bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification Method of Constitutive Material Parameters for Additively Manufactured Structures Using an Inverse Optimization Strategy
Authors: Andrikopoulos Konstantinos-Ioannis , Voerakos Georgios , Tsainis Andreas Marios , Papazafeiropoulos George , Stergiou Constantinos , Vairis Achilles
Published: February 2024

The parameters of a constitutive model of a fused deposition modeling (FDM) additively manufactured part were calculated with a novel computational tool of inverse optimization. The finite element (FE) model was used to calibrate the printed part’s properties, incorporates a composite shell section of linear elastic orthotopic material under plane stress, various design configurations following a Taguchi L18 orthogonal array, were modelled in Abaqus CAE 2021 following the classical laminate theory (CLT). The material studied was PLA. The plastic mechanical behavior was taken into account with various stress-based failure criteria normally used in fiber-reinforced composite materials. Initially an investigation based on experiments of 3D printed FDM specimens determined stress-strain curves for various types of geometry and loading. Then, inverse optimization was performed with the interior point (IP) method, which calculates material parameters of the constitutive model of the parts. It was shown that the experimental response of 3D printed FDM processed parts can be estimated accurately numerically with material parameters calculated with the new inverse optimization tool proposed.
Histological Study of Tissue Damage due to Composite-Coated Needle Insertion
Authors: Patel Kavi , Hutapea Parsaoran
Published: February 2024

Reducing the force required during needle insertion is vital to minimize tissue damage in percutaneous procedures. A composite coating of Polydopamine, Polytetrafluoroethylene, and Activated Carbon materials was applied to the needles to address this challenge. The coating reduces needle surface friction, which eventually helps to decrease the insertion force and minimize tissue damage. In this study, measuring the insertion and extraction forces inside a bovine kidney showed that the coated needles decreased the insertion force by 49% and the extraction force by 30%. In addition, a histological analysis was conducted to compare the tissue damage caused by coated and bare needles. The results revealed that coated needles insertion reduced tissue damage by 39.6% compared to bare needles. These findings highlight the potential of this composite coating approach to improve the safety and precision of percutaneous procedures.
Wake Dynamics of Complex Turning Vanes Using Time-Resolved Particle Image Velocimetry Measurements
Authors: Hayden Andrew P. , Gillespie John , Hefner Cole , Lowe Todd , Untaroiu Alexandrina
Published: February 2024

The use of turning vanes spans multiple engineering disciplines such as aerospace, ocean, and biomedical to effectively turn an otherwise uniform flowfield and achieve desired downstream flow angles. The presented work investigates the wake dynamics generated by sets of complex turning vanes which contained nonaxisymmetric geometries, spanwise variations in turning angle, and multiple vane junctions. Time-resolved particle image velocimetry (TR-PIV) measurements were performed to collect three-component velocity data downstream of the vane pack geometries. As the vanes contained blunt trailing edges, large-scale periodic structures (von Kármán vortices) dominated the unsteady wakes. Two post-processing methods, Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD), were employed to extract the wake energy or enstrophy content, corresponding spatial modes, and associated frequencies. This was completed for various parameters such as Reynolds number, vane turning angle, and vane trailing edge thickness. Spatial POD analyses showed that zero-turning vanes contained similar dynamics to that of a circular cylinder, and the total wake energy distributions were affected by freestream velocity. A spectral POD analysis in the wake of vane junctions found that the junction flow contained significant coherent content, and gave some insight into the mean flow. Lastly, vane parameters such as turning angle and TE thickness were found to play a large role in modifying the enstrophy content of the large-scale shedding modes.
Finite Element Analysis and Process Parameters Optimization of AA2024 – T351 Alloy Machining Under Different Cooling Environments
Authors: Pervaiz Salman , Kannan Sathish , Ali Shafahat
Published: February 2024

Aluminum alloys are popular in the industrial applications after steel and cast iron. The lower strength of Aluminum alloys can be improved by the addition of alloying elements and heat treatment related operations. AA 2024 – T351 is the alloy of aluminum with copper, and in addition tempering and stress relieving is performed as well to improve the strength related characteristics. AA2024-T351 is a high-strength aluminum alloy that has a combination of properties that make it particularly well-suited for use in aerospace and aircraft structural components. It is relatively lightweight, which makes it an attractive material for aircraft design, but it is also exceptionally strong and can withstand high stresses and loads. This combination of strength and lightness is particularly important in aerospace applications where weight is a critical factor. In addition to its strength and weight properties, AA2024-T351 is also highly resistant to corrosion. This makes it an ideal material for aircraft structures, which are exposed to a range of environmental conditions, including high altitude, extreme temperatures, and exposure to moisture and chemicals. There are several machining related challenges available when it comes to the machining performance of aluminum alloys. These challenges are linked with the chip formation due to sticky nature of material, strain hardening behavior and low thermal conductivity. Aluminum alloys can be difficult to machine due to the formation of long, stringy chips that can clog or damage cutting tools. This is because aluminum has a tendency to adhere to the cutting tool, which can lead to built-up edges and poor chip evacuation. Machining performance can be enhanced by the application of cutting fluids. The machining of AA2024-T351 can be carried out using various cooling methods, including dry, flood, and cryogenic cooling. Each of these methods has its advantages and disadvantages, and the choice of cooling method depends on various factors, such as the machining process parameters, tooling material and geometry, and workpiece material properties etc. The current study investigated the machining performance under the influence of different cooling environments such as dry, flood and liquid nitrogen based cryogenic. In this work, finite element based numerical modeling has been utilized to capture the behavior of machining AA2024-T351. The study varies cooling method, cutting speeds and feed levels using Taguchi design of experiments. The output responses of cutting forces, cutting temperature, cutting power were calculated. The findings were found in good agreement with the experimental data available in the literature.
Multiphysics-Informed Machine Learning for Mechanical-Induced Degradation of Silicon Anode
Authors: Bansal Parth , Li Yumeng
Published: February 2024

