bluuebunny/crossref_metadata_2025 huggingface dataset:
Installation Errors in Polyethylene Pipe for Natural Gas Service: Recent Case Histories by the National Transportation Safety Board (NTSB)
Authors: Zakar Frank
Published: January 2021

The National Transportation Safety Board investigated numerous accidents involving the release of natural gas from polyethylene pipelines. The industry manufactures polyethylene pipes and fittings in many shapes and they can be installed/joined in a variety of ways. New grades with improved material properties, such as high-density polyethylene (HDPE) and ultra-high-molecular-weight polyethylene (UHMWPE) have been introduced that show improved material properties compared to their medium-density polyethylene (MDPE) predecessors. However, improved material properties by themselves do not guarantee extended service life of an installed pipe or fitting. Simple errors, whether unintentional, unknown, or unaware by the installer, can lead to a gas leak and possibly a serious accident that causes injury or loss of life. These errors can significantly reduce the service life of a pipe or fitting.

The NTSB Materials Laboratory examined several polyethylene service tees that were involved in an accident as a result of a natural gas leak. Examples of gas leakage resulting from failure to follow best practice at installation will be mentioned. Certain service tee assemblies are joined to pipe segments by mechanical methods while others are joined by fusion methods, such as heat fusion or electrofusion process. An example is cited where a manufacturer of a mechanical tapping tee made several versions of the same design that required specific installation instructions that were different from their predecessors. When several versions of the same tee assembly are manufactured by the same company, one should be aware of identifiable features that differentiate one version from another and then carefully use installation instructions that apply to the model that will be installed. Another example is cited where a service tee that was joined by the heat fusion process had been contaminated prior to bonding.

Learning from mistakes that are made during installation, through examples, provides a foundation from which we can correct our procedures and avoid repeating the same mistakes in the future.
Influence of Steel Chemistry and Field Girth Welding Procedure on Performance of API X70 Line Pipe Steels
Authors: Mohammadijoo Mohsen , Collins Laurie , Rashid Muhammad , Arafin Muhammad
Published: January 2021

Owing to recent concerns regarding pipeline field girth weld performance, particularly heat affected zone (HAZ) softening and toughness, EVRAZ North America has initiated a research program to evaluate the response of API grade line pipe to the current field girth welding practices. In particular, this study aims to elucidate the role of steel alloy design as well as the welding procedure on field girth weld and HAZ properties. This understanding is critical to balance the detrimental effects of HAZ softening on the overall joint strength against factors affecting HAZ toughness. A selection of several different steels with different levels of alloying elements, Ceq and Pcm have been subjected to welding trials to assess the effects of chemistry on joint performance. Furthermore, an analysis on the effect of welding process parameters on the joint properties has been made. The welds, fabricated via a manual shielded metal arc welding (M-SMAW) process, were evaluated in terms of toughness, local vs global strain distribution during tensile testing using digital image correlation (DIC) technique, and hardness contour mapping of the weld and HAZ regions. The results explicitly show that the extent of HAZ softening decreased as the amount of Mo, Mn, Ti/N and Ceq increased. However, this alloying addition resulted in a detrimental effect on the HAZ toughness, particularly towards the cap and fill passes. The HAZ softening increased as the inter-pass temperature and the welding heat input increased. In addition, the strain analysis confirmed the weld passes towards the root/hot passes are more prone to HAZ softening compared with the upper cap and fill passes.
Research Progress of Sand Transport Mechanism and Critical Conditions in Pipelines
Authors: You YuanPeng , He LiMin , Luo Xiaoming , Shi KaiYue , Su JianPeng
Published: January 2021

Sand deposition and transportation in pipelines has become one of the major concerns for flow assurance in petroleum industry. However, research in this field is still in its infancy. This study describes the current development of sand deposition and sand transport in pipeline. The mechanism of particles deposition is described. The effects of particle properties, fluid properties and pipeline structure on the carrying capacity of single-phase and multiphase flow carrying sand are introduced, with emphasis on factors such as particle size, liquid viscosity, flow regime and pipeline inclination. As for modeling studies, the sand transport models can be classified to three categories based on the approach used to develop them: empirical, mechanistic, and semi-mechanistic. The methods for developing and extending models are illustrated in this study. Based on the experimental data, the prediction accuracy of four multiphase models for critical velocity in stratified flow is verified. Further researches should focus on the mechanisms and the establishment of the accurate model for sand flow pattern transformation boundary.
Improved Linepipe Specifications and Welding Practice for Resilient Pipelines
Authors: Wang Yong-Yi , Jia Dan , Warman Dave , Johnson David L. , Rapp Steve
Published: January 2021

At least 10 girth weld incidents in newly constructed pipelines are known to have occurred in North America. More than 30 girth weld incidents in newly constructed pipes have been identified worldwide. A review of the North American incidents identified a few main contributing factors: (1) weld strength undermatching, (2) heat-affected zone (HAZ) softening, and (3) elevated stresses/strains from normal settlement and other loads. Weld bevel geometries of manual welding processes that favor plastic straining along the softened HAZ and low strength root passes were also compounding contributing factors.

