bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving Efficiency of Automotive Coating and Curing Processes Through Deep Learning Algorithms and High-Fidelity CFD Modeling
Authors: Candido Sílvio , Pendar Mohammad-Reza , Páscoa José Carlos
Published: February 2024

The automobile industry has relied on computational fluid dynamics (CFD) simulations to analyze and optimize the coating and curing processes, speed up product development, and lower the cost of product development. However, CFD modelings of these processes are computationally expensive due to the complexity of the models and the large number of simulations needed, especially when its used complex sprays such as the nithrothermal electrospray. As a result, more efficient methods must be developed to reduce computing time without compromising accuracy. In this article, we analyze how deep learning techniques can be used to predict coating and curing processes using electrospray CFD simulation. A dataset of 3D Eulerian-Lagrangian CFD simulations of coating and curing processes employing electro-spray for the automotive industry has been used to train different deep-learning models. We investigated how hyperparameters such as batch size and layer count affected deep learning model performance compared to conventional CFD simulations. For this, we evaluated the deep learning models’ efficiency and accuracy in terms of computing time. We also investigated how hyperparameters such as batch size and layer count affected deep learning model performance. Also, we’ve looked at the target’s final droplet deposition, and distribution that is required to accurately estimate the distribution. Furthermore, we studied the percentage of snapshots of the droplet distribution electrospray necessary to predict the target’s final deposition from the Lagrangian distribution. According to our findings, deep learning models can drastically reduce the amount of time needed to run CFD simulations. Depending on the model and hyperparameters applied, we can forecast the whole CFD simulation by utilizing somewhere between 10% and 15% of the initial spray development. Also, we discovered that the use of recurrent cells as an LSTM model outperformed the other models in terms of accuracy and computational efficiency, where the LSTM layers can extract better the features of the input snapshots. Overall, our research demonstrates the potential of deep learning techniques to significantly shorten the computing time of CFD simulations of coating and curing processes for the automotive sector. The results of this study have significant implications for coating and curing process design and optimization in the automobile industry as well as in other industries where CFD simulations are frequently employed.
Simulating Soft Robotic Finger Joint Using Simplified Model Free Adaptive Control and Finite Element Analysis for Transmission Line Maintenance
Authors: Narayan Meenakshi , Yu Zhiyuan
Published: February 2024

The article describes a simulation model of a soft robot finger joint that can be used in robots mounted on unmanned autonomous drones for the inspection and repair of high voltage transmission lines. The model uses finite element analysis (FEA) to analyze the torque load on a spherical robot finger joint with a defined payload at variant joint roll-yaw-pitch angle under gravity using design of experiment (DOE). The data obtained from FEA is further analyzed in Matlab using curve fitting methods to obtain a model of the finger joint. A simplified version of Model Free Adaptive Control (SMFAC) algorithm is proposed to control the desired torque and orientation of the finger joint using FEA data. The simulation results show a faster convergence rate of 99.9% and lower settling times in milliseconds compared to PID, indicating that real-time control of robot fingers can be achieved using this control algorithm. The soft robot hands can also be used for a wide range of grasping tasks beyond powerline maintenance. The article suggests that future work will involve expanding the one-joint FEA model into a multibody dynamics model to simulate the mechanical behavior of the soft robot hand and designing and controlling soft finger prototypes attached to drones for power line inspection and repair.
In-Situ Damage Progression Observations in Cross-Ply CFRP Composite Beams Under Low-Velocity Impact and Quasi-Static Indentation Loading
Authors: Batmaz Onur Ali , Coker Demirkan
Published: February 2024

In this work, we conducted in-situ low-velocity impact (LVI) and quasi-static indentation (QSI) experiments on CFRP composite beams with two different layup configurations, [04/904/02]s and [02/902/02/902/02]s, to investigate the ply clustering effects on the LVI-induced damage mechanisms. The LVI experiments were conducted utilizing high-speed photography to observe the complete sequence of damage progression. We performed QSI experiments to qualitatively identify the damage mechanisms observed during LVI events since it reduces the complications in monitoring the damage progression in the short period of impact loading. QSI experiments allowed us to obtain magnified in-situ observations on one edge of the beam with a traveling digital microscope, while a high-resolution camera was employed on the opposite edge to measure full-field strain distributions using the digital image correlation (DIC) method. We observed nearly identical damages in terms of form, location, and sequence on the specimens with identical layup configurations in both LVI and QSI experiments. However, damage mechanisms differed in the [04/904/02]s and [02/902/02/902/02]s configurations, with the latter experiencing fiber breakage in addition to matrix cracking and delamination as observed in the former configuration. The magnified in-situ observations allowed us to detect macroscopically undetectable matrix cracks that did not significantly affect the global response of the beam. The continuous monitoring of the micro-scale damages in conjunction with the DIC analyses illuminated the details of damage mechanisms observed in cross-ply laminates under LVI loading.
Hydrodynamics of Metachronal Rowing at Intermediate Reynolds Numbers
Authors: Lei Menglong , Lou Zhipeng , Wang Junshi , Dong Haibo , Li Chengyu
Published: February 2024

