bluuebunny/crossref_metadata_2025 huggingface dataset:
Parameters Optimization of Submerged Friction Stir Welding for Dissimilar Alloys AA2024 and AA7075
Authors: Velukkudi Santhanam Senthil Kumar , Gopal Karthikeyan , Kuppusamy Raman
Published: January 2025

Friction stir welding (FSW) is a revolutionary material joining technique with significant advantages over traditional methods, such as eliminating hot cracking, porosity, and intermetallic layers. FSW is eco-friendly, producing no gas emissions, using minimal energy, and requiring no consumables. Submerged Friction Stir Welding (SFSW) further enhances these benefits by using an underwater environment, which improves cooling rates and material properties. This study focused on AA2024, used in aircraft wings and fuselages, and AA7075, used in space shuttle components. Various parameters were tested, including rotation speeds (800, 1200, and 1600 rpm), traversal speeds (45, 60, and 75 mm/min), and a constant water level of 20 mm. A square pin made of H13 steel with 48 HRC hardness was utilized to improve material flow. The maximum tensile strength recorded was 155 MPa at 1200 rpm, 60 mm/min traversal speed, and a 20 mm water head. The highest hardness value observed was 149 Hv at 1600 rpm and 75 mm/min traversal speed. Grey Relational Analysis (GRA) was performed to identify the optimal parameters for SFSW. The analysis determined that the ideal process parameters included a rotational speed of 1200 rpm and a traverse speed of 60 mm/min, yielding a joint efficiency of 57%.
In-Situ Strain Rate Analysis and Simulation in High-Speed Machining
Authors: Liu Xiaochen , Zhang Dong , Nie Guangchao , Yang Zhengyan , Zhang Xiaoming
Published: January 2025

High-speed machining involves nonlinear dynamic deformation characterized by high strain and strain rate in the shear zone. Research on deformation behavior within the primary shear zone in high-speed machining predominantly focused on chip examinations after cutting, lacking sufficient in situ experimental verification. This research presents a specially designed high-speed machining in-situ imaging platform, which can achieve high cutting speeds up to 25 m/s, and capture highly correlated images at short inter-frame time of up to 0.15 microseconds. Utilizing the digital image correlation (DIC) method, the study examines strain rate and shear angle within the shear zone during orthogonal cutting of AISI1045 steel at varying cutting speeds and rake angles. In addition, finite element simulations employing the coupled Euler-Lagrangian method are conducted under the same cutting conditions. Results reveal shear zone strain rates exceeding 105/s at a cutting speed of 17 m/s and uncut chip thickness of 0.2 mm. The trends in shear zone strain rate and angle with rake angle and cutting speed variations, as well as disparities between experimental and simulation results are also discussed in this study. The simulation’s observed stagnation zone offers insights into shear angle differences between the simulation and the DIC analysis results at negative rake angles.
Validation of Targets for Use in Evaluating Haul Truck Collision Warning and Avoidance System Detection Performance
Authors: Girman Matthew , Jobes Christopher , Zhang Yongjun
Published: January 2025

Surface mining haul trucks have been involved in 54 fatal accidents in the United States between 2005 and 2021 [1]. Collision warning and avoidance systems (CXS) could potentially alert drivers of hazards and prevent accidents from occurring. To ensure the efficacy of CXS, the object detection performance must be tested with a reliable detection target to represent an object that could be encountered at a mine, such as a pedestrian, berm, heavy machinery, or light vehicle. For reasons such as safety, cost, or convenience, it may be more desirable to use an alternative detection target in testing. The efficacy of alternative detection targets, when used to characterize the performance of CXS, should be evaluated to ensure that they do not cause any significant performance differences compared to using actual targets typically found in a mine. To address this question, researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted a target validation study to compare the detection accuracy of a radar-based CXS with four different detection targets. This research offers potential substitute targets that could be used in CXS testing. CXS manufacturers and mine operators should be mindful of the targets they employ as alternatives when evaluating CXS detection performance.
Optimizing Paper Helicopter Designs to Maximize Flight Time Using the Three-Step Process in Design of Experiments
Authors: Weaver Jonathan M. , Krolczyk Alena A. , Van Hook Noah M.
Published: January 2025

A paper helicopter experiment was designed to be integrated into a graduate-level Design of Experiments (DOE) course to provide hands-on learning. The experiment, aimed at maximizing paper helicopter flight time, involved three steps. Step 1 used a definitive screening design to identify key factors affecting flight time, focusing on geometric parameters and added weight at the helicopter’s base. Ratios of lengths were used to minimize factor interactions. In Step 2, results from Step 1 guided experiments along a path in the factor space to maximize ascent rate in flight time. These experiments started from the optimal point identified in Step 1 and continued until no further improvement was observed. The best point from Step 2 served as the center point for Step 3, which used a central composite design (CCD) with factor ranges chosen to ensure that the optimal values lie within the design space. Data analysis from the CCD produced a 2nd order model, which was then mathematically optimized. Confirmation experiments showed that helicopters built to the predicted optimal factor levels achieved very nearly the predicted flight time of about 3.63 seconds for 14 feet of steady-state flight. Results for all three steps pass a sanity check. The activity will be piloted in the course during the Fall 2024 semester.
Promotion and Dissemination of Scientific Research in Graduate Education
Authors: Najmi Lida , Hu Zhong
Published: January 2025

