Search results

In pure material design, the previous research has indicated that lots of optimization factors such as used algorithm and parameters have influence on the optimal solution. In other words, there are multiple local minima for the topological design of materials for extreme properties. Therefore, the purpose of this study is to attempt different or more concise algorithms to find much wider possible solutions to material design. As for the design of material microstructures for macro-structural performance, the previous studies test algorithms on 2D porous or composite materials only, it should be demonstrated for 3D problems to reveal numerical and computational performance of the used algorithm.

The presented paper is an attempt to use the strain energy method and the bi-directional evolutionary structural optimization (BESO) algorithm to tailor material microstructures so as to find the optimal topology with the selected objective functions. The adoption of the strain energy-based approach instead of the homogenization method significantly simplifies the numerical implementation. The BESO approach is well suited to the optimal design of porous materials, and the generated topology structures are described clearly which makes manufacturing easy.

As a result, the presented method shows high stability during the optimization process and requires little iterations for convergence. A number of interesting and valid material microstructures are obtained which verify the effectiveness of the proposed optimization algorithm. The numerical examples adequately consider effects of initial guesses of the representative unit cell (RUC) and of the volume constraints of solid materials on the final design. The presented paper also reveals that the optimized microstructure obtained from pure material design is not the optimal solution any more when considering the specific macro-structural performance. The optimal result depends on various effects such as the initial guess of RUC and the size dimension of the macrostructure itself.

This paper presents a new topology optimization method for the optimal design of 2D and 3D porous materials for extreme elastic properties and macro-structural performance. Unlike previous studies, the presented paper tests the proposed optimization algorithm for not only 2D porous material design but also 3D topology optimization to reveal numerical and computational performance of the used algorithm. In addition, some new and interesting material microstructural topologies have been obtained to provide wider possible solutions to the material design.

This paper aims to propose a gradient-based shape optimization framework in which traditional time-consuming conversions between computer-aided design and computer-aided engineering and the mesh update procedure are avoided/eliminated. The scheme is general so that it can be used in all cases as a black box, no matter what the objective and/or design variables are, whilst the efficiency and accuracy are guaranteed.

The authors integrated CAD and CAE by using isogeometric analysis (IGA), enabling the present methodology to be robust and accurate. To overcome the difficulty in evaluating the sensitivities of objective and/or constraint functions by analytic method in some cases, the authors adopt the finite difference method to calculate these sensitivities, thereby providing a universal approach. Moreover, to further eliminate the inefficiency caused by the finite difference method, the authors advance the exact reanalysis method, the indirect factorization updating (IFU), to exactly and efficiently calculate functions and their sensitivities, which guarantees its generality and efficiency at the same time.

The proposed isogeometric gradient-based shape optimization using our IFU approach is reliable and accurate, as well as general and efficient.

The authors proposed a gradient-based shape optimization framework in which they first integrate IGA and the proposed exact reanalysis method for applicability to structural response and sensitivity analysis.

The purpose of this paper is to enhance the feasibility of the edge-based smoothed triangular (EST) element, some modifications are made in this study.

First, an efficient strategy based on graph theory is proposed to construct the edge system. Second, the stress is smoothed in global coordinate system based on edge instead of strain, which makes the theory of EST more rigorous and can be easily extended to the situation of multi elements sharing the same edge. Third, the singular degree of freedoms (DOFs) of the nodes linked by edges are restrained in edge local coordinate system, which makes the global stiffness matrix non-singular and can be decomposed successfully.

First, an efficient edge constructing strategy can make EST element more standout. Second, some modifications should be made to EST element to extend it to the situation with multi elements sharing the same edge, so that EST element can deal with the geometrical models with this kind of features. Third, the way to restrain the singular DOFs of EST element must be different from normal isoparametric triangle element, because the stiffness matrix of the smoothing domain is not computed in local coordinate system.

The modified EST element performs stably in engineering analysis including large scale problems and the situation with multi elements sharing the same edge, and the efficiency of edge system constructing is no longer the bottleneck.

The purpose of this study is to promote Chinese indigenous research by examining a case in which adopting social capital (SC) scales developed in the Western context for Chinese samples can decontextualize inter-firm guanxi management in the Chinese context.

Adopting the existing Western scales to measure SC, we collected data from Chinese executives participating in executive master of business administration programs on buyer–supplier relationship. Using the same items and data source, we identified post hoc factors representing guanxi dimensions. Ordinary least squared regressions were used for both guanxi and SC dimensions to test the hypotheses.

Our analysis showed that Chinese natives responded to the Western SC items according to their understanding and mindsets rooted in guanxi. This was evidenced by the results from the post hoc-derived guanxi dimensions with the same data, which show better regression results for the hypotheses tested, although the construct validity was comparable. Adopting Western SC measurement scales deconceptualized the intricate Chinese context and inter-firm interactions.

It is inappropriate to borrow Western-developed scales for Chinese HRM research due to intricate differences in contexts. Doing so may run the risk of ignoring the Chinese context regarding the mechanisms and processes of complex human interactions, although it may produce superficial results consistent with the Western literature. Developing indigenous measurement scales should be considered not only as a preference but also as a requirement for Chinese management research.

We empirically compared the difference between Western-developed measurement scales and a Chinese indigenous construct, as well as their impact on relationship management in relation to indigenous Chinese management research.

This research explores the finite element modeling of the crater and material removal rate (MRR) in micro-electrical discharge machining (micro-EDM) with and without vibration of the workpiece. The application of workpiece vibration in the micro-EDM process improved flushing efficiency and enhanced material removal rate (MRR).

In this work, the two-dimensional axisymmetric finite element method (FEM) has been developed to predict the shape of the crater with and without vibration. The temperature distribution on the workpiece surface with and without vibration has been obtained in the form of the contour plot.

The MRR obtained from the numerical model revealed that there was an enhancement in MRR in micro-EDM with vibration as compared to without vibration. The effect of process parameters on MRR in micro-EDM with and without is also presented in this work.

In this work, the two-dimensional axisymmetric FEM model has been developed to predict the shape of the crater with and without vibration.

The purpose of this paper is to explore the underlying mechanisms through which interactivity and fairness perception impart influence on solvers’ continuance intention in crowdsourcing contest settings.

On basis of self-determination theory and social exchange theory, this study focuses on the mediating roles of motivation and platform trust to explain the underlying influence processes of interactivity and fairness perception on continuance intention. A sample of 306 solvers was obtained from an online crowdsourcing platform through two separated surveys. The hypotheses were tested using the partial least squares method and bias-corrected bootstrapping method.

The empirical results indicate that motivation and platform trust together fully mediate the effect of interactivity on continuance intention, and the effect of fairness perception on continuance intention is also fully mediated by motivation and platform trust. While motivation is found to have a stronger mediating effect than platform trust does.

This study contributes to the crowdsourcing research by figuring out the pathway through which interactivity and fairness perception influence solvers’ continuance intention.