Prior publications focused on the industry practices that led to the formation of those contributing factors. This paper covers the enhanced linepipe specifications and improved welding practice that aim to reduce the risk of similar girth weld incidents, thus leading to more resilient pipelines.

The enhanced linepipe specifications include interim recommendations that aim to limit the upper-bound longitudinal strength for a given pipe grade and reduce the linepipe steels’ susceptibility to HAZ softening. The implementation of the interim recommendations is assisted by allowing alternative hoop tensile tests.

The improved welding practice includes (1) the selection of welding procedures, including consumables, that minimizes the likelihood of weld strength undermatching and reduces the propensity for HAZ softening and (2) welding procedure qualification tests and requirements for the production of strain-resistant girth welds.

The recommendations covered in this paper principally target new pipeline construction projects but are also applicable to pipe replacement projects. It is expected that pipeline operators would incorporate the recommendations in their internal procedures and work with welding contractors to execute the recommendations. The improved linepipe specifications and welding practice are expected to increase the resilience of pipelines subjected to realistic construction and in-service loads. The implementation of the recommendations requires changes to some long-standing industry practices and can only occur with collaborative efforts from all stakeholders.
4D Inspection: A Comprehensive Platform to Digitize Pipeline Construction Inspection and Generate Data Driven Continuous Improvement
Authors: Gill Sukhi , Vogt Brett
Published: January 2021

Beginning in 2018, TC Energy began an effort to digitize inspection and construction management and internally named this concept the Dynamic, Digital, Data and Diagnostics platform otherwise known as “4D Inspection”. The 4D Inspection platform is built upon Project Consulting Service’s Epilogue® energy infrastructure construction management solution and is intended to evolve inspection reporting to a digital platform to create standardized construction reporting embedded with real-time compliance validations for efficient and effective management of field construction issues, progress tracking, and over-all construction quality monitoring. Currently, this effort is nearing the end of its first year of a multi-year implementation plan, the platform is in use on projects in both Canada and the United States spanning four different time zones with more than 595 inspectors on over $7.5 billion in capital projects. Even with implementation still underway, this concept’s key functionality, like automated inspection report document control, simplified photo capture with geo-tagging and automated daily progress reporting, has provided immediate benefits of more thorough, more reliable, and more efficient construction data than ever gathered using previous data collection processes. With improved data accuracy and detail, TC Energy gains insight and even foresight into how best to advance construction quality and safety while also impacting overall project costs and schedule.
Management of Ground Movement Hazards: An Overview of a JIP
Authors: Wang Yong-Yi , West Don , Dewar Doug , Mckenzie-Johnson Alex , Rapp Steve
Published: January 2021

Ground movements such as landslides, subsidence, and settlement can pose serious threats to the integrity of pipelines. The consequences of a ground movement event can vary greatly. Certain types of ground movements are slow-moving and can be monitored and mitigated before a catastrophic failure. Other forms of ground movements can be difficult to predict. The most effective approach could be hazard avoidance, proactive means to reduce strain demand on pipelines, and/or building sufficiently robust pipeline segments that have a high tolerance to the strain demand.

This paper provides an overview of a Joint Industry Project (JIP) aimed at developing a best-practice document on managing ground movement hazards. The hazards being focused on are landslides and ground settlement, including mine subsidence. This document attempts to address nearly all major elements necessary for the management of such hazards.

The most unique feature of the JIP is that the scope included the hazard management approach often practiced by geotechnical engineers and the fitness-for-service assessment of pipelines often performed by pipeline integrity engineers.

The document developed in the JIP provides a technical background of various existing and emerging technologies. The recommendations were developed based on a solid fundamental understanding of these technologies and a wide array of actual field experiences.

In addition to the various elements involved in the management of ground movement hazards, the JIP addresses some common misconceptions about the adequacy of codes and standards, including:

• The adequacy of design requirements in ASME B31.4 and B31.8 with respect to ground movement hazards,

• The adequacy of linepipe standards such as API 5L and welding standards such as API 1104 for producing strain-resistant pipelines,

• The proper interpretation of the longitudinal strain design limit of 2% strain in ASME B31.4 and B31.8, and

• The effectiveness of hydrostatic testing in “weeding out” low strain tolerance girth welds.
What Is the Leak Rate for a Liquid Slug Flowing Past a Side Branch?
Authors: Hartloper C. , Clavelle E. , Leong K. , Fitz M. , Epur S.
Published: January 2021

Chemical cleaning is used in gas pipelines to remove debris that was resistant to mechanical cleaning. The cleaner is a liquid mixture of a hydrocarbon-based solvent and a surfactant. It is transported down the pipeline either batched between two cleaning tools or pushed by a single tool.