Conducting and disseminating scientific research is an ethical and increasingly regulatory obligation for scientists and graduate students. It is widely believed that top-ranking journals attract a wider audience than specialized publications, and targeting high-impact journals has long been considered key for gaining visibility. However, given the intense competition gaining access to these top journals is challenging and does not necessarily guarantee broader exposure. The advent of the internet and digital media has revolutionized the dissemination of scientific research, providing greater opportunities for visibility. This article discusses the responsibility of higher education educators to prepare graduate students, especially those with less experience or knowledge, for effective research and dissemination. The Department of Mechanical Engineering at South Dakota State University has developed a new graduate course titled “Frontiers of Materials” to address these needs. In accordance with the program’s designated graduate learning outcomes, the course covers a broad range of introductory topics in advanced materials, including structures, properties, fabrication, computer modeling methods, and experimental characterization methods. By integrating scientific research and writing practice into the curriculum, the course aims to enhance students’ understanding of advanced materials and improve their ability to conduct scientific research and write high-quality scientific papers., including key rules, steps, measures, and activities for conducting scientific research to increase discoverability, readership, and impact. This case study exemplifies good practice in promoting and disseminating scientific research and writing in graduate engineering education, demonstrating a successful approach to improving current educational practices.
Availability Based Design (ABD): A New Methodology for Avoiding Machine Design Failure
Authors: Dupont Pierre
Published: January 2025

Conventional design process (CDP) considers delivery issues at latest stages of design process. Designers are focused on technical and quality aspects. In most instances, delivery issues are addressed separately by other teams of supply chain (“over the wall” approach, [3]). Machine design projects are nowadays highly time-sensitive (time to market is shortened), severely bound by deadlines, volatile and sometimes uncertain. Due to iterative nature of design process, amount of potential design combinations is large, and their inherent technical checks (TC) are time consuming. Designers must make relevant choices to be timely successful. To avoid unnecessary design effort, availability of components must be considered at early stage of design process: that is the way availability-based design methodology (ABD) acts. ABD thoroughly revises conventional design process (CDP) and reorders its main steps to preclude a new type of design failure: achieving a design that will not be compatible with delivery specifications. Current article aims to (1) elucidate ABD methodology, (2) compare it with conventional design process (CDP), and (3) establish a timeline model demonstrating the enhancements realized through ABD scheme. The present article examines the current overly complex design environment and validates the rationale for the proposed improved design methodology.
A Centrifugal Compressor - System Transient Digital Twin
Authors: Serena Alberto , Ilseth Pronk Ola , Bakken Lars Eirik
Published: January 2025

Off-design operation in turbomachinery entails several critical issues. The intrinsic flow unsteadiness is amplified by transients and interactions with the surrounding system, with detrimental effects on stability and components reliability.

In this paper, a description of the transient behaviour is achieved as a combination of theory, laboratory experiments, operational experience, data analysis and process simulation. This benefits from a responsive test rig, allowing the modification of layout and key parameters, as an inadequate test procedure might strongly affect the overall behaviour and transient evolution. Results are presented over a wide test matrix, including surge volume size and rotational speeds. These data are vital for a full compressor-system digital twin.

Among the main outcomes, are the establishment of the actual surge margin and a suitable recovery strategy, achieved by the necessary early detection.

The main focus area is the validation of the system model prediction of the trip trajectory, caused by severe voltage grid disturbance, or variations in inlet composition, or downstream pressure build-up. Tuning the model on experimental performance data is needed for reliable and faithful reproduction of real behaviour and interaction, as it would otherwise account only for overall degradation, not taking into account the intrinsic unsteadiness, flow channels unevenness, turbulence responsible for instabilities onset and evolution.

Results indicate the importance of ensuring reliable data acquisition and analysis, with adequate instrumentation range, accuracy, synchronization, responsiveness and positioning, so as to tune the model and provide closure to the predictions.
Design, Analysis and Test of Truck Frame and Bolster for Railway Vehicle
Authors: Hong Haifeng , Xue Shihai , Zhang Wenkang , Zhang Long , Yin Yanbo , Wu Lvxian , Lu Peng , Chen Qiubo
Published: January 2025

