bluuebunny/crossref_metadata_2025_split huggingface dataset:
Turbo-Rotor Balancing and Optimization Using Groove-Geometry Simulation Approach
Authors: Pagar Nitin D. 
Published: February 2024

Abstract
Turbochargers use the energy from the exhaust gases to power the compressor, improving the engine’s efficiency and reducing emissions. Working fluid runs past the turbine spin blades while the wheel rotates at high speeds with centrifugal forces acting on it. The primary focus of the work is on the turbine wheels of turbochargers. The wheels are prone to faults because they are manufactured using a casting process. Many failures and vibrations in the turbocharger are caused by mass imbalance. In order to mass balance the turbine wheel, back face material must be removed. The wheel’s strength and load-carrying capacity must be preserved when material is removed. The turbine wheels are made of inconel. Two-plane balance is used to make several adjustments to the back face. The balancing cut could put the wheel under more stress depending on a number of factors. Trial and error is still used frequently, but it is a time-consuming procedure that involves many iterations. The goal of this research is to determine the key elements that cause stress to rise during balancing cut, as well as how their behaviour can change, and to identify locations on the back face of the turbine wheel where stress levels are acceptable and material can be removed. In this work, the ANSYS simulation is used to validate analytical calculations for the cut and back face of the turbine wheel. Optimisation is used to determine the best location for the groove on the turbine wheel back face. Optimisation methods are applied within the ANSYS software to comprehend the nature of the response and DOEs and to obtain the best feasible solutions for the problem. High depth of cut and tip radius contribute to higher material removal, enhancing the balancing capacity by approximately 22.44%. The provided parametric correlation table allows for simple to understand the connection between all of the parameters considered in the balancing groove optimisation.
A New Perspective on Measuring Compressor Characteristics
Authors: Jing Zhenhao , Neumeier Yedidia , Prasad J. V. R. , James Darrell K. 
Published: February 2024

Abstract
This paper describes a method that enables the identification of compressor characteristics in parts that cannot be measured in traditional core test procedures. This capability is expected to help in identifying needed design changes following core tests. The method uses measurements of the mass flow rate in the compressor inlet along with the plenum pressure to infer the equilibrium characteristic of the compressor even as the compressor experiences non-equilibrium conditions, particularly so during transients to stall. A throttle control with feedback from the measured mass flow rate is used to drive the compressor into growing oscillations around the stability boundary, and a dynamic correction method is used to collapse the growing oscillations into a single line on the compressor map, which estimates the equilibrium characteristic. An unsteady mean line compressor flow model that is capable of capturing acoustic waves propagating through the rotor and stator blade cascades is used as a test compressor to evaluate the method. Results obtained using simulated compressor flow transient data demonstrate that the proposed identification method estimates both the smooth and the non-smooth characteristics with satisfactory accuracy.
Safety Evaluation of Isolated Island Operation on 1000MW Steam Turbine in NPP
Authors: Hu Xiao-dan , Chen Xu , Wu Fan , Shi Rui , Jiang Wei , Chen Tao , Yue Ya-nan , Xie Dan-mei 
Published: February 2024

Abstract
Steam turbine in NPP (nuclear power plant) will suffer drastic changes in load, mass flow and temperature during isolated island operation, which increases the chance of unit failure. In fact, cases of unsuccessful isolated island operation tests have occurred. Therefore, it is necessary to analyze the safety of steam turbine in NPP under isolated island operation condition. For safety assessment, the key factors influencing the safety of steam turbine in NPP under isolated island operation condition were simulated. The results shows that: under 100%PN load rejection, the highest dynamic speed overshoot of steam turbine is 4.99%, the maximum centrifugal stress of rotor is 262.61 MPa, the exhaust steam temperature of HP cylinder is increased by 47°C, and the critical mass flow condition for flutter of a typical type LSB (last-stage blade) is predicted. These results are within the range specified in the operating regulations for NPPs’ isolated island operation, indicating that the safety of 1000MW steam turbine is satisfactory.
Effects of Thermal Mechanical Fatigue on a 2.25Cr-1Mo Steam Header
Authors: Zimnoch Michael , Haddadi Elnaz , Perrin Ian , Tabarraei Alireza 
Published: February 2024

