N. TAKAHASHI, T. NAKATA and H. MORISHIGE
Thirteen computer codes developed by eleven groups are applied to the benchmark problem 20 (3‐D static force problem) for the TEAM Workshop. The solutions are compared with each…
Abstract
Thirteen computer codes developed by eleven groups are applied to the benchmark problem 20 (3‐D static force problem) for the TEAM Workshop. The solutions are compared with each other and with experimental results.
M. Kaltenbacher, S. Reitzinger, M. Schinnerl, J. Schöberl and H. Landes
The focus of this paper is on the efficient numerical computation of 3D electromagnetic field problems by using the finite element (FE) and multigrid (MG) methods. The magnetic…
Abstract
The focus of this paper is on the efficient numerical computation of 3D electromagnetic field problems by using the finite element (FE) and multigrid (MG) methods. The magnetic vector potential is used as the field variable and the discretization is performed by Lagrange (nodal) as well as Ne´de´lec (edge) finite elements. The resulting system of equations is solved by applying a preconditioned conjugate gradient (PCG) method with an adapted algebraic multigrid (AMG) as well as an appropriate geometric MG preconditioner.
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Irina Munteanu, Silvia Drobny, Thomas Weiland and Daniel Ioan
This paper presents a hybrid algorithm used, in conjunction with the Finite Integration Technique (FIT), for solving static and quasistatic electromagnetic field problems in…
Abstract
This paper presents a hybrid algorithm used, in conjunction with the Finite Integration Technique (FIT), for solving static and quasistatic electromagnetic field problems in nonlinear media. The hybrid technique is based on new theoretical results regarding the similarities between the Picard‐Banach fixed‐point (polarization) method and the Newton method. At each iteration, the solution is obtained as a linear combination of the old solution, and the new Picard‐Banach and Newton solutions. The numerical solutions are calculated through a “triangle” (bidimensional) minimization of the residual or of the energy functional. The goal of this combination is to increase the robustness of the iterative method, without losing the quadratic speed of convergence in the vicinity of the solution. The proposed method generalizes and unifies in a single algorithm the overrelaxed Picard‐Banach and the underrelaxed Newton methods.
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Yoshihiko Uematsu, Toshifumi Kakiuchi, Akiko Tajiri and Masaki Nakajima
The purpose of this paper is the proposal of fatigue-life-prediction curve for cast aluminum alloy A356-T6 with different casting defect sizes.
Abstract
Purpose
The purpose of this paper is the proposal of fatigue-life-prediction curve for cast aluminum alloy A356-T6 with different casting defect sizes.
Design/methodology/approach
Four kinds of A356-T6 fatigue specimens were sampled from the actual large-scale cast component, where the cooling rates were different. In addition, three kinds of A356 were casted under different casting conditions to simulate different defect sizes in the actual component. Subsequently, rotating bending fatigue tests were conducted using those samples. The maximum sizes of casting defects were quantitatively evaluated through microstructural observation and extreme value statistics. The fatigue limits of all samples were predicted using hardness and defect sizes based on modified Murakami’s equation.
Findings
The modified equation for fatigue limit prediction in A356-T6 was proposed. Fatigue limits were successfully predicted using the proposed equation.
Originality/value
Fatigue limit prediction method using hardness and maximum defect size was limited to steels. This paper proposed the modified method for A356-T6 aluminum alloy with lower elastic modulus. The method was valid for A356-T6 with different defect sizes.
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Xingyang Chen, Linlin Ma, Haoping Xie, Fengting Zhao, Yufeng Ye and Lin Zhang
The purpose of this paper is to present a crack initiation mechanism of the external hydrogen effect on type 304 stainless steel, as well as on fatigue crack propagation in the…
Abstract
Purpose
The purpose of this paper is to present a crack initiation mechanism of the external hydrogen effect on type 304 stainless steel, as well as on fatigue crack propagation in the presence of hydrogen gas.
Design/methodology/approach
The effects of external hydrogen on hydrogen-assisted crack initiation in type 304 stainless steel were discussed by performing fatigue crack growth rate and fatigue life tests in 5 MPa argon and hydrogen.
Findings
Hydrogen can reduce the incubation period of fatigue crack initiation of smooth fatigue specimens and greatly promote the fatigue crack growth rate during the subsequent fatigue cycle. During the fatigue cycle, hydrogen invades into matrix through the intrusion and extrusion and segregates at the boundaries of α′ martensite and austenite. As the fatigue cycle increased, hydrogen-induced cracks would initiate along the slip bands. The crack initiation progress would greatly accelerate in the presence of hydrogen.
Originality/value
To the best of the authors’ knowledge, this paper is an original work carried out by the authors on the hydrogen environment embrittlement of type 304 stainless steel. The effects of external hydrogen and argon were compared to provide understanding on the hydrogen-assisted crack initiation behaviors during cycle loading.