In North American railway industry, the truck design generally takes into consideration of several factors, e.g. the axle load, maximum operating and design speed, new and worn wheel diameter, arrangement of journal box, service life, safety, stability, ride quality and maintainability and etc. and the design typically follows applicable FRA, APTA and AAR standards. To ensure the truck frame and bolster have enough strength for loads during testing and revenue services, FEA is used to calculate stresses in the frame and bolster for static and fatigue load cases. Various static loading cases as specified in EN standard were simulated to make sure that these stresses shall not exceed half of the yield stress. The fatigue stress calculation is based on cyclic loads, taking into consideration of forces experienced during vehicle accelerating and braking. Von-Mises stresses are calculated for static load cases. The modified Goodman line is solved for the endurance limit using the yield strength of the material. Finally, static and fatigue testing are performed to compare and validate the simulated results.
A Comparative Digital Physical Ergonomics Analysis Between Manual and Semi-Automated Manufacturing Operations: Human-Centered Guidelines for Workstations Optimization
Authors: Brunzini Agnese , Micucci Filippo Maria , Ciccarelli Marianna , Papetti Alessandra , Germani Michele
Published: January 2025

Industry 5.0 marks a further shift towards human-centered industrial processes, driven by increased automation and innovative technologies. Understanding operator risks in this context is crucial for ensuring worker safety and well-being. This paper introduces an innovative framework for the comprehensive and objective analysis of industrial operators’ physical ergonomics. Conducted within a company that produces refrigeration systems, the study focuses on tasks such as hooks insertion and brazing on heat exchangers.

Combining subjective and objective methods, the analysis includes self-assessment questionnaires, the User Experience Questionnaire (UEQ), the Body Part Discomfort Scale (BPDS), and the Borg CR10 questionnaire. Utilizing the Xsens MVN Awinda motion capture system, the study captures operators’ movements and employs algorithmic analysis to assess ergonomics objectively. RULA analysis primarily concentrates on joint angles and hazardous postures, while the inclusion of Strain Index and NIOSH analyses provides further insight into the risks associated with hand and wrist movements and lifting tasks.

Preliminary findings indicate significant time reduction in high-risk postures with semi-automated processes. Moreover, there’s a noticeable decrease in medium-risk activity time for brazing. The study recommends guidelines for workstation redesign based on physical ergonomic analyses and human-centered design principles. Future work will involve cognitive ergonomics analysis and will include human factors in product and process redesign efforts.
Optimizing Chassis Design for Autonomous Vehicles in Challenging Environments Based on Finite Element Analysis and Genetic Algorithm
Authors: Sourani Yancheshmeh Sara , Ebrahimpour Arya , Deemyad Taher
Published: January 2025

The demand for autonomous vehicles capable of navigating challenging terrains has necessitated the development of innovative design solutions. It emphasizes the chassis’ role as a foundational framework for supporting the vehicle’s body and components, requiring both the strength to endure various stresses like shock and vibration, as well as sufficient bending stiffness for improved handling. This study introduces a chassis for a groundbreaking autonomous vehicle tailored for rough terrain navigation with a unique feature: an optimized chassis designed and equipped with quadcopter wireless charging systems. This study aimed to achieve an optimal balance between structural integrity and weight efficiency for the chassis. This is achieved through a combination of static and dynamic analyses, incorporating both existing theoretical knowledge and advanced analytical methods. Utilizing Finite Element Methods and MATLAB, the authors derived the optimum mass and length parameters for the chassis, ensuring robustness while minimizing material usage. The results indicate that this chassis not only offers a sustainable solution for rough terrain navigation but also provides a reliable charging platform for quadcopters. This integration of advanced design techniques with practical application paves the way for a new era of autonomous vehicles tailored for specialized environments.
Solar Trackers Using Six-Bar Linkages
Authors: Guntupalli Sumanth , Zhou Hong
Published: January 2025

A solar panel faces the sun or has the solar ray normal to its face to enhance power reaping. A fixed solar panel can only meet this condition at one moment. A solar panel’s orientation has to be adjusted in order to meet this condition during the daytime. A solar tracker is integrated with a single or a set of solar panels to make them better meet the condition and improve their solar power reaping. In addition to extra cost and maintenance, a solar tracker consumes power when it adjusts the orientation of its related solar panels. Only when the net power gaining from a set of solar panels that have their integrated solar tracker is considerably above that from the same set of solar panels without their solar tracker, it is then worthwhile for the solar tracker to be integrated with the solar panels. A solar tracker needs to have at least two degrees of freedom to make its solar panels face the sun during the daytime since there are two independent relative motions between earth and sun: rotation and revolution. If earth is considered as being stationary for developing solar trackers, sun then has its daily east-west rotation and yearly north-south tilting. It is evident that the sun’s east-west motion on any day is well above its north-south one. If the small north-south daily tilting is ignored for solar tracking, single-axis solar tracks have their advantages over two-axis or multi-axis counterparts because of relatively simple structure and low power consumption. A compromise among the current four-bar single-axis solar trackers is between solar tracking oscillation and self-locking function. Planar 4R solar trackers are capable of producing large solar tracking oscillation, but they lack self-locking function. On the other hand, planar 3R1P solar trackers have self-locking function, but they are incapable of producing large solar tracking oscillation. This compromise is surmounted by the 6R1P six-bar solar trackers that are studied in this research. They can not only generate reasonably large solar tracking oscillation, but also have self-locking function. The disadvantage of six-bar solar trackers is their structural complexity when compared with four-bar solar tracking counterparts. Six-bar solar tracking linkages are investigated in this research. Their solar tracking motion performance is analyzed. This research aims at improving single-axis solar tracking linkages.
Investigation of Impact Response of Corrugated Fiberboard Materials
Authors: Yildiz Salih , Biswal Amrut , Roth Arti , Upadhyaya Sam
Published: January 2025

