Zhiyong Wang, Jing Gu, Cheng Hou and Ming Song
The purpose of this paper is to propose the interaction integral method combing with a XFEM-based local mesh replacement method to evaluate both the stress intensity factors…
Abstract
Purpose
The purpose of this paper is to propose the interaction integral method combing with a XFEM-based local mesh replacement method to evaluate both the stress intensity factors (SIFs) and T-stress at the crack tip near a circular inclusion.
Design/methodology/approach
Special attention is pay to the effect of T-stress on crack initiation angle in 2D composite medium. The generalized maximum tangential stress criterion is employed during the simulation which simultaneously involves the effects of the mixed-mode SIFs, the T-stress and a physical length scale rc (the size of the fracture process zone).
Findings
It is shown that T-stress could affect the crack initiation angle significantly for mixed-mode conditions. Varies types of material mismatch are also considered and their influences on T-stress are given quantitatively.
Originality/value
The proposed numerical method allows a considerable flexibility for such problems and provides a basic framework for quasi-static crack growth in materials containing complex interfaces.
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Lixia Sun, Yuanwu Cai, Di Cheng, Xiaoyi Hu and Chunyang Zhou
Under the high-speed operating conditions, the effects of wheelset elastic deformation on the wheel rail dynamic forces will become more notable compared to the low-speed…
Abstract
Purpose
Under the high-speed operating conditions, the effects of wheelset elastic deformation on the wheel rail dynamic forces will become more notable compared to the low-speed condition. In order to meet different analysis requirements and selecting appropriate models to analyzing the wheel rail interaction, it is crucial to understand the influence of wheelset flexibility on the wheel-rail dynamics under different speeds and track excitations condition.
Design/methodology/approach
The wheel rail contact points solving method and vehicle dynamics equations considering wheelset flexibility in the trajectory body coordinate system were investigated in this paper. As for the wheel-rail contact forces, which is a particular force element in vehicle multibody system, a method for calculating the Jacobian matrix of the wheel-rail contact force is proposed to better couple the wheel-rail contact force calculation with the vehicle dynamics response calculation. Based on the flexible wheelset modeling approach in this paper, two vehicle dynamic models considering the wheelset as both elastic and rigid bodies are established, two kinds of track excitations, namely normal measured track irregularities and short-wave irregularities are used, wheel-rail geometric contact characteristic and wheel-rail contact forces in both time and frequency domains are compared with the two models in order to study the influence of flexible wheelset rotation effect on wheel rail contact force.
Findings
Under normal track irregularity excitations, the amplitudes of vertical, longitudinal and lateral forces computed by the flexible wheelset model are smaller than those of the rigid wheelset model, and the virtual penetration and equivalent contact patch are also slightly smaller. For the flexible wheelset model, the wheel rail longitudinal and lateral creepages will also decrease. The higher the vehicle speed, the larger the differences in wheel-rail forces computed by the flexible and rigid wheelset model. Under track short-wave irregularity excitations, the vertical force amplitude computed by the flexible wheelset is also smaller than that of the rigid wheelset. However, unlike the excitation case of measured track irregularity, under short-wave excitations, for the speed within the range of 200 to 350 km/h, the difference in the amplitude of the vertical force between the flexible and rigid wheelset models gradually decreases as the speed increase. This is partly due to the contribution of wheelset’s elastic vibration under short-wave excitations. For low-frequency wheel-rail force analysis problems at speeds of 350 km/h and above, as well as high-frequency wheel-rail interaction analysis problems under various speed conditions, the flexible wheelset model will give results agrees better with the reality.
Originality/value
This study provides reference for the modeling method of the flexible wheelset and the coupling method of wheel-rail contact force to the vehicle multibody dynamics system. Furthermore, by comparative research, the influence of wheelset flexibility and rotation on wheel-rail dynamic behavior are obtained, which is useful to the application scope of rigid and flexible wheelset models.