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Cheng Zhang, Liang Wu, Zilong Zhao, Guangsheng Huang, Bin Jiang, A. Atrens and Fusheng Pan
This paper aims to investigate microstructure, corrosion behavior and mechanical properties of Mg-4Li and Mg-4Li-3Al.
Abstract
Purpose
This paper aims to investigate microstructure, corrosion behavior and mechanical properties of Mg-4Li and Mg-4Li-3Al.
Design/methodology/approach
The microstructure was characterized by using scanning electron microscopy and electron backscatter diffraction. The corrosion behaviors were measured by hydrogen evolution and potentiodynamic polarization tests. The mechanical properties were evaluated by tensile tests.
Findings
The addition of Al results in the precipitation of some Mg-Al phase and Al3Li phase particles, and the formation of some fine recrystallized grains.
Originality/value
Mg-4Li-3Al showed a higher corrosion rate than that of Mg-4Li, attributed to the precipitate particles in Mg-4Li-3Al causing microgalvanic corrosion and the change of grain orientation. The addition of 3 Wt. per cent Al increased the tensile strength by solid solution strengthening, precipitation strengthening, refinement strengthening and texture strengthening, whilst the elongation decreased by almost half.
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Hardo Firmana Given Grace Manik, Rossalina Christanti and Wahyu Setiawan
This study aims to examine the dynamics of traditional wayang kulit or shadow puppet knowledge management in a community-based enterprise (CBE) known as “Wisata Wayang” in…
Abstract
Purpose
This study aims to examine the dynamics of traditional wayang kulit or shadow puppet knowledge management in a community-based enterprise (CBE) known as “Wisata Wayang” in Wukirsari Village, Yogyakarta, Indonesia.
Design/methodology/approach
A qualitative case study was adopted, which allows the author to explore the dynamics or uniqueness of an event or cultural phenomenon more deeply.
Findings
The shadow puppet is an artefact of Javanese culture with rich life philosophy and wisdom. It guides people the pursuit of harmony with themselves, others, the universe and God. The success of knowledge management of the shadow puppet at CBE was supported by the high entrepreneurial orientation of the administrators. This study showed that entrepreneurial orientation should be extended into sociopreneurial with additional aspects, including preservation mission and communality, promoting the emergence of grassroots innovations. The knowledge of shadow puppet craft in this village is passed through nyantrik, also known as apprenticeship.
Originality/value
No previous research has explored the dynamics of traditional knowledge management in the context of CBE in Indonesia. As Indonesia has rich traditional knowledge from hundreds of tribes and prominent communal cultures, this study of community-based knowledge management contributes new insights in the knowledge management literature.
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P. Ravi Kiran, Akriti Chaubey, Rajesh Kumar Shastri and Madhura Bedarkar
This study assesses the SDG-related well-being of indigenous communities in India using bibliometric analysis and the ADO-TCM framework. It provides insights into their alignment…
Abstract
Purpose
This study assesses the SDG-related well-being of indigenous communities in India using bibliometric analysis and the ADO-TCM framework. It provides insights into their alignment with sustainable development objectives.
Design/methodology/approach
This study analysed 74 high-impact journals using bibliometric analysis to evaluate the well-being of India’s indigenous peoples about the SDGs.
Findings
This study analyses the well-being of tribal communities in India using existing scholarly articles and the ADO-TCM framework. It emphasises the importance of implementing Sustainable Development Goals (SDGs) to promote the well-being of indigenous populations.
Originality/value
This study uses bibliometric analysis and the ADO-TCM framework to investigate factors impacting tribal community welfare. It proposes theoretical frameworks, contextual considerations and research methodologies to achieve objectives.
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Andrés Felipe Astaíza Martínez and Gina Alexandra Rojas León
Researchers from different disciplines have advocated for the incorporation of Systems Thinking in higher education in various fields such as environmental studies, engineering…
Abstract
Purpose
Researchers from different disciplines have advocated for the incorporation of Systems Thinking in higher education in various fields such as environmental studies, engineering, economics and management. Nevertheless, educational experiences that seek to integrate the systems approach and citizenship education are not numerous and have not been sufficiently documented. This research paper presents classroom research aimed at understanding how Systems Thinking and citizenship education are articulated within a general education course.
Design/methodology/approach
The research was designed using Grounded Theory within an exploratory-descriptive approach. To collect data, the following techniques were used: participant observation, focus group and documentary analysis. The data analysis was carried out through the constant comparative method in its open, axial, selective and theoretical contrast coding phases.
Findings
The data analysis highlights the potential of Systems Thinking within the context of Citizenship Education as a comprehensive set of cognitive, affective and methodological tools. Moreover, it sheds light on the pedagogical practices, the teaching strategies and the type of socioemotional interactions in the classroom that are key elements in promoting citizenship attitudes, ideas and behaviors.
Originality/value
The research underscores the importance of a systemic vision of education that explicitly incorporates social-emotional learning and experiences of citizen participation beyond the classroom where students can build new knowledge from first-hand interactions with processes of social transformation.