Metachronous rowing is a swimming mechanism widely adopted by small marine invertebrate like comb jellies, in which rows of appendages perform propulsive strokes sequentially in a coordinated manner with a fixed phase difference. To simulate metachronous rowing at intermediate Reynolds number, in this paper, a row of flexible cilia models was placed inside the flow field, with their roots stroke at a sinusoidal function of time and a fixed phase difference. A fully coupled two-way numerical solver was developed, which solves the Navier-Stokes equations for the fluid field coupled with the differential equation for the flexible cilia model. This numerical solver is applied to investigate how the row of cilia models are deformed by the hydrodynamic forces (pressure and shear) and momentum and thus impact hydrodynamic performance. Results show that the passive deformation of cilia potentially improve the hydrodynamic performance compared to the rigid cilia. With the metachronous rowing mechanism, the cilia generate the thrust to move forward. The approach used in this study presents a general way to explore the fluid dynamics of complex fluid-structure interaction problems.
Theoretical Study of Counter-Current Liquid-Vapor Flow Under Condensation Conditions Over Non-Isothermal Vertical Wall of Two-Phase Closed Thermosyphon
Authors: Zolfagharroshan Mohammad , Xu Minghan , Zueter Ahmad , Sasmito Agus
Published: February 2024

This paper proposes a new mathematical formulation describing the relationship between shear stress and film thickness to model condensing falling film of liquid in vertical thermosyphons. The mathematical model incorporates various factors, encompassing the contribution of shear stress resulting from friction force and phase change at the liquid-vapor interface, the impact of subcooling, and the influence of the convective boundary on film heat transfer. Vapor phase condensation in thermosyphons with relatively longer condenser lengths, where temperature variation is inevitable, is an area of interest for using the proposed model. The novel formulation is solved iteratively with the analytical solution of conservation equations, thermal equilibrium, and thermal resistance analogy. Optimized relaxation factors are used, and when the convergence criteria are met, the model marches over the condenser wall. The high accuracy of the model in regenerating literature data allowed the implementation of parametric study analyses on the variation of ambient air temperature, heat transfer coefficient, and wind velocity. The results are verified with a numerical model based on the modified Nusselt theory, and the underestimation of the latter approach in film thickness prediction and, consequently, heat flux has been discussed. The introduced model indicated the promising potential for laminar to wavy-laminar film regimes and could be applied to similar cases, such as co-current flows and evaporating thin films by minor revision.
Self-Sensing Piezoelectric Composite Structures via Generation and Reception of Ultrasonic Guided Waves
Authors: Zhou Shulong , Shen Yanfeng
Published: February 2024

This paper proposes a novel family of intelligent piezoelectric composite structures for the purpose of establishing structural self-awareness via integrating the function of load bearing with the capability of transmitting and receiving high frequency mechanical waves. To develop a deep insight into the mechanism of the intelligent structure, coupled-field Finite Element Models (FEM) are constructed to conduct the transient dynamic analysis for understanding the wave propagation characteristics in piezoelectric composite beams. In particular, the model employs the Equivalent Average Parameter (EAP) method, utilizing overall and nominal quantities, in order to simulate the self-sensing composites. The guided wave generation and tuning characteristics are investigated utilizing the harmonic analysis model with absorbing boundary conditions. Furthermore, meticulously crafted through a continuous process of material ratio optimization and process step refinement, sample piezoelectric composite plates are fabricated to ensure the highest degree of sensitivity and reliability during experimental demonstration. A pitch-catch active sensing setup is utilized to verify the capability of the piezoelectric composites for generating and receiving ultrasonic guided wave. Moreover, a Scanning Laser Doppler Vibrometer (SLDV) is applied to visualize the waves generated in the structure for analyzing the propagation modes of ultrasonic guided waves in the piezoelectric composite material. The numerical simulations and experimental demonstrations showcase that the proposed piezoelectric composite system possesses great potential for realizing self-awareness for future intelligent structures. The paper finished with summary, concluding remarks, and suggestions for future work.
Heat Transfer Enhancement for Circular Cylinders Undergoing Flow-Induced Vibrations: Effect of Spacing Ratio and Stagger Angle
Authors: Ali Ussama , Islam Md. , Janajreh Isam
Published: February 2024