Silicon (Si) anode based lithium-ion batteries (LIBs) are being developed and used in various portable electronic technologies because of their better life cycle performance and safety. These Si anode based LIBs also provide a better capacity due to the unique intercalating mechanisms of lithium (Li) into Si. However, due to this unique mechanism, volumetric changes upto 300% have been observed in these batteries that leads to the development of internal stresses in the Si anode which ultimately results in cracking and delamination in it. These two cracking and delamination failure modes along with the growth of the solid electrolyte interface (SEI) on the exposed surface of Si anode leads to loss in the overall capacity of the battery. The capacity degradation can be simulated using FE models but these models take a long time to run and are computationally expensive. Hence, in this study, we develop a physics-informed machine learning technique for the capacity degradation of the Si anode based LIBs. 3D finite element (FE) models are built to understand the volumetric stresses induced cracking and delamination along with the capacity loss due to the growth of the SEI layer. The outputs from these FE models are then used to train the Gaussian process regression (GPR) surrogate model which can be used for the design of LIBs towards application-oriented properties such as high energy storage, fast charging or optimal life time by quickly and accurately predicting the capacity degradation in the battery.
Materials Characterization of Recycled and Mixed Acrylonitrile Butadiene Styrene and Polylactic Acid for Use in Additive Manufacturing
Authors: Sang David , Llantero Parker , Eckstein Adam , Nguyen Chi , Nowicki Margaret , McDonald Kenneth
Published: February 2024

This work examines the physical and mechanical properties of composite filaments derived from acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and tensile testing. Composites made up of 0% to 100% in 25% intervals of ABS and PLA were prepared through a filament extrusion process. The composites were characterized using TGA and DSC with unprocessed ABS and PLA for comparison. To model the additive manufacturing and recycling process, each sample was exposed to heating and cooling cycles during DSC measurements. The 25% ABS and 75% PLA composite samples were determined to have the highest crystalline content based on the highest melting temperature. DSC data also indicated that the crystallinity of the materials degraded as glass transition and melting temperatures shifted higher with each repeated heating and cooling cycle. A tensile testing of the composite filaments was performed using a universal testing machine. The samples were pulled with tabs constructed from duct tape. From this analysis, the best-performing mixture was 50% ABS and 50% PLA. This data was compared against the DSC data to correlate the strength of the composites to the crystalline region after several recycling iterations.
Construction of a Strain-Based Bayesian Network for Assessing Pipeline Risk due to Ground Movement
Authors: Schell Colin A. , Lever Ernest , Groth Katrina M.
Published: February 2024

Ground movement events pose a significant threat to buried natural gas and oil pipelines which resulted in an estimated $388 million in damages from 2002 to 2022. Strain-based design and assessment (SBDA) methods are commonly used to manage pipeline integrity in ground movement scenarios but utility companies still face many challenges in applying SBDA to pipeline integrity management. This paper presents the development process of a Bayesian network structure using SBDA methods for managing pipeline integrity in the event of ground movement hazards such as landslides and ground subsidence. The Bayesian network model proposed in this work presents a first-of-its-kind approach to: (1) integrate the multiple risk factors and data sources required to model SBDA and assess pipeline risk; (2) identify the sources of uncertainty that affect pipeline risk estimates; and (3) provide a holistic tool for addressing pipeline risks stemming from ground movement events. Quantification and performance validation of the Bayesian network is an ongoing process, but the model is expected to utilize satellite-based ground movement data, infield strain measurements, in-line inspection defect data, strain accumulation models, metallurgical data, and knowledge of the past loading envelope of the pipeline to perform a quantitative risk assessment for a network of pipelines. In this paper, a novel SBDA taxonomy is presented, analytical strain capacity equations are selected for future use, and the overall model architecture is developed to support the creation of a comprehensive and robust model.
Teaching the Reachable and Dexterous Workspace of Articulated Robotic Manipulators Using MATLAB Animation
Authors: Kutzer Michael D. M. , Rodriguez-Seda Erick
Published: February 2024

