bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving the Yield of Biodiesel Production Using Waste Vegetable Oil Considering the Free Fatty Acid Content
Authors: Ityokumbul Igbax Saanyol , Swartling Daniel , ElSawy Ahmed , Idem Stephen
Published: February 2023

This paper investigates the use of waste vegetable oil (WVO) for production of biodiesel. The goal of this study was to explore the improvement of biodiesel production to achieve high yields. Different oil streams, including virgin canola oil and WVO, were used as the raw material for the transesterification processes. These oils had different fatty acid contents as a result of environmental or previous processing conditions. The main objective of this study was to assess the impact of free fatty acid (FFA) content on the resulting yield. In addition, the yield was influenced by production parameters such as reaction time, reaction temperature, molar/volume ratios of oil to alcohol, catalyst amount, and mechanical mixing. This was accomplished by automating the biodiesel production from WVO, thereby achieving improved processing and requiring minimal direct human involvement. A biodiesel production apparatus was developed with a Raspberry Pi 3 microcomputer to control the process. It was shown that the particular choice of these process parameters depended on the particular oil type. This research used mixtures of virgin and waste vegetable oils at different volume ratios (oil to alcohol) of 4:1, 6:1, and 8:1, which was determined by the FFA content of the oil. In addition to mechanical mixing, ultrasonication rated at 500W, 20kHz was used to enhance mixing by adding 450 kJ to the process, thereby reducing both the processing time and the amount of methoxide needed to perform a base-catalyzed transesterification. The production temperature was held within the range of 50–65°C. This research demonstrated that optimal yield depends on temperature, catalyst concentration, FFA content of the oil, and the energy introduced by sonication. A 96% yield was achieved with the following parameters: an oil to methanol volume ratio of 6:1, 0.6% weight concentration of catalyst (NaOH) at 6.25 g, and FFA values of approximately 5%. It was determined that the proposed system can produce acceptable quality biodiesel.
A Green and Sustainable Approach for Carbon Steel Acidic Corrosion Inhibition Using Agricultural Waste: Experimental and Theoretical Studies
Authors: Sanni Omotayo , Ren Jianwei , Jen Tien-Chien
Published: February 2023

Carbon steel corrosion in hydrochloric acid media is a huge challenge in the chemical industry; hence, creating green and more efficient inhibitors is an urgent task. Furthermore, the increasing amount of solid wastes arising from the municipality and other sources and its disposal consequence has been a major economic and environmental problem. Hence, in this research, the effect of agricultural waste as a natural inhibitor on the carbon steel dissolution in one molar hydrochloric acid solution was studied using electrochemical and surface techniques. The obtained results showed that the corrosion protection potential of the agricultural waste increases with the agricultural waste concentration and an optimum value of 95.92% was achieved at 500 ppm concentration. The waste adsorption on the metallic surface followed the Langmuir adsorption isotherm. The electrochemical impedance spectroscopy test shows that the inhibitor inhibits the metal against corrosion by getting adhered to the carbon steel surface. The scanning electron microscopy analysis proves that in the presence of the inhibitor, the surface of the carbon steel becomes smooth owing to the inhibitive films formed on the metal surface. The results demonstrated that the agricultural waste extract is an excellent green and eco-friendly corrosion inhibitor.
Modeling and Verification of Firing Dynamics of a Multiple Launch Rocket System
Authors: Aydın Berk , Ünver Hakkı Özgür
Published: February 2023

Multiple rocket launcher systems have great strategic importance in today’s defense systems. Therefore, the development and the quality of these strategically important systems are among the priorities of defense industry companies. The quality of the multiple launcher rocket systems is twofold. 1) Firing the ammunition with the appropriate time interval within the correct trajectories, 2) leaving the firing location quickly after completing the mission. In this study, stabilizer support legs were not used to increase vehicle mobility. The dynamics of a multiple rocket launch vehicle are modeled using rigid bodies and elastic elements with eight degrees of freedom in total. Since a 90-degree firing was performed relative to the longitudinal direction, half-vehicle modeling has been developed in the lateral direction of the vehicle. Firing tests had been executed without a support leg over a Multiple Launch Rocket System. During the firing, measurements were taken with a 3-axis accelerometer and gyroscope over the elevation and azimuth platforms. In addition, LPTs in vertical and lateral directions are placed on the superstructure. With these LPTs, the data obtained from the 3-axis accelerometer and gyroscope on the azimuth platform have been confirmed. The model parameters, stiffness/damping parameters of tires, suspensions, and hydraulic actuator, have been obtained using initial test results with MATLAB™ Parameter Estimator toolbox. The model’s accuracy has been verified with a second firing test result.
Control of Flight Vehicles From the Perspective of Non-Holonomic Constraint Manifold Dynamics: Quadrotor Application
Authors: Dahal Ambika P. , Barhorst Alan A.
Published: February 2023