Effective heat transfer is of utmost importance in the design and operation of industrial components, such as heat exchanger tube bundles, as it directly dictates their efficiency and durability. These components often encounter flow-induced vibrations, which subsequently influence the heat transfer characteristics. This study focuses on investigating heat transfer and flow-induced vibrations in two circular cylinders. The Reynolds number (Re) is set at 100, and the reduced velocity (Ur) is increased from 2 to 14. The cylinders’ dimensionless spacing (L/D), arranged in tandem, is changed from 1.5 to 6, and the stagger angle (α) between the cylinders is varied from tandem (0°) to staggered (45°) and side-by-side arrangement (90°). The lift (CL) and drag (CD) coefficients, streamwise and transverse vibrational amplitudes (Ax/D and Ay/D), average Nusselt number (Nuavg), Strouhal number (St), vortex shedding patterns, and temperature distribution are analyzed. Results reveal that the lock-in occurs at Ur = 8 for all arrangements. The results demonstrate that the Nuavg for the downstream cylinder is consistently lower than the upstream cylinder in the tandem arrangement due to the upstream cylinder providing a shielding effect. Rising L/D to 6 from 1.5 increases the Nuavg by 8.6% and 9.8% for downstream and upstream cylinders, respectively. As the L/D increases, the Nuavg for both cylinders increases, implying a reduction in the effect of each cylinder on the other. However, in the staggered and side-by-side arrangement, the Nuavg for both cylinders are similar, indicating that the cylinders have little to no influence on each other. The highest Nuavg is observed at the lock-in condition for all L/D and α values. The temperature contours mirror the vorticity contours, suggesting that vortex shedding has a positive effect on heat transfer.
Investigation of Off-centered Impact of Droplet on a Single Microhole
Authors: Shondhi Sakib Sadat , Alam Md Nur E. , Tan Hua
Published: February 2024

Droplet impact is central to numerous technological applications including spray coating, inkjet printing, additive manufacturing, etc. Droplet impact on solid surfaces leads to diverse outcomes, such as splashing, spreading, receding, jetting, and rebounding. In recent years, there is growing research interest on the droplet impact on mesh or holed surfaces. In this work, we investigate the dynamics associated with the off-centered impingement of a water droplet on a partially wetting substrate pierced with a single micro-hole via high-speed video photography. A 0.5-mm-diameter punch is used to produce circular holes of 630 μm diameter on a plastic film substrate of 240 μm thickness. A combination of a 10μL pipette tip and a syringe pump is used to dispense droplets of 2.8 mm in diameter. A high-speed camera with magnification lens is used to capture the entire process of droplet impact over the microhole. An in-house MATLAB code has been developed for the processing and data analysis of the captured images. In our study, the distance (referred to as off-center distance hereafter) between centers of droplet and microhole during the impact varies from 0 to 0.60 mm. The droplet release height is adjusted to vary the impact velocity from 0.49 to 1.40 m/s. Our results show that with sufficiently high impact velocity as the droplet spreads radially over the substrate, a downward jet driven by the impact inertia pinches off from the microhole and then breaks up into one or multiple droplets due to Plateau-Rayleigh instability. The jet is ejected with an angle from the axis of the microhole due to the off-center distance. A regime map has been produced to introduce the relation between Weber numbers and jet breakup conditions. We found the jetting mechanism and liquid volume penetrating through the microhole are directly influenced by the impact velocity of the droplet and the off-center distance. The jet ejection angle is dependent on Weber number and off-center distance. The jet pinch-off time was closely related to the capillary-inertial time scale. Our data indicate that the maximum spreading factor βmax generally follows the power law with the Weber number We as βmax ∼ We0.22. We also established a relationship between the number of satellite droplets and impact velocity. The volume of ejected single or satellite droplets was found to be dependent on the Weber number and off-center distance.
Nonreciprocal Transmission of Lamb Waves via Surface-Bonded Elastic Metamaterial Diode
Authors: Xu Hexuan , Shen Yanfeng
Published: February 2024

This paper presents two types of elastic meta-structural functional units with symmetric and antisymmetric layouts, synthetically collaborating for realizing one-way, nonreciprocal transmission of Lamb waves. The elastic meta-structural functional unit cells are comprised of Locally Resonant (LR) cylinders arranged in a periodic pattern bonded on an aluminum plate. The mechanism behind the metamaterial guided wave diode resides in the wave mode manipulation, including mode conversion and selective mode transmission. This study explores with a systematic parametric study on the antisymmetric elastic meta-structural unit cell with various shapes. The optimal configuration is determined from the parametric study to identify the most effective mode conversion performance. Highly effective mode conversion from S0 mode into A0 mode can be achieved by the antisymmetric units. The height of the unit cell stub and the amount of unit cells are respectively explored with a finite element model (FEM) using harmonic analysis. The performance of the proposed ultrasound mode convertor is further substantiated via the harmonic analysis of a metamaterial chain model, via showcasing the frequency spectrum of the transmitted wave modes. Subsequently, filtering of symmetric Lamb modes can be achieved by symmetric resonant elastic metamaterial. Modal analysis with Bloch-Floquet boundary condition is performed to obtain the dispersion features of the metamaterial system. By investigating the band structure and the resonant motions, a complete antisymmetric Lamb modes transmission band within the symmetric Lamb modes bandgap can be established in a wide frequency range. Afterwards, an elastic wave diode is constructed by combining the proposed unit cells for the nonreciprocal transmission manipulation of symmetric Lamb waves. The proposed nonreciprocal transmission capability may possess great potential for the purpose of one-way wave control and manipulation.
A Numerical and Experimental Analysis of Compression-Induced Cracking in Epoxy Composite Grout Under Thermo-Mechanical Loading
Authors: Waseetuddin Nahri S. , Abubakar Abba A. , Al-Athel Khaled S. , Akhtar Syed S.
Published: February 2024