In the context of articulated robotic manipulation, reachable and dexterous workspace define regions of space that can be reached by the end-effector or tool center point (TCP) of a robot. This paper presents an approach to teaching the concepts of reachable and dexterous workspace using MATLAB animations. These methods rely on existing MATLAB tools which limit the visualization to two dimensions (2D). Despite this limitation, these tools have produced a qualitative improvement in student understanding. This paper details the visualization approach used including a review of core concepts and algorithms. Results show reachable and dexterous workspace visualizations for three degree-of-freedom (DoF), planar articulated manipulators consisting of various configurations of revolute (rotational) and prismatic (linear) joints. Source code, documentation, and installation functions for the “Visualize Workspace Toolbox” are available at https://github.com/USNA-WRCE/VisualizeWorkspaceToolbox.
Comparative Analysis of Thermal and Hydraulic Performance of a Mini-Channel Heat Sink With Supercritical Carbon Dioxide and Water Coolants
Authors: Mansur Yamin , Habib Md. Ahosan , Paul Titan C. , Morshed A. K. M. Monjur
Published: February 2024

This study investigates the heat transfer performance of supercritical carbon dioxide (s-CO2) in comparison to water as a coolant within circular tubes. The study was conducted numerically using the commercially available software FLUENT. The study was conducted for the s-CO2 for the temperature range of 305 K to 316 K at 8 MPa covering the pseudocritical temperature for the CO2. The thermal and hydraulic performance, including heat transfer coefficient and pressure drop, under varying inlet temperature, mass flux, and heat flux conditions, were evaluated and compared with those of water. The study finds that for s-CO2, the heat transfer coefficient reaches its peak value at the pseudocritical temperature, which is around 307.9K at an operating pressure of 8 MPa. The bulk fluid temperature ranging from 306 K to 308 K offers better thermal and hydraulic performance for s-CO2, with a higher heat transfer coefficient and lower pressure drop than water. However, beyond this temperature range, both the heat transfer coefficient and pressure drop of s-CO2 become worse than water. Furthermore, the study observes that the heat transfer coefficient for s-CO2 increases with mass flux, similar to water. However, the slope is steeper than water, and it becomes steepest at an inlet temperature of 308K. An interesting trend for s-CO2 is noted, as the heat transfer coefficient decreases with an increase in heat flux beyond the peak temperature (the temperature at which the maximum heat flux was observed). Conversely, the reverse scenario has been observed prior to the peak temperature. Water, on the other hand, does not show any significant change in this regard. The thermophysical properties of s-CO2, including specific heat capacity, density, thermal conductivity, and viscosity, around its pseudocritical temperature at 308 K (at 8 MPa) are critical for interpreting these results. The study identifies the optimum conditions at which s-CO2 proves to be better than conventional coolants such as water.
Thermal Characterization of Functionalized Nanodiamond Enhanced Phase Change Materials for Fast Response to Demand
Authors: Oliver Jared , Languri Ethan , Davidson Jim , Costa Lino , Kerns David
Published: February 2024

The latent thermal energy storage (TES) system is a well-known concept that utilizes the energy exchange from solid-liquid phase change for energy storage. TES can shift electrical demand from on-peak to off-peak hours, reducing costs and fuel that electrical power plants use to supply the energy needs of facilities. While TES can be very beneficial, the slow response rate commonly seen in TES is a major reason why industry hesitates to engage large-scale TES implementation. However, the response rate can be increased via the addition of higher conductivity particulates into PCMs that are commonly used in TES. This paper investigates the role of functionalized five-nanometer size diamonds, “nanodiamond” added to and interact with the molecules of PCMs to increase their thermal conductivity significantly, hence their response rate to thermal demands. Due to the extremely high thermal conductivity of diamonds and the utilization of five-nm particle-size diamonds chemically interfacing with the PCM host material, the thermal conductivity of the overall medium will increase significantly. However, there are downsides to increasing the response rate by adding particulates. Aside from displacing higher capacity materials, the addition of particulates that increase the overall thermal conductivity appear to reduce the latent heat of fusion of the materials. This paper studies the macro- and nano-scale characterizations of the base PCM and functionalized nanodiamonds in the PCMs.
Experimental Analysis of the Effect of Fluidic Oscillator Geometry on Heat Transfer Performance
Authors: Gomes Rita C. S. , Barbosa Flavia V. , Constantino Erany D. G. , Teixeira Senhorinha C. F. , Teixeira José C. F.
Published: February 2024