Abstract
Thermal-mechanical fatigue (TMF) is a common problem that restricts the life expectancy of high-temperature components. TMF is often caused by inelastic strains arising from cyclic loading at high temperatures and pressures. Finite Element Analysis (FEA) is frequently employed to predict the development of inelastic strains within components. This study evaluates the predicted inelastic strain accumulation of a 2.25Cr-1Mo power plant header represented using the Chaboche non-linear kinematic hardening (NLKH) model. The Chaboche NLKH model coefficients were established for temperatures up to 600°C using data from virgin machined samples. The representative header unit is evaluated using Abaqus finite element software under operating conditions that simulate a typical pressure and temperature profile. The findings indicate that low-cycle fatigue is not likely to occur in response to a common transient. However, the results conflict with industrial experience, indicating that other factors may contribute to component failure.
Approximate Solutions to Governing Heat Conduction Equations With Uniform Heat Generation in Semi-Infinite Plates
Authors: Haidar Salim M. , Mohammadzadeh AliReza 
Published: February 2024

Abstract
In a previous paper, we introduced a new methodology for using integral methods to solve governing linear partial differential equations in the undergraduate heat transfer course [1]. In it, we considered heat conduction problems solely over finite domains. In this paper, we extend our approach to the case of linear transient heat conduction problems with a uniform internal energy generation over semi-infinite domains. In particular, we use the superposition principle and the heat-balance integral to determine the transient response of a semi-infinite solid with a volumetric heat generation that may be constant or time-dependent over the domain subject to prescribed uniform initial and boundary-surface temperatures. In effect, we construct approximate analytic solutions to the problem in question with accuracy acceptable by most engineering standards.
Classifying Human Thermal Images Using Deep Learning Technique in Artificial Intelligence
Authors: Gurupatham Sathish Kumar , Purimetla Ujjwal , Kumar Kaliga 
Published: February 2024

Abstract
Deep learning is a sub-field of machine learning that uses multi-layered artificial neural networks which has become very popular in recent times to perform tasks such as image and speech recognition, natural language processing, decision making and so on. It has several applications in mechanical engineering and especially in the manufacturing field, too. Applying image recognition concepts to inspect the defects in products (Quality control), scheduling maintenance of equipment based on the sensor data (Predictive maintenance), applying deep learning concepts to train the movements of robotic arms timely for welding & assembly in production workshops (Robotics), and using deep learning to optimize schedules & logistics (Supply chain optimization) could be some of the applications worth to mention. This paper focuses on classifying the thermal images of objects, especially thermal ones. This work discusses the application of three pre-trained convolutional neural network (CNN) models namely VGG16, MobileNetV2, and InceptionResNetV2 for classification of thermal images of two classes (two human faces) belonging to the same family with more resemblance in their appearance so as to increase the complexity in classifying. The procedure had two phases: The first phase has the training and testing with thermal images whereas the second phase has increased number of images with image augmentation technique to repeat the same process to improve the performance the models. The data-set used in the models consists of thermal images of two slightly different faces of the same family that were taken using a thermal imaging camera (Flir-E6). In the first phase, the data-set was divided into training, validation, and testing sets with each set consisting of 50 images, 30 images, and 20 images respectively. In the second phase, after the image augmentation, the data-set was divided into 350 training images, 120 validation images, and 50 testing images. The performance of the models was observed for 10,20, and 30 epochs. The learning rate was assigned to 0.0001 with Adam optimizer and a batch size of 10. The results showed that the model VGG16, in the initial phase, yields training and validation accuracy of 100% and 90% respectively. In the second phase, it yields training and validation accuracy of 100% and 90.83% respectively. The model could classify 19 out of 20 images correctly before image augmentation and 49 out of 50 images correctly after the image augmentation was applied. It shows an increase of 3% from 95% to 98% before and after image augmentation was applied. For the given input images, the other models, though they are well-established ones, did not perform better than VGG16.The confusion matrix was plotted for all the models for important results.
System Identification and Controller Design of Propeller Driven Pendulum (Bi-Copter)
Authors: Enikov Eniko T. , Zhang Qiuchen , Creery Lucas 
Published: February 2024