Investigating the impact response of corrugated fiberboard materials is crucial given their widespread use and the environmental implications of overpacked packaging systems. While these materials have been extensively studied under static loading conditions, understanding their behavior under impact loading is essential for optimizing application dimensions and mitigating environmental impact. In this study, an experimental setup was configured to analyze the response of corrugated fiberboards to concentrated loads, employing high-speed cameras to capture impact duration and track rebounded impactors. The influence of the aspect ratio of fiberboard corrugated boxes on absorbed energy was examined, providing valuable insights for optimizing packaging designs. Additionally, a computational model was developed to enhance understanding of the energy absorption mechanism in corrugated fiberboard boxes subjected to concentrated impact loads. By integrating experimental findings with computational simulations, the study offers a comprehensive analysis of the impact response of fiberboard materials, facilitating the development of robust packaging systems capable of withstanding both static and impact loading scenarios.

The experimental setup involved subjecting corrugated fiberboard samples to controlled impact loading using a specifically designed apparatus. The high-speed cameras allowed for precise measurement of impact duration and tracking of rebounded impactors, providing essential data for analyzing the response of the material under dynamic loading conditions. Furthermore, the aspect ratio of the corrugated fiberboard boxes was systematically varied to investigate its effect on energy absorption during impact events. This parameterization enabled a detailed examination of the structural factors influencing the ability of the material to dissipate energy and withstand impact forces.

In parallel to the experimental investigations, a computational model was developed to simulate the behavior of corrugated fiberboard under impact loading. The material model was calibrated by the in-house tests to predict the response of fiberboard boxes to concentrated impact loads.
National Science Foundation-Sponsored S-STEM - The Mechanical Engineering Retention, Academic Success and Career Pathway Program – Design and Implementation
Authors: Fertig Jan , Kumpaty Subha , Mahinfalah Mohammad
Published: January 2025

This project has successfully completed its fourth year and has made notable progress toward its goals. Its overarching objective is to increase mechanical engineering degree completion by low-income, high-achieving undergraduates who demonstrate financial need. Program objectives include the support of scholars in their ultimate entry into the engineering workforce or graduate school; the provision of extracurricular experiences that promote thriving; and the generation of knowledge for dissemination beyond the program location. This S-STEM enterprise has been successful in recruiting, selecting and retaining women and underrepresented minorities. The program supports a diverse group of about 20 undergraduate scholars in the achievement of their educational and professional aspirations through the employment of evidence-based strategies and related endeavors. Extracurricular activities include industry presentations and professional interactions; social events; peer learning collaborations; student-faculty interaction; and in-depth one-on-one meetings with faculty advisors. Scholars have received assistance in obtaining summer internship and REU experiences, and in expanding their professional networks with national and international contacts. Regular career guidance and success coaching sessions have supported academic performance and preparation of students for future mechanical engineering achievements. S-STEM has reportedly helped improve grades and study habits; enabled greater focus and persistence; stimulated greater interest in industry; and fomented personal growth and maturity. Data currently under analysis for dissemination include retention comparisons, student performance on assignments and capstone projects, and rubric ratings by advisors and coaches. This paper showcases preliminary data in addition to more detailed depictions of extracurricular activities to demonstrate the added value of the S-STEM Scholar experience.
Scientific Procedures for Design and Failure Analysis of Firearms Through Drop-Testing
Authors: Munsell William P.
Published: January 2025

Handguns are metal and plastic assemblies in which springs provide stored energy that is used to control and maintain the relative position of the internal components between intended trigger actuations. The hazard associated with a handgun inadvertently discharging due to inertial and impact forces has been recognized and addressed by designers since at least the 19th century [1–5]. Drop-testing is a prominent means of design verification and failure analysis used to evaluate handguns relative to this hazard. However, it is important to acknowledge that there is no consensus that limits the methods which may be used to develop scientifically valid data [6–12]. As with most scientific endeavors, each investigator is free to determine the parameters of their test, and their only obligation in that regard is to provide a complete description of the relevant parameters to subsequent investigators who wish to repeat their test. The relevant parameters for a drop-test are the height of the drop, the composition of the impact surface, the orientation of the gun at impact, the weight of the rounds in the magazine, the addition of any accessories, and the position of external safeties, if any.

