bluuebunny/crossref_metadata_2025 huggingface dataset:
Oil Temperature Prediction of Long-Distance Hot-Crude-Oil Pipeline Based on GA-BP Optimization
Authors: Yu Tao , Dong Peng , Yu Yang , Song Jinzhou , Zhang Jie
Published: January 2021

Due to the high pour point of the oil products transported in the long-distance high wax crude oil pipeline, in order to ensure the operation safety, it is necessary to adopt heating transmission technology, so as to ensure that the oil temperature along the pipeline is 3–5 °C higher than the pour point, that is to say, the oil temperature is the most important operation parameter of the long-distance hot oil pipeline, and the accurate prediction and control of the oil temperature is the premise of the pipeline safety optimization. Aiming at the problems of large prediction error and poor applicability of the previous theoretical formula, this paper studies the establishment of oil temperature prediction model by using data mining algorithms such as Back Propagation (BP) neural network, and improves the prediction efficiency and accuracy of the model by using Genetic Algorithm (GA) optimization. The correlation coefficient formula is used to calculate the influence coefficient of oil temperature, ground temperature, pipeline transportation and other parameters on the inlet oil temperature of the downstream station, so as to obtain the input parameters of the model.

The actual production data training model is downloaded through SCADA system, and the prediction accuracy of the control model is ±0.5 °C. Compared with BP model and other theoretical formulas, the accuracy and efficiency of GA-BP oil temperature prediction model are greatly improved, and the adaptability is better. The GA-BP oil temperature prediction model trained according to the actual production data can be effectively applied to the future pipeline big data platform, which lays a theoretical foundation for the intelligent control of the pipeline.
The Use of Optimized ERW Technique to Improve Low Temperature Fracture Toughness of Welded Pipes
Authors: Rashid Muhammad , Hylton Timothy , Anderson Neil , Collins Laurie , Li Leijun
Published: January 2021

It is understood that the bondline microstructure of the line pipe ERW seam can be a zone of weakness in the pipe. To overcome this weakness, several research projects utilizing various line pipe steel grades and welding and heat treatment techniques have been conducted at EVRAZ NA. The overall goal of these efforts has been to understand the development of bondline microstructure during the ERW process and improve the weld seam fracture toughness for low temperature applications. These research activities included mill trials and Gleeble simulations.

It was realized that a high toughness ERW weld seam is only possible through a tightly controlled combination of weld power, forging (squeeze) pressure, and welding speed. Research studies have indicated that the as-welded seam may not pass the standard ERW destructive tests if proper heat input and adequate squeeze pressure are not applied.

Post weld heat treatment (normalizing) practice was also found to be a key element in the development of the appropriate bondline microstructure for higher toughness. Samples from pipes normalized using different heat treatment practices produced different bondline microstructures and hence different toughness properties. It was found through this study that a low (but still higher than the upper critical temperature Ac3) normalizing peak temperature and adequate soak time at the peak temperature result in improved Charpy toughness of ERW bondline microstructure.
Estimation of Tensile Strain Capacity of Vintage Girth Welds
Authors: Wang Bo , Liu Banglin , Wang Yong-Yi , Huising Otto Jan
Published: January 2021

Being able to estimate the tensile strain capacity (TSC) of vintage girth welds is sometimes necessary for the integrity management of vintage pipelines. Assessing girth weld integrity could be a top priority after a confirmed ground movement event. Decisions may also be needed about the disposition of a girth weld when weld anomalies are found. Typical fitness-for-service (FFS) procedures, such as API 1104 Annex A and API 579/ASME FFS-1, generally target materials under nominally elastic conditions and strain demands less than 0.2%. These procedures may produce overly conservative results when the strain demand exceeds 0.2%.

This paper summarizes the development and validation of a TSC estimation tool for vintage girth welds under PRCI funding. The work consisted of three components: the development of a TSC model for vintage girth welds, the implementation of the model into a software tool, and the experimental validation of the performance of the tool using curved wide plate (CWP) tests.

The TSC model was developed following the procedures established through a previous PRCI-PHMSA cofounded work. Finite element analyses (FEA) were performed to obtain a crack-driving force database while considering the salient features of vintage girth welds, such as larger weld caps and weld strength mismatch levels. The TSC model was then derived from the crack-driving force database using apparent toughness values representative of vintage girth welds.

A graphical user interface (GUI) and a user manual were developed to facilitate the application of the TSC model. The software tool produces TSC estimates based on geometry, material, loading, and flaw characteristics of a girth weld. For inputs that might not have readily available values, recommended values are provided. The tool allows the evaluation of the impact of various input parameters on TSC.

The performance of the TSC estimation tool was evaluated against eight purposely designed CWP tests. Accompanying small-scale material characterization tests, including chemical composition, round bar tensile, microhardness, and Charpy impact tests, were performed to provide additional inputs for the evaluation of the tool. The tool is shown to provide reasonably conservative estimates for TSC.

