bluuebunny/crossref_metadata_2025 huggingface dataset:
An Experimental, Aerodynamic Evaluation of Design Choices for a Low-Pressure Compressor Transition Duct
Authors: Walker A. Duncan , Mariah Ian , Hall Chris
Published: January 2021

The S-shaped duct which transfers flow from the low-pressure fan to the engine core of modern large civil turbofans presents a challenging design problem. Aerodynamically it must accommodate a spatially and temporarily non-uniform inlet in conjunction with a complex flow field which will develop under the combined influence of pressure gradients and streamline curvature. It must also allow for the transfer of structural loads and services across the main gas path. This necessitates the use of structural vanes which can compromise aerodynamics, introduce unwanted component interactions and erode performance. Furthermore, this must all be achieved with minimum length/weight and without flow separation. This paper presents a comprehensive aerodynamic evaluation of three options for a low-pressure compressor transition duct containing (i) a long-chord, structural compressor outlet guide vane, (ii) a more aerodynamically optimal but non-structural outlet guide vane in conjunction with a small number of discrete radial load bearing struts and (iii) a fully integrated outlet guide vane and strut design. Evaluation was performed using a fully annular, low-speed test facility incorporating a 1 ½ stage axial compressor and transition duct representative of an engine design. Aerodynamic data were produced from miniature five-hole probe area traverses conducted at several locations with compressor/duct. The data suggest that all the options were viable. However, the aerodynamic vane and discrete struts produced the lowest system loss with the other two options being comparable. The performance of the structural vane was seen to be sensitive to off-design conditions producing a notably increased loss at a low flow coefficient. The more optimized aerodynamic vanes were much less sensitive to off-design conditions whilst the fully integrated design showed only very small changes in loss.
A Shape-Morphing Subsystem for Small Wind Energy Conversion Systems
Authors: Jauregui Juan , Herbert Francisco , Castillo Krystel
Published: January 2021

The purpose of the present document is to describe a design proposal for a flexible blade that can adapt its aerodynamic profile and fulfill the “Shape-Morphing concept.” The design is based on the analysis of the geometrical changes that a specific baseline aerodynamic profile must undergo during the shape-morphing process to another aerodynamic profile. The concept design assumes that the arc length of the aerodynamic profiles remains constant; therefore, the cord length changes from one configuration to the other. The proposed mechanism deforms the baseline profile in a way that it assures a continuous path between the aerodynamic forms. To demonstrate the effectiveness of the proposed mechanism, a flexible blade prototype was constructed and tested while morphing from a NACA 0012-based shape to a NACA 4412-based shape. The experimental results indicate that it is possible to implement a shape-morphing mechanism within small wind turbine blades that is able to accurately modify their geometrical shape and, thus, their aerodynamics, providing a novel alternative for control and operation optimization.
Autoregressive Bayesian Hierarchical Model to Predict Gas Turbine Degradation
Authors: Losi Enzo , Venturini Mauro , Manservigi Lucrezia
Published: January 2021

Gas turbine industry currently implements prognostic and health management systems as a fundamental task to predict the deteriorated characteristics of a gas turbine at future states and in turn plan maintenance actions. Thus, economic losses caused by system breakdowns and unnecessary repair actions can be reduced.

In this work, a data-driven Bayesian Hierarchical Model (BHM) is implemented by means of an innovative autoregressive structure to predict gas turbine progressive deterioration. The novel autoregressive model provides an estimate of the output variable which depends on time and its previous values.

In such a model, lagged values of the output are used as predictor variables. The autoregressive BHM, called ARBHM in this paper, is applied to highly heterogeneous field data taken from the literature, characterized by different degradation rates and referred to the power output of a large-size heavy duty gas turbine.

The ARBHM tested in this paper includes up to a third-order lag and is compared to a BHM that only uses time as the regression variable. The comparison is carried out by performing both single-step prediction and multi-step prediction of power output. The results demonstrate that, in the considered degradation scenarios, the innovative ARBHM is usually preferable to BHM, since prediction errors decrease up to 2.0 % in the best case.
Employing Space-Based Hyperspectral Imagery for Pipeline Leak Prevention, Detection and Compliance
Authors: Weaver R. Peter , Katz Dan , Prabahakar Tushar , Corcoran Katie A.
Published: January 2021

We are now living in what has been described as the Experience Era, where lines between the digital and physical are increasingly blurred. As such, we are just beginning to see how customized access to space will improve asset stewardship in ways that are still evolving, as customization of on-orbit technology pushes the bounds of how we receive and process information.

Specific to oil and gas operators, one technology being launched by microsatellite, hyperspectral imagery (HSI), is poised to enable unparalleled daily global pipeline leak prevention, detection and speciation, intrusion and change detection capabilities. This will replace conventional DOT pipeline patrol for compliance while contributing to our understanding of vapor emissions as regulated by the Environmental Protection Agency. This paper discusses both the evolving space marketplace and the state of the art for HSI, including current examples of hyperspectral findings regarding pipeline and terminal leaks.

