fuel and the conductivity of the surface materials in the combustion chamber affect the electrified properties of the combustion products to some extent. This study has a reference value for further analysis of the detectable electric field generated during scramjet operation.

Low emission stepped piston engine for marine outboard motor application

Separating the scavenging process from the lubrication methodology in conventional two-stroke engines is an effective method of reducing emissions. Segregation of scavenging by use of stepped pistons is one such method providing significant improvements in engine durability, and reduced lubricant consumption, together with reduced production cost. The study discusses the approaches used together with those applied to conventional engines. This paper focusses on a marine outboard motor application and cross-comparisons with a comparable four-stroke outboard motor are drawn within the study. One-dimensional computational fluid dynamics models of the engine types have allowed performance and emissions simulations. Where possible, data from experimental dynamometer testing is compared with the theoretical models. A reasonable level of correlation in terms of performance has been observed. Two-stroke cycle engines are able to demonstrate reduced oxides of nitrogen emissions when compared with conventional four-stroke engines. Models of the stepped piston engine have confirmed the lower NOx emission evident with operation on the two-stroke cycle.

Determination of Material and Fracture Properties of a Case-Hardened Planet Gear and Its Homogenisation Method to Obtain the Damage Mechanism Caused by Fragment Ingestion.

Before a new type of engine is introduced into civil aviation, it must comply with various safety regulations. These regulations include the analysis of secondary damage caused by the re-ingestion of a tooth fragment. The purpose is to prevent crack propagation through the gear rim, which would lead to catastrophic failure. In this context, identification of the initial crack location is crucial to determine the crack propagation path. Therefore, this paper presents a technique to determine and validate a constitutive material model and fracture locus for case-hardened spur gears. As the modelling of the surface-hardened layer is computationally intensive, it is necessary to homogenise the model. This paper comprehensively reviews and discusses the associated effects and errors. To determine the plastic behaviour of the case-hardened external gear (30CrNiMo8) and the nitrided internal gear (35CrAlNi7-10), the widely acknowledged Johnson-Cook material model is implemented using compression and Vickers indenter tests to define the necessary parameters. The fracture locus implementation is also based on the Johnson-Cook method and an axial shift of the fracture locus based on the hardness profile of the spur gears is determined by quasi-static pulsator tests. For validation, a project-specific gearbox test rig is used, enabling consistent ingestion of defined fragments. In addition, to check the likelihood of a tooth flank crack and to validate the results, a simplified ingestion experiment is performed.

High-throughput evaluation of hemolytic activity through precise measurement of colony and hemolytic zone sizes of engineered Bacillus subtilis on blood agar.

Biosurfactants have remarkable characteristics, such as environmental friendliness, high safety, and excellent biodegradability. Surfactin is one of the best-known biosurfactants produced by Bacillus subtilis. Because the biosynthetic pathways of biosurfactants, such as surfactin, are complex, mutagenesis is a useful alternative to typical metabolic engineering approaches for developing high-yield strains. Therefore, there is a need for high-throughput and accurate screening methods for high-yield strains derived from mutant libraries. The blood agar lysis method, which takes advantage of the hemolytic activity of biosurfactants, is one way of determining their concentration. This method includes inoculating microbial cells onto blood-containing agar plates, and biosurfactant production is assessed based on the size of the hemolytic zone formed around each colony. Challenges with the blood agar lysis method include low experimental reproducibility and a lack of established protocols for high-throughput screening. Therefore, in this study, we investigated the effects of the inoculation procedure and media composition on the formation of hemolytic zones. We also developed a workflow to evaluate the number of colonies using robotics. The results revealed that by arranging colonies at appropriate intervals and measuring the areas of colonies and hemolytic rings using image analysis software, it was possible to accurately compare the hemolytic activity among several colonies. Although the use of the blood agar lysis method for screening is limited to surfactants exhibiting hemolytic activity, it is believed that by considering the insights gained from this study, it can contribute to the accurate screening of strains with high productivity.

A COMMERCIAL TURBOFAN ENGINE MODELING AND EXERGY ANALYSIS

Turbofan engines are one of the most common types of engines used in modern commercial and military aircraft due to their efficiency and performance characteristics. In this study, a thermodynamic model is generated using GasTurb 14 software for a commercial two-spool, unmixed flow, and booster turbofan engine (CFM56-5A3) used in Boeing A320-212. Besides, an exergy analysis of the modeled turbofan engine is performed. Exergy performance criteria such as exergy efficiency, exergy development potential, exergy destruction ratio, productivity lack ratio, and fuel depletion ratio are evaluated for the engine components. In addition, how bypass ratio (BPR) affects net thrust and specific fuel consumption (SFC) for the modeled turbofan engine is investigated. As a result, the net thrust and SFC values of the modeled engine and the actual engine are overlapped with 14.0% and 7.2% deviation, respectively. The maximum exergy efficiency occurs at the high-pressure turbine as 0.992. When the bypass ratio is minimum, the maximum net thrust and SFC occur as 62.24 kN and 24.08 g kN-1 s-1, respectively. High pressure turbine has the minimum exergy development potential of 1528.5 kW.

Fast Pyrolysis oil from plastics waste as a Fuel for Gas Turbine Power Plants

Plastic production and usage increase every year due to its low cost, practicality, and flexibility. Despite the advantages of plastics as a raw material, it represents a serious environmental problem when it becomes waste. Most of the plastic is produced from petrol. Its chemical composition provides the opportunity to be transformed into a fuel via a pyrolysis process, with or without a catalyst. The pyrolysis process yields solid, liquid and gas fractions. The liquid fraction has properties similar to those of conventional fuels and can be used in internal combustion engines. However, although fast pyrolysis is cheaper, it produces lower quality products (longer carbon chains) not suitable for these types of engines. In the present paper, main properties of oils from fast pyrolysis are analysed and compared to those of Heavy Fuel Oils (HFO) to demonstrate that they represent a feasible alternative to decrease the impact of plastics in the environment and to obtain an alternative fuel to feed a power plant.

A REVIEW OF EGR APPLICATION FOR AUTOMOTIVE INDUSTRY

Exhaust gas recirculation (EGR) has been widely adopted as an effective strategy to reduce harmful emissions and improve fuel efficiency in internal combustion engines. This review paper aims to provide a comprehensive analysis of the utilization of EGR in various types of internal combustion engines. The review covers the principles of EGR operation, its effects on engine performance, emission reduction capabilities, challenges, and prospects. By evaluating the existing literature and research findings, this paper seeks to offer insights into the potential of EGR as a crucial technology for sustainable and environmentally friendly auto-motive propulsion systems.

ПРОГНОЗИРОВАНИЕ УСЛОВИЙ ЭФФЕКТИВНОЙ ЭКСПЛУАТАЦИИ ГИБРИДНЫХ АВТОМОБИЛЕЙ

The article provides a set of assessment methods that allow us to formulate criteria for the efficiency of hybrid cars. To predict the fuel efficiency of hybrid vehicles under given operating conditions, a theoretical calculation method is used, in which the hybrid engine is considered as a system in which energy from the gasoline engine is transmitted to the drive wheels through several energy chains. Taking into account the design features and the type of hybrid engine, energy trans-fer losses and fuel consumption are determined. As an example, the results of assessing the fuel consumption and CO2 emissions of cars with three types of hybrid engines when driving on the WLTC test cycle are presented. Based on the developed methods for assessing the operating efficiency and the method for predicting the fuel consumption of hybrid vehicles, the boundaries of their economically efficient operation were determined.