During a chemical cleaning run, liquid will leak into any side branch it passes. Consequently, gas quality problems may arise when the pipeline returns to regular operations as the leaked liquid hydrocarbons evaporate into the gas stream. Furthermore, operational problems such as flooded separators can occur if a large volume of liquid is lost.

Currently, there is no understanding of what factors influence the liquid’s leak rate into side branches. This paper aspires to address this knowledge gap. A water flow loop was set up to investigate the effect on leak rate of mainline pipe size, side branch pipe size, side branch length, and mainline liquid velocity. The leak rate is found to increase with the side branch pipe size, while remaining unaffected by the mainline pipe size and side branch length. At mainline velocities below the critical velocity, gravitational effects such as the downstream back pressure significantly affect the leak rate. At mainline velocities above the critical velocity these effects disappear, and the leak rate decreases as the mainline liquid velocity increases.
Development of an Optical Angle Sensor With a Mode-Locked Femtosecond Laser Source for Surface Profile Measurement
Authors: Shimizu Yuki , Takazono Shota , Kanda Yuri , Matsukuma Hiraku , Gao Wei , Inaba Hajime
Published: January 2021

Angle sensors based on the laser autocollimation are often employed to evaluate surface profiles of a target of interest. The authors have developed a femtosecond laser angle sensor, in which a spectrometer or an optical spectrum analyzer with a single-mode fiber is employed as the photodetector for simultaneous capturing of the multiple optical modes. In this paper, the concept of the femtosecond laser angle sensor is applied to evaluate the surface profile of a target of interest. An optical setup is designed in such a way that each mode in the spectrum of the mode-locked femtosecond is utilized as the laser beam to measure the local slope of a measurement target at each different point to evaluate the surface profile. Some basic experiments are carried out by using the developed optical setup with a mode-locked femtosecond laser source to evaluate basic performances of the developed optical setup as an optical angle sensor.
Materials Evaluation and Environmental Monitoring Utilizing an Acoustic Resonance
Authors: Tohmyoh Hironori
Published: January 2021

This paper presents the materials evaluation and environmental monitoring techniques utilizing the acoustic resonance, which have been developed by the authors. When the ultrasound passes through thin layer, the transmission and reflection coefficients take their maximum and the minimum values at the resonant frequency. We call this acoustic resonance. The acoustic properties of a polymer film, e.g., the acoustic impedance, ultrasonic velocity, and density, can be determined by observing the acoustic resonance, which occurs at the water/film/reflection plate interface. Acoustic resonance occurs at the reflection plate/film/outer environment interface sensitively changes depending on the outer environment. With use of this, the temperature of the water as an outer environment is tried to be monitored.
Sub-Micrometer Scale Laser Machining Using Position Controlled Photonic Nanojet
Authors: Uenohara Tsutomu , Mizutani Yasuhiro , Takaya Yasuhiro
Published: January 2021

A photonic nanojet (PNJ) is a fine and high intensity light beam that is generated from a dielectric microsphere irradiated by a laser. A PNJ has a smaller beam diameter than the wavelength of the incident laser and can propagate for longer than 1 μm with high intensity and minimal divergence. In other words, a PNJ has a long depth of focus. Due to its outstanding optical properties, PNJ is suitable for laser micro machining. In this paper, we theoretically and experimentally investigated machining characteristics of laser micro machining using a PNJ. First, electromagnetic simulations were conducted to estimate hole diameter when PNJ is irradiated to a sample by changing a distance from the microsphere to the sample. The simulation demonstrated that sub-micrometer scale hole diameter could be obtained even when PNJ is defocused by 1 μm due to the long depth of focus. Next, machining experiments were also conducted on a silicon substrate. A femtosecond laser was used as the machining laser. By holding the microsphere with a micropipette and controlling its position, the position of the PNJ can be controlled in the z direction. Micrometer and sub-micrometer scale hole diameters were obtained even when the position of PNJ in the z direction was changed by 1 μm. The hole diameters obtained in the experiment were consistent with the hole diameter estimated by the simulation. In conclusion, the long depth of focus of a photonic nanojet enable to create sub-micrometer scale structure.
Experimental Analysis of the Power Consumption of Feed Drive Systems Driven by Ball-Screw
Authors: Rigacci Massimiliano , Sato Ryuta , Shirase Keiichi
Published: January 2021