An example problem is presented to demonstrate the application of the tool. Gaps and future work to improve the tool are highlighted at the end of the paper.
Rational Limits of High-Low Misalignment in Girth Welds
Authors: Liu Banglin , Wang Yong-Yi , Jia Dan , Rapp Steve
Published: January 2021

High-low misalignment in girth welds introduces local bending stress and thus can potentially have detrimental effects on the stress capacity of girth welds. However, long-term pipeline service experience demonstrates that high levels of high-low misalignment do not always lead to reductions in the safety and integrity of pipelines. This paper discusses a PRCI-funded work that aimed to understand the impacts of misalignment on the integrity of girth welds and develop rational limits for misalignment for incorporation into existing standards.

Two sets of recommendations were developed: (1) recommendations on the incorporation of rational limits for misalignment into workmanship criteria, and (2) recommendations on rational limits for misalignment for application in alternative flaw acceptance criteria, such that those in API 1104 Annex A and CSA Z662 Annex K.

The recommendations for the workmanship criteria utilize extra weld reinforcement to compensate for stress capacity reduction due to misalignment. The recommendations consist of minimum values for key weld dimensions for a wide range of pipe wall thicknesses. The recommendations were developed based on a cross-weld tensile (CWT) test program and were validated using targeted finite element analysis (FEA).

The recommendations for the application of the engineering critical assessment (ECA) procedures provide a maximum permissible misalignment level, up to which the ECA procedures produce sufficiently conservative flaw acceptance criteria without needing to correct for misalignment. The maximum permissible misalignment was based on comparisons between FEA and the API 1104 Annex A ECA procedures. A concept of a safety margin was introduced to quantify the conservatism built into the Annex A procedures and to derive a maximum allowable misalignment value.
A Data Driven Validation of a Defect Assessment Model and its Safe Implementation
Authors: Kariyawasam Shahani , Zhang Shenwei , Yan Jason
Published: January 2021

This paper presents data analytics that demonstrates the safe implementation of defect assessment models which use uncertain measurements of defect and material properties as inputs. Even though this validation is done for a corrosion assessment model implementation, it can be generalized for any defect assessment validation where the inputs have uncertainty (as they do in implementation).

The questions arising from the validation of the Plausible Profiles (Psqr) model and related review led to a large amount of data analytics to demonstrate various aspects of safety in implementation. The data analytics demonstrates how the safety of model implementation can be verified using a well-designed set of data.

The validation of Psqr model was conducted on a unique set of data consisting of metal-loss corrosion clusters with Inline Inspection (ILI) reported size, laser scan-measured dimension, and well monitored burst testing pressure. Therefore, this validation provided an unprecedented set of validation data that could represent many perspectives, such as model performance (with all uncertainties associated with other parameters removed), in-the-ditch decision scenario, and ILI-based decision scenario. Moreover, the morphologies of the 30 corrosion clusters tested is a good representation of large corrosion clusters that have failed historically in the pipeline industry. One of learnings from post-ILI failures due to corrosion in the industry is that corrosion morphology played a significant role. Previous model validations were mostly performed on simple single anomalies or simple clusters with few individual corrosion anomalies. It is important that a corrosion model is validated using real corrosion morphologies that are representative of in-service conditions.

The analysis of this unprecedented and comprehensive set of data led to great learning and revealed how safety can be achieved optimally with good understanding of how uncertainties associated with ILI sizing error, material property, model error, and safety factors interact and play into integrity. It also revealed the role of common misunderstandings that are barriers to effective pipeline integrity assessment. Overcoming these misunderstandings have helped in developing a more effective ILI based corrosion management program that will avoid more failures and reduce unnecessary integrity actions.
Heat Affected Zone Softening Susceptibility Test
Authors: Dinovitzer A. , Begg D. , Quintana M. , Lazor R.
Published: January 2021

There have been a number of unexpected girth weld failures in pipelines, both in-service and during pre-service hydrostatic testing. Investigation of these incidents indicated that the line pipe met industry standard requirements, such as API 5L and the welding procedures had been qualified to API 1104 and construction welding/inspection had been completed according to industry standards. The investigation of these failures indicated that they were not related to hydrogen cracking or misalignment, however, line pipe chemical composition and tensile properties were identified as having contributed to these failures.

Low carbon and low carbon equivalent (CE) higher strength line pipe materials produced with thermo-mechanical controlled processing (TMCP) practice is believed to have contributed to the failures. Higher heat input welding in these lean chemistry steels can result in heat affected zone (HAZ) softening that produces a lower strength zone adjacent to the girth weld, making it susceptible to tensile failure from axial loading. In the presence of thermal or geohazard loading, these softened or lower strength HAZ’s become a concern where there has been pipe settlement or in strain-based assessment.

To understand the factors that influence the susceptibility to HAZ softening and identify those materials that can be considered at risk, a material testing procedure has been developed. This new testing procedure is a weld bead-in-plate test that was designed to maximize the potential for HAZ softening in an effort to identify those line pipe materials that may be susceptible to HAZ softening in construction or during in-service welding.

