Heng Xiao, Zi-Tao Li, Lin Zhan and Si-Yu Wang
The purpose of this study is to show how gradual strength degradation of metal beams under cyclic bending up to fatigue failure is simulated based on a new elastoplasticity model…
Abstract
Purpose
The purpose of this study is to show how gradual strength degradation of metal beams under cyclic bending up to fatigue failure is simulated based on a new elastoplasticity model free of any yield criterion.
Design/methodology/approach
A new approach is proposed toward accurately and explicitly prescribing evolution of non-uniform stress distribution on beam cross-section under cyclic bending and, as such, gradual degradation of the bending strength can be directly determined.
Findings
Explicit results for the bending response in a whole cyclic process up to fatigue failure are obtained and the fatigue characteristic curve is for the first time simulated directly between the curvature amplitude and the cycle number to failure.
Originality/value
First, explicit and accurate determination of the non-uniform stress distribution on beam cross-section is achieved with asymptotic softening effects. Second, degradation of the bending strength can be directly deduced cycle by cycle. Finally, the relationship between the bending moment and the curvature is calculated using new and efficient numerical algorithms, thus bypassing usual time-consuming calculations with finite element procedures. Numerical results are presented and in good agreement with experimental data.
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Zi-Han Xu, Lin Zhan, Si-Yu Wang, Hui-Feng Xi and Heng Xiao
A new approach is proposed toward accurately matching any given realistic hardening and softening data from uniaxial tensile test up to failure and moreover, toward bypassing…
Abstract
Purpose
A new approach is proposed toward accurately matching any given realistic hardening and softening data from uniaxial tensile test up to failure and moreover, toward bypassing usual tedious implicit trial-and-error iterative procedures in identifying numerous unknown parameters.
Design/methodology/approach
Finite strain response features of metals with realistic hardening-to-softening transition effects up to eventual failure are studied for the first time based on the self-consistent elastoplastic J2-flow model with the logarithmic stress rate. As contrasted with usual approximate and incomplete treatments merely considering certain particular types of hardening effects such as power type hardening, here a novel and explicit approach is proposed to obtain a complete form of the plastic-work-dependent yield strength over the whole hardening and softening range.
Findings
A new multi-axial evolution equation for both hardening and softening effects is established in an explicit form. Complete results for the purpose of model validation and prediction are presented for the finite strain responses of monotonic uniaxial stretching up to failure.
Originality/value
New finite strain elastoplastic equations are established with a new history-dependent variable equivalently in place of the usual plastic work. With these equations, a unified and accurate simulation of both gardening and softening effects up to failure is achieved for the first time in an explicit sense without involving usual tedious implicit trial-and-error iterative procedures.
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Xie-Fei Ding, Lin Zhan, Hui-Feng Xi and Heng Xiao
A direct and unified approach is proposed toward simultaneously simulating large strain elastic behaviors of gellan gels with different gellan polymer concentrations. The purpose…
Abstract
Purpose
A direct and unified approach is proposed toward simultaneously simulating large strain elastic behaviors of gellan gels with different gellan polymer concentrations. The purpose of this paper is to construct an elastic potential with certain parameters of direct physical meanings, based on well-designed invariants of Hencky’s logarithmic strain.
Design/methodology/approach
For each given value of the concentration, the values of the parameters incorporated may be determined in the sense of achieving accurate agreement with large strain uniaxial extension and compression data. By means of a new interpolating technique, each parameter as a function of the concentration is then obtained from a given set of parameter values for certain concentration values.
Findings
Then, the effects of gellan polymer concentrations on large strain elastic behaviors of gellan gels are studied in demonstrating how each parameter relies on the concentration. Plane-strain (simple shear) responses are also presented for gellan gels with different polymer concentrations.
Originality/value
A direct, unified approach was proposed toward achieving a simultaneous simulation of large elastic strain behaviors of gellan gels for different gellan polymer concentrations. Each parameter incorporated in the proposed elastic potential will be derived as a function of the polymer concentration in an explicit form, in the very sense of simultaneously simulating large strain data for different concentrations.