Fluidic oscillators are used in several areas such as acoustics, fluid mechanics, and heat transfer. These devices generate sweeping jets with different frequencies, operating without the need for external forces. Therefore, this study aims to experimentally analyze the geometric and dynamic parameters that influence the performance of oscillating jets. Based on this analysis, the geometry of a Double Feedback Loop (DFO) oscillator prototype was defined. The appropriate materials and manufacturing processes were carefully chosen for its construction and the design parameters were selected based on the factors and levels that mainly influence the dynamics of the sweeping jet flow according to an extensive literature review. The geometry of the feedback channel, mixing chamber, and control port were defined as a result. To investigate the effect of these variables on the flow dynamics, an experimental setup was meticulously designed and constructed. This setup enables the adjustment of the flow rate and the introduction of seeding particles into the system, allowing the characterization of flow dynamics using a Laser Doppler Anemometry system. Besides the analysis of the jet flow dynamics, the heat transfer rate was measured using a heat flux sensor, contributing to the determination of the optimal design.
The Effects of Balloon Thickness on the Viability of a Microfluidic Cell Compression Device
Authors: Emeigh Carson , Pineda Rose , Harms Brennan , Ryu Sangjin
Published: February 2024

Cells respond to mechanical stimuli, and microfluidic devices are used to create highly controlled environments for cellular mechanobiology studies. Previously, we developed a microfluidic cell compression device using photolithography and soft lithography. The device consisted of an array of thin polydimethylsiloxane (PDMS) balloons that would inflate under an applied pressure. Hydrogel scaffolds seeded with cells placed over these balloons were shown to be compressed during device operation. The height of the inflated balloons was found to depend on the balloon diameter, and the observed dependency was compared to a theoretical model. The theoretical model predicts that the balloon height is also affected by applied pressure, balloon thickness, and Young’s modulus and Poisson’s ratio of PDMS.

In this study, we investigated the effect of the balloon layer thickness on the height to which the balloons can be inflated, following the previous study. Two microfluidic cell compression devices with different balloon thicknesses were fabricated using a 3D printed plastic mold, PDMS, spin-coating, and soft lithography. The height and diameter of the balloons were measured by microscopy imaging and image processing. The device was redesigned to facilitate imaging and following image processing. Fabrication was also slightly altered to improve the control over the balloon thickness. Additionally, Young’s modulus of PDMS was experimentally measured.

We found that the balloon height increased with the balloon diameter as expected, but it did not show clear dependence on the balloon thickness, as predicted by the theoretical model. Disagreement with the theoretical model may be due to the assumptions of the model, and errors and uncertainties in fabrication, imaging, and image processing. Height measurements with a secondary method is required for validation of findings.
Effects of Deterministic Gust Modeling for Large, Multi-Rotor Drones
Authors: Hoang Samantha , Shen I. Y.
Published: February 2024

Multi-rotor drones are becoming increasingly popular as a method for accomplishing critical operations such as fighting fires, search and rescue, and agriculture. To accomplish these tasks, the drones need to fly over long distances and potentially carry heavy payloads. They also need to be capable of flying in harsh environments with sudden gust disturbances. When designing these drones, it is important to be able to accurately simulate their flight before building and testing the drone. This paper demonstrates that simulated flight trajectories of an 18-rotor drone, with an overall size of 3 m in diameter and 1 m tall, are very sensitive to various parameters of deterministic gust disturbances. A simple gust disturbance, where the magnitude of the wind, the wind direction, and the number of affected rotors were varied, was used to demonstrate this sensitivity. When the windspeed is varied for two wind directions, the amplitude of the oscillations in the trajectories grow with the increase in the wind amplitude. The amount of the variation was not consistent with the largest change of 2.0 m in trajectory corresponding to the smallest windspeed increase from 5 to 10 m/s at a constant angle of 45 degrees and inconsistent changes in the trajectory for selected windspeed variations. When the wind angle with vertical is varied at a constant windspeed of 20 m/s, the simulations demonstrated different responses depending on if the wind came from above or below the drone. The responses to wind coming from above the drone was larger than the responses to wind coming from below the drone by a factor of almost 100 when comparing the largest responses. Like when the windspeed was varied, there was no quantitative or qualitative predictability in the drone’s response. Finally, no similarities in response were observed when the number of affected rotors was varied. When half of the rotors are hit by the gust, the drone exhibits a 5 to 10 times larger horizontal response in both position and orientation than when all the rotors are hit by the gust. In contrast, the response in the vertical direction when only half of the rotors is hit by the gust is half the magnitude of the response when all of the drones are hit by the gust. These results demonstrate that the drone’s response to a gust disturbance is heavily dependent on the properties of the gust and are not predictable using deterministic simulations, thus demonstrating a need to use stochastic simulations to achieve accurate simulation results.
Impact of Number of Blades and Solidity on the Performance of a Darrieus Vertical Axis Wind Turbine With Helical Blades
Authors: Saad Ahmed S. , Ahmed Mahmoud
Published: February 2024

The number of blades and the solidity ratio for Darrieus vertical axis wind turbines are two factors that significantly influence the performance of these wind turbines. Therefore, the objective of the current study is to investigate the impact of varying numbers of blades (2, 3, and 4 blades) as well as various solidity ratios ranging from 0.3 to 0.65 on the performance of a helical-bladed Darrieus rotor with helical angle of 90 degrees. Accordingly, the Reynolds-Average Navier-Stokes equations in three dimensions along with the turbulent model of (SST) k-ω are developed and numerically simulated. In this study, experimental results from the literature are used to validate the results predicted by the current numerical model. Thus, numerical predictions of the variations of the coefficient of power versus tip speed ratio can be made.