Successful deployment of HSI will drive a decrease in the number and magnitude of pipeline leaks using persistent, global, high-resolution data collection, rapid and reliable analysis, and immediate reporting of actionable information.

For decades, satellite HSI technology has offered a promise of remote hydrocarbon detection and other features of interest. It is only now becoming scalable, accessible to, and cost-effective for the pipeline industry, and thus a reality for cost-effective pipeline stewardship.
An Empirical Fracture Control Model for Dense-Phase CO2 Carrying Pipelines
Authors: Michal Guillaume , Østby Erling , Davis Bradley J. , Røneid Sigbjørn , Lu Cheng
Published: January 2021

The control of a running ductile fracture in dense-phase CO2 carrying pipelines requires noticeably better fracture resistance than that typically required for the transport of lean or rich natural gas. The long saturation plateau of the decompression sustains a significant driving force at low fracture velocities.

Since 2012, at least four independent projects published data to better understand the applicability of the Battelle Two-Curve Method for CO2 transportation, provide insight on minimum toughness requirements and margins of safety. Nine full-scale propagation tests were executed across these projects. About 50 pipes had interactions with a running ductile fracture, 33 pipes supported the propagation of the fracture over their entire length, the other 17 pipes stopped the fracture.

The original BTCM is not considered applicable with dense-phase CO2. Despite the actual decompression velocity’s saturation plateau decreasing with velocity, and despite the pressure at the crack tip being typically 8 bar lower than predicted, the model can be significantly non-conservative. Correction factors on toughness and arrest pressure are required.

An empirical model for prediction of the minimum required toughness is proposed. It is supported by the data from the four aforementioned projects. The details and the limitations of the database are presented. The arrest boundary is expressed graphically in the frame commonly used to present the NG18 arrest pressure boundary.

A discussion on the location of the experimental data points relative to the arrest-propagation boundary is given. It supports the definition of three regions of interest: a region of likely propagation, a region of likely arrest, and a transition region between these two, where the boundary resides.

All current standard and recommended practices have seemingly similar gaps with respect to the control of a running ductile fracture. The empirical model brings along a set of recommendations and requirements to consider in the context of dense-phase CO2 applications.
Improved Surface Loading Stress Analysis Method Considering Protection Measures
Authors: Zhang Shenwei , Zhang Ken , Pino Maria , Law Jonathan , Matchim Tammie
Published: January 2021

This paper presents a methodology to evaluate pipe stress induced by surface vehicle loading at uncased road crossings that are protected by mat or bridging. When vehicles cross an existing pipeline, additional circumferential and longitudinal pipe stresses induced by surface vehicle loadings should be comprehensively considered to ensure pipe integrity and safe operation. Surface protection measures are sometimes installed to distribute the surface loading away from pipe centerline and reduce “footprint pressure”. A modified CEPA equation was proposed to calculate the radius of relative stiffness (or effective length) of mat and was validated by comparing with results from continuum FEA. The effective length calculated by the modified equation demonstrates good consistency with the FEA-predicted effective length. An approach was proposed to evaluate the pipe stress with user-defined free span of bridging, which provide flexibility for optimizing bridging protection in the field. A tool was developed to facilitate the assessment of surface loading stress of pipeline with mat or bridging protection.

Case studies were presented to demonstrate the application of the proposed methods and the effect of mat thickness or bridging free span on the reduction of live load stress. The proposed methods will benefit pipeline operators with derived cost-effective protection measures for vehicle crossing while assuring safety of pipeline operation.
Incorporating Inline Inspection Internal Measurement Unit Data Analysis Into Integrity Management Programs
Authors: Dewar Doug
Published: January 2021

Inline Inspection Internal Measurement Unit (ILI IMU) data analysis is a well understood but often under-utilized technology for detecting, defining, assessing and monitoring soil to pipeline interactions. The technology has been successfully used to detect landslide interactions since 1996 [1]. Operators can be provided with a vendor analysis (initial bending strain or run to run movements) and/or processed raw data for either internal or third-party raw data Analysis [2]. Vendor Analysis typically identifies major soil/pipeline interactions but primarily reports dig related settlements [3] and static construction related features. Raw data analysis is typically used to define interactions and provide detailed pipe shapes and deformations within targeted pipeline segments.

An approach for determining ILI IMU analysis/data requirements for individual ILI run segments for any size of pipeline system is presented. Guidelines for analysis are provided for Operators to optimize efforts based on the hazards encountered in individual pipelines or pipeline systems. The process includes feature screening, integrity/geotechnical specialist review and risk control/mitigation measures, if required.