This paper presents the results of experimental trials comparing the susceptibility of leaner chemistry materials to HAZ softening. The testing procedure is described along with opportunities to enhance the procedure to develop a standardized test for HAZ softening assessment. This test has the potential to be used to identify materials at risk to HAZ softening and may also be used to qualify line pipe to demonstrate its resistance to HAZ softening.
Asset Complexity Based Benchmarks in Support of Reliability Improvement Program
Authors: Di Blasi Martin , Denny Scott
Published: January 2021

Successfully executing maintenance & reliability improvement programs on a complex pipeline asset network tends to be challenging. Influencing the factors that affect reliability performance usually involves elements of culture, asset management & operations, resource allocation, reliability and maintenance strategy and maintenance execution. Frequently, the focus of attention is placed primarily on tracking detailed reliability & maintenance performance (i.e. tool time, average time between failures, planned work, etc.) because they tend to be easier to understand and measure. When some of the other key factors potentially holding back the full realization of significant reliability improvements may be at the resource allocation level where usually measuring and benchmarking can be more challenging. In this sense, being able to benchmark different operating areas in terms of maintenance, reliability and resources allocation performance can help understand higher level factors driving less than ideal asset reliability performance. Supporting the implementation of a Reliability Centered Maintenance (RCM) program on a vast liquid pipeline network, multi-attribute decision making (MADM) techniques and concepts were used to create assessment models that based around the notion of complexity were then used to benchmark multiple operating regions. From these assessment models, derived benchmarking indexes such as maintenance technicians per equivalent complexity or maintenance budget per equivalent complexity were created and used in support of resource allocation discussions. The paper will describe the use of a MADM techniques, discuss how different complexity models were developed working in collaboration with multiple maintenance SMEs, discuss some of the analysis and findings of different regional benchmarks and also comment on some of the cultural challenges encountered when using and communicating quantitative benchmarks to influence and drive reliability improvements. Hopefully this paper will help other professionals in the industry understand how SME experience can be captured and transformed into assessment tools for use in benchmarking.
When Metals and Microbes Meet: Preventing Microbial Corrosion in Crude Oil Transmission Pipelines
Authors: Gieg Lisa M. , Sharma Mohita , Place Trevor , Sargent Jennifer , Shen Yin
Published: January 2021

Corrosion of carbon steel infrastructure in the oil and gas industry can occur via a variety of chemical, physical, and/or microbiological mechanisms. Although microbial corrosion is known to lead to infrastructure failure in many upstream and downstream operations, predicting when and how microorganisms attack metal surfaces remains a challenge. In crude oil transmission pipelines, a kind of aggressive corrosion known as under deposit corrosion (UDC) can occur, wherein mixtures of solids (sands, clays, inorganic minerals), water, oily hydrocarbons, and microorganisms form discreet, (bio)corrosive sludges on the metal surface. To prevent UDC, operators will use physical cleaning methods (e.g., pigging) combined with chemical treatments such as biocides, corrosion inhibitors, and/or biodispersants. As such, it necessary to evaluate the efficacy of these treatments in preventing UDC by monitoring the sludge characteristics and the microorganisms that are potentially involved in the corrosion process.

The efficacies of a biocide, corrosion inhibitor, and biodispersant being used to prevent microbial corrosion in a crude oil transmission pipeline were evaluated. A combination of various microbiological analyses and corrosivity tests were performed using sludge samples collected during pigging operations. The results indicated that the combined treatment using inhibitor, biocide 1 and biodispersant was the most effective in preventing metal damage, and both growth-based and Next-Generation Sequencing approaches provided value towards understanding the effects of the chemical treatments. The efficacy of a different biocide (#2) could be discriminated using these test methods.

The results of this study demonstrate the importance of considering and monitoring for microbial corrosion of crucial metal infrastructure in the oil and gas industry, and the value of combining multiple lines of evidence to evaluate the performance of different chemical treatment scenarios.
The Use of Remote Real-Time GNSS to Monitor a Pipeline in an Active Landslide
Authors: Bracic Jan , McMahon Ryan
Published: January 2021

Pembina Pipeline Corporation (Pembina) monitored three active interacting [1] landslides utilizing arrays of remote real-time GNSS (Global Navigation Satellite System) sensors to assist in the confirmation of safe continued pipeline operation. Each case study utilized remote sending high-precision real-time GNSS sensors to monitor landslides of varying movement rates, from slow-moving landslides which could be condition-monitored for many years, to fast-moving landslides which required pipeline mitigation within months.

The first case study was Henderson Creek near Grande Prairie AB, which utilized remote real-time GNSS sensors to monitor over one meter of rotational slope movement in 6 months; both a conventionally-buried pipeline, and a temporary above-ground pipeline bridge were monitored before a permanent HDD replacement mitigation was completed. Sensors were installed on the temporary pipeline, the bridge, as well as shallow ground installations. The second case study was Athabasca River north slope near Ft McMurray AB, which utilized remote real-time GNSS sensors to monitor an above-ground pipeline in a slow-moving valley-scale landslide over a period of several years. The third case study was Smoky River east slope near Grande Cache AB, which utilized remote real-time GNSS sensors to monitor a rapidly-moving landslide on a conventionally-buried pipeline, which has plans for an HDD replacement mitigation in the near future.