This study presents an experimental analysis of the power consumption of feed drive systems. The relevant system components from the power consumption point of view are the motor, bearings, ball-screw and linear guides. The electric power consumption of the motor is investigated experimentally acquiring the inputted voltage and the current; then, through the study of its efficiency, it is shown that the electric efficiency of the motor heavily depends on the angular velocity and the supplied torque. The mechanical power consumption of each component of the feed drive is investigated showing that the component that affects the most the consumption is the ball-screw. Thus, four kind of ball-screws differing for the lead of the screw and the preload of screw-nut are investigated; it is clarified the relation between the mechanical power consumption and several system characteristics such as the lead of the screw, the preload condition, and the table working velocity. Finally, the advantages and disadvantages of each mechanical configuration of the feed drive are discussed, emphasizing that the most important driven factor of the power consumption is the angular velocity due to the trade-off between the motor efficiency and the mechanical power loss of the system components cause friction.
Light Environment Design Support System Using Light-Guiding Plate With Decorative Cut Surface: Effects of Stripe Pattern Decorative Cutting on Plates Made From Transparent Resin
Authors: Imada Takumi , Ogawa Keiji , Tachibana Takuya , Sera Tetsuya , Okabe Toru
Published: January 2021

To increase the transmission efficiency of incoming and outgoing light on the side of a transparent resin light guide, such as an acrylic plate, we created a machined surface that does not become cloudy and transmits visible light well by cutting it with a single crystal diamond tool. When light is guided to this mirror-finished acrylic plate using an LED light source, its uneven brightness or illuminance distribution may be noticeable, depending on the application. To suppress the uneven distribution, attempts have made the luminance distribution uniform by a decorative cut on the acrylic plates for a fine pattern shape. Our research is developing a light environment design support system using an acrylic light-guiding plate with a decorative cut surface. This system consists of a rapid decoration pattern design technique with optical simulation, a decorative cutting technique to satisfy the demanded optical characteristics, and a technique to maintain machining quality. We implemented decorative cutting tests for various stripe patterns by adjusting the cutting conditions for the acrylic plates. Estimation of the decorative shapes was based on the shape of the tool cutting edge and its trajectory. We controlled the decoration shape and dimensions. The tendency of luminance distributions estimated by optical simulation were corresponded with the actual distributions.
Machining Vibration Suppression of a Cylindrical Part by a Point-Contact Support
Authors: Matsubara Atsushi , Mori Kotaro , Kono Daisuke
Published: January 2021

Aircraft engine cases employ a thin-walled cylindrical structure for the reduction of fuel consumption. The machining of such parts requires support systems as cutting forces generate shell mode vibrations. There has been much research on the design of vibration suppression devices such as mass dampers, tuned mass dampers, active dampers, and fixturing stretch. Although such devices can offer excellent performance in vibration suppression, cost, and time for manufacturing and setup with tuning are problems. In this paper, the test results of a simple support system that suppresses the vibration modes of a cylindrical part are reported. A support element employs two-contacts in the curved surface. Multiple support elements are arranged according to the number of antinodes of shell modes. Each support has two rollers with a rotating head; the roller contact aligned in the curved surface. For the decision of the number of the support elements, modal analysis was carried out for a cylindrical part. An excitation test was carried out to evaluate the frequency response of a supported cylinder, and several peaks in frequency response were found to be suppressed. A cutting test with an endmill was carried out to evaluate the vibration levels. The experimental results show that the support can suppress forced vibration during machining.
Precise Identification of Principal Stress Directions Induced in Laser Cleaving Process
Authors: Zhang Duo , Yamada Keiji , Nakajima Yuki , Tanaka Ryutaro , Sekiya Katsuhiko
Published: January 2021

Crack propagation is induced by thermal stress in the laser cleaving process, which is a prospective technique for dividing the substrates of hard and brittle materials such as glass, ceramics, and some semiconductor materials. Because the control of thermal stress distribution is essential for achievement of high accuracy in the process, various models have been developed for theoretical analyses to predict the stress distribution and estimate the effect of it. Besides, authors have developed a photoelastic observation technique for stress distribution in the laser cleaving process. In the present paper, the authors propose a procedure to compensate the distribution of stress direction within the substrates in order to apply the observation technique for the laser cleaving of single crystalline substrates which exhibit anisotropic photoelasticity. Single crystalline sapphire substrates are used as specimen in experiment to confirm the proposed procedure. Obtained results show the discrepancies between the principal stress direction and the birefringence direction of observation light in plane polariscope. And, the discrepancy depends on the crystal orientation with respect to the vibration plane of polarized light of the polariscope. This result is used to compensate the distribution of principal stress caused within the sapphire substrates during the laser cleaving process.
Lubrication Effect of Smeared Oil on Workpiece Surface in Intermittent Cutting With Very Short Cutting Duration
Authors: Nakamura Yoshiki , Itoigawa Fumihiro , Hayakawa Shinya , Maegawa Satoru , Liu Xiaoxu
Published: January 2021

