Blade Production Research Articles

Heterogeneous graph neural network for modeling intelligent manufacturing systems

Abstract Currently, manufacturing systems have become more and more complex, often involving multiple machines, systems and processes to produce workpieces. In order to facilitate comprehensive analysis and control of manufacturing processes, the integration of connections between machine level, system level, and process level in manufacturing process modeling is needed. However, traditional graph deep learning models are unable to take into account the heterogeneity of different machines in the system when modeling manufacturing systems. To address this problem, this paper proposes a new approach: modeling manufacturing systems using the heterogeneous graph neural network sample and aggregate algorithm based on cutting-edge Bayesian neural networks and graph deep learning. This method considers the connection between different manufacturing system levels, treats machine operations as nodes, and connects different nodes through material flow and operational similarity. The effectiveness of the method is demonstrated through its application to model an aero-engine blade production line. Extensive numerical experiments show that the proposed graph modeling method is effective in expressing the heterogeneity of different machines and multi-level manufacturing processes. By integrating machine heterogeneity into the modeling of a manufacturing system, it not only facilitates comprehensive analysis and control of the manufacturing process, but also lays the foundation for cost savings and productivity improvements in the manufacturing system.

Effect of Al(OH)3 on the Properties of Silica-based Ceramic Cores Prepared by Laser Powder Bed Fusion Combined with Vacuum Infiltration

Silica-based ceramic cores, with low coefficients of thermal expansion, low sintering temperatures, and excellent acid and alkali leaching capabilities, are essential materials for the production of hollow blades. However, their mechanical properties are suboptimal, and they present various processing challenges. In this study, silica-based ceramic cores were prepared using a combination of vacuum infiltration (VI) and laser powder bed fusion (LPBF) techniques. Al(OH)3 was employed as a mineralizer to enhance the post-sintering mechanical properties and improve the efficiency of the vacuum infiltration process, thereby enhancing the overall performance of the silica-based ceramic cores. The VI process facilitated the penetration of nano-SiO2 into the samples, increasing their density and promoting the formation of cristobalite during sintering at 1225°C. Additionally, the Al(OH)3 powder, through pyrolysis into Al2O3 during sintering, reduced microcracks, inhibited excessive cristobalite transformation, and improved the VI process, resulting in enhanced room-temperature flexural strength. By optimizing the Al(OH)3 content and the VI process, significant improvements in the microstructure and properties of the silica-based ceramic cores were achieved. After three rounds of vacuum infiltration and the addition of 4wt.% Al(OH)3, the samples exhibited a high-temperature creep of 0.17mm, with flexural strengths of 15.23MPa at room temperature and 23.55MPa at high temperature.

A study of Early Upper Paleolithic blade production in the third cultural layer at Suyanggae Locality VI, Republic of Korea

A study of Early Upper Paleolithic blade production in the third cultural layer at Suyanggae Locality VI, Republic of Korea

Priority-based two-phase method for hierarchical service composition allocation in cloud manufacturing

Manufacturing service composition (MSC) is an essential issue in cloud manufacturing, which streamlines complex manufacturing tasks into manageable subtasks and integrates distributed services to enhance task completion. Existing studies allocate services for subtasks with maximizing quality of service (QoS) simultaneously, assuming that all subtasks are of equal importance. However, different subtasks hold varied significance and priorities. One rational method is to prioritize the allocation of premium or scarce services to important subtasks. Therefore, this study proposes a two-phase, subtask priority-based approach for the hierarchical allocation of the MSC. The initial phase applies a multi-attribute decision-making method based on complex networks, the Enhanced Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS-EK), to assess subtask importance. The TOPSIS-EK method ascertains subtask importance, delineating the subtasks into Key Manufacturing Subtasks (KMTs) and Ordinary Manufacturing Subtasks (OMTs). The second phase uses bilevel optimization for the hierarchical allocation of the MSC to KMTs and OMTs, respectively. A hybrid Particle Swarm Optimization and Genetic Algorithm with Chaos-sequence and Inheritance (PSOGA-CI) is developed to solve the model. The proposed approach is validated with a case on the production of an airplane engine turbine rotor blade.