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Heng Xiao, Wei-Hao Yan, Lin Zhan and Si-Yu Wang
A new and explicit form of the elastic strain-energy function for modeling large strain elastic responses of soft solids is constructed based on Hencky's logarithmic strain tensor.
Abstract
Purpose
A new and explicit form of the elastic strain-energy function for modeling large strain elastic responses of soft solids is constructed based on Hencky's logarithmic strain tensor.
Design/methodology/approach
Well-designed invariants of the Hencky strain are introduced for characterizing deformation modes and, furthermore, a new interpolating technique is proposed for combining piecewise splines into a single smooth function.
Findings
With this new form and this new technique, objectives in three respects may be achieved for the first time.
Originality/value
First, no adjustable parameters need to be treated. Second, large strain responses for three benchmark modes are derivable in a decoupled sense without involving strongly nonlinear coupling effects. Finally, large strain data may be automatically and accurately matched for three benchmark modes, including uniaxial, equi-biaxial and plane-strain extension. Numerical examples are presented and compared with usual approaches.
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Siyuan Lyu, Shijing Niu, Jing Yuan and Zehui Zhan
Preservice teacher (PST) professional development programs are crucial for cultivating high-quality STEAM teachers of the future, significantly impacting the quality of regional…
Abstract
Purpose
Preservice teacher (PST) professional development programs are crucial for cultivating high-quality STEAM teachers of the future, significantly impacting the quality of regional STEAM education. The Guangdong-Hong Kong-Macao Greater Bay Area, as a region of cross-border cooperation, integrates the resources and advantages of Guangdong, Hong Kong, and Macao, possessing rich cultural heritage and innovative capabilities. Transdisciplinary Education for Cultural Inheritance (C-STEAM) is an effective approach to promoting educational collaboration within the Greater Bay Area, facilitating the integration of both technological and humanities education. This study aims to develop a Technology-Enabled University-School-Enterprise (T-USE) collaborative education model and implement it in the Greater Bay Area, to explore its role as a support mechanism in professional development and its impact on C-STEAM PSTs' professional capital.
Design/methodology/approach
Adopting a qualitative methodology, the study interviewed PSTs who participated in a C-STEAM teacher education course under the T-USE model. Thematic coding is used to analyze their knowledge acquisition, interaction benefits with community members, and autonomous thinking and decision-making in theoretical learning and teaching practice.
Findings
The findings show that the T-USE model significantly enhanced the PSTs' human capital, including teaching beliefs, knowledge, and skills. In terms of social capital, PSTs benefited from collaboration with PST groups, university teaching teams, in-service teachers, and enterprises, though challenges such as varying levels of expertise among in-service teachers and occasional technical instability emerged. For decisional capital, the T-USE model provided opportunities for autonomous thinking and promoted teaching judgment skills through real teaching challenges and scenarios. Reflective practice activities also supported PSTs' professional growth.
Originality/value
This study reveals the effectiveness and internal mechanism of the T-USE model in C-STEAM PST training, offering significant theoretical and practical references for future PST education.
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Purpose: Despite the significance of filial piety in intergenerational relationships and its important influence on parental health and well-being, few studies have explored the…
Abstract
Purpose: Despite the significance of filial piety in intergenerational relationships and its important influence on parental health and well-being, few studies have explored the personal meaning of filial piety to older parents. This qualitative study aims to address this question.
Design: Responses to an open-ended question of “What makes a filial child in your view?” from a sample of 432 older parents in a rural Chinese county were collected face-to-face and analyzed using content analysis.
Findings: The personal meaning of filial piety varies. Seven broad themes emerged. These include widely persistent traditional filial piety beliefs (Be obedient, Respect, and Maintain frequent contact and show emotional care), filial piety values similar to filial obligations described in Western cultures (Help older parents when in times of need and Be a good citizen and take good care of themselves and their families), and traditional filial piety norms in the absolute form (Take care of every aspect of the parents’ life and Provide financial and material support to parents). Themes were also compared with dimensions of the intergenerational solidarity model.