To facilitate the feature screening process, a classification system for ILI IMU features is presented based on their type, activity and source modified from the system presented in [3].
Integrity Validation of Small Diameter-Thin Wall Pipeline Susceptible to Cracking or Crack-Like Indications: A Case Study
Authors: Parsibenehkohal Nima , Ilbagi Arash , Tatarov Alex , Gareau Frank
Published: January 2021

The integrity validation of small diameter, thin wall pipelines can be challenging. In-line inspection tool limitations for diameters below approximately 4.5-inch contribute significantly to this challenge. This paper will describe experiences related to the successful integrity validation of a 3-inch vintage high vapour pressure (propane) pipeline which was susceptible to external cracking as well as crack-like indications at the seam weld (e.g. hook cracks and lack of fusion). This line pipe was manufactured in 1967 with a low frequency electric resistance welding (ERW) process. The major threat was identified to be external corrosion since external metal loss up to 70% of the wall thickness was reported by in-line inspection (ILI). The cut-out samples obtained from integrity digs following the ILI were examined by magnetic particle inspection methods. Some external features on these cut-out samples were reported as cracks. The pipeline licensee involved Skystone to complete an engineering assessment and provide a short-term and long-term integrity plan to validate the integrity of the pipeline for continued service.

The cut-out samples were re-examined. This examination included cross-sectional metallography of the area suspected to contain crack-like indications. No external cracking was identified; however, crack-like indications such as lack of fusion were found on the ERW seam.

A pressure-spike test was designed as an integrity validation technique and completed successfully. This paper reviews the difference between the pressure-spike test and conventional pressure tests, the technical basis for the pressure-spike test, its limitations, and practical considerations that need to be considered. The regulatory recognition of spike testing as well as available recommended practices that refer to this approach will be discussed.

A long-term integrity plan was developed by establishing an interval for the next pressure-spike test using fatigue life estimation.
Influence of Small Volumetric Flaws on the Measurement of Crack Growth and Tearing Resistance in SENT Tests
Authors: Adriano Vitor , Cardon Eleine , De Waele Wim , Hertelé Stijn , Boone Matthieu
Published: January 2021

This study evaluates the influence of volumetric discontinuities on the SENT tearing resistance curve as measured using DCPD and UC techniques. In order to do that, a series of SENT tests was carried out on specimens containing small drilled holes in different locations to simulate the presence of volumetric weld flaws. In addition, porous welds were produced by robotic Gas Metal Arc Welding (GMAW). Welding parameters were fine-tuned in order to obtain specimens with different porosity levels. Afterward, the pores were characterized by means of X-ray Computed Tomography (CT) scans and their position, shape and location were determined. SENT tests were performed in a servo-hydraulic machine using a double clip gauge set up to measure crack opening and DCPD and UC for crack sizing. The results indicated that volumetric discontinuities can influence the accuracy of crack measurement techniques in particular, and the measured resistance curve as a whole.
An Approach to Establishing Manufacturing Process and Vintage of Line Pipe Using In-Situ Nondestructive Examination and Historical Manufacturing Data
Authors: Switzner Nathan , Veloo Peter , Rosenfeld Michael , Rovella Troy , Gibbs Jonathan
Published: January 2021

The October 2019 revisions to US federal rules governing natural gas pipelines require Operators to establish vintage and manufacturing process for line-pipe assets with incomplete records. Vintage and manufacturing process are considerations when establishing populations of pipe for maximum allowable operating pressure (MAOP) reconfirmation, materials verification, and integrity management programs. Additionally, the rule changes establish an allowance to utilize in-situ nondestructive examination (NDE) technologies to verify line-pipe material properties including strength, composition, microstructure, and hardness.

Economic and market demands have driven changes in steelmaking technologies and pipe-forming approaches. Knowledge of the relationships between processing, microstructure and mechanical properties have been fundamental to the evolution of steel line pipe manufacturing. Product specifications and standards for the manufacture and testing of pipe and tube have crystallized this evolution as performance expectations increased. The resulting manufacturing process changes have left a variety of “fingerprints” observable from in-situ materials verification NDE data, when analyzed holistically.

The purpose of this work is to enable operators to begin leveraging these fingerprints to illuminate the vintage and manufacturing process of their line pipe assets using the NDE data. A method is proposed to re-establish line-pipe asset manufacturing and vintage records using historical line pipe manufacturing practices and NDE materials verification data.
Axial Compressive Loading Capacity of Pressurized Energy Pipeline With Corrosion Defects
Authors: Liu Bing , Tan Xiao , Bolati Dinaer , An Hang , Jiang Jinxu
Published: January 2021