In this paper, we address the problem of flight path planning and control. We approach the problem from the perspective of non-holonomic generalized momenta. We first build a desired minimum Jerk trajectory that we use as a momentum manifold constraint for the vehicle. We then develop a trajectory reference model of the flight vehicle that evolves exactly on the flight path as a constraint, as if the vehicle were a bead on a wire in the generalized coordinate configuration space. This model uses non-holonomic generalized momenta and position and orientation variables as states, the model is of order 2N – M, where N is the full dimension of the vehicle model and M is the number of manifold constraints imposed. These momenta models are canonical without Lagrange Multipliers. Next, we build a full 2N order model of the flight vehicle and design an LQR controller linearized about nominal path independent flight. We then implement this control in the full flight model and use as the reference state trajectory the constrained momentum states computed on the desired flight path. We allow inflight disturbances. We demonstrate that this approach provides good performance for a Quadrotor flight vehicle.
Pipeline Leak Detection and Localization Based on Advanced Signal Processing and Negative Pressure Wave Analysis
Authors: Li Weiming
Published: February 2023

Pipeline monitoring and leak detection are critical for safe and economical operation as well as preventative maintenance in water and oil industry. They also provide environmental protection from crude oil emission or theft. Leak detection and localization play a key role in the overall integrity monitoring of a pipeline system especially for long residential water pipelines and midstream crude pipelines. Operational data such as fluid flow and pressure data are often utilized in many physics and computation-based leak detection and localization methods. However, noise in both flow and pressure affects recognition of actual leak pressure drop and results in false leak alarm and inaccurate leakage localization. In this paper a total variation regularized numerical differentiation (TVRegDiff) algorithm is used to estimate derivatives from noisy fluid flow and pressure data. Then possible leak events from both fluid flow data and pressure data are obtained by examining these derivatives against corresponding control limit lines. Customized parameter criteria of flow and operation activities are used to effectively filter flow and operation events from possible leak events. Therefore, earliest leak occurrence time and pressure meters can be identified. Finally, negative pressure wave (NPW) analysis is combined with the leak recognition to compute and locate leakage. Negative pressure wave methods are based on the principle that a leak will cause a sudden pressure alteration as well as a decrease in fluid flow speed which will result in an instantaneous pressure drop and speed variation along the pipeline. As the instantaneous pressure drop occurs, it generates a negative pressure wave starting at the leakage position and propagates with certain speeds towards both the upstream and downstream ends of the pipeline section. Depending on the leakage position from the two ends and actual negative pressure wave velocities towards upstream and downstream there are time sequence of the pressure wave arriving at both ends. The lapse of time arrival and negative pressure wave velocities are then used to calculate the actual leakage position within the pipeline section. A field leak case study indicates that actual leak pressure drop is correctly captured and pipeline leakage can be accurately located. The accuracy of leak localization is theoretically dependent on the pressure and flow meter frequency. With widely accepted industry standards for pressure devices used in industry applications it is proved to be a practical, efficient and accurate leak detection and localization method. This method can also be applied to not only residential water pipelines but crude oil pipelines.
Thermo-Mechanical Properties of SiC-Mineral Binder Composites for Space Applications
Authors: Chandrasekaran Sujithra , El-Ghannam Ahmed , Monroe James A. , Xu Chengying
Published: February 2023

Due to its excellent stiffness, thermal stability and low density, silicon carbide (SiC) is an excellent candidate for fabrication of lightweight substrates for space mirrors in telescopes and satellites. However, the strong Si-C covalent bond induces high thermal stability and mechanical strength which makes it difficult to manufacture dense SiC. Other ceramic mirror materials such as Cordierite (CO720) by Kyocera® and Spodumene (ZERODUR®) by Schott® are characterized by their light weight, near zero thermal expansion coefficient and excellent thermal properties. However, mirrors made of cordierite or spodumene have relatively low stiffness and unsatisfactory thermal conductivity. We hypothesize that composites made of SiC-Cordierite and SiC-Spodumene can serve as better mirror substrates characterized by high stiffness, high thermal conductivity and improved thermomechanical stability. The present study reports on the synthesis and characterization of SiC-Cordierite (SiC-Cord) and SiC-Spodumene (SiC-Spod) using powder metallurgy method. The densification and thermomechanical stability of the SiC-mineral composites are enhanced by a novel in situ mineralization mechanism at the interface between the SiC and mineral binders between 800 °C and 1200 °C. The densities of SiC-Cord and SiC-Spod composites were 2.74 g/cc and 2.61 g/cc, respectively, while the thermal conductivities were 6.737 W/m. K and 3.281 W/m. K, respectively. Polishing the SiC-Cord with SiC grit numbers 400–1200 and diamond/silica slurry resulted in a mirror surface with an average roughness of 2.32 nm on SiC particles. The nano indentation stiffness of the polished SiC-Cordierite composite measured 239.9 ± 20.6 GPa. The stiffness of the SiC-Cord composite is superior to that of pure cordierite (140 GPa) or Zerodur (80 GPa). The average Vickers hardness of SiC-Cordierite was 8.12 ± 4.5 GPa which was superior to that of Zerodur (6.08 GPa) and comparable to that of pure cordierite (8–8.5 GPa). The composite samples demonstrated high thermal shock resistance as indicated by their comparable compressive strength and dimensional stability before and after quenching from 1200 °C to room temperature in water. Taken altogether, the superior thermomechanical properties of SiC-Cordierite and SiC-Spodumene suggest their suitability for mirrors in space-based telescopes.
Research on Variation Law of Rolling Force of Three-Roll Skew Rolling Hollow Axle
Authors: Wang Jitai , Shu Xuedao , Xu Haijie , Ye Caoqi , Xia Yingxiang , Zhang Song
Published: February 2023

