bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pipeline Fracture Control Concepts for Norwegian Offshore Carbon Capture and Storage
Authors: Gruben Gaute , Macdonald Kenneth , Munkejord Svend T. , Skarsvåg Hans L. , Dumoulin Stephane 
Published: January 2021

Abstract
The Northern Lights onshore terminal will initially receive CO2 transported by ship tankers from industrial source sites located in south-eastern Norway and transport CO2 via a 12 ¾” OD offshore pipeline for injection into the Johansen storage reservoir, located south of the Troll field. The CO2 injection pipeline will be laid from the shore terminal to a subsea wellhead structure from where the liquid CO2 will be injected into the reservoir. Presently, demonstrating arrest of longitudinal propagating shear fracture in CO2 transport pipelines is specifically addressed in two international guidelines, ISO 27913 and DNVGL-RP-F104. The study reported here aims to develop a robust fracture control methodology unique to the Northern Lights pipeline. To this end, the maximum loading in terms of saturation pressure is conservatively estimated from temperature and pressure scenarios from the planned pipeline route and applied in numerical simulations of the running-fracture phenomenon using the SINTEF coupled FE-CFD code. It is shown that, with the given pipe material, diameter, and loading conditions, the proposed wall thickness of 15.9 mm is sufficient to arrest a propagating crack. Furthermore, the Battelle TCM with ISO 27913 or DNVGL-RP-F104 arrest- and load pressure correction is shown to provide a good first estimate in pipe design, although the arrest pressure saturates for low Charpy energy toughness values, indicating limited accuracy in this study.
In-Liquid Laser Nanomachining by Photonic Nanojet in Laser Trapping System
Authors: Rahman Reza Aulia , Uenohara Tsutomu , Mizutani Yasuhiro , Takaya Yasuhiro 
Published: January 2021

Abstract
Direct laser machining in sub-micron scale patterning at a surface of material remains a challenging task though the laser machining has been widely applied in various application. A photonic nanojet becomes a promising way to solve the problem by involving near-field focusing of light waves below the surface of a dielectric microsphere to fabricate pattern in micro- and nanometer size. By generating laser power to the microsphere and controlling the resulting photonic nanojet intensity distribution and position related to the workpiece, intended ablation size on the material could be controlled at the sub-micrometer scale. In this study, liquid is proposed as photonic nanojet machining medium due to several advantages that liquid offer during machining process. Laser trapping system is then introduced to the optical system to control the position of the microsphere during machining process. An in-liquid nanomachining by generating photonic nanojet in laser trapping configuration is a subject to study with the effect on the resulting ablation and viability of machining process from a set of parameters are investigated numerically using finite-difference time-domain (FDTD) technique. According to the findings of this study, nanometer scale, flexible, and fast novel laser nanomachining could be realized by combining photonic nanojet machining and laser trapping technique.
Effects of Position and Orientation Errors of Linear and Rotary Axis Average Lines of Five-Axis Controlled Machining Centre Onto its Motion Errors in Testing Method With Truncated Square Pyramid
Authors: Kikkawa Koichi , Mori Naoki , Mizugaki Yoshio , Ozaki Keisuke 
Published: January 2021

Abstract
In this paper, ‘position and orientation errors of linear and rotary axis average lines’ is newly named ‘geometrical mechanism deviations.’ This paper presents suggestive simulation results of tool motion error caused by geometrical mechanism deviations of a five-axis controlled machine tool. Firstly, there were assumed seven geometrical mechanism deviations consisting of three positional and four angular deviations. As positional deviations, the error of intersection is set to be 0.01 [mm] off-centre, and the squareness errors of the cross axes as angular deviations are 0.01 [°]. Secondly, there was simulated theoretically the shape of machined pyramidal surface according to the virtual cutter movement of a flat end mill along contouring tool paths. Thirdly, the correspondence of geometrical mechanism deviations and simulated flatness error was analysed and found to have two regularities. One of the two indicated that four pyramidal surfaces wave similarly with left half surface up and right half surface down. The other indicated that the centre of a specific pyramidal surface should be concave in the cases of squareness error between B-Z axes. Through the analysis of grouped flatness error, specific geometrical mechanism deviations seem to cause a particular deformation of pyramidal surface due to the misalignment of tool position and orientation.
Effect of Steady Rest in Cylindrical Traverse Grinding of Slender Workpiece
Authors: Fujii Hidetaka , Onishi Takashi , Lin Chinhu , Sakakura Moriaki , Ohashi Kazuhito 
Published: January 2021