Grouts are designed to withstand high loads while resisting water, high temperatures, chemicals, and other factors. They are commonly employed in various practical structural applications due to their desirable attributes, such as excellent bonding, rapid strength development, ease of preparation, and free-flow ability. Much study has recently been conducted into replacing traditional cementitious grout with polymer composites. Most grout structures are subjected to compressive loads and significant temperature variations during their operational lifetime. As a result, it is critical to consider how the variation in thermo-mechanical loading impacts the performance of polymer grouting materials. The study presents an experimental and numerical analysis of the fracture behavior of epoxy polymer grout under compressive loads and at different temperatures. The primary fracture mechanism considered in this study will be a compressive fracture on an inclined through-crack. XFEM simulates cracking in the epoxy grout at 25 °C and 65 °C, while the cementitious samples are only modeled at 25 °C. Experiments have been performed to benchmark the compression problem, and its results validate the XFEM simulation. The cementitious grout possesses meager compressive strength. The epoxy grout material can endure a very high load at 25 °C. However, the compressive strength of the epoxy grout significantly decreases with an increase in temperature. The decrease in compressive strength is due to the weakening of the epoxy polymeric chain, interface debonding, and the formation of voids at high temperatures. The presence of multiple flaws of different sizes and shapes significantly impacts the fracture behavior of epoxy grout, as confirmed by the XFEM simulations. Smaller-sized defects exhibit a higher possibility of cracking due to the high-stress concentrations.
An Agent-Based Modeling Approach for the Diffusion Analysis of Electric Vehicles With Two-Stage Purchase Choice Modeling
Authors: Xu Jiawen , Bi Youyi
Published: February 2024

Diffusion research of innovative technologies is crucial for new product positioning and strategic planning in product design. As a versatile system simulation method, agent-based modeling (ABM) has been used in many previous studies on the diffusion analysis of electrical vehicles (EVs). In these simulations, modeling consumers’ purchase decisions is a significant step. Previous studies often adopt simple rule-based decision criteria in this step, while a more accurate purchase decision model can contribute to more reasonable diffusion analysis of EVs. To fill this gap, this paper presents an agent-based modeling approach for the diffusion analysis of electric vehicles with two-stage choice modeling. The basic idea is to separate consumers’ decision-making process for purchasing a car into two stages. Consumers form a small choice set from the whole auto market in the first stage. In the second stage, consumers make the final choice from the choice set built in the first stage. In addition, the word-of-mouth (WOM) effect and consumers’ social network are also considered in the ABM, which can further improve the accuracy of the diffusion analysis of electric vehicles. A case study using data collected from Shanghai, China, is presented to demonstrate the proposed approach. The influence of factors such as government policy and technological improvement on the diffusion of EVs are also discussed. These insights can assist automakers in further improving their product design and enhancing their market competitiveness.
Model-Free Improvement of Contouring Accuracy of Nonsymmetric Planar 3PRR Parallel Kinematics Machine
Authors: Rosyid Abdur , El-Khasawneh Bashar
Published: February 2024

As the basic proportional-integral-derivative (PID) control with off-the-shelf control hardware is still the widely used standard of industrial control practice, it is important to find some practical ways to increase the contouring accuracy without a need to apply a model-based control scheme which requires tedious dynamic modeling and leads to high computational cost. This paper applied three model-free approaches, namely decentralized PID control with linear PID gain scheduling, decentralized PID control with velocity trajectory input, and decentralized PID control with high-order polynomial motion profile, to a geometrically nonsymmetric parallel kinematics machine (PKM) having 3PRR topology (3 = number of legs, P = prismatic joint, R = revolute joint) to improve its contouring accuracy. The experiments showed that the linear PID gain scheduling does not provide a significant improvement in the PKM contouring accuracy, whereas the velocity trajectory input and the higher-order motion profiles significantly improve the PKM contouring accuracy.
Forming Mechanism of Hollow Shafts With Heavy Section Shrinkage by Multi-Roll Tandem Skew Rolling
Authors: Zhang Song , Shu Xuedao , Li Zixuan
Published: February 2024

Hollow shafts with heavy section shrinkage have the advantages of material saving, weight reduction, easy maintenance and flaw detection, so they are widely used in automobile, aerospace and other fields. However, it is difficult to break through the bottleneck of 75% section shrinkage when forming hollow shaft by traditional rolling process, which limits its application. Therefore, a new process for short process flexible forming of hollow shafts with heavy section shrinkage, namely the multi-roll tandem skew rolling (MRTSR) process, has been proposed. In order to analyze the feasibility of forming hollow shafts with heavy section shrinkage by MRTSR, theoretical and simulation studies are conducted on the forming process. Firstly, the forming principle of hollow shaft by MRTSR is introduced, and the technological characteristics of multi-roll and single-roll skew rolling are compared. Then, the kinematic analysis of the rolling process is carried out to obtain the pitch of the roller pushing the rolling piece forward. Based on this, the stable rolling condition of the hollow shaft by MRTSR is deduced. Finally, a finite element model was established to simulate the forming process of a hollow shaft with heavy section shrinkage by MRTSR, and the distribution of the equivalent stress and strain in a hollow rolling piece with 81% section shrinkage was analyzed. The results show that it is feasible to form hollow shaft with heavy section shrinkage by MRTSR.
Sensitivity Improvement of Graphene-Based Gas Sensors by Direct Growth of Carbon Nanotubes on the Graphene
Authors: Suzuki Ken , Hirose Yuto , Qiao Xiangyu , Fu Wangyang , Miura Hideo
Published: February 2024