Predicted results revealed that the coefficients of power are higher for the helical-bladed Darrieus rotor with three blades at higher ranges of tip speed ratios with respect to rotors with two and four blades. The peak coefficient of power significantly increases with raising the solidity ratio up to an optimal value 0.5, then a deterioration in peak coefficient of power is attained by a further increment of solidity ratio beyond this value. The helical Darrieus rotor with three blades and solidity ratio of 0.5 attains the highest peak coefficient of power of 0.338. Helical Darrieus rotors have a wide range of tip speed ratios at which high power coefficients can be achieved when the solidity is lower. Furthermore, as rotor solidity increases, the optimal tip speed ratio of the helical Darrieus rotor tends to decrease.
Renewable Convective Heating by the Metallic Strips Heated via a Solar Vacuum Tube
Authors: Alshweiki Ali , Olukeye Tiwaloluwa , Demisse Wondwosen , Tyagi Pawan
Published: February 2024

The majority of power consumption nowadays goes to heating. Global warming, air and water pollution caused by burning fossil fuel for heating encourage researchers and engineers to focus more on renewable energy. The solar system is one of Earth’s primary sources of clean power. Apart from photovoltaic panels and their effectiveness of power generation contribution, solar heaters are primarily used in different applications to recover heating needs in residential and commercial buildings. This paper focuses on an experimental study to generate heat by a solar system using metallic strips immersed in cement inside a solar vacuum tube. Heat can be transferred from inside the tube to the outside using metallic strips with high conductivity. Then, the metallic strips can be used as a heater to heat water or air in an isolated tank by direct contact between the hot strips and the fluid. In order to keep the system providing heat after the absence of sun’s rays, cement is used in this experiment as a heat repository.
Application of Modal Superposition Method With Response Dependent Nonlinear Modes on the Forced Response Analysis of Bolted Joint Connections
Authors: Beyan Humeyra , Cigeroglu Ender
Published: February 2024

Due to ease of mounting, high strength feature and availability, bolted joints are one of the most common and widely used connection methods. Nonlinear modeling of bolted joints is a complex problem. One common approach of modeling bolted joints is the use of macroslip friction elements distributed around the bolted connection. The use of multiple macroslip friction elements increases the computational time of the analysis. Therefore, in this study, in order to decrease the computational time Modal Superposition Method (MSM) with Response Dependent Nonlinear Modes (RDNMs) is utilized to obtain the solution of the jointed structures. RDNMs, which are calculated during the solution, are a special set of normal modes which captures the dynamics of the nonlinear problem much more accurately than linear modes of the system. Therefore, use of RDNMs decreases the number of modes that should be used in the analysis drastically. Hence, the dimension of the nonlinear algebraic equation set to be solved and the resultant solution time decrease significantly. The obtained form of nonlinear algebraic equation set is solved by using Newton’s method with arc-length continuation. A half-lap bolted joint is considered as a case study. Performance of classical MSM that uses linear modes of the system is compared with the MSM with RDNMs.
Advanced Exergetic Evaluation of a Stig Cycle and Cooled Inlet Air Gas Turbine Powered by Mixtures of Natural Gas and Hydrogen in Tropical Climates
Authors: Fajardo Juan , Barreto Deibys , Yabrudy Daniel , Piña-Martinez Andrés
Published: February 2024

Using mixtures of hydrogen and natural gas as primary energy sources in current power generation systems with gas turbines is one of the worldwide trends for global decarbonization goals. However, despite the problems of adaptation of the existing assets for the use of hydrogen, little has been studied about its effects on gas turbine generation systems that operate in tropical climatic conditions where temperatures are higher than 30 °C, and relative humidity reaches values higher than 80%.The gas turbine generator plant with steam injection and cooled air inlet studied consisted of a General Electric LM5000 gas turbogenerator composed of a low-pressure compressor, high-pressure compressor, combustion chambers, turbine, and generator. The steam injection system comprises a heat recovery steam generator and two MUP pumps. The air-cooling system comprises two electric coolers, a cooling tower, two pumps, a cooling coil, two evaporators in series, and two condensers in parallel. The air-cooling system allows for reaching the minimum temperature of 8.8 °C. Plant with Stig cycle in ISO conditions (15°C and 60% RH) produces 52 MW with a thermal efficiency of 43%. The atmospheric conditions in the geographical location of the power plant are, on average, 32°C and 80% relative humidity at sea level. Therefore, the plant with the Stig cycle under local operating conditions produces a power of 44.4 MW with a thermal energy efficiency of 41.6 %. A simulation was conducted in a Stig cycle generation system with a gas turbine, steam injection in the combustion chamber, and cooling air at 8.8°C at the compressor inlet. The system is set to produce 44.4 MW for fuel mix ranges between 0–50% hydrogen.