In the research of part forming, forming force is one of the most concerned factors. To explore the variation law of rolling force in the process of three-roll skew rolling (TRSR) hollow axle, the process of TRSR hollow axle is tested and simulated in this paper. First, the working principle of TRSR hollow axle is described; Second, taking the hollow axle of LZ50 steel as the research object, according to the actual performance of TRSR mill, the blank and rolling process parameters are selected, and the finite element model is established; Third, combined experiment and numerical simulation, the evolution laws of the rolling force are obtained by exploring the forming process of TRSR hollow axles; Fourth, the evaluation standard of rolling force is determined on the basis of the evolution law of rolling force, combined with the typical process parameters, and the orthogonal test was carried out. The results show that the simulated evolution law of rolling force is basically consistent with the experimental result. The evolution curve is opposite to the surface shape of the rolled piece. Besides, the rolling force increases gradually with time. Through orthogonal test, the influence subsequence of process parameters on rolling force and relationship between them are determined. In addition, the quantitative relationship between process parameters and rolling force is established.
Design and Fabrication of a Test Rig for a New Approach on Health Monitoring of Roller Bearings Using Acoustic Emission
Authors: Bjarkason Heimir Rafn , Asgeirsson Saethor , Unnthorsson Runar
Published: February 2023

This article presents the design, equipment selection and implementation of a test rig using non-destructive evaluation (NDE) for rolling element bearings used in Vertical Axis Wind Turbines (VAWT), designed and manufactured by Icewind in Iceland. The design is outlined along with the description and preliminary results of a pilot test of the rig. Features of Acoustic emission waves are used for the health monitoring and fault detection. The proposed method of using AE wave segments to construct a surface plot of features is presented. The usage of a high precision encoder to map the acoustic wave over the rotation of the bearing is proposed and demonstrated. Using surface feature plots and the mapped location in the rotation is an intuitive way to characterise the AE signal for condition monitoring, and allows for the possibility to locate defects in bearings effectively providing additional information to time frequency analysis such as Fourier transformations on the acoustic signal.
Part Metrology and Defect Detection Using Machine Vision
Authors: Granitto Anthony , Chauhan Vedang
Published: February 2023

This paper focuses on the detection, classification & sorting of good and defective blade/automotive fuses through the utilization of Machine Vision Inspection (MVI). Fuses are an electrical safety device found in most vehicles and serve to protect their wiring and electrical devices against overcurrent. These small-size components are produced in large quantities, through a process involving the encasing of two metal prongs connected by a thin metal strip inside a plastic housing. Due to the nature of working with delicate metals and plastic, during the manufacturing process multiple defects can occur. The purpose of the project was to detect, classify and sort good and defective fuses, while performing part metrology solely on good fuses. Using NI Vision Builder Software, an image acquisition algorithm was written to generate a database of images for all the fuse classes. With this database, further algorithms were constructed to identify each class of fuse as it progressed along the conveyor. Utilizing vision inspection techniques such as pattern matching and distance measurement, the system was able to properly classify the fuses in the database. If the system determined the fuse to be defective, an I/O signal from the smart camera activated a pneumatic system that would remove the fuse. However, when the system classified a good fuse, it was allowed to continue along the conveyor and be collected after part metrology was performed by another algorithm. A graphical user interface (GUI) displayed these inspection statistics in realtime. This project was successful in completing all the defined goals for the system and proved to have an object classification accuracy of over 90%. This MVI system has the proper algorithms to be used in tandem with a high-speed smart camera, for adaptation into a real-world manufacturing application.
Relations of Radial Vibration of the Arterial Wall to Pulsatile Parameters in Blood Flow for Extraction of Arterial Indices
Authors: Hao Zhili
Published: February 2023