Abstract
In the case of traverse grinding of a slender workpiece, the ground workpiece is easily deformed by the normal grinding force due to its low stiffness. To reduce the form error caused by the elastic deformation of the workpiece, a steady rest is widely used. Generally, a steady rest is set to push the ground area of the workpiece. However, the stepped shape error is generated at the contact point where a steady rest pushed the workpiece because the pushing force of a steady rest is decreased after the material of the contact point is removed. In this study, to reduce the stepped shape error of the ground workpiece, we proposed a new method to set a steady rest. In this method, the steady rest was set to push the area where was not ground. In addition, the traverse speed of the workpiece was adjusted to keep the elastic deformation of the workpiece constant. The suitable method to control the traverse speed was estimated by using a beam model that could simulate the elastic deformation of the workpiece during the grinding process. It was confirmed that the new method could improve the form accuracy of a slender workpiece through grinding experiments.
Screw Forming by Semi-Solid Forging of Aluminum Alloy A7075
Authors: Ogawa Kyohei , Nishida Shinichi , Imai Shogo , Uematsu Daichi , Hagiwara Makoto , Kawawa Mizuki , Tsunoda Kentaro 
Published: January 2021

Abstract
This paper reports the screw forming of aluminum alloy A7075 by semi-solid forging. The experimental devices are a servo press machine and a die cushion. The program motion was used for forging. The nominal diameter of screw is M10. The molten aluminum alloy A7075 was stirred and then semi-solid forged into a female screw under 40 tons with 10 seconds holding during forging. The solid phase rate was 0.3. The microstructure of the specimen that is isometric crystal had sphericalization, and refinement. In the results of compression test at room temperature, the maximum compression rate was 29.4% and the maximum nominal stress was 540 MPa. The screw tightening torque was estimated over 57.55 N · m by torque test. This value indicates for produced M10 screw that the strength is over strength category 8.8 of JIS. These results are indicated that the produced screw is suitable for general applications. In the results of optical observation, the male screw of die transferred to the aluminum forgings. And the surface of screw portion had crack free surface. In summary, screw forming by semi-solid forging of aluminum alloy A7075 was possible.
A Hybrid Meta-Heuristic Approach Considering Workload Balancing for Vehicle Assignment and Routing Problem
Authors: Kawashima Takuma , Sakaguchi Tatsuhiko , Uchiyama Naoki 
Published: January 2021

Abstract
In recent years, due to the globalization of the market and the expansion of e-commerce, logistics optimization attracts keen interest from manufacturing companies and service providers. The service area expands wider and the number of customers increases rapidly, thus logistics service providers need to determine the customer assignments and the routes for their trucks considering not only the efficiency of logistics but also the balance of workload for each truck. Therefore, in this study, we propose a customer assignment and vehicle routing algorithm based on the saving method and the simulated annealing. The algorithm first determines the customer assignment and initial route for each truck based on the saving method to balance the workload consisting of the number of customers, the demand of the customers, and distance. Then the initial route is improved by applying the simulated annealing. To evaluate the effectiveness of the proposed method, we conducted computational experiments. In experiments, we solved the waste collection vehicle routing problem in a Japanese city where the wastes generated from over 1000 customers are collected by 10 trucks starting from 1 depot. We evaluated the total cost consisting of the number of waste collecting points, the amount of waste, and the distance for this case study.
Measurement of Residual Strains As a Parameter of Matrix Cracking in CFRP Laminates
Authors: Fikry M. J. Mohammad , Ogihara Shinji , Vinogradov Vladimir 
Published: January 2021