The study results showed that for every 5% by volume of hydrogen added to the H2-natural gas mixture, 5.6% kJ/m3 of energy is lost. Thermal efficiency decreases an average of 2.67% for every 10% increase in hydrogen, which forces an increase in the volume of the fuel mixture to generate the same power. For a percentage of 20% by volume of H2 in the fuel mixture, there are increases in global exergy destruction, avoidable exergy destruction, and unavoidable exergy destruction of 21.5%, 16%, and 31%, respectively. In comparison, the exergetic efficiency decreases by 13.7%. The component most affected by the use of the fuel mixture is the combustion chamber, in which exergy destruction increases by 17.8 MW compared to using 100% natural gas. In addition, the combustion chamber suffers an increase in exergy destruction of 29,2% for every 10% increase in the percentage of hydrogen injection in the fuel mixture. For every 10% increase in H2 volume, there is an average increase in the NOx concentration of 0.4% and a 5% decrease in the CO2 concentration.
Model Based Evaluation of a Turbocharged Engine Exhaust Heat Recovery by Auxiliary Turbine
Authors: Carapellucci Roberto , Di Battista Davide
Published: February 2024

Recent developments in terms of vehicle emissions and fuel consumption regulations have pushed the transportation sector toward electrification and hybridization of powertrains. In order to meet these environmental targets, a transition era, where the internal combustion engines (ICEs) still play a crucial role, is approaching, and technologies already mature should be rapidly applied to reduce fuel consumption. Waste heat recovery from exhaust gases has been studied for decades and can now be readly applied to existing engines, particularly in hybrid configurations, where the recovered energy is converted into electrical form and used on board. It is particularly important for heavy duty transportation, where the potential is enormous and the difficulties to fully electrify the powertrain are higher. Among various technologies proposed for waste heat recovery, the use of additional turbine in the engine exhaust is surely one of the most mature, although there are not many applications in the market. In this work, a 3.0 L turbocharged diesel engine, used to equip commercial and heavy duty vehicles, is considered. Having the opportunity to test the engine at representative working points, the potential of exhaust heat recovery using an additional turbine has been extensively explored. Data from the engine test bench has been used as a boundary condition to develop a mathematical model of the exhaust line and, in particular, the turbocharger. This is controlled by a variable geometry inlet nozzle, opening and closing a pre-statoric row of vanes on the turbine, in order to match the instantaneous requests of the compressor placed on the same shaft. Hence, a model of an auxiliary turbine has been derived and used to evaluate the possible energy recovery when it is placed downstream of the existing one (so-called series turbocompound). Results in terms of mechanical power produced (and possible electrical conversion) have been assessed, considering the real turbine behavior (expansion ratio vs. flow rate vs. revolution speed vs. efficiency) and has an average value of 6% in a wide range of operating conditions of the engine. The new thermodynamic conditions of the exhaust line have been re-evaluated, calculating the new equilibrium of the turbocharger when the additional turbine is introduced and its related backpressure increase on the exhaust, which can reduce the net power recovered value. In fact, the backpressure effect on the engine increases the specific fuel consumption, which should be compared to the benefit of the additional power produced by the turbocompound. Environmental considerations, such as the amount of CO2 avoided thanks to the recovery section, have been also calculated, showing very interesting results (averagely 45 g/kWh) considering emissions reduction policies worldwide and the electrification of fleets.
Dynamic Analysis of a Cracked Composite Beam
Authors: Sarker Pratik , Chakravarty Uttam K.
Published: February 2024

Composite materials tailored for specific applications exhibit customized properties which the ordinary materials do not possess. Therefore, performance analysis of composite materials for desired applications is important to ensure the longer life of the structure without failure. When subjected to dynamic loading, the crack growth and corresponding vibration behavior of the composite structures are of special interest. Therefore, in this research, vibration characteristics of a proposed cracked composite beam is investigated by conducting computational simulation. The composite structure is composed of four layers of fiberglass-epoxy material and a soft honeycomb structure sandwiched between the top and bottom layers of the composite material. Symmetric configurations of different ply angles of composites with respect to the midplane of the structure are used. The corresponding finite element model is created in the commercially available finite element package of Abaqus. A V-shaped crack is considered in the composite beam structure with various crack opening sizes. The variations of natural frequencies of vibration of the composite cracked beam with variations in the crack opening sizes are presented for different modes. Then the variations of natural frequencies with the depths and positions of the cracks along the length of the beam are studied. Variations of vibration characteristics are presented for the composite beam for the rotating and nonrotating cases. Convergence study for the solution accuracy of the beam is conducted for both the rotating and nonrotating cases.
Brake System Dynamics and Control for an Autonomous Personal Rapid Transit Vehicle
Authors: Patil Nikhil , Best Dustin , Hollar Seth
Published: February 2024

