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Article
Publication date: 9 August 2024

Muhammad Arif Mahmood, Marwan Khraisheh, Andrei C. Popescu and Frank Liou

This study aims to develop a holistic method that integrates finite element modeling, machine learning, and experimental validation to propose processing windows for optimizing…

82

Abstract

Purpose

This study aims to develop a holistic method that integrates finite element modeling, machine learning, and experimental validation to propose processing windows for optimizing the laser powder bed fusion (LPBF) process specific to the Al-357 alloy.

Design/methodology/approach

Validation of a 3D heat transfer simulation model was conducted to forecast melt pool dimensions, involving variations in laser power, laser scanning speed, powder bed thickness (PBT) and powder bed pre-heating (PHB). Using the validated model, a data set was compiled to establish a back-propagation-based machine learning capable of predicting melt pool dimensional ratios indicative of printing defects.

Findings

The study revealed that, apart from process parameters, PBT and PHB significantly influenced defect formation. Elevated PHBs were identified as contributors to increased lack of fusion and keyhole defects. Optimal combinations were pinpointed, such as 30.0 µm PBT with 90.0 and 120.0 °C PHBs and 50.0 µm PBT with 120.0 °C PHB.

Originality/value

The integrated process mapping approach showcased the potential to expedite the qualification of LPBF parameters for Al-357 alloy by minimizing the need for iterative physical testing.

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Article
Publication date: 15 December 2023

Muhammad Arif Mahmood, Chioibasu Diana, Uzair Sajjad, Sabin Mihai, Ion Tiseanu and Andrei C. Popescu

Porosity is a commonly analyzed defect in the laser-based additive manufacturing processes owing to the enormous thermal gradient caused by repeated melting and solidification…

117

Abstract

Purpose

Porosity is a commonly analyzed defect in the laser-based additive manufacturing processes owing to the enormous thermal gradient caused by repeated melting and solidification. Currently, the porosity estimation is limited to powder bed fusion. The porosity estimation needs to be explored in the laser melting deposition (LMD) process, particularly analytical models that provide cost- and time-effective solutions compared to finite element analysis. For this purpose, this study aims to formulate two mathematical models for deposited layer dimensions and corresponding porosity in the LMD process.

Design/methodology/approach

In this study, analytical models have been proposed. Initially, deposited layer dimensions, including layer height, width and depth, were calculated based on the operating parameters. These outputs were introduced in the second model to estimate the part porosity. The models were validated with experimental data for Ti6Al4V depositions on Ti6Al4V substrate. A calibration curve (CC) was also developed for Ti6Al4V material and characterized using X-ray computed tomography. The models were also validated with the experimental results adopted from literature. The validated models were linked with the deep neural network (DNN) for its training and testing using a total of 6,703 computations with 1,500 iterations. Here, laser power, laser scanning speed and powder feeding rate were selected inputs, whereas porosity was set as an output.

Findings

The computations indicate that owing to the simultaneous inclusion of powder particulates, the powder elements use a substantial percentage of the laser beam energy for their melting, resulting in laser beam energy attenuation and reducing thermal value at the substrate. The primary operating parameters are directly correlated with the number of layers and total height in CC. Through X-ray computed tomography analyses, the number of layers showed a straightforward correlation with mean sphericity, while a converse relation was identified with the number, mean volume and mean diameter of pores. DNN and analytical models showed 2%–3% and 7%–9% mean absolute deviations, respectively, compared to the experimental results.

Originality/value

This research provides a unique solution for LMD porosity estimation by linking the developed analytical computational models with artificial neural networking. The presented framework predicts the porosity in the LMD-ed parts efficiently.

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Article
Publication date: 29 March 2022

Muhammad Arif Mahmood, Andrei C. Popescu, Mihai Oane, Carmen Ristoscu and Ion N. Mihailescu

This paper aims to develop efficient and simple models for thermal distribution, melt pool dimensions and controlled phase change in the laser additive manufacturing (AM) of bulk…

178

Abstract

Purpose

This paper aims to develop efficient and simple models for thermal distribution, melt pool dimensions and controlled phase change in the laser additive manufacturing (AM) of bulk and powder particles ceramic materials.

Design/methodology/approach

This paper proposes new analytical models for the AM of bulk and powder bed ceramic materials. A volumetric moving heat source, along with the complete melting of bulk and powder particle materials, is taken into account. Different values of laser absorption coefficient in solid and liquid states have been used to investigate the phase transformation. Furthermore, the pores and voids dimensions are also included in the modeling. Theoretical predictions have been compared with the experimental analyses and finite element simulations in laser to silicon nitride and laser to alumina interaction. The analysis focuses on the impact of laser power and scanning speed on the melt pool width and depth evolution into the bulk substrate and powder bed.