To verify the results of the GNSS sensors, each of these three landslide sites were monitored utilizing multiple technologies which showed close correlation with the remote real-time GNSS sensors, including conventional ground surveys, monitoring pin surveys, SIs, and repeated ILI IMU caliper runs. The GNSS monitoring system was precise enough to detect operational changes of the above-ground pipelines, including filling of the pipeline with product, suspected changes in internal pipeline operating pressure, and pipeline expansion and contraction due to temperature changes from night to day and winter to summer.

Pembina successfully utilized a remote real-time GNSS monitoring system to allow greater assurance of safe continued pipeline operation at three separate moving slopes, until either a slope movement threshold was reached, or mitigation was completed. This paper highlights that pipeline operators can remotely condition-monitor their confirmed or suspected interacting pipelines in landslides with accuracy using remote real-time GNSS, on a real-time continuous basis as part of their Geohazard Management Program.
Burnishing Characteristics of Sliding Burnishing Process With Active Rotary Tool Targeting Stainless Steel
Authors: Okada Masato , Terada Shin , Kataoka Yuki , Kihara Takeshi , Miura Takuya , Otsu Masaaki
Published: January 2021

This paper investigates the burnishing characteristics of a developed sliding burnishing method with active rotary tool targeting a martensitic stainless steel. Two types of martensitic stainless steel, annealing (AN) stainless steel and quenching and tempering (QT) stainless steel, were targeted. The burnishing characteristics evaluated included surface roughness, profile, microstructure, subsurface hardness, bending property, and corrosion resistance. A sufficiently smooth surface, approximately Ra = 0.1 μm and Ra = 0.025 μm in both materials, respectively, was obtained using the developed burnishing method; irregular profile smoothing occurred due to the material flow of the subsurface. The subsurface hardness increased at a depth of 40 μm or more when using the developed burnishing method on the AN material, but no effect was observed for the QT material. Moreover, the bending yield point and strength of the sheet shape workpiece increased by applying the burnishing process to the AN material. The influence of the burnishing process on the bending properties was also observed for the QT material. Corrosion resistance can be improved through the burnishing process.
Performance Improvement of Ultrasonic-Assisted Grinding Using PCD Micropin Tools
Authors: Egashira Kai , Yamaguchi Keishi , Ota Minoru
Published: January 2021

In the present study it was attempted to improve the performance of ultrasonic-assisted grinding using polycrystalline diamond (PCD) micropin tools processed by electrical discharge machining. The micropins acted as grinding tools because the convex parts of discharge craters can serve as cutting edges of abrasive grains in grinding wheels. The drilling conditions to prevent chippings and cracks on the hole edge were experimentally determined and then employed for the drilling of microholes less than 10 μm in diameter. As a result, microholes as small as 5.5 μm in diameter were successfully drilled in hard and brittle materials such as crown glass and monocrystalline silicon. The high wear resistance of PCD improved the tool life, making it possible to mill trenches and to mass-produce holes using a small number of tools. Moreover, the tool life was further improved by processing the tool peripheral surface at a low electrical discharge energy.
Investigation of Orthogonal Turn-Milling for Higher Machining Efficiency and Accuracy: Relationship Between Material Removal Rate and Measured Tool Flank Temperature
Authors: Shimanuki Koji , Hosokawa Akira , Koyano Tomohiro , Furumoto Tatsuaki , Hashimoto Yohei
Published: January 2021

Tool flank temperature at various intervals after cutting in dry turn-milling of AISI 1045 steel is measured using a two-color pyrometer with an optical fiber. Complicated undeformed chip geometry, which depends on cutting tool diameter, nose radius, number of tooth, workpiece diameter, tool-work revolution speed ratio, depth of cut, feed per tooth, tool axis offset and cutting distance, is analyzed and visualized by the 3D-CAD system. The effect of cutting parameters associated with material removal rate MRR such as workpiece diameter, workpiece revolution speed and feed rate on tool flank temperature is investigated in this paper. Workpiece diameter affects tool flank temperature, and 10 mm larger diameter causes approximately 40 °C higher temperature in any workpiece revolution speed due to the variation of undeformed chip geometry analyzed by 3D-CAD. Tool flank temperature increases with feed rate and workpiece revolution speed because the cross-sectional cutting area of undeformed chip increases with workpiece revolution speed, and cutting time during the engagement of each flute also increases with feed rate. Almost same values are obtained between the tool flank temperature and the material removal rate MRR when both workpiece revolution speed and feed rate are changed.
Optimization Method of Rotational Axis Motion in 5-Axis Controlled Machining to Keep Command Tool Feed Rate
Authors: Nakamura Takayuki , Ichikawa Kohei , Hasegawa Masanobu , Kaneko Jun'ichi , Abe Takeyuki
Published: January 2021