Corrosion defects are dreadfully damaging to the stability of pipelines. Using the finite element (FE) simulation method, a model of API 5L X65 steel pipeline is established in this work to study its buckling behavior subjected to axial compressive loading. The local buckling state of the pipe at the ultimate axial compressive capacity was captured. Compared with the global compressive strain capacity (CSCglobal), the local compressive strain capacity (CSClocal) is more conservative. Extensive parametric analysis, including approximately 115 FE cases, was conducted to study the influence of the corrosion defect sizes and internal pressure on the corroded pipe’s compressive loading capacity (CLC) and CSC. Results show that the enlarged size of the corrosion defect decreases both the CLC and the CSC of the pipeline, but the CLC almost keeps unchanged as the length of corrosion defects increases. The CLC decreases with the increase of the length of corrosion defects when the length is less than 1.5Dt and greater than 0.7Dt. The CSC drops significantly until the length of the corrosion defect reached 1.8Dt. The deeper the corrosion defect, the smaller the CLC and the CSC. An increase in the width of corrosion defects tends to correspond to a decrease in the CLC and the CSC. With the increase of internal pressure, the CSC of the pipe gets greater while the CLC gets smaller. Based on the 115 FE results, a machine learning model based on support vector regression theory was developed to predict the pipe’s CSC. The regression coefficient between SVR predicted value and FEM actual value is 98.87%, which proves that the SVR model can predict the CSC with high accuracy and efficiency.
Development of a Burst Capacity Model for Corroded Pipelines Under Internal Pressure and Axial Compression Using Artificial Neural Network
Authors: Zhang Shulong , Zhou Wenxing , Zhang Shenwei
Published: January 2021

In-service pipelines are often subjected to longitudinal forces and bending moments resulting from, for example, ground movement or formation of free spans in addition to internal pressures. In practice, there are some site-specific cases where corrosion anomalies interact with the external loads. A refined assessment model is required to understand the load carrying capacity of pipe.

In this study, a burst capacity model for corroded pipelines under combined internal pressure and axial compression is developed based on extensive parametric three-dimensional (3D) elasto-plastic finite element analyses (FEA) and artificial neural network (ANN) technique. The parametric FEA employs the ultimate tensile strength (UTS)-based burst criterion and idealizes corrosion defects as semi-ellipsoidal shaped flaws. The FEA model is validated by full-scale burst tests of pipe specimens containing semi-ellipsoidal shaped flaws reported in the literature. Extensive parametric FEA are carried out to evaluate the burst capacity of corroded pipelines under combined internal pressure and axial compression by varying the pipe geometric and material properties, defect depth, length and width, and magnitude of axial compressive stress. Based on the FEA results, an ANN model is developed utilizing the open-source platform PYTHON to predict the burst capacity of corroded pipelines under combined internal pressure and axial compression. The well-trained ANN model is further validated by full-scale burst tests of corroded pipelines under combined internal pressure and axial compression carried out by Det Norske Veritas (DNV).
Numerical Assessment of Dented Pipe Using Inline Inspection Data
Authors: Murugathasan Parththeeban , Dhar Ashutosh Sutra , Debnath Suborno , Muntakim Abu , Roy Kshama
Published: January 2021

The current finite element (FE) assessment methods of dented pipes are based on specific dent profiles, which are generally created based on the shape of indenters. However, the actual dent profile in real case scenarios is mostly irregular in shape, depending on the cause of damage. In this paper, FE analyses of dented pipes using inline inspection (ILI) data are presented. Based on the ILI data, the dent profile is generated by applying the nodal displacements to all the pipe nodes. The validation of this nodal displacement approach is discussed in this paper. Besides, a parametric study is carried out to study the behavior of dent for different dent depth, pipe geometry, and pipe grades. The significance of residual stresses generated during the dent formation on the behavior of dented pipe during the service life is also discussed. Finally, the remaining life estimation of dented pipes according to the API 579-1 is presented using FE analysis results.
A Review of Pipe-Soil Interaction Models for Strain Demand Estimation
Authors: Yu Dunji , Wang Yong-Yi , Liu Banglin , Chen Xiaotong
Published: January 2021

Since the mid-1970s, various pipe-soil interaction (PSI) models have been developed to estimate the strain demand imposed on buried pipelines by the movement of the surrounding soil. These PSI models can be broadly divided into four categories: analytical models, soil-spring models, full continuum models and discrete element method models. These models can be used for strain-based design, fitness-for-service evaluation of in-service pipelines, and post-event failure analysis.

In this paper, the working principles and modeling characteristics of the four types of PSI models for strain demand estimation are briefly reviewed and summarized. Analytical models calculate the bending and/or membrane strains from functions that describe the deflected profile of the pipe. The other three types of models utilize finite element (FE) modeling to predict the pipe displacement and the corresponding strain demand under given soil movement patterns. The primary difference between the three types of PSI FE models is the representation of the soil geometry and its interaction with the pipe. The four types of PSI models have their own strengths and limitations, which are discussed in terms of their applicability, accuracy, and the level of effort needed for model application. Two case studies were presented to demonstrate the potential differences in strain demand estimates using different PSI models.
Development of Lifting and Lowering-in Plan for the Control of Construction Stresses
Authors: Wang Jiawei , Wang Yong-Yi , Bruce William A. , Rapp Steve , Scoles Russell
Published: January 2021

Construction of a cross-country pipeline involves lifting the pipeline off the skids and lowering it into the trench (lifting and lowering-in). This can introduce the highest stress magnitude that the pipe may experience over its service life. If not managed properly, overly high stresses may cause integrity issues during construction and/or service. If the girth welds are qualified and accepted using alternative flaw acceptance criteria, such as those in API 1104 Annex A and CSA Z662 Annex K, these stresses must be kept below a preset level during lifting and lowering-in to satisfy the requirements of those standards.

