bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Characterization of the Mechanical Properties of Medical-Grade Dental Implants, Fabricated Using Vat-Photopolymerization Additive Manufacturing Process
Authors: Raines Regan , Day James B. , Salary Roozbeh (Ross) 
Published: September 2022

Abstract
The overarching goal of this research work is to fabricate mechanically-robust and dimensionally-accurate dental implants for the treatment of dental fractures, anomalies, and structural deformities with a focus on oral and maxillofacial surgery applications. In pursuit of this goal, the objective of the work is to investigate the mechanical properties of several triply periodic minimal surface (TPMS) scaffolds, composed of a medical-grade photopolymer resin, fabricated using digital light processing (DLP) process. DLP is a vat-photopolymerization additive manufacturing process; it has emerged as a high-resolution method for the fabrication of a broad spectrum of biological tissues and constructs for tissue engineering applications. However, the DLP process is intrinsically complex; the complexity of the process stems from complex physiochemical phenomena (such as UV light photopolymerization) as well as resin (photopolymer)-process interactions, which may adversely influence the mechanical properties, the surface morphology, and ultimately the functional characteristics of fabricated dental scaffolds. Consequently, physics-based process and material characterization would be an inevitable need. In this study, several TPMS scaffolds (having complex internal geometries) were fabricated, based on a medical-grade photopolymer resin. The compression properties of the fabricated dental scaffolds were measured using a compression testing machine. In addition, the bioactivity of the scaffolds was assessed in a simulated body fluid (SBF). The outcomes of this study pave the way for the fabrication of complex dental implants with tunable medical and functional properties.
Investigation of the Influence of Hydroxyapatite and Polysaccharide Concentration on the Mechanical Properties of Bone Scaffolds, Fabricated Using Freeze Drying Process
Authors: Ekstrom Tanner , Day James B. , Salary Roozbeh (Ross) 
Published: September 2022

Abstract
The overarching goal of this research work is to synthesize and fabricate mechanically robust, dimensionally accurate, and porous bone scaffolds for the clinical treatment of osseous fractures, defects, and diseases. In pursuit of this goal, the objective of the work is to investigate the influence of hydroxyapatite (HA) as well as polysaccharide concentration on the mechanical properties of bone scaffolds, fabricated using freeze drying process. Freeze drying or lyophilization has emerged as a robust method for the fabrication of a broad spectrum of tissue constructs. Freeze Drying allows for multi-material fabrication of structures with complex pore morphology for soft and hard tissue engineering applications. However, the process is intrinsically complex; the complexity of the process, to a great extent, stems from complex physical phenomena (such as sublimation) as well as material-process interactions, which may adversely affect the mechanical properties, the surface morphology, and ultimately the functional characteristics of fabricated bone scaffolds. Consequently, physics-based process and material characterization would be an inevitable need. In this study, the influence of HA and polysaccharide concentration was investigated using a central composite design (CCD). The concentration of both HA and polysaccharide was changed in the range of 5%–15% with the aim to obtain mechanically robust structures. The compression properties of the fabricated bone scaffolds were measured using a compression testing machine. The outcomes of this study pave the way for the fabrication of complex, mechanically strong, and porous bone-like scaffolds with tunable medical and functional properties.
Vision-Sensor Fusion-Based Low-Cost Dimension Measurement System for Machining Shop Floor
Authors: Singh Swarit Anand , Kumar Aitha Sudheer , Sorathiya Pratik C. , Desai K. A. 
Published: September 2022

Abstract
The majority of industrial inspection activities across the globe involve considerable human efforts due to the requirements of robust detection abilities under varying lighting conditions, large field of view, higher speeds, and dynamic range of operation. In recent years, the motivation for integrating inspection and manufacturing operations on the shop floor has grown considerably to maximize the potential benefits of implementing Industry 4.0 initiatives. It is essential to digitize and integrate inspection of raw materials, in-process inventory, and finished components with manufacturing operations for achieving autonomous manufacturing goals. Machine vision offers an excellent alternative to manual inspection at a reduced cost, increased productivity, digital output, and negligible errors. However, its utility is restricted to the finished component inspection currently due to exorbitant equipment costs, requirements of specific lighting conditions, and a controlled operating environment. This paper presents the development of an integrated system combining a camera and ultrasonic sensor to develop a low-cost dimensional measurement system for inspection of raw material and in-process machined components in the shop floor setting. An indigenous inspection system is developed by integrating a camera, ultrasonic sensor, power source, and interactive user interface with onboard processing abilities. The augmentation of the ultrasonic sensor serves a dual purpose of eliminating the need for image calibration and dimensions measurement in the system. An interactive graphical user interface with acquisition trigger abilities and results display is developed using an open-source TkInter framework of the Python environment. A set of dimension measurements are performed for common raw material and in-process machined shapes using the developed setup. The comparison of results obtained using developed inspection setup and commercial machine vision system showed good agreement for common shapes. The efficacy of the developed system is validated for inspection of simple shapes with machining operations on the shop floor in the present work. The proposed system can be easily extended to inspect complex shapes such as gear profiles or camshafts as subsequent research work.
Process Temperatures and Material Flow in Friction Stir Welding of High Density Polyethylene (HDPE)
Authors: Sheikh-Ahmad Jamal , Rehman Razi Ur , Deveci Suleyman , Almaskari Fahad 
Published: September 2022