Graphene and carbon nanotubes (CNTs) have attracted extensive attention because of their excellent physicochemical properties, such as high electron mobility, superior mechanical strength, and excellent thermal conductivity. In addition, the electronic resistance of graphene and CNTs changes when various molecules are adsorbed on their surfaces, which has great potential in gas sensing. However, since ultra-sensitive sensing at the ppb level is still a challenge, we have proposed a vertically aligned CNT-graphene hybrid structure to improve the sensitivity and verified its effectiveness by evaluating the sensitivity to H2O gas in this study. The effect of the CNT layer structure synthesized directly on the graphene surface on the sensor sensitivity was investigated. The sensor sensitivity improved with the larger area of the CNT layer covering the graphene surface and the higher density of CNTs. On the other hand, increasing the thickness of the CNT layer to 15 μm or more did not significantly improve sensitivity. The CNT-graphene hybrid gas sensor with a graphene layer thickness of 15 μm showed a resistance change of 0.6% per 1% humidity, indicating that our proposed CNT-graphene hybrid structure can improve sensor sensitivity more than ten times.
Mechanical Characterization of Li-Ion Cells and the Calibration of Numerical Models Using Proper Generalized Decomposition
Authors: Schmid Alexander , Pasquale Angelo , Ellersdorfer Christian , Raffler Marco , Champaney Victor , Ziane Mustapha , Chinesta Francisco , Feist Florian
Published: February 2024

The behavior of lithium-ion cells under mechanical load is determined by both experiments and simulations. Extensive experimental data are required for the calibration and validation of complex numerical models. The possible experiments may differ in dimension (component, cell, cell stack and module) and in boundary conditions during the experiments (e.g. loading rate, sample condition). This study covers two aspects: The characterization and the modeling: First an overview on innovative experimental procedures is given. Second, it is shown how to quickly calibrate a macroscopic cell model against the experimental data. The calibration effort increases strongly with the number of calibration parameters as with the number of test configurations against which the model is calibrated. A new calibration procedure is presented to overcome this hurdle: First, a meta-model is created, covering the calibration parameters and calibration load cases, employing Proper Generalized Decomposition. Once the meta-model is adequately trained, the optimization of calibration parameters is conducted in real-time employing the meta-model. So a macroscopic cell model can be calibrated very quickly against a given set of experimental data sets. This is important because there are constant improvements and changes to the batteries in terms of materials, dimensions and structure.
Effect of Foot Additional Mass on the Clinical Angles of Knee Extension Exercise
Authors: Caruntu Dumitru I. , Trejo Alfirio , Rodriguez Eric , Alvarez Barriga Camila Tatiana
Published: February 2024

This study investigates the effect of foot additional mass on the abduction and internal rotation knee angles during knee extension exercise. Three subjects (two male and one female) performed four sets of ten repetitions of the knee extension exercise for the right leg. For the first set, the subject performed the exercise with no additional weight. For each set after, weight was added around the subject’s right foot and the subject was allowed a rest period before beginning the next set. The weights for sets 1, 2, 3, and 4 were 0.00kg (no additional weight), 0.82kg, 1.64kg, and 2.27kg respectively. The subject’s motion during the knee extension exercise was tracked by utilizing VICON motion analysis system to capture position data of markers placed on the femur and tibia. This data was filtered with a low pass Butterworth filter and used to create tibial and femoral coordinate systems’ unit vectors. These unit vectors were used to determine the knee joint coordinate system. The joint coordinate system was then used to calculate the clinical angles: knee extension, abduction, and internal rotation. After averaging ten repetitions for each set (additional mass), the effect of additional mass on clinical angles was reported. The data showed that each subject had a differing natural motion when performing the exercise. The amount of internal rotation during the first 90° to 30° of flexion can vary between subjects. However, the screw-home mechanism is observed, i.e. tibia externally rotates with respect to femur as the knee extends. This is true for all subjects. On the other hand, the abduction of the tibia varies greatly between subjects. This finding has been acknowledged in the literature. Although the initial and final values for the clinical angles were affected when additional weight was added, the amount was insignificant and unpredictable.
Mechanical Properties and Interfacial Strength of Active Material Layer / Copper Foil of Anode Sheet in Lithium-Ion Battery (LiB)
Authors: Ogata Kazuma , Takano Yoshinori , Yasuda Shotaro , Shibayama Yuto , Yonezu Akio
Published: February 2024