This paper covers the development and usage of a stress analysis tool for the continuous lifting and lowering-in of pipe strings without a concrete coating or river weights. The outcome of the stress analysis can be used to develop lifting and lowering-in plans for construction crews.

The core functionality of the application tool is to calculate the stresses from bending in the vertical and horizontal planes. The stresses from vertical bending are derived from an extensive analysis of continuous lifting and lowering-in processes. The stresses from horizontal bending are calculated using closed-form analytical solutions. The tool provides a graphical interface that interprets the background stress analysis results and displays information necessary for the development of lifting and lowering-in plans. The tool can be used to evaluate what-if scenarios for various tentative lifting and lowering-in scenarios.

The process of using the tool to develop lifting and lowering-in plans is demonstrated in this paper through an example problem. The number of sidebooms and other lifting and lowering-in parameters such as sideboom spacing and lifting height range are changed to make the lifting and lowering-in plan easy to use for the laying contractors. Such tradeoffs can be addressed proactively with construction contractors to ensure that a mutually acceptable approach to lifting and lowering-in is taken.
Generation and Monitoring of Synthetic Crack-Like Features in Pipeline Materials Using Cyclic Pressure Loading
Authors: Alexander Chris , Rickert Jon , Dotson Rhett , Freitas Felipe , Slater Simon , De Leon Christopher
Published: January 2021

Crack management has become a major focus for many gas and liquid transmission pipeline operators. Failures associated with crack-like features have been a concern for both pipe operators and regulatory agencies. As a result, pipeline operators are excavating large numbers of features for not only in-line inspection (ILI) validation purposes, but also to make repairs. Additionally, ILI technologies have advanced significantly in recent years and are identifying an increasing number of features with greater levels of accuracy. With increased data generation, operators are faced with an unprecedented amount of information that requires response prioritization.

Because of high levels of conservatism associated with today’s assessment methods, pipeline operators are spending a significant amount of capital excavating crack-like features. There is a need for improved assessment methods that integrates testing simulated / synthetic crack-like features. This paper will provide details on a study funded to systematically generate crack-like features in pipeline materials with the application of cyclic internal pressure loading. Synthetic crack-like features were generated in 12.75-inch × 0.250-inch, Grade X42 pipe material using electronic discharge machining (EDM) to form notches. Notch depths were 10% of the nominal wall thickness and ranged from 1-inch to 3-inches in length. The pipe samples were then pressure cycled to achieve microcracking at the base of each notch.

Initial stages of the program involved sectioning features to quantify crack growth levels. Once a systematic process for growing cracks from EDM starter notches had been validated, testing involved cyclic pressure fatigue to failure and burst testing. The advantage with the crack generation methodology used in this study was the ability to generate sharp, crack-like features without altering the microstructure of the pipe material in the vicinity of the feature. Programs such as the one presented in this paper are useful for both generating features in pipeline materials and quantifying behavior of pipeline materials subjected to cyclic pressure and burst loading.
Use of Spoolable Pipe Technologies As a Means for Rehabilitating Small Diameter High Pressure Pipeline Systems
Authors: Denowh Chantz , Alexander Chris , Cox Frank , Kania Richard
Published: January 2021

The aging infrastructure of pipeline systems around the world requires operators to explore novel and innovative methods for rehabilitating pipelines. Conventional repair methods involve the installation of steel sleeves or composite repair systems. While these repair methods are reliable and provide operators with options for pipeline repair, a major drawback is the requirement that pipelines must be excavated. Activities related to excavation have inherent risk in the form of personnel and environment safety along with the applicable cost of excavation activities. If extensive flaws are present in a pipeline system, efforts associated with a comprehensive pipeline repair system can be cost-prohibitive. Additionally, the rehabilitation of pipelines that were installed via horizontal direction drilling, using current repair methods, is near to impossible.