Findings

This study shows that the powder particles exhibit a higher thermal distribution value than the bulk substrate because of voids in the powder layer. The laser beam experiences multiple reflections in the presence of porosity/voids, thus increasing the surface absorption coefficient, which becomes relevant with the increment in the pore/void dimension. A direct relationship has been found between the laser power and melt pool dimensions, while the scanning speed displayed an inverse relationship for the melt pool width and length. Larger melt dimensions were inferred in the case of laser–powder particle interaction compared with laser–bulk substrate interaction. A close correlation was found between the analytical simulations, experimental investigations and numerical simulation results within the range of 4%–8%.

Originality/value

This paper fulfills an identified need to develop efficient and simplified models for ceramics laser AM by taking into account different laser absorption coefficients in solid and liquid form, voids and pores dimensions and controlled phase transformation to avoid vapors and plasma formation. The limitation of the finite element simulation model is that the solution is strongly dependent on the mesh quality and accuracy directly linked to the computation efficiency and time. A finer mesh requires a longer computing time than a coarse mesh. Finite element simulations require, however, specialized skills.

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Book part
Publication date: 9 August 2022

Cătălin Popescu, Eglantina Hysa and Mirela Panait

The future of human society has to take into account on the one hand, the natural requirements of the society as a whole, and, on the other hand, the influences generated by…

Abstract

The future of human society has to take into account on the one hand, the natural requirements of the society as a whole, and, on the other hand, the influences generated by economic, social, informational factors but also in relation to the environment. Therefore, the future is seen and described in relation to the need to create the conditions for achieving sustainable development goals. The unpredictable evolution and uncertainties of recent years explain the need to include in the decisions of organizations, responsibly applied approaches. In order to achieve and maintain a balance between the interests of various actors on a global scale, it is necessary to practice responsible management, which deals with both the management of current critical issues worldwide, but also in relation to the need to ensure living conditions and the prosperity of future generations. Thus, as an adequate response of companies and organizations of various types to these complex challenges is integrated as a defining element of business strategies a principle of responsible management called social responsibility. This means that, through the elaborated decisions, these companies have to find a way of treatment balanced between the fulfillment of their own financial objectives and the social obligation of the contributions of these entities to the sustainable development of the economy in which they operate. This results, in fact, in the large-scale development and implementation of the concept of corporate social responsibility (CSR). On the other hand, the functioning of all companies in the realities of the present times, characterized by volatility, uncertainty, complexity & ambiguity (VUCA) requires significant efforts and resources on their part, so that, by collecting an important and comprehensive volume of data, there is the possibility of generating reliable forecasts.

Details

Agile Management and VUCA-RR: Opportunities and Threats in Industry 4.0 towards Society 5.0
Type: Book
ISBN: 978-1-80262-326-0

Keywords

Available. Content available
Book part
Publication date: 2 September 2024

Abstract

Details

Emerging Patterns and Behaviors in a Green Resilient Economy
Type: Book
ISBN: 978-1-83549-781-4

Available. Content available
Book part
Publication date: 4 July 2024

Abstract

Details

Entrepreneurship and Development for a Green Resilient Economy
Type: Book
ISBN: 978-1-83797-089-6

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Book part
Publication date: 29 October 2018

Aleksei V. Bogoviz, Olga A. Mishchenko, Svetlana G. Bychkova, Marina V. Bogdanova and Elena N. Kolomoets

The purpose of the chapter is to study the European experience of formation of information economy.

Abstract

Purpose

The purpose of the chapter is to study the European experience of formation of information economy.

Methodology

The methodology of this chapter is based on the method of statistical analysis, which is used for calculation of direct average of the values of the indicators of European countries for each indicator of information economy, scatter (variation), and deviation of the average value of European countries from the average value among the leading countries of the world (average global value). The objects of research of the European experience of information economy’s formation are the leading countries of Europe that have the largest potential and achieved the largest progress, setting the tone for other members of the European region. The leading countries are UK, Germany, and France. The data of 2017 are used.

Results

The results substantiate that modern Europe achieved sufficient progress in information economy’s formation, and differentiation of the level of informatization of economic systems is expressed vividly, but only in certain aspects. In general, it is possible to determine common tendencies and peculiarities based on offered conceptual model of establishment and development of information economy in European countries. This new conceptual model takes into account and reflects the existing disproportions, of which the most vivid is overestimated massive technosphere, which is not implemented to the full potential due to social problems. Against its background, sociosphere and economic sphere that are standard for modern leading countries seem to diminish. At the same time, due to the strong role of the state in economy of European countries, high effectiveness of state regulation in the process of information economy’s formation is achieved if high share of high-tech export is expressed with smaller expenditures for innovations in the ICT spheres.