Economic Impact Assessment of Structural Health Monitoring Systems on the Lifecycle of a Helicopter Blade

Structural Health Monitoring Systems (SHMS) are currently widely investigated in the literature, however, their application to the aerospace industry is still limited. One of the reasons lies in the lack of methods aimed at evaluating their economic impact on the lifecycle of the structural element to be monitored [1]. In this work the economic impact of FBG-based SHMS was evaluated on a composite helicopter rotor blade, considering two perspectives: Beginning Of Life (BOL), concerning the blade production, and Middle Of Life (MOL), concerning its usage. The processes were modeled using the IDEF0 methodology, which allowed deriving the cost models for two scenarios: the current one, and the one including the SHMS. In BOL, the SHMS was supposed providing support to the development of new composite rotor blades, including the curing cycle definition and certification tests. In MOL the SHMS was supposed performing automatic scheduled inspections coupled with the traditional ones. The cost model was implemented in the Probabilistic Damage Tolerance Analysis [2] to compare the scenarios having the same blade Probability Of Failure and considering the performances of the SHMS in terms of Probability Of Detection and Probability of False Alarm. Results show that an economic benefit may be achieved using the SHMS in the development of new blades, potentially reducing the number of blades tested and number of autoclave cycles. Moreover, it was found that the traditional scheduled detailed inspection intervals could be extended if automatic SHMS inspections are performed in addition, maintaining the same Probability Of Failure. [1] Büchter, K. D. et al. (2022). Modeling of an aircraft structural health monitoring sensor network for operational impact assessment. Structural Health Monitoring, 21(1), 208-224. [2] Lin, K. Y., & Styuart, A. V. (2007). Probabilistic approach to damage tolerance design of aircraft composite structures. Journal of Aircraft, 44(4), 1309-1317.

Correlation analysis of primal cuts weight, fat contents, and auction prices in Landrace × Yorkshire × Duroc pig carcasses by VCS2000.

Currently, in pork auctions in Korea, only carcass weight and backfat thickness provide information on meat quantity, while the production volume of primal cuts and fat contents remains largely unknown. This study aims to predict the production of primal cuts in pigs and investigate how these carcass traits affect pricing. Using the VCS2000, the production of shoulder blade, loin, belly, shoulder picnic, and ham was measured for gilts (17,257 pigs) and barrows (16,365 pigs) of LYD (Landrace × Yorkshire × Duroc) pigs. Single and multiple regression analysis were conducted to analyze the relationship between the primal cuts and carcass weight. The study also examined the correlation between each primal cut, backfat thickness (1st thoracic vertebra backfat thickness, grading backfat thickness, and Multi-brached muscle middle backfat thickness), pork belly fat percentage, total fat yield, and auction price. A multiple regression analysis was conducted between the carcass traits that showed a high correlation and the auction price. After conducting a single regression analysis on the primal cuts of gilt and barrow, all coefficients of determination (R2) were 0.77 or higher. In the multiple regression analysis, the R2 value was 0.98 or higher. The correlation coefficient between the carcass weights and the auction price exceeded 0.70, while the correlation coefficients between the primal cuts and the auction prices were above 0.65. In terms of fat content, the backfat thickness of gilt exhibited a correlation coefficient of 0.70, and all other items had a correlation coefficient of 0.47 or higher. The correlation coefficients between the Forequarter, Middle, and Hindquarter and the auction price were 0.62 or higher. The R2 values of the multiple regression analysis between carcass traits and auction price were 0.5 or higher for gilts and 0.4 or higher for barrows. The regression equations between carcass weight and primal cuts derived in this study exhibited high determination coefficients, suggesting that they could serve as reliable means to predict primal cut production from pig carcasses. Elucidating the correlation between primal cuts, fat contents and auction prices can provide economic indicators for pork and assist in guiding the direction of pig farming.