Lithium-ion batteries (LiB) are widely used in industrial field, and its safety is increasingly attracting attention. In the LiB, anode sheet has a layered structure consisting of an active material layer (including a binder and active material) and a copper foil as current collector. Generally, active material layer is mechanically weak, and often shows mechanically degradation due to mechanical loading. In addition, LiB cases interfacial delamination during the fabrication process and practical usage. Interfacial delamination leads degradation of the electrical performance and causes an internal short circuit. Therefore, for battery safety and better mechanical design, this study evaluated the adhesion strength of the interface between active material layer / copper foil in anode sheet using Laser Shock Adhesion Test (LaSAT). In addition, repeated LaSAT was also conducted to apply cyclic loading to the interface, and its fatigue interfacial strength was evaluated.
Computational Analysis of the Compressive Behavior of TPMS Graded Lattice Structures Versus Primitive TPM Lattice Structures Produced by Additive Manufacturing
Authors: Abdelaal Ahmed F. , Al-Athel Khaled , Abubakar Abba , Ali Usman , Akhtar Syed Sohail
Published: February 2024

Additive manufacturing (AM) provides an opportunity to fabricate complex geometries such as lattice structures that have unique mechanical, thermal, and fluid-dynamic properties, which are difficult to achieve using traditional subtractive methods. Lattice structures are utilized in the lightweight of automotive and aerostructures, sandwich cores, energy absorption, and blast protection. To ensure that the lattice-structured parts meet the required design criteria such as stiffness and strength, it is important to predict their mechanical behavior accurately. Triply periodic minimal surfaces (TPMS) are widely used for designing lattice structures due to their unique geometric properties. Although graded TPMS lattice structures have been shown to improve their mechanical properties by tailoring their properties across the structure, there is still a lack of understanding of how the graded structure affects their compressive behavior. This study aims to compare the compressive behavior of the Schwarz-diamond (SD) TPMS lattice structures for graded and primitive produced by additive manufacturing. Finite element analysis is used to capture the effect of both lattice structures on the mechanical behavior. This study provides valuable insights into the compressive behavior of SD-TPMS lattice structures and contributes to improved design and optimization techniques for additive-manufactured lattice structures.
Nonlinear Vibrations of a Shallow Spherical Cap Under Pressure Loading
Authors: Iarriccio Giovanni , Zippo Antonio , Pellicano Francesco
Published: February 2024

The nonlinear vibrations of shallow spherical caps, under the action of static and fluctuating pressure, are studied. A meshless method based on the Novozhilov’s nonlinear thin shell theory is considered to reduce the partial differential equations (PDEs) to a set of ordinary differential equations (ODEs): the displacement fields are expanded though a mixed series of Legendre polynomials and harmonic functions in the meridional and circumferential directions respectively. The ODEs are obtained by taking advantage from the Lagrange equations and are analysed using continuation and direct integration techniques. Results show that nonlinear interactions can result in the activation of non-symmetric vibrational states characterized by weakly chaotic features.
Voxel Printing of a Multi-Material 3D Printed Prosthetic Socket Based on FEM Simulations
Authors: Pigazzi Riccardo , Bertolini Michele , Rossoni Marco , Colombo Giorgio
Published: February 2024

Prosthetic socket for lower limb amputation needs to be customized based on the residual limb characteristics to satisfy functional and comfort requirements. One of the main causes for ill-fitting socket is the lack of appropriate application of material properties that match the characteristics of the amputee’s biological tissue. Additive manufacturing has the ability to confer inhomogeneous properties to the printed object. This paper presents a digital workflow for the design and fabrication of a prosthetic socket based on the results of numerical simulations and the use of multi-material voxel printing. A voxel model of the socket is generated and the contact pressure between the residual limb and the socket derived from FEA is mapped to the voxels, which were correspondingly assigned a material. This allow to define a material distribution at the voxel level and to generate printing instructions as a stack of bitmap images for voxel printing. The goal is to obtain a socket characterized by a spatial variation of material stiffness, according to the pressure map extracted from simulation, in order to adapt the socket to the patient’s anatomy and, consequently, to reduce contact pressure and discomfort.
Atomistic Investigation of the Effect of Non-Glide Stress on the Deformation and Dislocation Transfer at Hexagonal Close-Packed Metal Grain Boundary
Authors: Oyinbo Sunday Temitope , Oviroh Peter Ozaveshe , Jen Tien-Chien
Published: February 2024