Abstract
Matrix cracking in CFRP laminates results in degradation of mechanical properties of the material and appearance of residual strains. In this study, the residual strains investigated are experimentally and analytically for CFRP [0/756]s laminates. The strain gauges were used in this study to measure the strains. Due to very small residual strains at the unloading condition, the residual strains were also measured at different stress levels for laminates with different crack densities and are compared with theoretical predictions. Time-dependent viscoelastic behavior of the material is also considered to accurately measure the residual strains due to the occurrence of matrix cracks. This was done by using the strain recovery test when the loads were stopped for 1–1.5 hours during unloading and the strain changes during these times were recorded. The experimental results of the residual strains are in reasonably good agreement with the theoretical predictions. The fiber non-linearity properties of the laminates may cause some experimental data to shift above the analytical line.
Ultrasonic Nondestructive Evaluation Methods Applicable to High-Temperature Environments Based on Optical Fiber Remote Sensing
Authors: Okabe Yoji , Yu Fengming , Saito Osamu 
Published: January 2021

Abstract
The development of reliable heat-resistant structural materials requires nondestructive evaluation (NDE) techniques to evaluate the damage progress during material testing at elevated temperatures. Hence, our optical fiber ultrasonic sensing system with a phase-shifted fiber Bragg grating (PSFBG) sensor was improved to a remote AE measurement system at high temperature. The optical fiber was used as an ultrasonic waveguide from an object material in a high-temperature furnace to the PSFBG sensor placed far from the furnace. As a result, AE signals at about 1000°C were successfully detected keeping their precise waveform. Therefore this method will be useful to evaluate the damage progress in heat-resistant materials under high temperature. Furthermore, the remote PSFBG ultrasonic sensing system was incorporated into the receiving part of a laser ultrasonic visualizing inspector (LUVI) for a high-temperature NDE. The LUVI can visualize the propagation behavior of ultrasonic guided waves in complex shape structures. As a result, the improved LUVI with the optical fiber ultrasonic receiver succeeded in clear visualization of the ultrasonic wave propagation in a ceramic plate at 1000°C. Then an artificial damage formed in the ceramic plate was able to be detected by the observation of reflection waves from the damage. Hence, this system has a potential as an effective and intuitive NDE method in high-temperature environments.
Grinding Performance and Delamination Analysis of FeSiB Metallic Glass Laminate
Authors: Fang Zhenglong , Nagato Keisuke , Sugita Naohiko , Nakao Masayuki 
Published: January 2021

Abstract
FeSiB metallic glass laminate is a state-of-the-art structure for improving the magnetic performance of magnetic core. Extreme strength and hardness due to the amorphous matrix challenge its grinding process with severe tool wear and pronounced delamination. An amount of heat generated during grinding process brings a considerable problem in material crystallization, resulting in an increased magnetic deterioration. In this work, grinding data is presented for grind wheel wear, cutting force and surface quality when routing 8 mm thick FeSiB metallic glass laminate using electroplated CBN grinding points. Grinding experiments were carried out with grinding speeds of 0.5 and 1.5 m/s to investigate the formation of delamination. Energy dispersive x-ray spectroscopy (EDS) and electron back scattered diffraction pattern (EBSD) analyses were conducted to inspect the delamination between the metallic foil layers and detailed microstructure of machined surface, respectively. The relation between the cutting force and delamination was discussed associated with the identification of crystallization condition of machined surface. As a result, plastic deformation between the layers is the primary reason for the inter-laminate circuit short. Load-displacement curve from nano indenter indicated the strain hardening level near machined surface increased with cutting speed.
Microstructure and Mechanical Properties of AlSi12CuNi Alloy Fabricated by Selective Laser Melting
Authors: Hirayama Akihiro , Kaizu Koichi , Kimura Masaaki , Kusaka Masahiro 
Published: January 2021