Abstract
In this study we investigate the effect of material temperatures on material flow and weld quality in the friction stir welding of bi-modal high density polyethylene (HDPE). The heat input to the process was controlled by varying the tool rotational speed, welding speed and the material initial temperature. Preheating of the HDPE blanks on the bottom surface of the weld was incorporated in order to increase the material flow in this relatively colder region. Temperatures on the boundary surfaces of the HDPE blanks were measured using an infrared camera and thermocouples. Material flow patterns were observed by welding two different colors of the polymer blanks, white on the advancing side and black on the retreating side. Joint quality was assessed using optical microscopy and joint strength was measured by tensile testing. It was found that material temperatures greatly affect the material flow in the weld zone, which in turn affects the tendency to form defects and the overall joint quality. High joint efficiencies and large elongations in excess of 100% were obtained when the material temperatures across the thickness were in excess of 100 °C.
Dynamic Simulation Analysis of Multi-Support Rotary Shaft System
Authors: Mei Jiangnuo , Zheng Yinhuan , Lu Hong , Li Zhangjie , Zhang Wei , Peng Di , Lin Huang , Liu Qiong 
Published: September 2022

Abstract
The multi-support rotary shafting system, represented by the ship propulsion shafting, is widely used in the power transmission device of the ship, and its working condition has a great influence on the operational safety of the ship. Therefore, it is necessary to conduct a dynamic analysis of the ship propulsion shafting. The ship propulsion shafting is used as a prototype to design a transmission shaft system fault detection platform based on the dual-engine parallel transmission mode. In order to accurately simulate the load loaded by the magnetic powder brake in the fault detection platform of the transmission shaft system, the control strategy of the magnetic powder brake loading is studied, including conventional PID control, Smith control, fuzzy Smith control and fuzzy Smith with integral action. The control realizes the ideal control effect of the magnetic powder brake. On the basis of the accurate load control effect, use the Adams software to conduct dynamic simulation analysis on the rigid-flexible hybrid model of the ship propulsion shafting. The dynamic characteristics of the shaft system under normal and fault conditions are studied, the research shows that the occurrence of collision and friction faults will increase the force fluctuation range of the shaft system, the shafting vibration will become more complex, and the characteristic frequency will have a large number of high-multiplication frequencies. The above analysis results have certain significance for the fault analysis of the transmission shaft system.
A Novel Objective Function for the Inverse Problem of Simultaneous Identification of Unknown Youngs Modulus and Boundary Conditions With Noisy and Partial Observation
Authors: Xu Tian , Du Shilun , Li Murong , Hu Yingda , Wang Zhen , Lei Yong 
Published: September 2022

Abstract
The biomechanical models of the surgical navigation systems need patient-specific elastic properties and boundary conditions to calculate the deformation of soft tissues. However, these information cannot be directly obtained in a real endoscopic surgical scenarios. Many studies have been carried out focusing on identification of unknown elastic parameters and boundary conditions. But they rarely estimate these unknown parameters together. For the convergence of unknown parameters with observation error, some methods add regularization terms to the objective functions which are complex and sometimes rely on experience. In this paper, a novel objective function based on the gradient of displacement field is proposed, which can ensure the convergence of unknown Young’s modulus and boundary conditions without additional regularization terms. A “two field” construction method, which can convert this ill-posed inverse problem to two well-posed problems, is introduced to construct this objective function. The sensitivity analysis is conducted based on approximate differential method and the Gauss-Newton (GN) method is applied to minimize the objective function and update unknown parameters. The proposed objective function is compared with a few classical objective functions in a series of numerical experiments based on the linear elastic finite element model. The results of numerical experiments show the advantages and feasibility of the proposed objective function.
3D Printing and Mechanical Behavior of Anisogrid Composite Lattice Cylindrical Structures
Authors: Stan Felicia , Sandu Ionut-Laurentiu , Fetecau Catalin 
Published: September 2022