In the metal cutting, generally, application of lubricant to a cutting edge is one of the methods in order to suppress temperature rise of the cutting edge by reducing frictional heat. However, the reduction in friction with lubricant disappears at higher temperature environment because of the loss of lubricant oiliness associated with temperature rise. Conversely, this reduction effect might work only in the initial stage immediately after cutting edge /work engagement because the temperature is not so high. Therefore, if the cutting duration of each blade of end-mill is shorten by limiting the cutting length per once, the cutting temperature can be suppressed to be lower than the moderate magnitude for lubrication. On the other hand, Ti-alloys with low thermal conductivity would experience quite high temperature increase during the high-speed cutting process. Therefore, it is thought that lubricant cannot be used properly with conventional cutting methods. In this study, the high-speed milling method mentioned above was used to implement the machining of Ti-alloys, and the lubricant effects of different types oils were compared from two aspects as tool wear and cutting force. As a result, when using low-viscosity synthetic ester oil, the damage to the cutting edge was suppressed most. At the same time, there was no fluctuation in cutting force by repeated machining. From this result, it was suggested that the lubricant performance, in intermittent cutting with very short cutting duration, depends on the heat resistance and permeability of the oil.
Development of Tool Path Generation Method for Complex Deep Groove Shape With Simultaneous 4-Axis Machining
Authors: Ichikawa Kohei , Nakamura Takayuki , Kaneko Jun'ichi , Hasegawa Masanobu , Abe Takeyuki
Published: January 2021

In recent years, aero engine parts with complex shapes are increasing due to demand on improved performance and weight reduction. In one example, some of those parts have groove which are deep, narrow and complex surface. They are processed by Simultaneous 5-axis machining with small ball end-mill. However, its complex groove shape cause greatly move of tool posture, thereby it cause greatly and discontinuous move of rotational and tilting axis of machine tool. As a result, actual feed speed cannot follow the commanded feed speed, so low process efficiency is problem. It can be considered simultaneous 4-axis machining which with fixed tilting axis as countermeasure. However it is difficult to generating tool path of simultaneous 4-axis machining by commercial Computer Aided Manufacturing (CAM) software for these deep groove shapes because of its tool collision avoidance algorithm. In this study, we developed method of generating tool path that can be machining simultaneous 4-axis machining while avoiding collision of workpiece and tool as an aim of increasing process efficiency. Furthermore, In order to effect of further improve the feed speed, we studied about posture planning way with possible to continuous moving of rotational axis, and we conducted verification test of increasing of feed speed with proposed method.
Tool Posture Planning Method for Low Rigidity Workpiece Considering Elastic Deformation Caused by Cutting Force
Authors: Kaneko Jun'ichi , Okuma Yuki , Sugita Shumpei , Abe Takeyuki
Published: January 2021

In machining process for a workpiece with low rigidity such as a blade shape, it is required to consider elastic deformation of the workpiece shape itself due to cutting force. Conventionally, reduction of the cutting force in machining process is achieved by optimization of feed rate value in NC program. On the other hand, since a decrease in the feed rate causes an increase in machining time. So, other optimization algorithm is required.

In this paper, a new method to suppress the elastic deformation of the workpiece by changing tool posture in multi-axis controlled machining is proposed. The proposed method is intended for finish machining process for blade shape with a ball end mill. In the proposed method, first, the cutting force loaded on the workpiece surface in a certain posture candidate is predicted, and an instantaneous cutting force at the moment when the machining surface is generated is estimated by model-based computer simulation. Based on this results, the amount of elastic deformation on the machined surface is estimated by FEM. This process is repeated at each cutter location and tool posture candidate, and the new tool posture that can minimize machining error caused by the elastic deformation is determined at each cutter location.
Effects of Alpha-Cellulose Supply on the Working Life of MCF Slurry in MCF Polishing
Authors: Nonaka Yuta , Nomura Mitsuyoshi , Fujii Tatsuya , Suzuki Tsunehisa , Wu Yongbo
Published: January 2021

High precision surfaces exhibit prominent capabilities for enhancing the imaging quality, expanding the visibility of equipment, simplifying structures, and reducing total costs of optical systems. Hence, they are regarded as essential optical surfaces for replacing traditional elements to modify optical systems, including space systems, optical inspection systems, and smart devices.

Single point diamond turning (SPDT) and ultra-precision grinding have been adopted preliminarily to manufacture high-quality elements. However, these processes create sub-surface damage and tool marks on the work surface. To meet performance requirements, polishing is critical for post-processing to improve the quality of the products.

MCF (Magnetic Compound Fluid) polishing, which is one of polishing methods using magnetic fields, is a processing method for finishing hard and brittle materials with high accuracy. Previous research has shown that MCF polishing is effective for hard and brittle materials. However, despite the high cost of the magnetic fluid that is a component of the MCF slurry, the MCF slurry used for polishing has been discarded. Another major issue was that unused MCF slurry could not be used due to drying. The purpose of this study is to recycle MCF slurry to solve this problem, and to develop high precision finishing technology. Therefore, in this study, a novel MCF polishing method using ultrasonic atomization is proposed, and the effects of α-cellulose on the MCF polishing are investigated. In addition, in order to make it possible to reuse the MCF slurry, In addition, experiments are conducted to enable reuse of MCF slurry.
Effects of Cold Air Supply on Cutting Characteristics in Small Hole Drilling of PEEK
Authors: Ito Shogo , Nomura Mitsuyoshi , Fujii Tatsuya , Suzuki Tsunehisa
Published: January 2021

A polyetheretherketone (PEEK) is one of the thermoplastic resins. The material is superior in mechanical strength, heat resistance and chemical resistance. Therefore, it is suitable for industrial components such as automotive parts, machine parts, electrical and electronics parts. Particularly, it is used for an inspection socket of a connector and the semiconductor package in the field of electronic components. Consequently, a demand of the high efficiency machining in small drilling for the PEEK increases with a miniaturization and diversification of the industrial equipment. However, PEEK, which is a thermoplastic resin, has a problem that the hole accuracy is lowered due to the cutting heat.