36 drop tests were conducted with a handgun currently available in the market which was identified in U.S. Army testing as susceptible to drop-test failures: the early-design Sig Sauer P320 [13]. Another 30 drop tests were conducted with a fixture instrumented to evaluate the acceleration associated with the impact surfaces used in selected parameter sets [6–12]. This data, along with the kinetic energy associated with the designated drop heights, was used to compare the severity of drop-test regimes described by the Sporting Arms and Ammunition Manufacturer’s Institute (SAAMI), the National Institute of Justice (NIJ), the U.S. Army, Glock, the State of Massachusetts, the State of California, and two modified versions of the U.S. Army protocol. In addition, the arbitrary nature of the designated impact orientations relative to internal and external design features was evaluated. The data generated provides a baseline from which engineering and scientific investigators can determine appropriate parameters and methods to answer the specific questions before them.

The results show that the test parameters used by ANSI/SAAMI Z299.5-2016 provided the least rigorous test, applying low kinetic energy, the least dense impact surface, and in-plane gun impact orientations limited to 0, 90, 180, and 270 degrees. As a result, the SAAMI test failed to detect the known defect present in the SIG Sauer P320. Testing under a modified version of the U.S. Army protocol, however, successfully demonstrated the defect. Under this test regime, the Sig Sauer P320 exhibited failures in 57% of tests conducted with impact at muzzle orientations ranging from 139–154 degrees.
A Human-Centric Architecture for Assistive Cobot Workflow
Authors: Harada Yohmei , Sharma Manoj , Kitts Christopher
Published: January 2025

Cobots have an ethos of sharing a common workspace with humans is crucial in a production environment as humans generally excel in tasks that lean towards dexterity, cognitive reasoning and decision making. These mutually-exclusive advantages paired with speed and precision of a robot in a shared workspace has potential to carry out tasks which are forsaken by traditional robots. In this paper we provide a multi-modal framework for an human enteric human-robot manipulation techniques where we describe gesture based robot programming and subsequently utilizing robot as a helper while human focuses on dexterous tasks.
Implementing Activity-Based Learning to Enhance Thermodynamics Education
Authors: Guo Qi , Xie Bei , Liu Qiu
Published: January 2025

Thermodynamics, an entry-level engineering class, is critical for students pursuing engineering degrees across various engineering disciplines. Thermodynamics heavily relies on physics and calculus, containing abstract concepts that can be difficult for students to understand. Given the interdisciplinary nature of thermodynamics and because the course is shared among multiple engineering programs, it is essential to develop and implement innovative instructional methods. These methods can be shared among multiple engineering programs. The goal is to increase student motivation, persistence, and success in engineering and STEM fields.

This paper aims to demonstrate the implementation of novel activity-based learning strategies specifically tailored for thermodynamics teaching. The implementation of activity-based learning strategies in Thermodynamics classes shows positive outcomes through students’ exam grades and the students’ course evaluation surveys.
Prediction of Temperature Distribution Using Coupled Eulerian-Lagrangian (CEL) Finite Element Modelling of Plunging Stage During Additive Friction Stir Deposition
Authors: Raj Amit , Singh Abhishek , Jain Rahul , Sharma Shashank , Patra Anirban , Narasimhan Krishnaiyengar , Dahotre Narendra B.
Published: January 2025

A friction-based additive manufacturing technique called Additive Friction Stir Deposition (AFSD) produces metallic solid objects with lower residual stresses, free from hot-cracking, less porosity, and other defects than traditional fusion-based additive manufacturing. In this work, the thermo-mechanical deformation behavior of the AFSD process during the plunging stage is studied using a Coupled Eulerian-Lagrangian (CEL) finite element simulation framework. The model considers the substrate as an aluminum alloy (AL6061-T6) and the rigid tool as an H13 steel. The study envisaged that the model is suitable for predicting the temperature distribution of the substrate material at any location. The model establishes a physics-based relation between thermal evolution and phenomenological parameters such as the rotational speed of the tool, frictional contact, and plastic dissipation during the AFSD process. The model accounts for the complex interaction between tool, substrate, and process parameters. The developed model provides significant insights for process optimization and control. The study is the first step towards modeling the complete AFSD process in a finite element model framework.
Disc Golf Materials Strength and Composition
Authors: Muse Matthew
Published: January 2025

Injection molding, a manufacturing technique, involves the production of parts by injecting molten plastic into a mold where it then cools and solidifies into the mold shape. One such application of this method is the production of disc golf discs, where varying material characteristics are achieved using different polymer and elastomer plastic mixtures. These varied mixtures result in plastics with diverse physical and mechanical properties. This study investigates these properties for several commercially available discs through tensile testing per the ASTM D638 standard. Tensile samples were prepared by both laser cutting and die cutting purchased discs. To better understand the influence of plastic composition on mechanical properties, samples from each disc were analyzed by FTIR, CHN, ICP-OES, and TGA to elucidate their chemical make-up. Tensile test results showed discs with lower carbon/nitrogen content are much more brittle than plastics made with higher carbon/nitrogen mixtures. The brittle plastic also had little to no oxygen content and had more filler polyurethane material. Physical testing of the discs was also simulated by creating a launching mechanism to track the flights of new discs. The discs are then launched into a wall to create deterioration and wear. The materials are compared by how the flight properties change from this test procedure. This comprehensive study illustrates that injection molding plastics can be used to manufacture a broad spectrum of polymers, each exhibiting distinct material characteristics.
Enhancement of Pool Boiling Heat Transfer Through Induced Vibrations - A Cascaded Lattice Boltzmann Study
Authors: Das Sonali Priyadarshini , Bhattacharya Anandaroop
Published: January 2025