Abstract
In this study, the microstructure and mechanical properties of AlSi12CuNi alloy fabricated by Selective Laser Melting (SLM) were investigated. Wide range of laser irradiation conditions were selected to optimize the process in terms of optimum volume density. As a result, fabricated objects with a relative density of 99% or higher and no crack could be obtained. The as-fabricated alloy exhibited significantly good mechanical properties; an ultimate tensile strength, a breaking elongation, and micro-hardness in comparison with the conventional die casting AlSi12CuNi alloy. The fine microstructures composed of the α-Al phase and nano-sized eutectic Al-Si network could be observed. The dimensions of the microstructures were smaller than that of the conventional die casting AlSi12CuNi alloy. The superior mechanical properties were attributed to the microstructure associated with the rapid solidification of the SLM process. The influence of building direction of mechanical properties on fabricated objects was evaluated. The ultimate tensile strength and breaking elongation were significantly affected by the building direction, which was higher in the case of a parallel direction to the roller moving direction. AlSi12CuNi alloy with good characteristics can be successfully fabricated by the SLM process.
Measurement and Evaluation of the Static Friction Coefficient Between Fixed Coupling Surfaces Under Face Contact and High Contact Pressure
Authors: Inagaki Fumihiko , Morita Noboru , Hidai Hirofumi , Matsusaka Souta , Ohmori Tatsuo , Chiba Akira , Matsumoto Yuichiro , Shimizu Shinji 
Published: January 2021

Abstract
At the joints of the mechanical systems, it is well known that the parameters such as contact stiffness, static friction coefficient, kinetic friction coefficient and attenuation coefficient affect static, kinetic, thermal and motion characteristic of them strongly. In these parameters, the static friction coefficient reigns the character of maximum fixing resistance. However, there’s difficulties for measure the precise static friction coefficient on the coupling surfaces due to tiny contact surface, unstable loading method and moment force acts on the contact surface of the former device. Therefore, we developed novel measurement device and evaluated influence of the surface parameters given to static friction coefficient.
Through the validity evaluation, it was confirmed that the new measurement device enables face contact and uniform surface pressure. In addition, there’s no moment force by optimizing the loading position of the tangential force. Furthermore, validity of the static friction coefficient was checked and verified that frequency of the sampling rate is fine enough.
Finally, we proceeded to applied test with this new measurement device for evaluate the influence of the surface roughness and grinding direction given to static friction coefficient. A pair of die steels and cemented carbides was selected for specimen and static friction coefficient was measured under 60 MPa of contact pressure. Regarding influence of surface roughness, the result showed tendency that rougher surface generates lower value of the static friction coefficient. Now for grinding direction, combination of the specimen ground in orthogonal direction against tangential force showed maximum value and the specimen ground in parallel direction against tangential force showed minimum.
Study on Method to Avoid Chatter Vibration Based on Machine Tool Rigidity
Authors: Hayashi Akio , Ishibashi Hiroto , Morimoto Yoshitaka , Kaneko Yoshiyuki , Suzuki Naohiko 
Published: January 2021

Abstract
Chatter vibration decreases machining accuracy and thus presents a problem in manufacturing. In order to eliminate chatter vibration based on the estimation of stable cutting conditions from a stability limit diagram and to determine the cutting conditions accordingly has been proposed. However, changing the cutting conditions may lead to a decrease in productivity. The stability limit is estimated from the relationship between machine rigidity and the cutting conditions.
In the present study, we proposed a system to avoid chatter vibration by changing the rigidity of the machine tool. We developed the desktop machine tool that can change its rigidity by varying the preload of a brace bar attached to the frame. In order to clarify the relationship between the chatter vibration and the rigidity of the desktop machine tool, the stability limit of the desktop machine tool was determined by conducting machining tests and comparing the results with a simulated stable limit diagram. We then investigated the frequency response function within the simulation. The results showed that the transition of the stability limit can be accomplished by changing the rigidity of the desktop machine tool, and indicate that chatter vibration can be avoided by simulation.
Debonding Detection at Core/Skin Interfaces in a Honeycomb Sandwich Structure Using a Laser Ultrasonic Visualization Method
Authors: Sen Enhi , Saito Osamu , Higuchi Nobuhiro , Okabe Yoji 
Published: January 2021