Abstract
Undergraduate control courses are usually significantly improved when in-class instruction is backed up with experiments aimed at providing the students an opportunity of experiential learning. The rapid development of computer multimedia technology has resulted in a tendency toward a hands-on laboratory that incorporates simulation tools and computer-controlled equipment. However, most of the open-source hardware prototyping platforms require programming environments, installation of additional software, and additional plug-in modules that hinders the large-scale deployment of such systems. Therefore, the goal of this project was to create a simple mechatronic system (the “Bi-Copter”) that uses broadly available components along with MATLAB computing environment, in order to demonstrate an experiment that can be adopted at any educational institution with access to MATLAB.
The main part of the setup consists of two small dc electric motors attached to each side of the beam with the propellers. By controlling the motors, the angular position of the beam can be changed to a desired one. A circuit board utilizing a breadboard and off-the-shelf plug-in microcontroller connected to a serial-to-USB cable is used to control the motors. Unlike traditional controls experiments which start with a modelling task based on first principles, in this experiment a black-box model auto-regressive model with exogenous input (ARX) is used. Model parameters are obtained from open-loop experiment. The extracted model is then used to design a feedback controller and evaluate its performance.
The bicopter system was tested with over 50 students coming from the courses “Design of Mechatronic Systems” and “System Identification” of the academic years 2020–2022. The activity lasts eight weeks including 6 home assignments. During this period students work in groups of two and learn how to program the micro-controllers, carry out the system identificaiton experiments, design and implement feedback controllers. The laboratory allows students to build models of various complexity. To provide laboratory experience to students with various levels of expertise, this lab makes use of the Control Systems and System Identification toolboxes of MATLAB. Both graduate and undergraduate students utilized the apparatus and completed the design tasks. The bi-copter project was tested in a Design of Mechatronic Systems course at the University of Arizona. Since mechanical engineering students typically lack formal training in system identification methods, the course includes a brief introduction of this topic. One of the main outcomes from their experiments is appreciation of the importance of selecting proper input test sequence and the sensitivity of the resulting model to the bandwidth and amplitude of the input test sequence.
A Thorough Characterization Study of the Critical Al-Fin Bond Between the Ni-Resist Insert and Aluminum Base Material in a Heavy-Duty Engine Piston
Authors: Kumpaty Subha , Coen Nolan , Coen Liam 
Published: February 2024

Abstract
The Ni-Resist insert used in the INNIO Waukesha’s VHP piston is bonded to the piston during casting by the Al-Fin bond process. This bond is critical to the manufacture and performance of pistons used in heavy duty engines with aluminum pistons.
Iron has a strong solubility in the molten aluminum but does not at room temperature. The typical preparation of the Ni-Resist inserts to be installed in a piston mold prior to filling the mold is to immerse the insert in a bath of molten aluminum for a predetermined amount of time. The dissolution of alloys from the Ni-Resist insert into the bath make control of the bath composition a critical parameter. Negligent bath maintenance can result in the potential of forming undesirable intermetallics in the bond region. This means the Al-Fin bond can be brittle and sensitive to variation in tooling pressure during machining.
Any flaws introduced the bond during piston casting or machining can propagate during engine operation and result in a power cylinder failure, leading to collateral damage of other engine components and a lengthy repair time. The disciplined use of ultrasonic inspection in the rough machined as well as the finished piston will catch defects and prevent faulty pistons from being released to a customer. However, if problems are identified at these late stages, they can result in product delivery delays and even the shutting down of the engine factory assembly line.
This paper will highlight the modern material characterization methods used to identify a satisfactory bond. The understanding of the challenging nature of the bond between the Ni-Resist insert and the piston material has been gained through these methods. This knowledge has helped resolve problems by both quickly getting to their root cause and taking corrective action.
Failure Analysis of Transmission Components of Rail Transit Vehicles
Authors: Zhang Long , Yin Yanbo , Shan Zhenghui , Wang Zida , Zhang Yanping , Wu Lvxian , Lu Hang , Zhang Hong 
Published: February 2024