The objective of this study is to achieve high precision and high efficiency machining process for industrial components of the PEEK such as an inspection socket of a connector or the semiconductor package. In order to solve these problems, this study carries out cooling workpiece by cold air supply. This paper describes the investigation result of the effect of cold air cooling on hole accuracy and cutting state in the small hole machining of PEEK. As a result, it was found that cooling the workpiece is effective to suppressing the cutting heat and improve hole accuracy. Within the experimental conditions, the combination of non-step drilling and cooling enables high-precision drilling with approximately the same accuracy as step drilling.
Experimental Investigation of Plastic Injection Molding Heating System Using Hydrogen Absorbing Alloys
Authors: Fukushima Yoshio , Kosaka Masataka
Published: January 2021

Much focus from various fields is being placed on the hydrogen and utilizing the technique. Nowadays, the applied researches of hydrogen energy have been trying as one of an alternative energy source for fossil fuel. And, since we could not think lightly of consumed energy by machine tools and industrial machinery, Eco-friendly manufacturing is going to be achieved by hydrogen energy. In this study, to prevent the weldline that is a representative defect in the field of plastic injection molding, heat & cool technology using hydrogen energy, LmNi4.90Mn0.10 hydride, is applied to the mold. This method can achieve heat & cool technology by using only hydrogen energy. So, since electricity and warm/cool water that are for heating/cooling the mold are not necessary, this method should thus be at an engineering advantage in terms of eco-friendly manufacturing. After manufacturing the hydrogen-used-prototype-mold that is dedicated to preventing the weldline, the comparison between the experimental data and numerical simulation was carried out. As result, using this approach, the mold surface temperature difference from initial temperature was rapidly increasing to 40 K, in 18 seconds from the beginning of hydrogen-absorbing and the maximum temperature difference ΔT in this experiment has become 48 K.
Generation of Micro Texture Including Calcium and Phosphorus Elements on Titanium Alloy for Improvement of Biocompatibility With Laser Induced Mist Surface Treatment
Authors: Ezura Atsushi , Katahira Kazutoshi , Komotori Jun
Published: January 2021

Titanium alloys are widely used for the hard tissue substitute implants. However, it is necessary to improve interfacial biocompatibility for reduce adhesion period. For improvement of biocompatibility of titanium alloys, texture and chemical composition on contact part with biological tissue play very important roles. In this research, mist of glycerophosphoric acid calcium aqueous solution was applied on the laser irradiated area. As result, micro texture including Ca and P elements was generated on the Ti-6Al-4V-ELI alloys surfaces. When laser was irradiated, glycerophosphoric acid calcium aqueous solution applied as mist flowed on the test pieces as droplet. The velocity of droplet fluid was relatively fast, so that laser irradiation was unhindered access to the surface of specimens and the treatment was stable. In order to estimate biocompatibility of treated surfaces having micro texture with Ca and P element, culture assays using osteoblast cells were conducted. As result, it was clearly that biocompatibility of the specimen treated by laser with glycerophosphoric acid calcium aqueous solution mist more improved than treated specimen soaked in glycerophosphoric acid calcium aqueous solution.
Energy Consideration in the Micro-Extrusion of Aluminum Alloy 6063
Authors: Sucharitwatskul Sedthawatt , Mahayotsanun Numpon , Bureerat Sujin , Dohda Kuniaki
Published: January 2021

This paper investigated key factors influencing energy consumption in the micro-extrusion process. The considered factors were: extrusion ratio (ER), die angle (α), billet length (BL), bearing length (LB), coefficient of friction (COF), and die shift (DS). The finite element simulation was carried out to determine the extrusion energy required to complete one extrusion cycle. The simulation results showed that the increased values of all the considered factors (except the die shift) led to increased extrusion energy. The results also provided percentages of energy variation in steps, which helped evaluate the energy savings with regards to the crucial other production considerations. The percentage increase in energy consumption in the lower ER values was considered higher than those of, the higher ER values. Increasing die angle (α) from 60° to 90° barely affected the consumed energy. The highest increase percentage of extrusion energy was found while increasing billet lengths (BL) from 3.00 mm to 4.00 mm. The lower bearing length (LB) values offered lower consumed energy. The consumed extrusion energy linearly increased with COF. The die shift (DS) did not affect the extrusion energy, but the final part geometry (curved pins). The results and analysis from this study could be used to potential energy savings and overall production costs of the micro-extrusion process.
Effect of Insert Material on Microstructure and Strength of Aluminum Alloy to Zinc-Coated Steel Dissimilar Metal Weld
Authors: Walker Luke , Lu Ying , Hilla Colleen , Zhang Wei , Ou Byoung , Hunter Scott
Published: January 2021