Parametric study on the effect of material properties, tool geometry, and tolerances on preform quality in wind turbine blade manufacturing

Increasing throughput in wind turbine blade production can be achieved by separately manufacturing pre-shaped binder-stabilised dry preforms, and subsequently placing them in the blade mould. To avoid manufacturing defects, a trade-off between the formability and the handleability of the preform is necessary. In this paper, an experimentally validated preform model is used to study how variations in material properties, tool geometry, and placement tolerances influence defect generation. The results from three studies are presented. In the first study, a preform is formed over a ramp transition with variations in geometry. The results from this study indicate that a short ramp promotes transverse shearing of the preform. In the second study, the material properties of the preform are varied. The results indicate that a high mode I cohesive law of the binder and a high bending stiffness of the fabric promote transverse shearing and remove wrinkles. In the last study, placement tolerances for a pre-shaped preform are studied. The results show that if the preform can shear between the preform edge and the tool edge, it can conform to the mould even with large placement offsets. Process engineers and blade designers can readily use these results to help reduce forming-induced wrinkles.

Core Reduction Methods of Mizyn Industry of Epigravettian Techno-Complex

Mizyn is one of the main sites of the Epigravettian techno-complex of the Middle Dnipro Basin. One of the modern approaches to the study of the material culture of Upper Palaeolithic societies is the study of technological features of flintknapping. The purpose of this study is to determine the core reduction strategy of the Mizyn site in particular and the Mizyn industry in general. To achieve this goal, an attributional analysis of the artefacts from the lithic assemblage of excavation area no. 1 of the Mizyn site was carried out. Fragments of raw material, core-like pieces, and lamellar pieces have been analysed. This paper focuses on the study of the assemblage of core-like pieces, taking into account the imperfections of the 70-year-old field research methodology. The main outcome of this study was the elucidation of discrete core reduction strategies of the Mizyn site. Rounded raw material played a greater role in the production of blades from narrow flaking surface cores and sub-cylindrical cores (fig. 4). Narrow flaking surface cores (fig. 6) made from plate-like raw materials were used to produce blades and micro-blades. Blades were necessary blanks for making a “home” set of tools. Bladelets and micro-blades were used for hunting equipment. Both strategies are characterised by unidirectional splitting and the use of the hard hammer-stone. Crested and débordante lamellar pieces were required to maintain the convexity of the core’s flaking surface. The overhang trimming method was also used, most commonly for bladelets and micro-blade cores. The main reason for core discard was the occurrence of hinge fractures on the flaking surface, which were repaired by using an opposite striking platform. The same features of the lithic assemblage are found at the Barmaky site. As a result, discrete strategies of the core reduction are a typical feature for the Mizyn industry. As Barmaky and Mizyn are the oldest Epigravettian sites in the Middle Dnipro basin, this feature can be explained by a chronological factor. However, the choice of a strategy can also be explained by the regional characteristics of the landscape and the adaptation of the primary inhabitants to them.

Making wind turbine blades more sustainable

Researchers at Virginia Tech’s College of Engineering will use new methods of additive manufacturing, computational design, and a recyclable, high strength thermoplastic material to improve the environmental footprint of wind turbine blade production.

Lithic stories of broken relations after the Storegga tsunami in Mesolithic western Norway?

ABSTRACT Major changes in lithic technologies are often explained by either migration or crisis. Here we argue that continuity and minor adjustments in lithic production can tell equally dramatic tales of altered social situations. We base our interpretations on identified lithic blade production concepts and raw materials at 30 sites dating 7500–5000BC, i.e. from before and after the massive Storegga tsunami hit the coast of western South-Norway around 6150BC. Regional continuation, but also local variations in lithic production are interpreted inspired by a machine-oriented ontological framework. The tsunami disrupts the environment, society and its lithic traditions are affected. Although no immediate major breaks are observed, sometime after the tsunami, societies or lithic production as ‘machines’ in separate regions had begun to hum to different tunes. We suggest that variation in tsunami impact had created differing local social contexts which in turn pushed the lithic traditions down diverging paths.

Non-Gaussian Multivariate Process Capability Based on the Copulas Method: An Application to Aircraft Engine Fan Blades