A numerical study on enhancement of pool boiling heat transfer by vertical heater vibration is conducted using cascaded lattice Boltzmann method (CLBM). A wide range of frequencies from 0–1000Hz was chosen for the study. The amplitude was varied from 0 to 3mm. The effect of variation of frequency and amplitude on the bubble dynamics and pool boiling heat transfer performance was studied. At a constant amplitude, it was observed that for a lower frequency range (f < 100Hz), there exists an optimum frequency for which the non-dimensional surface superheat or the Jacob number (Ja) is the lowest for a given space-time-averaged heat flux (q”) and the Nusselt number (Nu) are the highest when compared to baseline scenario (non-vibrating heater). For the higher frequency range (f ≥ 100Hz), the trend is monotonous where Ja decreases or, q” and Nu increases with increase in the frequency, at a constant amplitude. The effect of amplitude variation on boiling heat transfer performance at a given frequency also differed for different frequency ranges. For the lower frequency range, the Nusselt number decreased with an increase in amplitude till a minimum value, after which it increased. In contrast, for the higher frequency range, Nu increased with an increase in amplitude till an optimum amplitude, after which it decreased. A maximum of 20.5% and 30.04% increment in q” and Nu were observed compared to a non-vibrating heater. A closer look at the effect of vibration on the bubble dynamics revealed that vibration, in general, leads to faster bubble nucleation and enhanced bubble departure frequency, though the level of impact depends on the combination of amplitude and frequency. A high amplitude and higher frequency promoted the continuous formation of vapor film, leading to transition to film boiling. In contrast, there was no continuous vapor film formation for low-amplitude and high-frequency combinations.
Ultrasonic Monitoring Roller Load Variation Induced by Roller Wear
Authors: Zhou Rui , Chen Li , Zhang Rongfeng , Geng Yu , Qi Shemiao , Liu Yi , Liu Heng
Published: January 2025

Bearing roller load largely determines the service performance of rolling bearing. In the actual operation, the bearing will always wear. Once bearing wear occurs, it will change the bearing clearance, which will affect the bearing capability. Thus, the accurate roller load measurement can help predict the useful service life. At present, the commonly used method to measure the load of rolling element is strain gauge method, but it is difficult to apply in the field. In this paper, an ultrasonic method is used to measure the roller load variation during the change of clearance caused by roller wear. The reflected pulses were collected with a planar ultrasonic probe mounted on the bearing outer ring. One roller of the cylindrical roller bearing is replaced by that with a 30μm reduction in the diameter to simulate the reduction of bearing clearance caused by roller wear. The roller load for a complete revolution of the bearing is calculated. Comparing the measurements of normal and abnormal bearing, the results show that the ultrasonic technique can effectively monitor roller load variation when bearing clearance changed. The similar trend of the minimum reflection coefficient of the contact interface is also observed.
Structural Investigation of an Additively Manufactured Stator of a Transverse Flux Machine
Authors: Knecht Simon , Schmid Martin , Reisch Isabell , Parspour Nejila , Albers Albert
Published: January 2025

The transverse flux machine (TFM) offers potentials for use in applications, where a high torque density is necessary. Existing designs use either soft magnetic composites or electrical sheet as stator material to reduce eddy current losses. Additive manufacturing creates new design possibilities for stator core geometries. However, 3D-printed bulk iron brings with it high eddy current losses. Slits incorporated into the stator core can mitigate these losses. The slits however reduce the structural integrity of the stator core. In this work we investigate the actual mechanical behavior of the slitted stator core. We show that the stator cannot withstand the loads during operation. Additional measures, such as molding the stator and coil in epoxy resin, increase the structural integrity to a sufficient level. A polygonal shaft-hub connection is a promising alternative to the current keyed shaft-hub connection.
Predicting Microstructure-Property of Silica Aerogel Materials via Bayesian Convolutional Neural Networks Surrogate Model
Authors: Islam Md Azharul , Deighan Dwyer Scout , Faghihi Danial
Published: January 2025