Abstract
Anisogrid cylindrical lattice (ACL) structures have been successfully used in space applications, demonstrating high mechanical performance and weight efficiency. However, the manufacturing process for the composite ACL structures is very complex and, traditionally, involves different technologies, including winding of filaments or prepregs and curing. Tacking the advantage of the fused deposition modeling (FDM) to manufacture completely integral composite parts with complex shape, in this paper, the FDM-3D printing of ACL structures using carbon fiber (CF) and glass fiber (GF) reinforced polyamide 12 (PA12) composites has been investigated. The mechanical behavior of 3D printed ACL structures has been analyzed in terms of the static stiffness, specific load, and failure mode through axial and transverse compression tests, as a function of the geometrical parameters of the lattice structure.
It was observed that, under transverse compression, after the initial linear elastic response, the applied load changed its slope and continued to increase with increasing displacement up to a specified displacement (inner radius of the ACL structures) without visible fracture or delamination between layers, demonstrating that the 3D printed composite ACL structures are robust and highly efficient in the nodes. Under axial compression, the applied load increased with displacement up to a maximum load and then decreased until fracture, mainly, due to local buckling and material failure of the helical ribs. The 3D printed CF/PA12 ACL structures were found to be more efficient than either the GF/PA12 or PA12 ACL structures taking into account both the axial and transverse specific load and stiffness. The increase in the shell thickness, helical rib width or number of helical ribs resulted in a remarkable increase in the stiffness and load-bearing capacity of the 3D printed composite ACL structures. From the manufacturing perspective, it was shown that the FDM-3D printing technology holds promise for the development of mechanically robust composite ACL structures with excellent reliability.
Precision Evaluation of Large Payload SCARA Robot for PCB Assembly
Authors: Nimon Andrew S. , Sherehiy Andriy , Alqatamin Moath , Wei Danming , Popa Dan O. 
Published: September 2022

Abstract
The placement of SMD components is usually performed with Cartesian type robots, a task known as pick-and-place (P&P). Small Selective Compliance Articulated Robot Arm (SCARA) robots are also growing in popularity for this use because of their quick and accurate performance. This paper describes the use of the Lean Robotic Micromanufacturing (LRM) framework applied on a large, 10kg payload, industrial SCARA robot for PCB assembly. The LRM framework guided the precision evaluation of the PCB assembly process and provided a prediction of the placement precision and yield. We experimentally evaluated the repeatability of the system, as well as the resulting collective errors during the assembly. Results confirm that the P&P task can achieve the required assembly tolerance of 200 microns without employing closed-loop visual servoing, therefore considerably decreasing the system complexity and assembly time.
Research on Positioning Error of Dual-Drive Feed System Based on Virtual Axis-Electronic Cam Strategy
Authors: Deng Zhanyun , Lu Hong , Liu Qi , Meng Lanqi , Dai Jiashun , Liu Qiong 
Published: September 2022

Abstract
The dual-drive feed system (DDFS) is widely used in highspeed, high-precision and heavy-duty applications due to its good vibration resistance, high rigidity and rapid response. Positioning accuracy is an important performance index characteristic of CNC (Computer Numerical Control) machine tools, which can directly determine the processing quality of the workpiece, but the existence of positioning errors always damages the performance and processing accuracy of CNC equipment. This paper firstly analyzes the source of the positioning error of the DDFS. Then, according to the structure of the DDFS, the multi-body system (MBS) theory and the modeling method of homogeneous transfer matrix (HTM) is used. The error modeling of the DDFS is carried out, and the positioning error model is obtained. According to the positioning error model, a reasonable positioning error detection program is designed. And the experimentally measured positioning error values are fitted. Finally, by using the virtual axis-electronic cam error compensation function in the TwinCAT software of the German BECKHOFF control system, the error compensation method of virtual axis-electronic cam is used on the built DDFS platform to carry out error compensation experiments. The experimental results show that the error compensation method of virtual axis-electronic cam can effectively reduce the positioning error.
Acoustic Emission Sensors to Monitor Early Onset of Necking During Uniaxial Tension
Authors: Baral Madhav , Al-Jewad Ali , Breunig Alexander , Ha Jinjin , Groche Peter , Korkolis Yannis P. , Kinsey Brad L. 
Published: September 2022

Abstract
Elastic waves are generated and propagate when a material undergoes plastic deformation and can be detected by acoustic emission (AE). In this work, AE measurements are obtained during a uniaxial tension (UT) test using a custom-made sensor employing piezoelectric crystals. The UT tests are performed on an MTS machine with two AE sensors clamped on each end of the specimen gage section. A low pass Butterworth filter is designed to attenuate the high frequency noise from the AE signals. Also, full-field strain measurements on the specimen surface are acquired using the 2-D digital image correlation (DIC) method. A typical result from a UT test reveals, as the plastic deformation increases, the AE signals from each sensor increase until they reach a maximum value followed by a drop of signal until the specimen fractures. It is found through interrogation of the DIC images that the maximum amplitude from the AE signals corresponds to the early onset of localized necking. The goal of this work is to implement the UT findings in an actual forming process (e.g., cup drawing) and monitor the event in real time using closed loop control to achieve improved formability.
Effect of Inherently Porous Structure Produced by Metal Fused Filament Fabrication on the Tribological Behavior of Lubricated Steel-Steel Contact
Authors: Liu Rui , Greeley Andrew , Zhang Shuhuan , Cormier Denis , Iglesias Victoria Patricia 
Published: September 2022