This paper presents an overview of the brake system development and control strategy for an autonomous personal rapid transit vehicle prototype. An electro-hydraulic system is developed using a set of electric linear actuators and master cylinders to allow the onboard computer to stop the vehicle or control the speed. A classical electronic braking force distribution is incorporated into the system to maximize deceleration and avoid wheel lock-up during emergency braking. The incompressible braking fluid yields fast response time for brake pressure gain, thus a spring loaded mechanism is introduced to obtain higher resolution in controlling the brake gain and subsequently the vehicle’s deceleration. The authors propose an optimal control strategy based on Pontryagin’s minimum principle for vehicle speed reduction to improve passenger comfort by reducing acceleration during the braking duration. The optimization problem is set up to be simulated in Matlab Simulink environment, and results are discussed.
A Municipal Waste Heat Dissipation Modular Approach for Open Field Heated Agriculture
Authors: Dell Robert , Mitchell Nicholas , Mehta Ritesh , Grutman Maya , Mignano Christopher , Petur Palsson Olafur , Unnthorsson Runar
Published: February 2024

Waste heat from low temperature geothermal resources, industrial, municipal district heating services, and combined heat and power (CHP) systems is a valuable resource that can be dissipated in open field heated agricultural systems. Since 2008 the authors have been developing and field testing an energy intensive year-round shallow soil warming technology. Heated green roof test beds in New York City and heated gardens in Iceland are analogous to heated sidewalks. Heat dissipation rates for the test beds varied from 0.086–0.336 kW/m2, depending upon working fluid temperatures, weather conditions, soil types, soil depths and moisture content. Plant growth increases of 20% and growing season prolongation are documented when a soil temperature of 25–30°C is maintained continually at a depth of 8 cm. This enables the survival of cultivars that normally thrive in more than two United States Department of Agriculture climate zones to the south. This coincidentally mirrors some global climate changes predictive models. The authors have developed a basic 5 × 10 square meter module based on their 10 years of experience, which can be used alone or combined for larger installations. Construction guidelines, thermal projections, and expected plant growth results are provided for both urban and municipal installations.
Relaxation Effects of Soft Artificial Fabric Muscle Actuators for Launch and Recovery Systems
Authors: Smith Michael P. , Cavallaro Paul , Redington Allison , O’Donnell Jacob , Warner Eric
Published: February 2024

This research investigated the time-dependent stress relaxation and creep performance of McKibben-type artificial soft fabric muscles (ASFMs). The ASFMs are constructed of High Performance Fibers (HPF) encompassing an oversized, pleated, nonstructural fluid bladder. These ASFMs have potential applications for the launch, recovery, positioning and control of undersea and surface vehicles and interface platforms. Glass and aramid braid materials were evaluated analytically and experimentally. The analytical model utilized a modified General Maxwell Model to capture the stress relaxation and creep behaviors of ASFMs. This model was then compared with the experimental results.
Modeling Thermal Runaway in Prismatic Lithium-Ion Batteries
Authors: Khan Shehzad , Anwar Sohail , Casa Jairo , Hasnain Muhammad , Ahmed Hossain , Sezer Hayri
Published: February 2024

Lithium-ion batteries (LIBs) are widely used in various applications due to their high energy density and long cycle life, but their safety is a significant concern because of the potential for thermal runaway, which can lead to catastrophic failure. The present study investigates thermal runaway (TR) for prismatic cell geometries with inter-cell contact resistances using finite volume based PDE solver implemented in MATLAB and Julia. This solver can handle transient, convection, diffusion, and linear and constant source terms in all cartesian, cylindrical, and spherical coordinates. It provides convenient postprocessing capabilities and a direct graphical interface. The results obtained from the finite volume approach are compared with two other models, GPYRO and COMSOL Multiphysics, and show good agreement between them. The study finds that the inter-cell contact resistance has a significant effect on the thermal behavior of LIBs and must be considered when designing and modeling battery systems. The FVM toolbox is demonstrated to be a reliable and efficient tool for predicting the critical conditions for thermal runaway in LIBs, providing valuable insights into the complex heat and mass transfer processes that govern thermal runaway. The study highlights the potential of the FVM toolbox for use in battery design and safety analysis, guiding the development of safer and more reliable energy storage systems. By accurately predicting the onset of thermal runaway, the FVM toolbox can identify critical design parameters and provide insights into the effects of changes in cell geometry and inter-cell contact resistance on the thermal behavior of LIBs.
Predicting Oscillatory Patterns of Mud Circulating Along the Well-Bore in Drilling Procedures: A Finite Element Model
Authors: Marquez Eleazar
Published: February 2024