Deep neural networks have become essential for developing data-driven surrogate models of complex multiscale and multi-physics simulations. Trained with high-fidelity simulation data, these surrogate models enable computational predictions with significantly reduced time and resources compared to physics-based simulations. Surrogate models based on Convolutional Neural Networks (CNNs) are emerging as powerful tools for learning the complex relationships between microstructural images and the corresponding macroscopic properties of materials, facilitating tasks once computationally prohibitive, such as optimal design and synthesizing materials with target properties. However, the common neural network training method, relying on maximum likelihood parameter estimation, limits CNNs’ ability to handle uncertainty due to sparse and limited high-fidelity data generated by physics-based simulations. This often leads to overfitting and overly confident predictions, compromising the reliability of CNNs, especially in high-consequence tasks such as model-based material design. This contribution proposes a Bayesian CNN for surrogate modeling by treating the network’s training as statistical inference to overcome the formidable challenge of uncertainty assessment in predictions provided by neural network-based models. We employ Variational Inference to introduce probability distributions over the CNN’s weights, ensuring accurate uncertainty estimation. The proposed Bayesian CNN surrogate model is applied to learn microstructure image-mechanical property relations in silica aerogel porous materials, known for its superior insulation properties but suffer from low mechanical strength. Training data is obtained from elastic deformation simulations of the solid phase in the porous materials governed by stochastic partial differential equations. Results demonstrate the effectiveness of the Bayesian CNN in predicting the strain energy corresponding to a given microstructure image while considering confidence levels in predictions. The impact of training data points on prediction accuracy and reliability is also investigated using Bayesian CNN.
Assessment of Process Induced Welding Flaws in Structural Steel Members Using Phased Array Ultrasonic Nondestructive Testing
Authors: Williams Caleb , Lappin Elsie , Taheri Hossein
Published: January 2025

Welding is indispensable in structural steel members due to its ability to create strong, durable, and versatile connections essential for constructing safe, efficient, and resilient infrastructure. Welded parts must be inspected to ensure they meet required quality and integrity standards. Quality assurance measures such as nondestructive testing (NDT) can be employed to verify the integrity of welds, providing confidence in the structural integrity of steel members. A range of nondestructive testing (NDT) techniques may be used for welding inspection which depends on several factors including geometry and configuration of the joints, material, thickness of the welded parts, and inspection environment. Among the variety of NDT methods, configurations of ultrasonic testing (UT) are identified as efficient techniques of inspection for welding. Despite the effectiveness of the traditional UT techniques, the accuracy and repeatability of them can be significantly improved via advanced phased array technology. In this study, phased array UT (PAUT) is used to evaluate the quality of the welding in steel samples which were fabricated in various welding processing conditions. Potential flaws have been identified and verified by material characterization procedures. Results show that the phased array ultrasonic testing can provide localized quality information of the weld and correlate to the mechanical properties (e.g., strength) of the part in welding region.
Exploring the Influence of Channel Diameter, Fill Ratio, and Adiabatic Length Variation on Long Oscillating Heat Pipes
Authors: Santana Marcos S. , Cabrera Anthony , Sperling Apryl E. , Kuo Jim , Bellardo John , Daimaru Takuro , Sunada Eric , Roberts Scott N.
Published: January 2025

Oscillating heat pipes (OHPs) represent a promising advancement over traditional heat pipes, yet their operational boundaries, especially for long OHPs, remain insufficiently understood. This study investigates the impact of varying adiabatic length, channel diameter, and fill ratio on thermal performance, crucial for assessing their suitability for engineering applications like spacecraft thermal management. Three long OHPs, ranging from 451 mm to 770 mm in total length, were subjected to multiple performance tests, employing channel diameters of 1.1 mm and 1.9 mm, along with adiabatic lengths of 305 mm and 610 mm. The experimental setup involved mounting the OHPs onto a testbed, monitored by nine K-type thermocouples. The tests, conducted horizontally to eliminate gravity-assistance, revealed that thermal performance is significantly influenced by channel diameter, adiabatic length, and fill ratio. Notably, optimal performance was observed at a 50% fill ratio, while reductions in diameter hindered start-up at a 70% fill ratio and failed to start-up at 30% fill ratio. These findings highlight the limitations of long OHPs, which is crucial to determine the limits of their applicability and dimensional constraints.
Comparing the Whipstitch and Fibertag Tendon Suture Techniques: A Proposed Methodology
Authors: Clark Madeline , Kampert Haley , Clumpner Brandon , Nowicki Margaret , Donohue Michael , Colantonio Donald , Gee Shawn
Published: January 2025

The analysis of tendon repair suture techniques can help identify best practices for surgeons. Currently, a gap exists in the understanding of the biomechanics and failure of tendon repair utilizing a traditional Whipstitch method as compared to a suture construct that includes a suture scaffold augment (FiberTag, Arthrex, Inc, Naples, FL). The purpose of this study was to conduct biomechanical testing of both the Whipstitch and FiberTag suture technique to identify modes, locations, and loads of failure of each technique.