Abstract Process capability indices (PCIs) are major tools in geometric dimensioning and tolerancing (GD&T) for quantifying the production quality, monitoring production, or prioritizing projects. Initially, PCIs were constructed for studying each characteristic of the process independently. Then, they have been extended to analyze several dependent characteristics simultaneously. Nowadays, with the increasing complexity of the production parts, for example, in aircraft engines, the conformity of one part may rely on the conformity of hundreds of characteristics. Also, because those characteristics are dependent, it may be misleading to make decisions based only on univariate PCIs. However, classical multivariate PCIs in the literature do not allow treating such amount of data efficiently, unless assuming Gaussian distribution, which may be false. Regarding those issues, we advocate for PCI based on some transformation of the conformity rates. This presents the advantage of being free from distributional assumptions, such as the Gaussian distribution. In addition, it has direct interpretation, allowing it to compare different processes. To estimate the PCIs of parts with hundreds of characteristics, we propose to use Vine Copulas. This is a very flexible class of models, which gives precise estimation even in high dimension. From an industrial perspective, the computation of the estimator can be costly. To answer this point, one explains how to compute a lower bound of the proposed PCI, which is faster to calculate. We illustrate our method adaptability with simulations under Gaussian and non-Gaussian distributions. We apply it to compare the production of fan blades of two different factories.

Knowledge-based digital twin system: Using a knowlege-driven approach for manufacturing process modeling

The Knowledge-Based Digital Twin System is a digital twin system developed on the foundation of a knowledge graph, aimed at serving the complex manufacturing process. This system embraces a knowledge-driven modeling approach, aspiring to construct a digital twin model for the manufacturing process, thereby enabling precise description, management, prediction, and optimization of the process. The core of this system lies in the comprehensive knowledge graph that encapsulates all pertinent information about the manufacturing process, facilitating dynamic modeling and iteration through knowledge matching and inference within the knowledge, geometry, and decision model. This approach not only ensures consistency across models but also addresses the challenge of coupling multi-source heterogeneous information, creating a holistic and precise information model. As the manufacturing process deepens and knowledge accumulates, the model's understanding of the process progressively enhances, promoting self-evolution and continuous optimization. The developed knowledge-decision-geometry model acts as the ontological layer within the digital twin framework, laying a foundational conceptual framework for the digital twin of the manufacturing process. Validated on an aero-engine blade production line in a factory, the results demonstrate that the knowledge model, as the core driver, enables continuous self-updating of the geometric model for an accurate depiction of the entire manufacturing process, while the decision model provides deep insights for decision-makers based on knowledge. The system not only effectively controls, predicts, and optimizes the manufacturing process but also continually evolves as the process advances. This research offers a new perspective on the realization of the digital twin for the manufacturing process, providing solid theoretical support with a knowledge-driven approach.

A Cold Habitat: Mapping Blade Assemblages Between the Siberian Altai and the Tibetan Plateau During MIS 3

How and why early hunter–gatherers expanded into the challenging environments of the Tibetan Plateau during the Pleistocene remain largely unexplained. The discovery of the archaeological site of Nwya Devu, characterized by lithic blade production, brings new evidence of human expansion to high elevations ca. 40–30 ka. The blade assemblage currently lacks technological antecedents in East Asia. During Marine Isotope Stage 3, the surrounding lowlands to the Plateau were dominated by a distinct type of industry broadly named “core and flake.” It is suggested that the Nwya Devu blade assemblage derives from traditions in the eastern Eurasian Steppe, a clustered hub for Upper Paleolithic blade technology. In contrast to the East Asian lowlands, the Tibetan Plateau shares a number of environmental similarities with North and Central Asia such as low temperature and humidity, long winters, strong seasonality, and grassland landscapes. Blade and core-and-flake technologies tend to be associated with different environments in eastern Asia. We hypothesize that this geographic distribution indicates different sets of behavioral adaptations that map onto distinct ecozones and are relevant to human expansion to the Tibetan Plateau during Marine Isotope Stage 3. To evaluate the working model, we characterized the environmental parameters for both blade and core-and-flake technologies in eastern Asia during the period. The results show that environmental conditions on the Plateau and at the Nwya Devu site align with those of blade assemblages documented in the Eurasian Steppe and contrast with those of core-and-flake assemblages. Blade technology is strongly associated with low-temperature environments. These findings suggest that hunter–gatherers from the steppe belt may have benefited from their behaviorally adaptive advantages when moving into the highland environments of the Tibetan Plateau, 40–30 ka.