In light of the utility of radial vibration of the arterial wall for clinical values, this paper presents a theoretical study on the relations of radial vibration of the arterial wall to pulsatile parameters in blood flow. Pulse wave propagation in an artery is formulated as a combination of the governing equations of blood flow and the arterial wall and no-slip conditions at the blood-wall interface. A free wave propagation analysis is conducted on the problem to obtain the wave velocity and the theoretical expressions for blood flow rate and arterial radial displacement in terms of pulsatile pressure. With the harmonics of a pulse signal, mathematical relations of radial vibration of the arterial wall to pulsatile parameters in blood flow are derived under two conditions: without and with wave reflection. These mathematical relations identify the assumptions for the simplified relations employed in the utility of radial vibration of the arterial wall for extraction of arterial indices. With the arterial wall treated as a unit-mass vibration system, these simplified relations are utilized for extraction of arterial indices from radial vibration of the arterial wall. Some other aspects of radial vibration of the arterial wall are further discussed.
Finite Element-Incorporated Multiscale Micromechanics Modelling of Vehicle Crashworthiness for 3-Phases Hybrid Fibres Reinforced Graphene Nano-Composite Materials
Authors: Elmasry Ahmed , Azoti Wiyao , Elmarakbi Ahmed
Published: February 2023

Crashworthiness focuses on the safety and protection of occupants. In addition, not only do energy absorbing members have to absorb sufficient collision energy, but the vehicle structure must be lightweight to improve power consumption. Nevertheless, estimating vehicle crashworthiness is experimentally expensive and time-consuming. Explicit nonlinear finite element analysis (FEA) is probably the most commonly used modelling technique to evaluate vehicle behaviour during a crash. However, commercial FE software still lacks efficient explicit modelling of lightweight graphene-based nano-composites. This work develops a simple approach to studying 3-phases hybrid fibres/graphene nanoplatelets-reinforced polymer matrix composites through multiscale modelling. Thermo-elasto-plastic response of composites is considered. The heterogeneous material problem is resolved through a kinematic integral equation. A linear spring model LSM is adopted to account for the interfacial behaviour in a modified Mori-Tanaka scheme The non-linear response is established in the framework of the J2 plasticity flow rule coupled with the “Lemaitre-Chaboche” ductile damage. The considered material is short glass -fibres/graphene nanoplatelet/Polyamide-Nylon 6 composite. The model is implemented as a UMAT within LS-DYNA® software for automotive crashworthiness applications. The results highlight the crash performance’s impact, incorporating the influence of the interfacial behaviour and material damage on the peak crash force and specific energy absorption SEA.
Studies on Fatigue Damage Progression in Post-Impacted CFRP Composite Through Passive Thermography and Stiffness Measurement
Authors: Prakash Raghu V.
Published: February 2023

Reinforced polymer composite materials are widely used in several areas of aerospace, other civilian structures, in view of tailor-suiting to the design requirements. During service, barely visible damages are induced due to accidental tool drops, hail storms and bird strikes, and they can propagate due to fatigue cycles applied during a mission. The damage progression can result in loss of load carrying capacity and ultimate failure. Damage progression due to fatigue in composites has been an important aspect of study as it can result in loss of load carrying capacity and ultimate failure.

In this study, the stiffness degradation in a quasi-isotropic carbon fiber polymer composite specimen subjected to FALSTAFF (Fighter Aircraft Loading Standard for Fatigue) spectrum was assessed, after it has been subjected to a drop-impact. Fatigue test was carried out post-impact till specimen failure, which meant testing over several days. The unloading stiffness of the specimen was estimated from the load versus displacement data that was recorded after every block of FALSTAFF loading. It is observed that the stiffness of the specimen degrades with the progression of damage.

An Infrared thermal imaging camera (TIM 160 from MicroEpsilon, Germany) was used in passive mode to monitor the temperature changes in the specimen during fatigue cycling. In view of the long duration of fatigue test spanning several days and IR camera cooling requirements, the test was periodically interrupted after certain blocks of FALSTAFF loading. Temperature data during fatigue cycling was compared with stiffness degradation to understand the fatigue damage progression in specimens. The first derivative of temperature response data was found to have a reasonable correlation with the first derivative of stiffness.
Impact of Processing Parameters in Mechanical Properties of the Additively Manufactured Acrylonitrile Styrene Acrylate
Authors: Billah Kazi Md Masum , Sarker Md Rashedul , Gonzalez Mario Barron , Ramirez Jose Anibal , Hamidi Youssef K.
Published: February 2023