In this paper, a mathematical model is proposed to further understand the dynamic effects [drilling] mud exerts on the drill-string assembly. The proposed model consists of a rotor subjected to various revolutions per minute (RPM’s), an axial force which accounts for the weight-on bit requirements, and a harmonic excitation simulating fluid mud circulating along the well-bore. In this regard, Euler-Bernoulli beam theory is incorporated to establish a multi-degree-of-freedom (MDOF) mathematical expression of a specific section of the BHA. In this regard, a finite element methodology was implemented to determine the corresponding parameters of the equation of motion and elucidate the elastic characteristics of the drill-string assembly. A two-node element containing two displacements and two rotations per node was adopted to describe the rotor as a uniform, elastic beam. In addition, gyroscopic effects of the drill-string assembly were accounted in the equation of motion. The motion of the mud on the drill-string is characterized by implementing damped oscillators on nodes one, three, five, and seven.
Investigation of Thermal Metamaterial Designs to Harvest Energy by Guiding Heat Energy
Authors: Khan Md Arif Iqbal , Sadaf Asef Ishraq , Ahmed Riaz , Ahmed Hossain
Published: February 2024

A novel method to harvest energy by guiding heat using a thermal metamaterial system is presented in this study. Compared to various other promising features that thermal metamaterials are being designed for in the last decade, heat guiding characteristics is one of the unprecedented phenomena which has numerous applications in thermal management and energy harvesting technologies. While thermal metamaterials are envisioned to guide heat in a specific direction, utilizing thermoelectric materials has the potential to significantly increase energy harvesting efficiency. In this study, a numerical model is developed using the commercial finite element solver COMSOL Multiphysics. Using this model, three different types of thermal metamaterial design are investigated to estimate their ability to control the flow of thermal energy through a base material. Initially, the base material is stainless steel whereas the constituents of the thermal metamaterials are high heat conductive Copper and insulator-like Polydimethylsiloxane (PDMS). The unit cell geometries of the thermal metamaterials are designed as circular sectors and varied in such a way that three distinct designs are achieved. In these unit cells, circular sectors are arranged periodically, and the material properties of these sectors are alternatively assigned to Copper and PDMS so that sufficient anisotropy is achieved. While the copper acts as the primary carrier of heat, the PDMS restricts heat energy from being dissipated. The unit cell is placed in the path of heat flow through a rectangular channel. A central circular area is selected near the cross-section to place a thermoelectric patch. The incorporation of thermoelectric materials such as Bismuth telluride (Bi2Te3) into the thermal metamaterial system significantly enhances its capability to harvest energy by converting the heat energy to usable electrical energy. A comparison is made by means of the increase in temperature of the central circular area over a range of temperature difference to estimate the efficiency of the unit cell designs. In this numerical analysis, convective and radiative heat transfer are assumed to be zero while only conductive heat transfer is considered.
Predicting Needle Deflection in Soft Tissue: a Computational Modeling Approach
Authors: Al-Safadi Samer , Hutapea Parsaoran
Published: February 2024

This study explores the mechanical interactions between surgical needles and soft tissues during procedures like biopsies and brachytherapy. A key challenge is needle tip deflection, which can cause deviation from the intended target. The study aims to develop an analytical model that predicts needle tip deflection during insertion by combining principles from interfacial mechanics and soft tissue deformation. A modified version of the dynamic Euler-Bernoulli beam theory is employed to model needle insertion and predict needle tip deflection. The model’s predictions are then compared to experimental data obtained from needle insertions in real tissues. The research aims to deepen our understanding of needle-tissue interactions and develop a reliable model for predicting needle deflection, ultimately enhancing surgical robots and navigation systems for safer and more precise percutaneous procedures. Pig organs are used as a material data source for a viscoelastic model, simulating needle insertion into kidney-like environments and analyzing organ deformation. The modified Euler-Bernoulli beam theory considers the viscoelastic properties of the tissue. Deflection is then calculated and compared to experimental data, with analytical deflection measurements exhibiting a 5–10% difference compared to experimental results.
Supercharging of a 4-Stroke Spark Ignition Junkers Engine
Authors: Brójo Francisco , Abreu José
Published: February 2024

In the field of aviation, supercharging allows piston engines to develop maximum power when operating at high altitudes or boost an aircraft’s power during take-off. This project aims to supercharge a four-stroke spark ignition Junkers engine with a turbocharger to improve its performance. A new exhaust system and an intake system containing an air capacitor were designed and fabricated to allow the supercharging of the engine. An Eddy current dynamometer and various sensors connected to the engine control unit were utilised to measure the engine parameters during the tests. The engine performance was quantified by the values of torque, power and specific fuel consumption. A comparison between the naturally aspirated and supercharged engine is analysed and it is concluded that supercharging improves its performance, increasing torque and power values, and decreasing specific fuel consumption, making the use of this type of engine viable for small aircrafts.