Recommendations

It is recommended to use the offered conceptual model to study the process of formation of information economy in European countries and comparing the effectiveness of this process in other regions of the world.

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Book part
Publication date: 2 September 2024

Hiranya Dissanayake, Hareendra Dissabandara, Roshan Ajward, Wasantha Perera, Catalin Popescu and Irina Gabriela Radulescu

This bibliometric analysis underscores the increasing importance of corporate sustainability in the post-COVID-19 era. Despite existing confusion and a dearth of studies on…

Abstract

This bibliometric analysis underscores the increasing importance of corporate sustainability in the post-COVID-19 era. Despite existing confusion and a dearth of studies on measuring corporate sustainability, the study identifies a significant methodological gap and endeavors to address it by proposing a comprehensive measure. The primary goal is to bridge this gap by conducting a bibliometric analysis on the scale of corporate sustainability, examining 126 documents spanning from 2001 to 2022. The study employs an expert opinion survey to identify and finalize dimensions and sub-dimensions of corporate sustainability, followed by a literature mapping process to formulate questionnaire items. A pilot survey is then conducted to ensure the reliability of the questionnaire. The study proposes utilizing the Organisation for Economic Co-operation and Development (OECD) index construction methodology to establish the Corporate Sustainability Index (CSI). The key findings reveal that corporate sustainability comprises economic, environmental, and social sustainability. Environmental sustainability encompasses aspects such as air, water, land, biodiversity, ocean preservation, waste prevention, and environmental management. Social sustainability involves the satisfaction of various stakeholders, including employees, shareholders, customers, community, government, nongovernmental organizations (NGOs), and suppliers. Economic sustainability is characterized by long-term profits, cost efficiency, trade-offs, sustainable investments, and spin-offs. Rooted in stakeholder theory, the proposed scale holds theoretical significance for researchers and is pertinent to policymakers striving to achieve sustainable development goals (SDGs) by 2030. Additionally, it serves as a crucial tool for practitioners and companies to assess their level of corporate sustainability.

Details

Emerging Patterns and Behaviors in a Green Resilient Economy
Type: Book
ISBN: 978-1-83549-781-4

Keywords

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Book part
Publication date: 4 July 2024

Catalin Popescu, Gabriela Oprea, Daniela Steluţa Uţă, Augustin Mitu and Alina Gabriela Brezoi

The European Union (EU) is providing a wide range of instruments to its members in implementing a green, resilient economy. These instruments are not designed only for governments…

Abstract

The European Union (EU) is providing a wide range of instruments to its members in implementing a green, resilient economy. These instruments are not designed only for governments and state representatives but also for small businesses and entrepreneurs. The ability of those two-targeted audiences to understand and adopt these instruments, as well as their way to react and profit from the EU-stated drives, determines one’s country capacity to absorb European funding and create economic growth. The present chapter proposes a presentation of the new European model for economic growth and of the advantages proposed with the European Green Deal, the European proposal to the world for a resilient, adaptable, and environmentally friendly economy.

Details

Entrepreneurship and Development for a Green Resilient Economy
Type: Book
ISBN: 978-1-83797-089-6

Keywords

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Article
Publication date: 11 January 2024

Julia Anamaria Sisu, Andrei Constantin Tirnovanu, Cristina-Claudia Patriche, Marian Nastase and George Cristian Schin

This study explores the enablers of students “entrepreneurial intentions by identifying the factors that raise students” interest in embracing an entrepreneurial career.

715

Abstract

Purpose

This study explores the enablers of students “entrepreneurial intentions by identifying the factors that raise students” interest in embracing an entrepreneurial career.

Design/methodology/approach

Entrepreneurship education is increasingly attracting attention as a means of fostering entrepreneurial activity and creating a culture of innovation. Developing students' entrepreneurial intentions is critical to promote entrepreneurship. This research is built on a mixed method approach of partial least squares structural equation modelling and fuzzy-set qualitative comparative analysis.

Findings

The factors that influence students ‘entrepreneurial intentions are identified: business incubation programmes, non-reimbursable grants for entrepreneurial students, networking events to promote entrepreneurship, mentoring services, innovation labs for business idea validation and entrepreneurship courses. This knowledge can help develop effective entrepreneurship education programmes. The study also provides actionable insights for educational institutions and policymakers. It underscores the need for innovative educational platforms such as entrepreneurial bootcamps. It also highlights the value of advanced learning environments such as decision theatres to foster a culture of entrepreneurship and innovation.

Originality/value

The study contributes to the body of knowledge on entrepreneurship education. It highlights the need for a multidisciplinary approach to understand the factors that shape students’ entrepreneurial intentions.

Details

International Journal of Entrepreneurial Behavior & Research, vol. 30 no. 4
Type: Research Article
ISSN: 1355-2554

Keywords

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