In this study, a relatively new and low-cost commodity-type 3D printing filament material, acrylonitrile styrene acrylate (ASA), was used as a feedstock to a commercially available, desktop fused filament fabrication 3D printer. The aim was to correlate the mechanical properties of the 3D printed specimen to the raster orientation and extrusion temperature. Although ASA bears multiple similarities to ABS (acrylonitrile butadiene styrene), its superior UV-resistant properties facilitate a wider adoption in various indoor and outdoor industrial applications. Following ASTM (American Society for Testing and Materials) D 638 standard, ASA specimens were 3D printed at raster orientation angles of 0°/90°, 30°/60°, and +45°/−45° at three different temperatures, namely: 230°C, 250°C, and 270°C. The fabricated specimens were then tensile tested and relevant mechanical properties characterized, including the modulus of elasticity, ultimate tensile stress (UTS), and tensile strain at failure. Overall, ASA material showed promising strength properties for various printing parameters. In addition, the 0°/90° raster orientation was observed to yield the highest mechanical properties, with an average UTS of 34 MPa. The +45°/−45° and 30°/60° specimens showed lower but quite comparable properties with an average UTS of 31 MPa. The results also indicated a strong relationship between the print orientations and the extrusion temperatures. Furthermore, fractured surfaces of the tested specimens were a brittle and craze type of failure on the bulk of the bead. The results of this research may not only aid consumer-level manufacturing endeavors, but also support the industrial-scale manufacturing as well as the numerical modeling community to accurately predict appropriate manufacturing conditions and materials performance.
Active Meta Materials and the Change of the Path of Elastic Waves and Blast Waves
Authors: Hanagud Sathyanara
Published: February 2023

The concept of a negative refractive index stimulated research activity in 1960s. One researcher showed that it is possible to realize negative refractive index if we have a material that can have simultaneous negative electric permeability and negative magnetic permittivity, at the same frequency. At that time, no such material was available.

After three decades, several physicists started to explore the possibility of using meta materials to achieve the objective. Meta materials are materials with specially designed internal structure. They extended the research further to design a coordinate transformation technique, with distributed permeability and permittivity to steer the optical wave in any desired path. It was difficult to achieve these objectives because the optical wave lengths are very small.

Then, the interest shifted to impacting elastic waves where the wave lengths are large. However, the goal of steering the wave required a new distribution of the elastic modulus and a new distribution of density, in the material after active meta material control. In this paper, a method of achieving such a distribution by using active meta materials and the associated control procedures is presented. Three basic structures are considered. They are the structures that resist flexural vibrations, longitudinal waves and torsional waves. All three cases result in identical active meta material control equations and control procedures with different natural frequencies that are functions of both the density and elastic constants.
Transformation Field Analysis in Clustering Discretization Method in Micromechanics of Random Structure Composites
Authors: Braginsky Michael , Buryachenko Valeriy
Published: February 2023

A linear composite medium consisting of a homogeneous matrix containing either the periodic or random set of heterogeneities is considered. One of the first reduced-order model (ROM) Transformation Field Analysis (TFA) by Dvorak for strains is modified in terms of eigenstresses for implementation to clustering-based ROMs (CROMs) initiated by the self-consistent clustering analysis (SCA) by WK Liu. A set of consistency conditions are obtained for both the effective properties and modified eigenstress concentration factors. One dissects that modified TFA represents a unified background of the central clustering-based ROMs comprising the self-consistent clustering analysis and FEM-clustering analysis. The other presents the scheme of estimation of inhomogeneous strain concentration factors in some prescribed clusters analyzed by the SCA. For statistically homogeneous CMs, a localized version of the modified TFA is proposed for clustering of the matrix (virtual coating) in the vicinity of inclusions. Only linear offline stage is considered whereas analysis of nonlinear online stage is beyond the scope of the current presentation.
Evaluation of Simulated Railhead Weld-Defect Repairs Using Ultrasound Techniques
Authors: Broderick Demario , Basit Munshi , Aglan Heshmat
Published: February 2023

In this study, the quality of simulated welded pearlitic railhead steel has been assessed using regular and phase array ultrasonic techniques. Three 136 RE premium, head hardened rail sections, 18 inch in length, were used. The rail sections were acquired from the Transportation Technology Center (TTCI), Pueblo Colorado. Slots of 1 inch (25.4 mm) in length and 0.75 inch (19 mm) in depth were machined into the center of the railheads. The welding process was optimized via preheating to promote weld flow, consequently yielding better fusion between the parent and the weld material. The rails were preheated using two electrical heating strips (6-inch length and 2.5-inch width) attached to the rail web below the slot. The rail section to be welded was held in a box filled with ceramic fiber to insulate the rail section from the surroundings. The maximum pre-heated temperature was 500 °C. The slots were then filled using POSTALLOY® 2892-SPL hard facing filler wire.