Originality: Findings reflect the coexistence of traditional and modern filial values in relation to participants’ interpretation of filial piety, indicating that traditional filial piety beliefs are fading even in one of the least developed areas in China. Implications for interventions enhancing offspring’s filial performance are discussed.
Research limitations: Future studies on the understanding of filial piety from the perspective of offspring are warranted to draw a holistic picture of this topic.
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A mathematical model and numerical method for water flow and solute transport in a tidal river network is presented. The tidal river network is defined as a system of open…
Abstract
A mathematical model and numerical method for water flow and solute transport in a tidal river network is presented. The tidal river network is defined as a system of open channels or rivers with junctions and cross sections. As an example, the Pearl River in China is represented by a network of 104 channels, 62 nodes, and a total of 330 cross sections with 11 boundary sections for one of the applications. The simulations are performed with a supercomputer for seven scenarios of water flow and/or solute transport in the Pearl River, China, with different hydrological and weather conditions. Comparisons with available data are shown. The intention of this study is to summarize previous works and to provide a useful tool for water environmental management in a tidal river network, particularly for the Pearl River, China.
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Zehui Zhan, Wenyao Shen, Zhichao Xu, Shijing Niu and Ge You
This study aims to provide a comprehensive review and bibliometric analysis of the literature in the field of science, technology, engineering and mathematics (STEM) education…
Abstract
Purpose
This study aims to provide a comprehensive review and bibliometric analysis of the literature in the field of science, technology, engineering and mathematics (STEM) education over the past 15 years, with a specific focus on global distribution and research trends.
Design/methodology/approach
This study collected 1,718 documents from the Web of Science (WOS) database and analyzed their timeline distribution, geographical distribution, research topics, subject areas, learning stages and citation burst using a bibliometric approach with VOSviewer and Citespace.
Findings
Results indicated that: overall, STEM education has increasingly gained scholarly attention and is developing diversely by emphasizing interdisciplinary, cross-domain and regional collaboration. In terms of global collaboration, a collaborative network with the USA in the center is gradually expanding to a global scope. In terms of research themes, four key topics can be outlined including educational equity, pedagogy, empirical effects and career development. Social, cultural and economic factors influence the way STEM education is implemented across different countries. The developed Western countries highlighted educational equity and disciplinary integration, while the developing countries tend to focus more on pedagogical practices. As for research trends, eastern countries are emphasizing humanistic leadership and cultural integration in STEM education; in terms of teachers’ professional development, teachers’ abilities of interdisciplinary integration, technology adoption and pedagogy application are of the greatest importance. With regards to pedagogy, the main focus is for developing students’ higher-order abilities. In terms of education equity, issues of gender and ethnicity were still the hottest topics, while the unbalanced development of STEM education across regions needs further research.
Originality/value
This study provides a global landscape of STEM education along the timeline, which illustrates the yearly progressive development of STEM education and indicates the future trends.
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Shunsuke Managi, Jingyu Wang and Lulu Zhang
The purpose of this paper is to provide the extensive review on dynamic monitoring of forestry area in China.
Abstract
Purpose
The purpose of this paper is to provide the extensive review on dynamic monitoring of forestry area in China.
Design/methodology/approach
Countermeasure and suggestions were proposed for three aspects including the establishment of data sets with unified standards, top-level design of monitoring and assessment and analysis models, and establishment of the decision support platform with multiple scenario simulation.
Findings
Finally, the authors proposed key research area in this field, i.e., improving the systematic and optimal forest management through integrating and improving the data, models and simulation platforms and coupling the data integration system, assessment system and decision support system.
Originality/value
The authors explored the limitation of dynamic monitoring and state of the art research on data accumulation, professional model development and the analytical platform.