In recent machining processes, 5-axis controlled machine tool is widely used for machining complicated workpiece shape with curved surface. In such process, to achieve high productivity, planning method of cutting conditions to satisfy both following the commanded tool feed rate in machining process and realization of good surface roughness are required. In conventional study, it is known that lead angle of tool posture against local machined surface influence the surface roughness. Then, common commercial CAM systems have already functioned to avoid interference and control the lead angle in each cutter location. However, in the generated cutter locations by the conventional algorithms, when the tool posture changes rapidly, there is a problem that actual feed rate does not reach the command value and machining time becomes longer than expected. In this paper, we propose the new tool posture correction algorithm. In the proposed method, first, the rotational axis that causes the feed speed rate decline is specified by preliminary experiments. And, the jerk value that is the threshold for the feed speed decline is investigated. After that, for the NC program, the command value of the target axis is modified within a range where interference of cutting tool does not occur, thereby preventing a decline in the actual feed rate. This paper describes an outline of the proposed modification method and the effect of the modification of the target axis positions on the lead angle and the actual feed rate.
Micro Grooving of Cemented Carbide Using PCD Blade
Authors: Yamaguchi Keishi , Sugimoto Takumi , Ota Minoru , Egashira Kai
Published: January 2021

Ultra–Agile Advanced Manufacturing System (U–AMS) has been proposed for an agile prototyping system of research and development, and Super Processing Center (SPC) has been developing as a core machine tool of U–AMS. SPC has high accuracy and rigidity by double column structure based on a vertical precision machining center, hydrostatic oil guides and hydro static/dynamic hybrid oil bearing. In addition, SPC can perform various processing functions by mounting various processing units. Micro grooving by grinding has been researching for one of the SPC unit. PCD blade was developed for micro grooving using SPC. PCD blade was made from PCD disc using wire electrical discharge machining. This paper describes the fabrication method of PCD blade, and the machining characteristics of cemented carbide using PCD blade. In the fabrication method of PCD blade, it was clarified that the cross-sectional shape of PCD blade depended on the feed speed of wire electrode. Micro grooving on cemented carbide surface was performed using developed PCD blade and SPC. As a result, it was confirmed that the micro grooves can be machined using PCD blade, and the width of groove was almost same value as the width of PCD blade. The wear of PCD blade after grooving with 200 grooves was estimated by the depth of grooves. As a result, it was clarified that the wear of PCD blade is approximately 5 μm.
Development of a Machining Center Structure Made of Carbon Fiber Reinforced Plastic and Aluminum Honeycomb
Authors: Kizaki Toru , Iwama Masatoshi , Shiraishi Masaru , Sugita Naohiko
Published: January 2021

Reduction of size and weight are required in a development of machine tools that are mainly used in prototyping purposes. It is generally known, however, that when the reduction of size and weight of the structure were both pursued the machining accuracy can possibly be degraded due to insufficient stiffness. It is important to increase the specific stiffness and thermal stability of a machine tools structure for better machining accuracy. In this study we have applied a sheet of carbon fiber reinforced plastic and a sheet of aluminum honeycomb. A sandwich structure made of both materials and the ribs made of carbon fiber reinforced plastic was proposed. The proposed structure showed the increased specific stiffness and the thermal stability which are suited to the machine tools of high accuracy. We investigated the basic performance of the proposed structure by using several beam-shaped samples, in which the static stiffness and thermal expansion was measured and compared. The inserted ribs in the proposed structure was revealed to be suppressing the thermal expansion of the aluminum honeycomb core. After the basic investigation, a 5-axis machining center with the proposed structure was designed. The mechanical and thermal performance of the structure was tested in the finite element analyses. Finally the machining center was manufactured.
Effect of Casting Conditions on Fluidity of Aluminum Alloy in Die Casting
Authors: Haga Toshio , Imamura Sinjiro , Watari Hisaki , Nishida Shinichi
Published: January 2021

The fluidity of pure aluminum and Al-Si alloys was investigated for casting thin products using a spiral die in die casting. An aluminum alloy with good fluidity can be die-cast into thin products. For a Si content of less than 6 mass%, the fluidity increased with decreasing Si content. For a Si content of greater than 6 mass%, the fluidity increased with increasing Si content. The fluidity was affected by latent heat, flowability in the semisolid state, and heat transfer between the die and metal. For pure aluminum, the latent heat is small and there is no semisolid state. However, pure aluminum has excellent fluidity because the heat transfer between the die and metal is small. For Al-25%Si, the latent heat is very large and flowability increases in the semisolid state. Therefore, the fluidity of Al-25%Si is high. Fluidity typically increases with increasing die temperature. The increase in fluidity due to an increase in die temperature for the pure aluminum is small compared with that for hypoeutectic Al-Si alloys. This means that the heat transfer between the pure aluminum and the die is smaller than that for hypoeutectic Al-Si alloys. Therefore, the influence of die temperature on the fluidity of the pure aluminum is small. It is estimated that the chill layer of the pure aluminum rapidly peels from the die, decreasing the heat transfer between the pure aluminum and the die.
3D Laser Forming of Metal Foam Sandwich Panels
Authors: Bucher Tizian , Finn Connor , Verma Ravi , Li Wayne , Yao Y. Lawrence
Published: January 2021