Ultrasonic interlayered resistance spot welding (Ulti-RSW) is a recently developed method for dissimilar metal joining of aluminum alloy to advanced high strength steel. It makes use of a thin insert (or interlayer) which is first ultrasonic spot welded to one of the two sheets. The second sheet is then resistance spot welded to the insert side of the first sheet. In the present study, two inserts were tested, 0.3-mm-thick AA3003-H14 and 0.25-mm-thick stainless steel 316, for joining 0.8-mm-thick Zn-coated (galvannealed) dual phase steel 590 to 1.2-mm-thinck aluminum AA6022-T4. The joint with the aluminum insert achieved a peak tensile-shear strength of 4.1kN and a fracture energy of 1.7J, while the joint with the stainless steel insert achieved a peak strength of 4.5kN and a fracture energy of 2.6J. Both welds were much stronger than a direct resistance spot weld between the two sheets which had a strength of 3.3kN and an inferior fracture energy of 0.87J. The increase in strength and fracture energy achieved using stainless steel insert over aluminum insert was discussed based on the nugget diameter and the interface microstructure.
Simulation of Complex Plastic Flows in Machining of Metal Polycrystals Using Remeshing
Authors: Salilkumar Vandana A. , Sundaram Narayan K.
Published: January 2021

The simulation of machining of soft metals at the 100 microns-few mm length-scale requires capturing complex flow physics induced by the high ductility and polycrystalline aggregate nature of these metals. This work presents a remeshing and mesh-to-mesh transfer approach that can successfully simulate complex flows including highly sinuous flow with surface folding in polycrystalline aggregate cutting. The meshing scheme is both graded and adaptive, with the ability to automatically refine regions such as self-contacts. Notably, the presence of microstructure makes these simulations far more complex than their homogeneous counterparts, with several additional constraints on the remeshing algorithm. The approach is general, with no limitations on rake angle, grain-size, or friction coefficient, and does not use an artificial, predefined separation layer. The scheme accurately tracks individual grains and allows grain splitting in a manner consistent with imaging experiments. The plastic strain field, cutting-force evolution, and deformed grain shape from several annealed-copper cutting simulations are presented, representing a range of rake angles and friction coefficients as high as 0.5. The simulations accurately capture the thick chips, high cutting force, and highly undulating streaklines of flow that characterize sinuous flow, as well as the experimental observation that the sinuous flow is suppressed on using a high rake-angle for the cutting. Moreover, in grains that are split between the chip and residual surface, we can accurately capture the extreme grain stretching that is observed prior to splitting in imaging experiments. Remeshing also provides a way to accurately capture the residual surface plastic strains and strain gradients. The latter are particularly steep, with the strain falling from a value greater than 10 to 2 within a distance of 30 microns. The use of remeshing has numerous advantages over a predefined separation layer, including the fact that one can parametrically explore the effect of variables like the extent of yield stress inhomogeneity on the flow pattern with no limitations. Interestingly, the technique allows us to find the actual line of material separation in such cutting processes: As opposed to a horizontal line, this is typically an undulating curve with a deviation of about 0.06 of the undeformed chip thickness on either side of the horizontal. This fraction increases with the extent of sinuous flow. A simple, pseudograin model with spatial inhomogeneity in flow stress is used to represent the microstructure in the present work, but the present scheme can easily be used with more complex microstructural models as well.
Woven Carbon Fiber Reinforced Laminate Matrix Composite Through Fused Deposition Modeling
Authors: Ranjan Rachit , Raote Piyush , Bajpai Vivek
Published: January 2021

A novel fused deposition modeling (FDM) based fabrication technique for Woven carbon fiber (WCF) reinforced PLA matrix laminated composite was proposed. The composite was fabricated by placing a layer of carbon fiber (CF) after every 5th layer of PLA matrix such that there was a total of 3 layers of CF in every tensile specimen fabricated. The parameter such as extrusion temperature, feed rate, and bed temperature was initially optimized by the Taguchi L9 optimization technique to get high-density low surface roughness specimens. Mechanical properties such as tensile strength and flexural strength of the specimen were measured in Hounsfield tensile testing machine. The composite has the yield and ultimate tensile strength of 43.378 MPa and 70.84 MPa which is 114.01% and 172.94% higher than the unreinforced specimen. The Flexural strength of the composite was found to be 117.88 MPa which is 17.91 % higher than the unreinforced 3D printed specimen. The proposed technique has offered a potential strategy to fabricate low-cost products with variable design for versatile applications such as aerospace and automobile industries.
Tip Induced Growth of Zinc Oxide Nanoflakes Through Electrochemical Discharge Deposition Process and Their Optical Characterization
Authors: Kumar Deepak , Bishwakarma Harish , Kumar Mohan , Singh Nirmal Kumar , Bajpai Vivek
Published: January 2021