Abstract
Honeycomb sandwich structures are widely used in aircraft owing to the superior characteristics, such as the light weight, the high specific bending stiffness and the high specific in-plane compressive strength. However the honeycomb sandwich structures are prone to have debonding damages at the interfaces between the skin and the honeycomb core, which degrades the mechanical properties largely. For inspection of damages in plate-like structures, the propagation of ultrasonic guided waves along the plate is effective. In this research, we attempted to detect the debonding at the skin/core interfaces in a honeycomb sandwich panel by using a laser ultrasonic visualization method. Debonding damages were artificially introduced in a sandwich panel consisting of two CFRP skin plates and an aluminum honeycomb core. Then, ultrasonic guided waves were excited in the panel through scanning of a laser irradiation on a surface of the plate and were received by a piezoelectric sensor installed on the same surface by using a laser ultrasonic visualizing inspector. As a result, we obtained visualization animations of the ultrasonic propagation behavior. From the change in the maximum amplitude distribution of the guided wave, we were able to identify the debonding damages at the skin/core interfaces in both the laser-irradiation side and the opposite side. Furthermore, a finite element analysis of the ultrasonic propagation in the honeycomb sandwich panel was conducted to confirm the phenomena observed in the experiments. From the calculation results, the mechanism of the observed phenomena was able to be clarified.
Control of Laser-Induced Periodic Surface Structures Assisted by Mechanical Processing
Authors: Kodama Shuhei , Takase Ryohei , Shimada Keita , Mizutani Masayoshi , Kuriyagawa Tsunemoto 
Published: January 2021

Abstract
Fine structures provide materials with various functionalities such as friction reduction and water repellency. A short-pulsed laser is a suitable method to effectively fabricate fine structures through self-organization, called as LIPSS (laser induced periodic structures). However, this method has difficulty in control of LIPSS since the principles and the phenomena have not been clarified completely. It has been reported that LIPSS follow debris on a material surface, hence, the short-pulsed laser assisted by mechanical processing was proposed, and the straightness and the aspect ratio of LIPSS were improved by laser irradiation on the surface with the straight microgooves. The short-pulsed laser assisted by mechanical processing was developed to control LIPSS and fabricate zigzag LIPSS, and the effects of the surface geometry before laser irradiation on LIPSS were investigated. Firstly, laser irradiation was conducted on the microgrooved surfaces with changing the angle of laser polarization to investigate the effects of the angle between groove direction and laser polarization on LIPSS. When the angle were from 45° to 90°, LIPSS followed the microgrooves regardless of the laser polarization. Based on the results, the laser was irradiated on the surfaces with zigzag microgrooves created by ultraprecision cutting, and zigzag LIPSS were fabricated as following zigzag microgrooves under the proper conditions. This study demonstrated the importance of the initial surface shape and the effectiveness of the short-pulsed laser assisted by mechanical machining to control LIPSS freely since the surface plasma waves are propagated from unevenness on the material surface.
Effect of Interfacial Nanostructure on Mode Mixity in Directly Bonded Carbon Fiber Reinforced Thermoplastic Laminates and Aluminum Alloy With Thermal Stresses
Authors: Ota Hiroki , Jespersen Kristine Munk , Saito Kei , Wada Keita , Okamoto Kazuki , Hosoi Atsushi , Kawada Hiroyuki 
Published: January 2021

Abstract
In recent years, for the aim of weight reduction of transportation equipment, carbon fiber reinforced thermoplastics (CFRTPs), which have high recyclability and formability, are becoming suitable for mass production. Additionally, with the development of multi-material structures, excellent technologies for joining metal and CFRTPs are required. In present industry, joining between dissimilar materials include adhesive bonding and mechanical joining methods, however, these methods still have some problems, and therefore an alternative bonding method without adhesive and mechanical joining is required for joining CFRTPs and metals. Thus, this study focused on direct bonding between CFRTP and an aluminum alloy, by producing a nanostructure on the surface of the aluminum alloy. The nanostructure penetrates the CFRTP matrix causing an anchoring effect, which results in significant bonding strength improvement. The influence of the nanostructure on the fracture toughness for the directly bonded CFRTP and aluminum was evaluated by static double cantilever beam (DCB) testing. Due to the difference of the thermal expansion coefficients between the CFRTP laminates and the aluminum alloy, significant residual stresses are generated. The effect of the thermal residual stresses on the fracture toughness along with the resulting mode mixity (mode I and II) was calculated. It is found that the thermal stresses introduce a significant mode mixity of the fracture toughness.