The molecular dynamics method was utilized in this study to investigate the dislocation transfer mechanism at the atomic scale at basal and prismatic (BP) boundaries in Magnesium. Firstly, uniaxial deformation (pre-tensile and pre-compression) is dynamically applied at the BP interface. The results demonstrate that when plastic deformation increases, there is a remarkable change in the structure of the BP interface. Furthermore, the interaction mechanism between the BP interface and basal dislocations (edge and screw) was observed. The results show that for the basal and the prismatic slip when the Burgers vector is aligned in a direction that is perpendicular to the interface, a basal dislocation is transmuted to a prismatic dislocation and vice versa. The critical resolved shear stress for first basal screw dislocation transmutation is considerably higher than edge dislocation. The pre-normal strain and temperature analyses for the BP interface were also performed to understand the interactions’ mechanism better. As the pre-tensile strain increases, the maximum critical resolved shear stresses to initiate basal edge and screw dislocation transmutation through the BP interface are progressively reduced. In contrast, when the pre-compression strain increases, the maximum critical resolved shear stresses increase.
Vision-Based Tool Wear Classification During End-Milling of Inconel 718 Using a Pre-Trained Convolutional Neural Network
Authors: Kumar Aitha Sudheer , Agarwal Ankit , Jansari Vinita Gangaram , Desai K. A. , Chattopadhyay Chiranjoy , Mears Laine
Published: February 2024

Nickel-Based Superalloys (NBSAs) are widely used for components subjected to high-temperature applications due to their excellent mechanical strength, toughness, and corrosion resistance. Despite favorable properties, NBSAs work-harden during machining, resulting in acute temperature rise at the cutting edge, severe plastic deformation, and rapid tool wear. The lower thermal conductivity, intense friction at the chip-tool interface, chemical affinity with tool material, and temperature gradients typically lead to abrupt crater formation or cutting-edge chipping in addition to rapid flank wear. Three distinct phenomena characterize tool wear during end milling of NBSAs; rapid flank wear, abrupt crater formation, and cutting-edge chipping. The continued use of worn or damaged cutting tools leads to poor surface finish and, eventually, catastrophic failures, resulting in significant machine downtime. As each tool wear condition has a unique mitigation strategy, timely identification and classification are imperative to implement solutions that minimize wear and guide tool replacement.

In recent years, the augmentation of vision-based systems with pre-trained Convolutional Neural Networks (CNNs) has shown great promise in failure identification and classification tasks. The present work develops an image-based classification model using a pre-trained CNN, Efficient-Net-b3, for identifying three tool wear conditions during end milling of Inconel 718 (IN718). The network training uses labeled image datasets that capture various tool wear characteristics generated using end-milling experiments. The extensive training dataset requirement of the CNN was met using image augmentation techniques by varying the brightness, contrast, and orientation of the captured images. The prediction abilities of the algorithm were corroborated by validating the model on a validation dataset and further testing on new unseen datasets. It has been shown that Efficient-Net-b3 demonstrates robust prediction accuracy for all three tool wear conditions. The proposed classification model can be further employed for developing an on-machine vision-based tool wear classification system.
Efficient Modeling of Blades via Beam Element in the Multi-Objective Optimization of Small Wind Turbine Blades
Authors: Kayran Altan , Çöker Demirkan , Muyan Can , Batmaz Onur Ali , Pourrajabian Abolfazl , Wood David
Published: February 2024

A study is conducted to propose an efficient structural analysis method to be included in the multi-objective optimization of small wind turbine (SWT) blades. For this purpose, initially aerodynamic optimization of a SWT blade is performed utilizing a multi-objective function including the power output and the starting time. Structural analyses of the aerodynamically optimized blade are performed utilizing different fidelity finite element models for justifying the use of the reduced-order finite element (FE) model with beam elements. As a reference, higher fidelity three-dimensional (3-D) FE analyses of the blade are performed and alternative 1-D beam-blade models are evaluated utilizing the results of 3-D FE solutions. In this respect, tapered and multi-section non-tapered 1-D beam-blade model alternatives are evaluated as potential lower fidelity reduced-order models to be employed as efficient structural solvers in a future multi-objective optimization of the small wind turbine (SWT) blade. It is shown that multi-section non-tapered beam-blade FE model of the SWT blade is a robust model which handles unsmooth section transitions, which are encountered in meta-heuristic optimization of blades, effectively unlike the tapered beam-blade model and it can be used in a future constrained optimization involving structural metrics as constraints and/or objective functions.
Part 1: Gyroscopic Control of Robotic Smart Vehicles Using SO(3)
Authors: Chen Jason , Kim Eunkyu , Leppitsch Calder , Meiner Benjamin , Zaretsky Daniel , Rykkje Thorstein Ravneberg , Luchtenburg Dirk M. , Impelluso Thomas J.
Published: February 2024

In response to challenges faced in engineering education, this paper presents the Moving Frame Method (MFM) as an alternative to the existing pedagogies. This paper, and a companion paper, present the MFM for the analysis of rigid single-bodies, in the context of an international collaborative senior design project between two engineering schools: The Cooper Union in New York, NY and The Western Norway University of Applied Sciences in Bergen, Norway.

Students at Cooper Union analyzed the smart vehicle as a single-body problem; a second team in Norway used the same method to model the problem as a multi-body. Both teams modeled the gyroscopic lift effect using the foundational theory of the MFM. This first paper presents the underlying theory of how the MFM uses the Special Orthogonal Group, SO(3), to model the problem of gyroscopic lift of a smart vehicle. It presents the underlying theory: motion of a reference frame in terms of the reference frame; and the various properties of SO(3) and its associated algebra as applied to a new, undergraduate approach to dynamics.