This paper provides an in-depth presentation on a comprehensive study completed to evaluate the use of a spoolable pipeline technology as a means for rehabilitating pipelines. Results are included from an industry survey with responses from 15 pipeline operators on the use of spoolable pipe technologies. One outcome from the survey was the lack of full-scale test data associated with combined loading, which was a central feature in the current study. The combined loads considered in the year-long study included burst testing and cyclic pressure testing utilizing torsion, axial tension, and axial compression loads. More than 30 full-scale test samples were destructively tested in combined loading scenarios, utilizing up to 100,000 pressure cycles to the full operating pressure of the pipeline system. The approach employed in this study, and the associated test results, provides a model for evaluating a spoolable pipeline technology prior to implementation for rehabilitating pipelines. This approach is in addition to the required product qualification standards accepted by industry.
Twin Roll Casting of Copper Alloy C19210 Using Commercial Scale Machine
Authors: Imai Shogo , Nishida Shinichi , Ogawa Kyohei , Hagiwara Makoto , Uematsu Daichi , Kawawa Mizuki , Horigome Yuto
Published: January 2021

Copper alloy C19210 have excellent corrosion resistance, heat resistance, and conductivity, and is used for precision electronic parts such as lead frame materials. Conventionally, copper alloy strips are manufactured by repeating heat treatment and cold rolling, and have a problem that it is multi-process and production cost is expensive. On the other hand, twin roll casting can improve the above problems because strips are made directly from molten metals. In this study, twin roll strip casting of copper alloy C19210 using commercial scale machine was operated. The aims of this study is to investigate the possibility of strip casting for copper alloy. The effect of the side dam and release agent was researched. The effect of rolls speed on the strip surface condition was researched. The improved side dam prevented molten metal leakage. The release agent prevented sticking of the manufactured strip to the roll surface. The strip produced at roll speed of 7 m/min and 10 m/min had a lot of metallic luster. Moreover, the strip produced at roll speed of 7 m/min had more metallic luster than the strip produced at roll speed of 10 m/min. The lower the roll speed is, the greater the rolling load is. At a roll speed of 7 m / min, the rolling load became the maximum rolling load of the equipment. For producing strips with copper alloy C19210, higher rolling loads are preferred.
High-Speed Machining of Ti-6Al-4V With a Micro Textured Cutting Tool Focusing on Coolant Behaviors
Authors: Hasegawa Mitsuru , Sugihara Tatsuya
Published: January 2021

In the cutting of Ti-6Al-4V alloy, the cutting speed is limited as a high cutting temperature leads to severe tool wear and short tool life, resulting in poor production efficiency. However, some recent literature has reported that various beneficial effects can be provided by forming micro-textures on the tool surface in the metal cutting process. In this study, in order to achieve high-performance machining of Ti-6Al-4V, we first investigated the mechanism of the tool failure process for a cemented carbide cutting tool in high-speed turning of Ti-6Al-4V. Based on the results, cutting tools with micro textured surfaces were developed under the consideration of a cutting fluid action. A series of experiments showed that the textured rake face significantly suppresses both crater wear and flank wear. In addition, optimum texture structures and the mechanism of the texture effects in high-speed machining of Ti-6Al-4V alloy were discussed.
Effect of Al Content of TiAlN Coating on Cutting Performance in Driven Rotary Cutting of Hardened Steel
Authors: Sakai Hiroyuki , Kato Hideharu , Yoshikawa Taira , Kubota Kazuyuki
Published: January 2021

A finishing efficiency improvement of hardened steel has not been achieved because the tool life is reduced due to significant progress in tool wear and the occurrence of tool chipping. Therefore, a machining efficiency improvement is desired. In previous research, a machining efficiency improvement of 3 to 5 times can be achieved by increasing the feed rate in the finish machining of hardened steel by driven rotary machining. The cutting atmosphere affects the oxidation control of the film, and thus micro dry ice powder is applied to the cutting edge. To increase machining efficiency, the feed rate and cutting velocity must be increased, but this would shorten of tool life by increasing the cutting temperature. Therefore, it is essential to improve both the atmosphere and the oxidation resistance of the tool coating. In this study, the effect of coated tools with different Al contents on cutting performance was investigated for high-efficiency machining by high-speed cutting. At a high cutting velocity (3.34 m/s), the coated tool with the highest Al content had the longest tool life. It was found that high-efficiency cutting is possible even with a high-cutting velocity by increasing in the Al content of the coating.
Micro/Nano-Printing of Metal and Nanoparticle Thin Film and its Application to MEMS Device
Authors: Kaneko Arata , Mori Akihiro , Kanada Keisuke , Sumin Chen , Ke Wang
Published: January 2021