Metal foam sandwich panels have been subject of many concept studies, due to their exceptional stiffness, light weight, and crash absorption capacity. Yet, the industrial production of the material has been hampered by the fact that it is challenging to bend the material into practical engineering shapes. Only recently it has been shown that bending of metal foam sandwich panels is possible using lasers. It was shown that the material can be bent into Euclidean (2D) geometries, and the governing laser-induced bending mechanisms were analyzed.

This study was focused on laser forming of metal foam sandwich panels into non-Euclidean (3D) geometries. It was investigated whether the knowledge about the bending mechanisms translates to 3D deformation, and whether the combination of process parameters that were identified for 2D laser forming are still appropriate. Moreover, the impact of the laser scan length was determined by comparing different scan patterns that achieve the same 3D geometries.

It was shown that 3D deformation could be induced for both the bowl and saddle shapes, the two most fundamental non-Euclidean geometries. The amount of laser-induced bending and in-plane strains vary depending on process conditions and thus bending mechanisms. Lastly, the laser scan length was shown to become more important for metal foam sandwich panels, where the panel thickness tends to be large.
Material Flow Behavior Modelling and Strain Distribution Prediction During Self-Reacting Friction Stir Welding Process Based on Computational Fluid Dynamics Method
Authors: Zhao Chenyu , Liu Xun , Zhang Wei , Cao Weiyu
Published: January 2021

Self-reacting friction stir welding (SRFSW) is an advanced variant of friction stir welding (FSW) and shows several superiorities with the double-sided tool configuration. Despite the considerable amount of experimental studies in this field, most of the tool development efforts are still empirical and resort to trial-and-error solutions. To reveal effects of tool features on process physics and guide tool designs, in this study, a multi-physics SRFSW process model is developed within the framework of computational fluid dynamics (CFD). A shear stress boundary condition is applied at the tool-workpiece contact interface. First, the velocity distribution at weld cross section are calculated and the results show that the threads on the pin contribute to the enhancement of stirring effect. Second, the temperature evolutions at advancing side (AS) and retreating side (RS) are compared, and position in RS has higher temperature than position in AS accordingly. Finally, the plastic strain distribution behind pin tool is calculated by integrating effective stain rate along pathlines. The result shows that AS has a more definable strain boundary than RS, which corresponds to the general macroscopic observations in SRFSW. The results may provide a reference on SRFSW tool design.
Fiber Filled Hybrid Hydrogel for Bio-Manufacturing
Authors: Habib Ahasan , Khoda Bashir
Published: January 2021

The extrusion based three-dimensional (3D) bio-printing deposits cell-laden bio-ink with high spatial resolution and may offer living tissue regeneration. Due to the biocompatibility, less cytotoxicity and high water content, natural hydrogels are commonly considered as the bio-ink for scaffold fabrication. However, due to the low mechanical integrity, a large scale scaffold (> 10 layers) with intricate architecture is a challenge. In this paper, Cellulose-based nano-fiber and CMC are added with alginate material to improve the rheological behavior of the hybrid hydrogel. Shear-thinning behavior, shape fidelity, printability of the composition are investigated and evaluated for various compositions. Finally, both regular and freeform 3D scaffolds are fabricated with the proposed hybrid hydrogel to validate its printability and shape fidelity. The required properties of bio-ink are highly dependent upon the percentage composition and the solid content.
In-Situ Monitoring of Laser Powder Bed Fusion Process Anomalies via a Comprehensive Analysis of Off-Axis Camera Data
Authors: Vallabh Chaitanya Krishna Prasad , Xiong Yubo , Zhao Xiayun
Published: January 2021

In-situ monitoring of a Laser Powder-Bed Fusion (LPBF) additive manufacturing process is crucial in enhancing the process efficiency and ensuring the built part integrity. In this work, we present an in-situ monitoring method using an off-axis camera for monitoring layer-wise process anomalies. The in-situ monitoring is performed with a spatial resolution of 512 × 512 pixels, with each pixel representing 250 × 250 μm and a relatively high data acquisition rate of 500 Hz. An experimental study is conducted by using the developed in-situ off-axis method for monitoring the build process for a standard tensile bar. Real-time video data is acquired for each printed layer. Data analytics methods are developed to identify layer-wise anomalies, observe powder bed characteristics, reconstruct 3D part structure, and track the spatter dynamics. A deep neural network architecture is trained using the acquired layer-wise images and tested by images embedded with artificial anomalies. The real-time video data is also used to perform a preliminary spatter analysis along the laser scan path. The developed methodology is aimed to extract as much information as possible from a single set of camera video data. It will provide the AM community with an efficient and capable process monitoring tool for process control and quality assurance while using LPBF to produce high-standard components in industrial (such as, aerospace and biomedical industries) applications.
Evaluation of Soybean Oil-Based MQL As a Potential Replacement for Emulsion Flood Cooling Strategy for High-Speed Face Milling of Inconel 718
Authors: Okafor Anthony Chukwujekwu , Nwoguh Theodore Obumselu
Published: January 2021