Nondestructive inspection for weld discontinuities and porosity was performed using the OLYMPUS EPOCH 1000i ultrasonic flaw detector. The transducer/probe detects a variety of defects, forms, and sizes caused by welding flaws and/or slag inclusions. The same probe was used in the calibration of the equipment so that multiple variables such as specimen thickness, intensity of the reflected beam off the rear wall, and frequency could be preset. The device was calibrated, and a grid was constructed to guide the probe’s movement during the phased array and ultrasonic tests, ensuring that a high level of accuracy was achieved. A coupling agent was applied to the surface (cross-section) of the railhead at the end of the rail section. The phase array probe was placed on that surface, pressed gently, and moved across the rail cross-section. The parameters utilized for conventional ultrasound techniques were a 5 MHz frequency, a velocity of 0.2320 in/μs and a gain of 30 dB. In phase angle mode, an angle of 45 was utilized. These parameters were optimized and chosen for the calibration of the device with a section of the parent rail having the same length as a welded rail. All three samples were evaluated; sample A had no defects, while samples B and C had defects with a diameter of 1/20 inch (1.25 mm) and 1/10 inch (2.5 mm), respectively.

According to the American Railway Engineering and Maintenance-of-Way Association (AREMA), standard, defects that are below a diameter of 1/16 inch (1.56 mm) within the sound path located on the railhead are acceptable. Thus, based on the AREMA standard, two of the rails passed the ultrasound inspection and one did not pass. Destructive testing is being performed to slice the welded rail sections to locate the defects in order to confirm the resolution of the ultrasound techniques used.
Dependency Evaluation of Defect Formation and Printing Location in Additive Manufacturing
Authors: Safari Kosar , Khalfalla Shihab , Imani Farhad
Published: February 2023

At present, components manufactured with laser powder bed fusion (LPBF) platforms face various quality and repeatability issues, restricting the use of this technology primarily to prototyping. While in-situ imaging offers a capability of deciphering complex LPBF process and characterizing influential parameters (e.g., design, machine parameters, and material) on part quality, the current analysis ignores the effect of the print location and scan strategy. This paper presents a systematic image-guided analysis to characterize the influence of the component location and scan pattern on final part quality. Specifically, a data-driven model is developed to extract the impact of these process parameters on melt pool signatures such as shape, size, and the number of spatters. Next, we perform the post-build analysis based on x-ray computed tomography (XCT) to quantify process parameters’ effect on trackwise part quality, according to the magnitude of distortion and porosity. Finally, hyperdimensional computing is established to take into account the part location and scan pattern impacts and connect in-situ melt pool signatures to the quality of each track. Experimental results on four identical components positioned in different locations on the build plate show that as the part location deviates from the midpoint, melt pool fluctuation increases, and the track quality deteriorates substantially. In addition, the scan patterns with a shorter length lead to more variations in melt pool length and poor trackwise quality.
Jet Formation After Droplet Impact on Microholed Hydrophilic Surfaces
Authors: Alam Md Nur E. , Tan Hua
Published: February 2023

Droplet impacts on solid surfaces produce a wide variety of phenomena such as spreading, splashing, jetting, receding, and rebounding. In microholed surfaces, downward jets through the hole can be caused by the high impact inertia during the spreading phase of the droplet over the substrate as well as the cavity collapse during recoil phase of the droplet. We investigate the dynamics of the jet formed through the single hole during the impacting phase of the droplet on a micro-holed hydrophilic substrate. The sub-millimeter circular holes are created on the 0.2 mm-thickness hydrophilic plastic films using a 0.5 mm punch. Great care has been taken to ensure that the millimeter-sized droplets of water dispensed by a syringe pump through a micropipette tip can impact directly over the microholes. A high-speed video photography camera is employed to capture the full event of impacting and jetting. A MATLAB code has been developed to process the captured videos for data analysis. We study the effect of impact velocity on the jet formation including jet velocity, ejected droplet volume, and breakup process. We find that the Weber number significantly affects outcomes of the drop impact and jetting mechanism. We also examine the dynamic contact angle of the contact line during the spreading and the receding phase.
Sagittal Plane Dynamic Model Using Tibiofemoral Articular Geometric Center and Experimental Tibiofemoral Center of Rotation to Predict Joint Forces During Knee Extension Exercise
Authors: Salinas Jose Mario , Caruntu Dumitru I.
Published: February 2023

A 2-dimensional anatomical dynamic model of the patellofemoral joint was developed for investigating the forces that contribute to patellar motion during the knee extension exercise. Sagittal bone profiles were aligned to kinematic experimental data to simulate bone motion. Kinematic experimental data was collected using VICON motion analysis system. Marker coordinate data was used to set body-fixed coordinate systems on femur and tibia. These body-fixed coordinate systems were used to drive the femur and tibia geometric profiles during the knee extension exercise. Kinematic experimental data was used to calculate the relative instant center of rotation of markers on tibia with respect to femur’s body-fixed coordinate system. The instant center was then used as an alignment point for the geometric center of femur’s posterior lateral condyle. A geometric approach was implemented to predict patellar motion. The position of patella’s center of mass was assumed to be a function of the position of the tibial tuberosity and the geometric center of the femoral condyle. Newton’s second law of motion was used to calculate the force exerted by the quadriceps muscle during the knee extension exercise. The patellofemoral contact was modeled as a deformable articular surface, which was represented mathematically as the overlapping area between bone profiles. Overall, the forces calculated for the quadriceps force were greater than those observed for the patellofemoral contact. The quadriceps force displayed an increasing trend as the flexion angle decreased until reaching its maximum value of 1,920 N at full extension. On the other hand, the patellofemoral contact force displayed an increasing trend as the flexion angle decreased until reaching its maximum value of 805 N at 37° of flexion.
Growth-Based Design of a Conducting Solid Cooled by Conjugate Gas Conduction and Surface Radiation
Authors: Sevart Chadwick D. , Bergman Theodore L.
Published: February 2023