This present paper describes some test results about fabrication of micro/nano-structure for MEMS using printing techniques of metal and nanoparticle thin films. Transfer-printing of a bi-layered film of graphene oxide (GO) and Au is processed on a PET substrate. Nano-particles of GO are cast on a micro-ridged poly-dimethyl-siloxane stamp that is previously coated with Au by solution casting. The layer of GO nanoparticles functions as a reinforcing material to strengthen the layered film while the Au thin-film is a matrix that links the GO nanoparticles. The thickness of GO nanoparticles varies with concentration of GO suspension. In the case of thicker coating of GO with an average thickness of 13 nm, the transfer-printing makes the GO/Au bi-layered film form into 50-μm-wide two-dimensional line patterns on the PET substrate. Additionally, transfer-printing of another bi-layered film with a 128 nm thickness fabricates a three-dimensional microstructure of a rectangular-corrugated film on the PET substrate because the entire bi-layered film is transferred from the stamp. The modulus of transfer-printed GO/Au bi-layered film is investigated by a simple bending tests using AFM cantilever. FEM analysis of the bending test results indicates that the mechanical modulus of the GO/Au film is not less than 120 GPa, and this significantly exceeds that of the Au film by itself. The present study also fabricated a capacitive MEMS sensor by a combination of transfer-printing and inkjet printing. Inkjet printing makes GO nanoparticles on the 100-μm-wide comb-like microelectrode, which is previously fabricated by transfer-printing of Au thin film. The fabricated MEMS sensor successfully shows its change of capacitance with relative humidity in the range of 40% to 80%. These results demonstrate that the printing of Au and GO nanoparticles is effective for MEMS fabrication.
Investigation of Fabrication Condition of Metal Matrix Piezoelectric Composite Using Surface Oxidized Metal Fiber As Internal Electrode
Authors: Yanaseko Tetsuro , Kuboki Isao , Sato Hiroshi , Asanuma Hiroshi
Published: January 2021

Piezoelectric ceramics are widely used as sensors and actuators because of their excellent electrical-mechanical energy conversion function. However, the piezoelectric ceramics have the disadvantage of being brittle and not suitable for applications where a large load is applied.

To overcome this problem, a metal matrix piezoelectric composite in which piezoelectric ceramics are embedded in a metal matrix with excellent strength has been developed. The developed metal matrix piezoelectric composite is fabricated from a metal-core piezoelectric fiber as the piezoelectric material and aluminum matrix, the metal-core and metal matrix are used as the electrodes. The metal-core piezoelectric fiber/aluminum composite has an output voltage anisotropy with respect to strain, thus, it has unique characteristics as a sensor. Previous studies revealed that this output voltage anisotropy depends on the electrode structure, suggesting that the output voltage characteristics can be adjusted by designing the electrode structure. However, the metal-core piezoelectric fiber is manufactured by extrusion method, and the cross-sectional shape cannot be changed, that is, the output voltage characteristic design is impossible. Therefore, a metal matrix piezoelectric composite that can be designed output voltage characteristics by using surface oxidized metal fibers as internal electrodes has been developed.

In this study, the fabrication conditions of this metal matrix piezoelectric composite were investigated. The embedding temperature and pressure were changed, and the structure of the resulting composite was observed and elemental analysis was performed to confirm the presence of chemical reaction between the matrix and the piezoelectric ceramics. As a result, it is found that a range of conditions where the oxide films and the piezoelectric ceramics can be embedded in the matrix without damage.
Plane Bending Fatigue in TIG and MIG Welds of Non-Combustible Magnesium Alloy
Authors: Shao Xuanyi , Binti Ismail Rafidah , Miyashita Yukio
Published: January 2021

Fatigue strength tests were carried out under plane banding loading with different stress ratio in Mg-Al-Ca-Mn alloy and its TIG and MIG welds. The welds showed lower fatigue strength compared to the base material. Weld defects were observed as fatigue crack origins in both TIG and MIG welds. It was speculated that difference in size of weld defect and multiple cracking occurred in MIG weld might affect fatigue strength characteristics in the welds. Effect of stress ratio on fatigue strength at 107 cycles was not significantly observed in fatigue test results obtained with different stress ratio in the base material and the welds. Scatter in size and distribution of weld defect could influence fatigue fracture behavior in the welds.
Profile Measurement by Using a Femtosecond Laser Chromatic Confocal Probe
Authors: Sato Ryo , Shimizu Yuki , Matsukuma Hiraku , Gao Wei
Published: January 2021

Confocal probes are widely employed in many industrial fields due to the depth-sectioning effect. The author’s group has also proposed a chromatic confocal probe employing a mode-locked femtosecond laser source which can realize an axial resolution of 30 nm and a measurement range of 40 μm Efforts have also been made to improve the thermal stability of the developed femtosecond laser chromatic confocal probe so that the probe can be applied for long-term displacement measurement or surface profile measurement. Meanwhile, surface profile measurement has not been carried out by using the developed femtosecond laser chromatic confocal probe. For the verification of the performance of developed probe in profile measurement, in this paper, an experimental setup is built and a basic experiment is carried out. By using the probe with further improved thermal stability, the measurement of a sample surface profile is carried out. In this paper, the development of the experimental setup with the femtosecond laser chromatic confocal probe, as well as the results of the surface profile measurements, is presented.
Optimization of Friction Crush Welding of Two Dissimilar Metals: Aluminium 6061 T-6 and Stainless Steel AISI 304
Authors: Singh Prem , Deepak Dharmpal , Brar Gurinder Singh
Published: January 2021