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Iveta Palečková, Lenka Přečková and Roman Hlawiczka
This chapter explores the influence of the banking and insurance sectors on the economic growth of Czechia, a nation with unique financial dynamics ideal for this study. Our aim…
Abstract
This chapter explores the influence of the banking and insurance sectors on the economic growth of Czechia, a nation with unique financial dynamics ideal for this study. Our aim is to ascertain the contribution of these financial institutions to economic growth, addressing the divergence in empirical findings that have marked this research area for decades. We scrutinise the impact of various factors, including sectoral development and the efficiency and stability of these institutions, all within the Czech context. Utilising the Granger causality test, we assess the role of several indicators related to the development of the banking and insurance sectors. Our findings reveal that in Czechia, the evolution and operational efficiency of these financial institutions significantly drive economic growth. This study provides an in-depth understanding of the role these sectors play in the Czech economic landscape, affirming their crucial contribution to the nation's economic prosperity.
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The purpose of this paper is to investigate the neural-network-based containment control of multi-agent systems with unknown nonlinear dynamics. Moreover, communication…
Abstract
Purpose
The purpose of this paper is to investigate the neural-network-based containment control of multi-agent systems with unknown nonlinear dynamics. Moreover, communication constraints are taken into account to reflect more realistic communication networks.
Design/methodology/approach
Based on the approximation property of the radial basis function neural networks, the control protocol for each agent is designed, where all the information is exchanged in the form of sampled data instead of ideal continuous-time communications.
Findings
By utilizing the Lyapunov stability theory and the Lyapunov–Krasovskii functional approach, sufficient conditions are developed to guarantee that all the followers can converge to the convex hull spanned by the stationary leaders.
Originality/value
As ideal continuous-time communications of the multi-agent systems are very difficult or even unavailable to achieve, the neural-network-based containment control of nonlinear multi-agent systems is solved under communication constraints. More precisely, sampled-data information is exchanged, which is more applicable and practical in the real-world applications.
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Rudra P. Pradhan, Mak B. Arvin, Neville R. Norman and Sahar Bahmani
The paper investigates whether Granger causal relationships exist between bond market development, stock market development, economic growth and two other macroeconomic variables…
Abstract
Purpose
The paper investigates whether Granger causal relationships exist between bond market development, stock market development, economic growth and two other macroeconomic variables, namely, inflation rate and real interest rate. The study aims to expand the domain of economic growth by including a more in-depth analysis of the possible impact that bond market and stock market development has on economic growth than is normally found in the literature.
Design/methodology/approach
This paper uses a panel data set of the G-20 countries for the period 1991-2016. It uses a panel vector auto-regression model to reveal the nature of any Granger causality among the five variables.
Findings
The paper provides empirical insights that both bond market development and stock market development are cointegrated with economic growth, inflation rate and real interest rate. The most robust result from the panel Granger causality test is that bond market development, stock market development, inflation rate and real interest rate are demonstrable drivers of economic growth in the long run.
Research limitations/implications
Because of the chosen research approach, the research results may lack theoretical foundations. Therefore, perhaps the more fully grounded interactive findings of this study can inspire theorists to fill the missing gap.
Practical implications
This paper includes lessons for policymakers in the G-20 countries seeking to stimulate economic growth in the long run and how they need to ensure greater stability of the interest rate and inflation rate as well as fully developing their financial markets, as both bond markets and stock markets are obvious drivers of economic growth.
Originality/value
This paper fulfills an identified need to study causal relationships between bond market development, stock market development, economic growth and two other macroeconomic variables, i.e. inflation rate and real interest rate.
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Tingting Hou, Xusen Cheng and Xiankun Cheng
The purpose of this paper is to explore the trust antecedents and the effect of trust and transaction cost on passengers' e-loyalty in the context of mobile commerce enabled…
Abstract
Purpose
The purpose of this paper is to explore the trust antecedents and the effect of trust and transaction cost on passengers' e-loyalty in the context of mobile commerce enabled ride-sharing.
Design/methodology/approach
A mixed-methods research is adopted to investigate the phenomena of interest. The qualitative study was used to identify the context-specific trust antecedents. The quantitative study investigated the effects of trust and transaction cost on e-loyalty by combining the results of qualitative study.