Obsidian-tipped Spears from the Admiralty Islands in the Oceania Collection of the Museum of Ethnography in Budapest

The authors studied 36 obsidian-tipped spears in the Oceania collection of the Museum of Ethnography in Budapest. In addition to describing the objects from the Admiralty Islands collected before 1897, the paper provides a summary of the related ethnographic information, including the technological and technical details of spear point making and the characterisation of the obsidian raw material used.The blades used for making the obsidian points presented in this study showed no sign of standardisation (an indicator of advanced blade technology) in the spear point-making process. According to 19th-century ethnographic sources, the functional part of the points was the most important, and much time and effort were invested in ensuring that the blades were effective weapons. Later, as a sign of decline, primary production of obsidian blades ceased, and manufacturers started scavenging old artefacts and utilising waste and by-products. As a result, the blades decreased in size and became more irregular, and an increasingly large number included parts of the cortex, the crust of obsidian. After 1911, the relative importance of decoration increased, and the type became more standardised.The irregular shape of the spear points presented in the study and the thin, weak shafts with an awkward curvature raise questions about whether the spears were actual weapons. At the same time, the artistic decoration of the mounting sockets and ethnographic parallels suggest that the pieces in the collection were likely status objects instead.

Investigation of electrolyte pressure effect on blisk blades during electrochemical machining

PurposeThe purpose of this study is analysis of deformation and vibrations of turbine blades produced by high electrolyte pressure during electrochemical machining.Design/methodology/approachAn experimental setup was designed, experiments were conducted and the obtained results were compared with the finite element results. The deformations were measured according to various flow rates of electrolyte. In finite element calculations, the pressure distribution created by the electrolyte on the blade surface was obtained in the ANSYS® (A finite element analysis software) Fluent software and transferred to the static structural where the deformation analysis was carried out. Three different parameters were examined, namely blade thickness, blade material and electrolyte pressure on blade disk caused by mass flow rate. The deformation results were compared with the gap distances between cathode and anode.FindingsLarge deformations were obtained at the free end of the blade and the most curved part of it. The appropriate pressure values for the electrolyte to be used in the production of blisk blades were proposed numerically. It has been determined that high pressure applications are not suitable for gap distance lower than 0.5 mm.Originality/valueWhen the literature is examined, it is required that the high speed flow of the electrolyte is desired in order to remove the parts that are separated from the anode from the machining area during electrochemical machining. However, the electrolyte flowing at high speeds causes high pressure in the blisk blades, excessive deformation and vibration of the machined part, and as a result, contact of the anode with the cathode. This study provides important findings for smooth electro chemical machining at high electrolyte flows.

Lithic tool provisioning in the western Aztec provinces: A view from Calixtlahuaca

AbstractWe describe an analysis of the flaked stone tools recovered from households in the Postclassic central Mexican city of Calixtlahuaca (a.d.1130–1530). Most artifacts are obsidian and represent the blade-core technology, but biface and bipolar artifacts are also represented. Even though household residents were involved in limited biface and bipolar reduction, it appears that the city did not have any resident blade producers. This finding is at odds with the views of many archaeologists, who tend to associate craft production with the emergence of complex Mesoamerican urban centers. We examine the technologies from temporally distinct Calixtlahuacan household assemblages. We discuss why the quantity and quality artifacts associated with blade production are not consistent with resident blade making in the city. Finally, we examine four models for blade provisioning: (1) whole-blade trade, (2) processed-blade trade, (3) long-distance itinerant craftsmen, and (4) local, hinterland-based craftsmen. Evaluating how the Calixtlahuacans got their flaked stone tools has important implications for the comparative understanding of the organization and scale of economic provisioning systems in Postclassic central Mexico. This analysis supports new inferences about the nature of commercial networks that supplied the Toluca Valley prior to the arrival of the Spanish in the sixteenth century.

Orientation control of multiple single crystal blades using a novel high-throughput mold via seeding-grain selection technique

As the increasing demand for high temperature performance of the Ni-based single crystal blades, the orientation consistency of the blades has become more and more important. In this work, a novel high-throughput mold capable of producing four single crystal blades with exactly the same orientation was proposed. The effects of the two important parameters as connector height and blade placement angle on single crystal growth were investigated by ProCAST simulation. The results showed that the 90° connector with a height of 50 mm could obtain the most appropriate temperature gradient for the production of single crystal blades, and when the blades were placed at 120° and 270°, the flattest liquid isotherm could be obtained. However, due to the difference in the distance of the nucleation points from the mold center and the direction where the thin edge of the blade platform faced, the blade placed at 120° had a larger platform area occupied by the stray grains. Therefore, the structure of this mold was determined by using a 90° connector and placing blades at 270°. At last, using this mold, four single crystal blades with the same three-dimensional orientation and no stray grains were successfully produced. These results fully demonstrated the feasibility of this novel mold and also provided ideas for using simulation methods to guide the design of the new mold structure.