A solid growth model (SGM) is developed to identify desirable configurations of a conducting solid that is cooled by conduction through a stagnant gas and surface radiation. Thermal performance is quantified by the overall thermal resistance, as well as a figure of merit that rewards both (i) low thermal resistance and (ii) use of a small amount of solid. The results show that radiation affects both the evolution of the solid shape and the thermal performance. Predictions of the novel SGM are compared to those of a formal topology optimization (TO) method, which incorporates the effects of radiation after the solid shape is determined by considering conduction only. While application of the TO method yields a lower overall thermal resistance when a high solid thermal conductivity is considered, the SGM leads to better thermal performance when a low solid thermal conductivity is involved.
Numerical Analysis of the Vibration of Slender Beams
Authors: Sarker Pratik , Chakravarty Uttam K. .
Published: February 2023

The use of rotating beam-like structures is very common in engineering systems including power generation machines, automotive systems, aircraft structures, energy harvesting systems, and many more. The dynamic response analysis of these systems is of utmost importance for proper prediction of their performance and life. Among different outcomes of the dynamic response analysis, one of the major parameters is the frequency of the free vibration. Because of realistic loads and couplings between different degrees-of-freedom of motion, for majority of the cases, there is no analytical solution available. Hence, the governing equations need to be solved numerically. There are several numerical approaches available to solve for the coupled frequency of free vibration of rotating beams. In this paper, an overview of the different numerical methods is presented for coupled, free vibration analysis of slender, rotating beam-like structures. Three different degrees-of-freedom including out-of-plane bending, in-plane bending, and torsional deformations are considered for the most general case. At first, the eigen value problem of the coupled, mathematical model of free vibration of the beam is presented analytically. Following that, the use of different numerical methods is presented with relevant examples and corresponding beam parameters. Finally, the implementation of the finite difference method is presented to compare the corresponding results with that obtained by other methods.
Nonlinear Stability Analysis of a Reconfigurable Origami-Inspired Structure
Authors: Moshtaghzadeh Mojtaba , Bakhtiari Ali , Mardanpour Pezhman
Published: February 2023

This study thoroughly investigates the stability of a reconfigurable origami-inspired structure using the Finite Element Method (FEM). We use the Kresling pattern to design this foldable origami structure. We evaluate how the design’s geometric parameters, such as length ratio, number of polygon sides, and circumscribed circle’s radius, change the origami structure’s stability. We discover that the buckling load drops by increasing the structure’s length ratio. Furthermore, the results illustrate that the structure with less polygon side can be folded under less force. The circumscribed circle’s radius plays a significant role in mechanical responses to a tip force applied to an origami structure. Based on the results, it appears that the crease lines carry the greatest amount of tip load. The results and conclusions are analyzed to provide a complete design guide that can be used to improve origami structure performance.
2-D Analytical Model of Heat and Moisture Diffusion in Bonded Single Lap Joints
Authors: Gerini-Romagnoli Marco , Nassar Sayed A.
Published: February 2023

A two-dimensional elastic analytical model for bonded single lap joints subjected to heat and moisture diffusion is presented. The distributions of peel and shear stress in the bond area are calculated. Local moisture concentration and bondline temperature determine the properties of the adhesive layer, which vary in the space and time coordinates. Adhesive diffusivity coefficient and absolute saturated concentration are affected by the material temperature, and scenarios of individual and combined heat and moisture diffusion are analyzed. The governing partial differential equations are solved numerically, and a simplified shear stress formulation is introduced for low-modulus adhesives.

Two-dimensional gradients in the adhesive properties affect the peel and shear stress in the bondline. Diffusive patterns in the direction of the loading axis of the joint can contribute to a positive stress redistribution along the overlap, while the results of this study show that softening patterns in the transverse direction may severely impact the joint performance. In the initial stages of environmental exposure, significant increases in peak shear stress are observed in the innermost portions of the bond area. Less significant gradients are observed for the peel stress distribution, under the same conditions. A 3-D Finite Elements Analysis is used to compute adhesive peel and shear stresses, and the results are in reasonable agreement with the proposed analytical model.
A Reduced Three-Phase Model for Solidification of Liquid in Large Tanks
Authors: Terala Shashank , Mazumder Sandip , Matharu Gurpreet , Vaishnav Dhaval , Ali Syed
Published: February 2023