Findings
Three important context-specific trust antecedents were identified in qualitative study, namely online rating score, service quality and driving skills. The quantitative study indicates that driving skills, explicit cost and implicit cost are positively associated with trust. Trust and implicit cost have direct and positive effects on e-loyalty.
Research limitations/implications
This study contributes to understanding passengers' trust towards drivers in the context of mobile commerce enabled ride-sharing and the effect of trust on e-loyalty by including the transaction cost.
Practical implications
Management to enhance passengers' e-loyalty to ride-sharing might involve the measures to promote trust relationship.
Originality/value
Limited research has explored trust relationship for enhancing e-loyalty in the context of ride-sharing. The current study provides a novel contribution through an exploration of trust antecedents and the effects of transaction cost and trust on e-loyalty. The study has thrown light on the use of mixed-methods design in the research of user behavior in sharing economy.
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Tingting Hou, Shixuan Fu, Yichen Cao, Xiaojiang Zheng and Jianhua (Jordan) Yu
This research is motivated by the increasing need for international interactions during the gradual recovery of the tourism industry. By recognizing the paucity of research on…
Abstract
Purpose
This research is motivated by the increasing need for international interactions during the gradual recovery of the tourism industry. By recognizing the paucity of research on cultural closeness and accommodation categories, this research aims to illuminate the influencing mechanisms of psychological closeness and travelers’ willingness to book an accommodation-sharing property while booking an accommodation.
Design/methodology/approach
The authors employ a mixed-methods approach, including an experiment and semistructured interviews.
Findings
Results show that hosts’ higher cultural identity congruence leads to travelers’ higher willingness to book an accommodation-sharing property. Psychological closeness mediates the positive effect of cultural identity congruence on travelers’ willingness to book. The authors further explore the moderating role of room types (entire room vs. private room) and find that the mediation effect is stronger for booking an entire room.
Originality/value
The current research underlines the importance of cultural identity congruence and accommodation type on travelers’ willingness to book an accommodation-sharing property and psychological closeness.
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The purpose of this paper is to contribute to empirical evidence by recognizing the importance of stock markets in the financial system and consequently its causality to economic…
Abstract
Purpose
The purpose of this paper is to contribute to empirical evidence by recognizing the importance of stock markets in the financial system and consequently its causality to economic growth and vice versa.
Design/methodology/approach
The study used the autoregressive distribute lag model (ARDL) with bound testing procedures, the sample covered quarterly time-series data from 2001q1 to 2019q2 in Tanzania.
Findings
The results suggest that stock market development have both negative and positive causality for both short-run dynamics and long-run relationship with economic growth. Economic growth is found to only cause and relate negatively to liquidity both in the short-run and in the long-run. The results show predominantly a unidirectional causality flow from stock market development to economic growth and finds partial causality flow from economic growth to stock market development, as represented by stock market turnover which proxied liquidity.
Originality/value
The use of quarterly data to reflect more realistically the dynamics of the variables because yearly data may sometimes cover-up specific dynamics that may be useful for prediction and policy planning. The study uses indices to capture general aspects within the stock market against economic growth as an intuitive way to aggregate the stock market development effects.
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Hou Cheng Huang and Jing Yu Zhang
We describe how to improve the accuracy of stress in the application of the hybrid finite element method. The idea is based on the fact that the assumed stress hybrid method is…
Abstract
We describe how to improve the accuracy of stress in the application of the hybrid finite element method. The idea is based on the fact that the assumed stress hybrid method is equivalent to both the principle of minimum complementary energy within the interior of each element and the principle of the minimum potential energy in the entire domain. It is known that when a good hybrid model is used for the displacement solution, the stress model must satisfy equilibrium within individual elements and be comparable with the boundary displacements. However, the compatibility in the elements is usually ignored and through variational operation it may be only approximately satisfied. So the stress model cannot approach a corresponding analytical stress field. In the present study, after nodal displacements are solved, we propose that a different stress model could be used to find the stress coefficients according to the principle of minimum complementary energy in each element in order to get an improved stress field.