This paper presents the results of comparative evaluation of soybean oil based MQL oil flow rates at 10, 30, 50, 70, and 90 ml/h with emulsion flood coolant (EC) at 1200 l/h as a benchmark in face milling of Inconel 718 using coated carbide inserts. Resultant cutting force, tool wear/ mechanism, and surface roughness are the machining performance parameters analyzed. The results show that MQL oil flow rate at 70 ml/h gave the least tool wear comparable to that of EC, while 10 ml/h gave the highest tool wear. Also, 70 ml/h gave the lowest resultant cutting force among all MQL flow rates. Increasing soybean oil-based MQL flow rate improves surface roughness and reduces tool wear by providing enough thin lubrication film but also leads to an increase in chip affinity and formation of large built-up-edges (BUEs) as the MQL flow rate reaches 90 ml/h. At lower soybean oil-based MQL flow rate, tool wear mechanism is predominantly abrasion due to large surface friction, while at higher soybean oil-based MQL flow rate, tool wear mechanism is adhesion leading to excessive BUEs. Soybean oil-based MQL flow rate at 70 ml/h is recommended when face milling Inconel 718 and is demonstrated to be a potential replacement of EC for machining difficult-to-cut metal.
The Geometric Error Measurement and Compensation for a Five-Axis Machining Center’s Tilting Rotary Table
Authors: Liu Kuo , Han Wei , Liu Haibo , Sun Mingjia , Xie Nan , Wang Yongqing
Published: January 2021

The geometric error measurement and compensation for a five-axis machining center’s tilting rotary table is a difficult problem in the machine tool industry. Aiming at this problem, and based on a thorough study of the geometric error of a vertical five-axis machining center’s tilting rotary table, a method has been suggested in this paper to measure the geometric error of the tilting rotary table using the ball bar performing a three-axis circular interpolation. Eight center bias values in the X and Y directions were obtained by the use of four specific three-axis circular interpolation tests. According to the geometric relations of these four specific forms of circular tests, a geometric error separation model of the tilting rotary table was established. The process of circle test of A-axis and C-axis for vertical five-axis machining center is given in detail. The contrast tests, before and after compensation, were carried out in a vertical five-axis machining center. The experimental results showed that the positional errors and angular errors after compensation were much smaller than those before compensation. The positional error decreased from the maximum value of - 0.089 mm before compensation to the maximum value of - 0.004 mm, and the angle error decreased from the maximum value of - 0.012° before compensation to the maximum value of 0.002°. This method has provided an important reference for the geometric error measurement and compensation for a vertical five-axis machining center’s tilting rotary table.
Asset Condition Management: A Framework for Smart, Health-Ready Manufacturing Systems
Authors: Diaz-Elsayed Nancy , Hernandez Luis , Rajamani Ravi , Weiss Brian A.
Published: January 2021

Unscheduled downtime in manufacturing systems can be a major source of lost productivity, profits, and, ultimately, reduced process quality and reliability. However, the incorporation of asset condition management (ACM) into manufacturing systems offers an approach to improve equipment and plant operations by providing real-time condition awareness, system diagnostics, and estimates of future health to enable predictive maintenance. ACM is a framework for assessing the current and future state of health of a manufacturing system and integrating that knowledge with enterprise applications to meet the demand of production operations. In manufacturing systems, successful operations rely on the ability to maintain production assets at their optimal working levels to optimize operations and system performance. Some large corporations have made great strides in incorporating smart technologies to enhance their asset management strategy; however, small- and medium-sized enterprises (SMEs) face distinct challenges. One of the key challenges is that most SMEs do not have the wherewithal to invest in new machines nor is there standard guidance on how older machines can be integrated into an ACM solution, so that their end-to-end manufacturing process can be optimized from a health management point of view. This research presents a framework for ACM to facilitate its introduction into manufacturing systems based on their “health-ready” capabilities. Specifically, an ACM system architecture is defined for manufacturing systems, the health-ready principles and capability levels from the aerospace and automotive industries are adapted to the manufacturing domain, and the results from the outreach effort to the manufacturing community are discussed.
Simulation of Fabry-Perot Resonance for 3D Printable Complex Holey Acoustic Metamaterials
Authors: Ravichandran Sanjay , Wu Xin , Su Yutai , Shi Jing
Published: January 2021