Abstract
This paper presents a recent gearbox failure in a rail transit vehicle. The damaged components, pinion bearing and large gear, were analyzed from macroscopic, microscopic, and performance perspectives. Through a comprehensive analysis of the test results, the two main factors causing the failure were identified: fatigue damage of the pinion bearing due to abnormal external load and the presence of brittle non-metallic inclusions, which initiated fatigue cracks leading to gear drop blocks. To improve gearbox reliability, suggestions were made to optimize operating conditions and improve the metallurgical purity of metal materials.
Computational Fluid Dynamics and Heat Transfer for Maze Solving and Piping Applications
Authors: Zhang Kevin , Li Puxuan 
Published: February 2024

Abstract
Solving mazes is an important scientific and engineering topic with various applications in the areas of image processing, intelligent traffic control, pipe network flow assurance, etc. There are many existing algorithms for solving mazes, which are mostly in the field of computer science. In this paper, two engineering approaches using computational fluid dynamics (CFD) and computational heat transfer (CHT) are presented. The hypothesis is, if a maze is injected with water or heat from the entrance, the water and heat should find their way to the exit naturally. If we can visually track the movement of the water and heat, the maze pathways can be shown and the maze can be solved. Computer simulations using both CFD and CHT methods were conducted to test the hypothesis and to analyze the performance of the two methods. The results show that both flow and heat from the inlet of the maze successfully find the outlet and the movement of water and heat can be clearly shown by the visual tools from the simulation soft, therefore the maze is successfully solved by both methods. The performance and simulation time between CFD and CHT approaches were compared, and it can be concluded that using CHT is more efficient than CFD since the heat transfer equations are less expensive to solve. In addition, a maze-solving-related application was presented in the paper to analyze the flow distributions of pipes in a network arrangement.
Numerical and Experimental Investigation for Recoil Dynamics of Machine Gun Used in Small Size – Unmanned Aerial Vehicle
Authors: Gümüşel Hasan Tolga , Acar Bülent , Yetgin Ali 
Published: February 2024

Abstract
In Unmanned Aerial Vehicle (UAV) with machine gun system, recoil dynamic is very critical phenomenon that occurs when a fast-moving object collides with a stationary or moving object causing a transfer of momentum. In this study, the main objective is to quantify differences in the recoil dynamic behavior of the machine gun affected by UAV structure including its weight, recoil reduction spring and damping pad properties. To do this, dynamic modeling of the whole system is established. Through the study, the effect of UAV structural properties is investigated to meet design requirements basically defined as higher shooting performance and higher stability of platform. The significance of all parameters is evaluated using with Pareto chart. Also, to verify these simulations, a recoil force measurement system on the ground is developed. In this equipment, a compression-type load cell is used together with the data acquisition system to measure the recoil forces. Since the recoil event is expected to be quite short, a high data sample rate is needed. The sampling frequency of the data acquisition system is selected as 20 kHz to be able to observe the recoil dynamics. Several firing tests have been conducted on the ground and impact force versus time data has been presented for each test. In addition, a finite element model of the UAV structure with a machine gun is generated to obtain the dynamic response of the structure in the air. It is found that the numerical simulation with ground test condition results show a good agreement with the data gathered from the experiments. In future, with the help of the verified model, it is aimed that firing performance during a mission in the air can be estimated according to main design goal which is to have higher platform stability while firing.
Resonator-Based Piezoelectric Metastructures: Efficient Bandgap Estimation and Parametric Analysis
Authors: Astudillo Diego , Ruiz Rafael O. 
Published: February 2024