In order to cater increasing need of lightweight and strong structures to be used in various industries like ship manufacturing, railways transportation, vehicle body cell etc., efforts have been made to develop and assess various welding or joining techniques. Dissimilar metal welding offers promising solution in this direction due to modification of properties by combining two dissimilar metals in terms of mechanical properties and better corrosion or electrical properties with lesser specific weight. Stainless steel of grade AISI 304 is widely used for manufacturing application in different industries and aluminum alloy 6061 T-6 has gaining importance in welding due to its high corrosive resistance and high weldability properties. In the present work, welding of dissimilar metals i.e. Aluminium 6061 T-6 and Stainless Steel – AISI 304 was carried out with new welding technique i.e. Friction Crush Welding (FCW). Dissimilar welds prepared at different levels of tool rotation and feed rate were characterized in terms of bond strength. Taguchi L9 Design of Experiments (DOE) was used to find optimal process parameters for dissimilar FCW. The theoretical optimum bond strength calculated using Taguchi L9 was 5134.53 N at tool rotation of 740 rpm and feed rate of 45 mm/mim. The theoretical optimum value was in line with the experimental results.
Generation of Surfaces With Isotropic and Anisotropic Wetting Properties by Curved Water Jet Guided Laser Micro-Machining
Authors: Shi Yi , Cao Jian , Ehmann Kornel F.
Published: January 2021

This experimental work utilizes a newly developed method, curved water jet guided laser micro-machining, to generate micro features on metallic surfaces. During the process, material is removed by a high-power nanosecond laser beam which is transmitted through a high-pressure micro water jet via total internal reflection. To achieve intricate texturing patterns, a secondary motion component is superimposed on the XY motion of the workpiece provided by the motion stage. The secondary motion is generated by deflecting the water jet trajectory by a controllable dielectrophoretic force. The induced secondary motion of the water jet cuts the processing time to one half when generating texture patterns for isotropic wetting as compared to processes with only XY motion. The ability to alter the water jet’s trajectory by tens of microns at high frequencies, which is beyond the capability of conventional CNC machines, allows a wide range of different micro patterns to be generated, profoundly increasing the flexibility and efficiency of the process as compared to conventional approaches. As a demonstration, surface textures for isotropic and anisotropic behaviors are generated on stainless steel surfaces. The influence of feature spacing, motion speed (frequency) and texturing patterns on surface wettability are studied.
Research on Positioning Error Analysis and Compensation Experiment of the Dual-Driving Feed Worktable
Authors: Xue Jiafu , Lu Hong , Liu Qi , Liu Qiong , Dou Haoyu , Wang Dong , Ling Zhi
Published: January 2021

The dual-driving feed worktable (DDFW) is widely used in feed system because of its high stability and load capacity, while its feed system is one of the important parts that affects the feed accuracy of machine tools. Due to the influence of assembly, manufacturing and other factors, the positioning error of DDFW is produced, which reduces the machining accuracy of the machine tools. Therefore, the research on the positioning error compensation of DDFW is of great significance. In this paper, the positioning error of DDFW is measured with absolute optical scale and the positioning error model of DDFW is established by modeling method of orthogonal polynomials at first. Then an electronic cam combined with virtual axis compensation strategy is designed for DDFW to reduce positioning error. Finally, the compensation experiment is carried out and the error compensation results are analyzed to verify the effectiveness of the error compensation strategy designed in this paper.
Delamination in Surface Machining of CFRP Composites Using Rotary Ultrasonic Machining With Horizontal Ultrasonic Vibration
Authors: Wang Hui , Zhang Dongzhe , Li Yunze , Cong Weilong , Burks Anthony R.
Published: January 2021

Surface machining of carbon fiber reinforced plastic (CFRP) using rotary ultrasonic machining (RUM) with vertical ultrasonic vibration was effective in reducing many issues, including high cutting force, high torque, and high tool wear rate. The vertical ultrasonic vibration also induced damages to machined CFRP surfaces and then resulted in increased surface roughness. To simultaneously decrease surface roughness and cutting force, the direction of ultrasonic vibration needed to be parallel with the surface generation direction (horizontal feeding direction). The horizontal ultrasonic vibration was then developed and applied for RUM surface machining of CFRP. The application of horizontal ultrasonic vibration in RUM surface machining produced simultaneously decreased surface roughness and cutting force. However, there were no investigations on delamination in such a process, and delamination was considered as one of the major factors to reject the machined CFRP products. This investigation would study the delamination under different machining-variable groups, the delamination generation mechanisms, and the relationships between delamination and cutting forces through the experimental method in surface machining of CFRP using RUM with horizontal ultrasonic vibration. Smaller cutting force and delamination thickness would be produced by the smaller depth of cut, smaller feedrate, or larger tool rotation speed. Smaller indentation depth was generated by larger tool rotation speed or smaller feedrate. Smaller material removal rate and abrasive-grain number taking part in the cutting process were produced by the smaller depth of cut. The delamination initiation at larger uncut CFRP thickness would be induced by higher cutting force.