ZnO nanoflakes with varying thickness (10–120 nm) and width (250–1600 nm) were synthesized on the tooltip (∅ ≤ 200 μm) by a novel route method called electrochemical spark deposition and growth method. The leaf-like nanostructures were found under varying pulsated DC voltage potentials (50–80V) at normal room temperature (25°C). Equimolar concentration (0.1M) of zinc nitrate hexahydrate (Zn(NO3)2.6H2O) and methenamine ((CH2)6N4) HMTA) mixture was used as a growth (precursor) solution. The anodization time (deposition and growth time) was varying from 10 seconds to 25 seconds. Further, the consequence of pulse voltage on the growth morphology was examined critically. The structural evolution and elemental composition were investigated by field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDX) respectively. The size distribution (thickness and width) of ZnO nanoflakes were estimated by image processing software (Image J). Ultimately, the ultraviolet visible infrared spectroscopy (UV-Vis) analysis was carried out to determine the excitation energy of the zinc oxide nanoflakes. The estimated bandgap energy (via. Tauc plot) of the nanoflakes was found approximately 2.63 eV.
3D Freeze Printing: Development of an Experimental Setup and Determination of 3D Printing Parameters
Authors: Tetik Halil , Lin Dong
Published: January 2021

3D freeze printing is a hybrid manufacturing method composed of freeze casting and inkjet-based printing. It is a facile method to fabricate lightweight, porous, and functional structures. Freeze casting is a well-known method for fabricating porous bodies and is capable of manipulating the micro-structure of the resulting product. Freeze casting simply involves solidification of a liquid suspension using low temperature and sublimation of the solvent using low temperature and pressure. After the sublimation of the solvent crystals, we obtain a porous structure where the pores are a replica of solvent crystal. Making use of the temperature gradient, as seen in unidirectional and bidirectional freeze casting, during the solidification with low temperature values, the solvent crystals grow along the temperature gradient. Furthermore, by manipulating the freezing kinetics during solidification, we can have a control on the average pore size distribution. For instance, when lower freezing temperatures result in finer pores with higher amount, higher freezing temperatures result in coarser pores with less amount. Also, the use of some additives inside the suspension leads to changes in the morphology of the solvent crystals as well as the resulting pores. However, the macro-structure of the fabricated body is highly dependent on the mold used during the process. In order to eliminate the dependency on the mold during the freeze casting process, our group recently combined this technique with inkjet-based 3D printing. With inkjet-based 3D printing, we fabricated uniform lines from single droplets, and complex 3D shapes from the lines. This provided us the ability of tailoring the macro structure of the final product without any dependency on a mold as seen in freeze casting. As a result of the 3D freeze printing process, we achieved fabricating lightweight, porous, and functional bodies with engineered micro and macro-structures. However, achieving fine droplets, and uniform lines by merging the droplets requires a good combination of fabrication parameters such as pressure adjustment inside the print head, print head speed, jetting frequency. Also, fabricating complex shapes from uniform lines requires well-adjusted parameters such as line thickness and layer height. In this study, we briefly explained the mechanics of the 3D freeze printing process. Following that we presented the development process of an open-source inkjet-based 3D printer. Finally, we explained the determination of inkjet dispensing and 3D printing parameters required for a high-quality 3D printing. During our experiments for the determination of fabrication parameters, we used a nanocellulose crystals-based ink due to its low cost and ease of preparation.
Evaluation of Microstructure and Mechanical Properties of Al-TaC Composites Developed by Muti-Step Stir Casting Process
Authors: Khalkho J. S. , Vidyasagar Ch. S. , Karunakar D. B.
Published: January 2021

In the present study, four AA7075 composite samples reinforced with varying amounts of TaC in the range of 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, were developed using a multi-step stir casting to improve the mechanical properties. The mechanical properties of the developed samples such as microhardness, tensile strength, compression strength, and elongation were characterized using a computerized Vickers hardness testing machine for microhardness and a Universal Testing Machine for both tensile and compression respectively. The effect of Tantalum carbide on the microstructures of the composite samples was characterized using an optical microscope. The microstructures and the mechanical properties of the developed composites were correlated. The results show a gradual increase in the mechanical properties with an increase in TaC reinforcement, However, the elongation decreased gradually with the increase in TaC content. The highest mechanical properties were found in the composite reinforced with 0.4. wt% TaC with the highest microhardness of 121 Hv, Ultimate Tensile Strength of 369 MPa, Yield Strength of 338 MPa and compression strength of 784 MPa.