Abstract
The integration of piezoelectric elements as resonators inside a periodic structure for vibration suppression and energy harvesting (at low frequencies) was experimentally demonstrated recently. In particular, employing a square array of free-standing piezoelectric cantilevers attached to a primary structural frame. The configuration could be understood as a periodic cell that contains a series of cantilevered Piezoelectric Energy Harvesters (PEHs). This work aims to implement a finite element model of a piezoelectric periodic structure capable of presenting vibration suppression and energy harvesting and use it to study the influence of the model parameters on the generated bandgaps. Different frame geometries with cantilever piezoelectric beams are studied. Through these geometrical arrangements, it is found that the domain of the wave vectors that must be evaluated in the Floquet-Bloch periodic condition to identify bandgaps can be restricted to only 5 wave vectors contained in the first Brillouin zone. This issue can be exploited to generate a large decrease in computational resources when optimizing this configuration. The work also presents a parametric analysis to identify the model parameters’ influence on the bandgap’s location and size. The parametric analysis also reveals the need to incorporate uncertainty quantification in the design and optimization process, simultaneously offering comprehensive information about the continuity of the bandgap in relation to the model parameters.
A Numerical Model of Microstructure Formation Considering Nanoparticle Distribution During Selective Laser Melting Process
Authors: Alam Taosif , Amin M. Ruhul 
Published: February 2024

Abstract
Selective laser melting (SLM) is a popular metal additive manufacturing technique that allows the development of new metal matrix nanocomposites by fusing metallic powders with nanoparticles. In the current study, a novel numerical model was proposed to simulate microstructure formation considering local nanoparticle distribution during the SLM process. The proposed model formulates a three-dimensional computational fluid dynamics (CFD) model with Lagrangian particle tracking to simulate a single-track, single-layer SLM process of aluminum alloy reinforced with TiB2 nanoparticles in ANSYS FLUENT. A very low weight fraction (0.0009%) of nanoparticles was considered due to the computational limitations of the software package. The temperature distribution and particle distribution results calculated by the 3D CFD model were one-way coupled with a 2D Cellular Automata (CA) model to predict the solidified microstructure using MATLAB. The coupled CFD-CA model and Lagrangian particle tracking were separately validated in this study. The result showed that the nanoparticles move along the recirculation zones generated by the Marangoni and natural convection in the molten pool fluid. The microstructure predicted by this model showed that the introduction of the nanoparticles increased bulk nucleation during solidification. It disrupted columnar grain growth by promoting small, randomly oriented equiaxed grains. The average grain diameter decreased by 40% when nanoparticles were present compared to microstructures without nanoparticles.
Numerical Simulation of Rotary Friction Welding of a Titanium Alloy
Authors: Chen Wenxue , Xu Yaxin , Vairis Achilles , Bikmeyev Alexander , Li Wenya 
Published: February 2024

Abstract
A two-dimensional model of continuous drive friction welding (CDFW) of Ti-6Al-4V tubes was developed using the ABAQUS modeling software. The effect of interface temperature on frictional behavior was investigated during welding, where non-linear temperature dependent material properties were considered. The effects of rotational speed and friction pressure on the temperature field, flash morphology, interface temperature and axial shortening of the joints were studied. Results show that the interface temperature rises rapidly early in the process, to reach a plateau at 1270 °C. For a constant welding time, the temperature gradients and axial shortening of the joints increase with increasing the rotating speed and friction pressure; The steady-state temperature of the interface increases with the increase of rotational speed and decreases with the increase of axial pressure; Following welding, the expelled material in the form of a flash curls on the outer wall of the pipe, while being symmetrical about the welding interface. Modeling results were validated with CDFW experiments.