The paper presents two design alternatives to lift a vehicle, the first one uses two gyroscopes and the second a single reaction wheel. The modeling and analysis process led to the design that employs a single reaction wheel. Next, it examines the model-generated estimates for torque generated and subsequent motion of the car. After analysis using the initial model, the Cooper Union Team pivoted a design approach before entering the rapid prototyping phase of the project. Then, it discusses the manufacturing process for the final version of the car and the construction of a test enclosure for ensuring safety by containing the heavy reaction wheel spinning at high speeds. Finally, it describes the testing of the car, which involves measurement of angular impulse due to a braking event. The results from initial experiments on the prototype validate the model and confirm that the car can lift itself using the selected method.
Tensile and Fatigue Response of Steel Parts Fabricated by the Additive Friction-Stir Deposition Process
Authors: Alam Chowdhury Sadid , Ahmed Radif Uddin , Rahman M. Shafiqur
Published: February 2024

Additive Friction Stir Deposition (AFSD) is a relatively new solid-state additive manufacturing (AM) process that utilizes frictional heating and plastic deformation for the layer-by-layer deposition of materials (e.g., metals and alloys). This study characterizes the mechanical behavior of AFSD-processed AISI 4340 steel parts under various tensile and fatigue loading conditions. A distinct scale of AISI 4340 steel specimens, namely the standard ASTM rectangular dog bone specimen is considered for the analysis. A finite element (FE) model is developed to predict the tensile and fatigue behavior of AFSD-processed steel AISI 4340 parts under multiple loading circumstances. The FE model can generate results for the von-Mises stress, strain, total deformation, fatigue life, factor of safety, and fatigue limit under various loading conditions. Experimental data for the tensile and fatigue responses are compared with the mechanical behavior obtained from the FE model at room temperature. The modeling results for the maximum tensile stress, deformation, and fatigue life exhibit excellent agreement with the experimental findings, which successfully confirms the validation of the FE model. The FE modeling for the fatigue analyses is conducted for a unit load ratio and by applying zero-based cyclic loads at different frequencies. Results from the current study successfully lead to generating a stress-life curve for the AFSD-processed AISI 4340 steel parts. According to the findings, the AFSD-processed components show higher strength than that of the parts created by conventional manufacturing techniques. In all cases, the AFSD specimens show extended lifespan compared to the conventionally manufactured specimens.
A Heterogenous Hydrogel Brain Phantom for Convection-Enhanced Drug Delivery
Authors: Pineda Rose , Ryu Sangjin , Kim Seunghee , Zhang Chi
Published: February 2024

Hydrogel plays an important role in several biomedical engineering applications, one being convection enhanced drug delivery (CED). During CED, a drug is locally injected into the brain to attack diseased or cancerous cells via infusion under pressure. Predicting the flow path of the injected drug during CED has been challenging because fluid infiltration through brain tissue will cause the solid to deform, causing a change in the resultant flow pattern. To characterize the pharmacodynamics of the injected drug through brain tissue, an accurate in vitro engineering model that emulates material properties of brain tissue is highly demanded. We thus propose to develop and characterize a heterogenous hydrogel structure to replicate the soft, porous, and complex structure of the organ, for further exploration of how injected fluid affects deformation which in turn affects the flow. In this study, we created and characterized a heterogeneous gel brain phantom consisting of hydrogel gel beads and matrix of different Young’s moduli.

Agar gel beads were fabricated from the gel solution (1 or 2 w/v%) using a rotating-liquid-based drop generator. With needles of two different inner diameters (0.413 and 1.372 mm), 1 w/v% solution resulted in beads of a diameter of 1.17 mm and 1.47 mm, respectively, and 2 w/v% solution resulted in beads of a diameter of 1.70 mm and 1.99 mm, respectively. Through microscopic compression tests, the Young’s moduli of agar beads were measured to be 34.2 kPa and 100.8 kPa for 1 and 2 w/v% cases, respectively. For validation, homogeneous agar discs were fabricated and tested: macroscopic Young’s modulus values were 57.1 kPa and 143.2 kPa for 1 and 2 w/v%, respectively.

The heterogeneous brain phantom was fabricated by embedding prepared agar gel beads into agar matrix of different concentrations (1% beads in 2% matrix and vice versa). Fabricated heterogeneous gel discs were characterized via compression tests, and the overall Young’s modulus of the heterogenous phantom was found to be lower than that of the matrix. Discs made with 1% agar beads and 2% agar matrix resulted in a Young’s modulus of 45.24 kPa, whereas discs made with 2% agar beads and 1% agar matrix resulted in a Young’s modulus value of 18.95 kPa. Although simply binary, fabricated heterogenous agar discs demonstrate that their mechanical behavior differs from their homogeneous counterpart, which clearly supports urgent need for heterogenous gel phantom for advancing CED.