An acoustic metamaterial is a kind of material that is artificially designed in such a way that it can manipulate, control and direct sound waves. To date, various designs for acoustic metamaterials in the imaging applications have been proposed. However, these designs are generally simple due to the restriction from conventional manufacturing methods. By taking advantage of the additive manufacturing (AM) techniques, many complex acoustic metamaterials could be realized. However, the research on the complex structures for imaging applications has been very limited. In this paper, various 3D printable holey structured metamaterials with only one aperture are proposed, and the application possibility for sub-wavelength acoustic imaging in the audible frequency range is investigated. By using numerical simulation method, the effect of transmission properties of incident evanescent waves is analyzed to see whether these waves can completely transmit through the metamaterial. The phenomenon of Fabry-Perot resonances (FPR) that occur inside the hole for five different aperture shapes which are air-filled is studied, and the possibility of operating in a broadband resonance condition for the five designs are analyzed. These results can also be used to obtain valuable information for realizing a broadband acoustic hyperlens, which is an emerging application of 3D printable acoustic metamaterials.
Fabrication and Characterization of Conical Micro Dimple Textures on Ti6Al4V for Higher Biocompatibility
Authors: Jain Ankit , Yatirajula Suresh Kumar , Bajpai Vivek
Published: January 2021

In lab-developed micromachining facility has been utilized to fabricate conical micro dimple textured surfaces of different density on the Ti6Al4V implant surface to improve the surface properties for higher biocompatibility and osseointegration rate. The surface topography, roughness, quality, shape, and size of the formed textures were analyzed by cross-sectional form measurement using probe-type contact surface profilometer and FESEM (Field Emission Scanning Electron Microscope) analysis. Further, the surface composition of both textured and un-textured surfaces was studied by EDS (Energy-dispersive X-ray spectroscopy) analysis. The equilibrium contact angle of water was measured using the sessile drop technique of drop shape analyzer on both (textured and un-textured) surfaces. Further, the thermodynamic work of adhesion has been calculated by the Young-Dupre equation for both the surfaces. The formed textures are in good shape, size and quality. Each texture is uniform and equally spaced as per the design of experiment. Further, EDS analyses show that the surface composition of textured surfaces does not alter due to micromachining. The surface roughness values inside the dimple are almost the same, which indicates that the effect of tool wear is negligible. The hydrophilicity and work of adhesion of textured surfaces are significantly improved as compared to the untextured surface.
Machining of Through Holes in Non-Conductive Aluminum Nitride Ceramic Using Electrical Discharge Machining Process
Authors: Rashid Asif , Jahan Muhammad P. , Perveen Asma , Ma Jianfeng
Published: January 2021

Ceramic materials are known for their high hardness and strength-to-weight ratio, resistance to wear, and chemical inertness. These materials can be deployed at elevated temperature even to the limit where super alloys cannot be used. The distinctive properties of ceramics make them difficult to machine by conventional processes because of their brittleness. Electrical discharge machining (EDM) is a non-contact machining process that can machine any workpiece irrespective of its hardness, as long as the material is electrically conductive. Therefore, the challenge that comes with the EDM of ceramics is the electrical non-conductivity. In this study, an innovative method (modified assisted-electrode method) has been proposed, which can be used to successfully machine through holes in pure and non-conductive ceramic materials using the EDM process. The effect of machining parameters and conductive coating has been studied. In addition, the possible material removal method has been investigated using the scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis. It is found that multi-layer coating with conductive copper tape sandwiched with graphene and carbon nanotubes in between the tape worked as a successful assistive electrode method. The SEM and EDS analysis indicates melting and thermal spalling as possible material removal mechanisms during EDM of electrically non-conductive Aluminum nitride (AlN) ceramics. The deposition of carbon at the edge of the holes indicate generation of conductive carbon layer favoring continuous sparking during the machining process, and this makes the EDM of non-conductive AlN possible. The walls of the drilled holes become conductive and allow the machining to go through even beyond the conductive layer range. The performance characteristics depends on both the electrical parameters and assistive electrode method.
Characteristics of Diamond Abrasive Used in Magnetic Abrasive Finishing of Nickel-Based Superalloys
Authors: Ratay Jason , Yamaguchi Hitomi
Published: January 2021

Nickel-based superalloys have a wide range of high-temperature applications, such as turbine blades. The complex geometries of these applications and the specific properties of the materials raise difficulties in the surface finishing. Magnetic abrasive finishing (MAF) has proven effective in finishing the complex geometries. In MAF, the magnetic properties of the workpiece, tool, and abrasive play important roles in controlling finishing characteristics. This paper presents the effects of nickel coating on the abrasive behavior during finishing and resulting finishing characteristics of Ni-based superalloys. The Ni-coated diamond abrasive is more attracted to the magnet than the Ni-based superalloy surface. As a result, fewer Ni-coated diamond abrasive particles, which are stuck between the magnetic-particle brush and the target surface, participate in surface finishing. Because of this, coupled with the reduced sharpness of abrasive cutting edges due to the coating, Ni-coated diamond abrasive cannot effectively smooth the target surface in MAF. However, the Ni coating is worn off during finishing of the hard, rough, additively manufactured surface. Then, the diamond abrasive participates in finishing as uncoated diamond abrasive and facilitates the material removal, finishing the target surface.