Abstract
By introducing local depressions, as small reservoirs for lubricants and wear debris, on a flat surface, the surface texture has been proven to positively affect the friction and wear behavior of lubricated sliding surfaces. However, the effectiveness of the surface texture diminishes and disappears eventually as wear develops at the contact interface. In order to achieve a longer-lasting beneficial effect on the sliding surface, this work develops an approach to print an inherently porous structure up to a certain depth beneath the contact surface to retain the benefits associated with surface texture. A test structure was created from 17-4 PH stainless steel using a metal fused filament fabrication system. The performance of the printed porous structure was evaluated using a steel ball in a ball-on-flat reciprocating tribometer under lubricated conditions with mineral oil. By comparing with the solid sample, it was found that the printed structure with inherent porosity improved the tribological performance by reducing the friction up to 20% and the wear rate up to 90%. The experimental results also indicate that the effectiveness of the printed texture is strongly correlated to the shape and the distribution of the pores on the wear track, which requires further research in the following studies.
Synthesizing and Printing of Tin Oxide Nanoparticles Using a Single Ultrafast Laser System: A Feasibility Study
Authors: Contreras Lopez Enrique , Ahmed Farid , Li Jianzhi 
Published: September 2022

Abstract
In laser-based manufacturing, processing setup customization is one of the popular approaches used to enhance diversity in material processing using a single laser. In this study, we propose setup design modification of an ultrafast laser system to demonstrate both Tin Oxide (SnO2) nanoparticle synthesis from bulk metal, and post printing of said nanoparticles using Laser Induced Forward Transfer (LIFT) method. Using the Pulse Laser Ablation in Liquid (PLA-L) method, nanoparticles were synthesized from a bulk tin metal cube submerged in distilled water. Such nanoparticles dispersed in water can form colloidal ink that can be used for different printed electronics applications. Pulse energy was varied to investigate the influence on morphological properties of the nanoparticles. It was observed that a decrease in average particle size, and an increase in the number of particles synthesized occurred as the pulse energy was increased. In our study, we adapted the same laser system to enable LIFT operation for printing of the SnO2 nanoparticles. The colloidal ink prepared was then used in LIFT method to study feasibility of printing the synthesized nanoparticles. By varying not only the laser parameters but process parameters such as coating thickness and drying time, printed results can be improved. Experimental results show great potential for both synthesizing and printing of the nanoparticles using a single laser system. This study serves as a proof of concept that a single laser system can turn bulk metal into nanoparticles-based applications without the need for extra processing from other machines/systems, opening the door to highly customizable prints with reduced lead times.
Extracting the In-Process Structural Dynamics Parameters in Micro-Milling Operations
Authors: Hashemitaheri Maryam , Mittal Rinku , Cherukuri Harish , Singh Ramesh 
Published: September 2022

Abstract
Stability properties of micro-milling operations are characterized by the Stability Lobe Diagram (SLD). The material removal rates during micro-milling operations depend on the optimal values chosen for the depth of cut and also spindle speed. Theoretically, the stability boundary is calculated having the structural dynamics and the cutting parameters. However, some discrepancies are usually observed between the empirical results and the expected results that the theory supports. The driver of such a gap is that the dynamics is affected during machining operation by parameters such as the spindle speed, cutting loads, thermal changes, feed rate, etc whereas the theory is based on the structural dynamics parameters in the idle state of the machine (zero speed). Consequently, the selection of chatter-free values for cutting depth and spindle speed based on SLD in the idle state of the machine is not reliable. In addition, measuring structural dynamics parameters under cutting conditions is difficult. In this study, a novel approach is introduced to determine in-process structural dynamics parameters based on a multivariate Newton-Raphson method. Having the empirical SLD characterized by experimental data, our method tries to find the structural parameters under which the theory can support the given empirical SLD. Note that the theoretical SLD is usually characterized as a function of the cutting and structural dynamics parameters. Here our method follows the inverse flow and utilizes the empirical SLD to return the underlying parameters. The parameters returned by our method are those supported by the physics-based theories. Therefore, our approach is a hybrid method where the physics-based model is combined with the experimental results. For any given empirical SLD, with the cutting parameters fixed, the in-process structural dynamics parameters are determined using the proposed inverse approach. We use a multivariate Newton-Raphson method approach where through the iterations, an initial guess selected for the set of the parameters is adjusted step-by-step until the final set of the parameters can justify the empirical SLD based upon physics-based models.