A liquid water-urea mixture is stored onboard diesel vehicles and used for exhaust aftertreatment. In cold weather conditions, the mixture may freeze and the freezing process may span over a day. In the first part of our study (Journal of Thermal Science and Engineering Applications — Transactions of the ASME, Vol. 13, p. 011008, 2021) it was shown that traditional computational methods are impractical for modeling such large-duration freezing processes because of restrictions in the time-step size posed by numerical stability and physical time-scale considerations. A model, in which natural convection driven thermal transport is treated as a diffusive process, was developed and demonstrated. Since the flow field was not computed in this model, the computations were found to be orders of magnitude more efficient than traditional methods. This preliminary model did not account for the expansion of ice. Here, a new model that accounts for the expansion of ice and the consequent rise of the initial air-water/ice interface (ice dome formation) is presented. An additional conservation equation for excess volume fraction is introduced to this end and is solved using the unstructured finite-volume procedure and sub-time-stepping. Since the flow field is not computed, the air-water/ice interface is tracked using a new algorithm similar to the traditional volume-of-fluid method, but one that constructs fluxes using a diffusive formulation rather than an advective one. Validation studies in full-scale three-dimensional tanks show good agreement with measured temperature-time data. It is found that the air-water/ice interface first evolves to a concave shape before finally becoming a convex ice dome after full solidification.
Gearbox Vibration Analysis Using a Spectrogram and Power Spectrum Approach
Authors: Mohammed Sufyan A. , Ghazaly Nouby M. , Abdo Jamil
Published: February 2023

Vibration analysis is essential in rotating machinery fault diagnosis. As a vibration contains the dynamic information of a machine, improvement based on analysis has an effective role in predictive and preventive maintenance. In the present paper, the short Fourier transform is applied to determine the frequency variation of a gearbox signal with time due to different loads and driver speeds. In addition, the power spectral density (PSD) is used to represent the randomness of the signal since many frequencies occur simultaneously. The gearbox health condition is measured, and signal fault is simulated as tooth breakage for five cases: 0% (healthy), 25%, 50%, 75%, and 100% (complete tooth breakage). The obtained results proved that it is more powerful to use both spectrograms and PSD for gearbox fault diagnosis. This method is also improved with the ability to distinguish gearbox vibration signals for anomaly detection.
Effect of Dual Environment Aging on Flexible Polyurethane Based Adhesive
Authors: Shaafaey Mamoon , Bahrololoumi Amir , Dargazany Roozbeh
Published: February 2023

Environmental degradation of adhesives naturally increases with the intensity of the ambient weathering agents involved. During service life, these materials are never subjected to a constant environmental loading. Real-time applications expose the material to multiple weather conditions, ranging from dry to humid or fully wet conditions. While some understanding exists about aging environments in isolation, we intend to investigate the effect of multiple environments on the constitutive behavior of the materials in question. The extent of damage can be accessed by analyzing the changes in constitutive behavior and toughness of aged material. Therefore, this aging experiment was designed around two-way aging regimes involving combinations of thermo-oxidation, hydrolytic and hygrothermal aging environments. We selected a polyurethane based flexible adhesive which is commonly used in the automotive industry as a glass sealant. The aged specimens were subjected to uniaxial tensile tests, and variation in material toughness and constitutive behavior was analyzed to ascertain the mechanics involved in the case of each environmental exposure. We outlined how different environments affect the material in isolation and how they interact with other weathering conditions. This study will help better understand and model the damage mechanics involved in exposure to multiple environmental conditions.
Developing a Consistent Resonance-Induced Fatigue Testing Method on Novel Freely Supported Specimens
Authors: Napper Lorean
Published: February 2023

A fatigue test employing vibration-based fatigue known as the “Free-Free” has been in use inside the Turbine Engine Fatigue Facility (TEFF) of the Air Force Research Laboratory. The vibration-setup utilizes free boundary conditions by suspending a specimen on its nodal line that when excited, allows for deflection in its first bending mode. The excitation source is an electromagnet coil that attracts and repels a permanent magnet located on the specimen. The experimental specimens, 0.4 mm cold-rolled Ti6Al-4V, are thin specimens representative of geometries that undergo large amounts of cyclic loading during system operations expected for supersonic and hypersonic aerospace technologies. The Free-Free offers an ideal solution to addressing key structural assessment needs for these critical technologies. In the past, the Free-Frees’ usage in the TEFF has resulted in inconsistent experimental setups that lead to increased risk in data repeatability. Diagnosing the known and unknown inconsistencies in the vibration test setup and strategizing solutions to fix the issues are of the utmost concern. Complications in the test setup parameters are artifacts of the uniqueness of the Free-Free test itself. Therefore, a greater understanding of how to achieve reliable and consistent Free-Free fatigue results is crucial for the advancement of aerospace structures and systems.