30 ten-centimeter bovine tendons with nine-millimeters diameter were prepared for this protocol. Tendons were assigned to one of two suture techniques: Whipstitch and the FiberTag technique. An Instron Test Instrument with a 5kN load cell was utilized for all iterations. Specimens were secured with a hook through the suture on one end and a clamp directly affixed to the tendon on the other end. Specimens were then cyclically preloaded with a fluctuating axial load at 1 Hz for 10 cycles. Specimens were then loaded with a fluctuating axial load of three distinct ranges at 1 Hz for 1,000 cycles, and then the specimen was loaded to failure at 2 mm/min. Tendons were split into 3 groups to test three cyclic loading protocols. Video was recorded for the entire duration of the tests to identify failure modes, failure location, and any trends applicable to surgical repair of tendons.

Linear models evaluated each suture method for its displacement due to cyclic loading and its load to failure due to a set rate of displacement.

After reviewing the data, Group 3 proved to be the most ideal methodology to compare the Whipstitch and FiberTag technique. Group 3 allowed both sutures to fail in the load to failure, and therefore ensured that both tendons could reach their maximum ultimate tensile strength. Group 3 is the preferred experimental procedure for continued research in this field.
Evaluation of Eutectic Freeze Crystallization (EFC) Performance of Reverse Osmosis Brine
Authors: Nemmour Amira , El Kadi Khadije , Islam MD , Janajreh Isam
Published: January 2025

Eutectic freeze crystallization (EFC) is a sustainable and cost-effective method for the water treatment process that can produce both water and salts. Applying EFC on a multicomponent high-concentration brine solution results in a lower freezing point and eutectic temperature where pure water as ice can be separated from pure salts that precipitate at their eutectic crystallization points. This work presents a theoretical design of a Zero-liquid discharge (ZLD) crystallizer system using EFC technology. The development of an EFC process flowsheet (OLI ESP flowsheet) based on thermodynamic modeling is illustrated for a case study of reverse osmosis (RO) retentate from an industrial plant. The model enables the prediction of eutectic temperatures, the production rate of both ice and salts and their recoveries using mass balance calculations, and the evaluation of the major energy requirements. Based on the thermodynamic modeling results, two major salt hydrates form with ice. These sequentially, the Na2SO4.10H2O salt hydrate can be crystallized out at about −8 °C followed by the NaCl.2H2O hydrate forming at −24 °C. Additionally, preliminary results showed that the proposed design can achieve a water recovery of about 86 % with an energy consumption of 57 kWh/m3.
Experimental Investigation of the Influence of Restrictive and Dual Methods for Design for Manufacturing
Authors: Doellken Markus , Peters Julian , Matthiesen Sven
Published: January 2025

Research in context of conceptual design methods has presented a classification of restrictive and dual methods, which were primarily described by design for additive manufacturing (DfAM). However, there is a lack of extensive research to apply dual methods to other manufacturing processes. The authors experimentally investigate the influence of restrictive and dual methods in the context of design for sheet metal (DfSM). Within this work the experimental study examines this influence with 74 participants, of whom were 46 students and 28 design engineers. The participants were exposed to either a restrictive method or a dual method before working on a design task. The final design outcomes (concepts) obtained by the participants were evaluated with regard to (1) manufacturability, and (2) manufacturing effort. The results show that the dual method, in comparison to the restrictive method, tends to positively influence the manufacturability of the concepts of students. In addition, the dual method significantly improves the ability of design engineers to reduce manufacturing effort. This study revealed that dual methods could elevate the potential of design engineers to develop designs considering manufacturing. Therefore, we recommend extending dual methods for design for manufacturing (DfM) and applying them to various manufacturing processes other than DfAM and DfSM.
Navigating Complex Vascular Pathways With “Meet in the Middle” Magnetic Guidewire Navigation Technique
Authors: Nwankwo Chijioke Christopher , Kelly Damian , Srivastava Rupal
Published: January 2025

In interventional cardiology and endovascular surgery, navigating tortuous and occluded vascular pathways presents a significant challenge. The “meet in the middle” magnetic guidewire navigation technique is a promising strategy to address this challenge. This innovative approach leverages the principles of magnetic attraction and repulsion to guide a magnetic guidewire through intricate vascular networks, allowing for precise and controlled navigation. This study investigates the efficacy and feasibility of the “meet in the middle” magnetic guidewire navigation technique in navigating complex vascular lesions. The guidewire tip has a copper coil generates the magnetic field through electromagnetic induction. Through experiments, observations are made to understand the intensity of the electromagnetic induction guidewire system for varying cooper coil turns and wire diameters. Additionally, considerations such as magnetic field strength, guidewire design, and compatibility with existing interventional tools are explored to present a future framework to optimize the navigation process. The findings from this study hold significant implications for interventional cardiologists, endovascular surgeons, and medical device developers, offering a novel approach to enhance procedural success rates and patient outcomes in navigating challenging vascular lesions. By advancing our understanding of magnetic guidewire navigation techniques, this research contributes to the evolution of minimally invasive vascular interventions, ultimately improving patient care and clinical outcomes.