Lithic Industry of the Kamyane-Zavallia Linearbandkeramik Site in Ukraine (2019 Campaign)

The paper treats a selection of lithic finds from Kamyane-Zavallia (Kam’âne-Zavallâ) – the easternmost Linearbandkeramik culture (LBK) site ever excavated. The lithic assemblage belongs to typical representatives of the early farming lithic industries in the region. It is characterized by prismatic cores for blade production, end-scrapers on fragmented blades and flakes, retouched blades, perforators, and a blade fragment with “sickle gloss”. There is a single projectile point of unidentifiable morphology. The authors argue that there is no trace of “Mesolithic heritage” in the assemblage of Kamyane-Zavallia. The assemblage finds close parallels in the sites of Nicolaevca V, Dănceni I, and other LBK sites from Moldova and Romania.

Non-contact sensing for anomaly detection in wind turbine blades: A focus-SVDD with complex-valued auto-encoder approach

The occurrence of manufacturing defects in wind turbine blade (WTB) production can result in significant increases in operation and maintenance costs of WTBs, reduce capacity factors of wind farms, and occasionally lead to severe and disastrous consequences. Therefore, inspection during the manufacturing process is crucial to ensure consistent fabrication of composite materials. Non-contact sensing techniques, such as Frequency Modulated Continuous Wave (FMCW) radar, are becoming increasingly popular as they offer a full view – cross sectional analysis – of these complex structures during assembly and curing. In this paper, we enhance the quality assurance of WTB manufacturing utilising FMCW radar as a non-destructive sensing modality. Additionally, a novel anomaly detection pipeline is developed that offers the following advantages: (1) We use the analytic representation of the Intermediate Frequency signal of the FMCW radar as a feature to disentangle material-specific and round-trip delay information from the received wave. (2) We propose a novel anomaly detection methodology called focus Support Vector Data Description (focus-SVDD). This methodology involves defining the limit boundaries of the dataset after removing healthy data features, thereby focusing on the attributes of anomalies. (3) The proposed method employs a complex-valued autoencoder to remove healthy features and we introduces a new activation function called Exponential Amplitude Decay (EAD). EAD takes advantage of the Rayleigh distribution, which characterises an instantaneous amplitude signal. The effectiveness of the proposed method is demonstrated through its application to collected data, where it shows superior performance compared to other state-of-the-art unsupervised anomaly detection methods. This method is expected to make a significant contribution not only to structural health monitoring but also to the field of deep complex-valued data processing and SVDD application. The code and dataset will be made publicly available. The code and dataset are available here 11https://github.com/FrusqueGaetan/Focus_SVDD_EAD.

Refits, cobbles, and fire: Approaching the temporal nature of an expedient Gravettian lithic assemblage from Lagar Velho (Leiria, Portugal).

Upper Paleolithic lithic assemblages have traditionally been considered a paramount example of the high level of complexity characterizing the technological behavior of prehistoric modern humans. The diversity and standardization of tools, as well as the systematic production of blades and bladelets, show the high investment of time, energy and knowledge often associated with Upper Paleolithic technocomplexes. However, more expedient behaviors have also been documented. In some cases, such low-cost behaviors can be dominant or almost exclusive, giving assemblages of Upper Paleolithic age an "archaic" appearance. In this paper, we address these expedient Upper Paleolithic technologies through the study of a lithic assemblage recovered from a Gravettian-age layer from the Lagar Velho rockshelter (Leiria, Portugal). Due to the specific formation processes characterizing this site, we also discuss the distinction between artifacts and geofacts, an aspect that is particularly difficult in expedient assemblages. Moreover, the combination of lithic refitting and data on thermal damage allows us to approach the temporal nature of the lithic assemblage and the timing of the different agents contributing to its formation.