Search results

The purpose of this paper is to present an adaptive binary-tree element subdivision method (BTSM) for the evaluation of nearly singular integrals in three-dimensional boundary element method, which can facilitate automatic and high-quality patch generation.

In this method, the nearly singular element is split into two sub-elements. Each sub-element is then examined to determine if it is to be subdivided based on a specific subdivision criterion. The specific subdivision ensures that those sub-elements far from the source point are sparse. And then those sub-elements in close proximity to the source point are replaced by regular triangular elements.

With the proposed method, the sub-elements obtained are automatically refined as they approach the projection point, and they are “good” in shape and size for standard Gaussian quadrature. Thus, the proposed method can be used to evaluate nearly singular integrals accurately for cases of different element shapes and various locations of the source point.

Numerical examples for surface elements with various relative locations of the source point are presented. The results demonstrate that the proposed method has much better accuracy and robustness than some other methods.

This paper aims to propose a boundary element analysis of two-dimensional linear elasticity problems by a new expanding element interpolation method.

The expanding element is made up based on a traditional discontinuous element by adding virtual nodes along the perimeter of the element. The internal nodes of the original discontinuous element are referred to as source nodes and its shape function as raw shape function. The shape functions of the expanding element constructed on both source nodes and virtual nodes are referred as fine shape functions. Boundary variables are interpolated by the fine shape functions, while the boundary integral equations are collocated on source nodes.

The expanding element inherits the advantages of both the continuous and discontinuous elements while overcomes their disadvantages. The polynomial order of fine shape functions of the expanding elements increases by two compared with their corresponding raw shape functions, while the expanding elements still keep independence to each other as the original discontinuous elements. This feature makes the expanding elements able to naturally and accurately interpolate both continuous and discontinuous fields.

Numerical examples are presented to verify the proposed method. Results have demonstrated that the accuracy, efficiency and convergence rate of the expanding element method.

The Convolution Quadrature Method (CQM) has been widely applied to solve transient elastodynamic problems because of its stability and generality. However, the CQM suffers from the problems of huge memory requirement in case of direct implementation in time domain or CPU time in case of its reformulation in Laplace domain. The purpose of this paper is to combine the CQM with the pseudo-initial condition method (PICM) to achieve a good balance between memory requirement and CPU time.

The combined methods first subdivide the whole analysis into a few sub-analyses, which is dealt with the PICM, namely, the results obtained by previous sub-analysis are used as the initial conditions for the next sub-analysis. In each sub-analysis, the time interval is further discretized into a number of sub-steps and dealt with the CQM. For non-zero initial conditions, the pseudo-force method is used to transform them into equivalent body forces. The boundary face method is employed in the numerical implementation. Three examples are analyzed. Results are compared with analytical solutions or FEM results and the results of reformulated CQM.

Results demonstrate that the computation time and the storage requirement can be reduced significantly as compared to the CQM, by using the combined approach.

The combined methods can be successfully applied to the problems of long-time dynamic response, which requires a large amount of computer memory when CQM is applied, while preserving the CQM stability. If the number of time steps is high, then the accuracy of the proposed approach can be deteriorated because of the pseudo-force method.

Oil is crucial for industrial development. This paper investigates the impacts of oil price changes on China's industrial growth and examines whether the impacts are asymmetric. The estimations can help determine how oil price shocks are transmitted throughout the economy.

This paper adopts West Texas Intermediate (WTI) crude oil price and industrial sector output and uses monthly data. The recently developed nonlinear autoregressive distributed lag (NARDL) model is employed to illustrate the effects in both the short term and long term. Importantly, under NARDL framework, this paper examines whether the impacts are asymmetric by decomposing oil price shocks into their positive and negative partial sums.

The empirical results prove clear evidence of asymmetries in the short term, long term or both terms. Specifically, some sectors benefit from, rather than suffer from higher oil prices, even some energy-intensive sectors, i.e. C31 (Smelting and Pressing of Ferrous Metals) and C32 (Smelting and Pressing of Non-ferrous Metals). However, the effects on some other energy-intensive sectors appear insignificant. Additionally, the results prove significantly negative responses in some sectors in the long term, and most of these sectors are in the top half of the ranking by energy consumptions.

This paper studies the economic responses at a disaggregated level by employing industry-level data. NARDL method is used to decompose oil price changes into their increases and decreases and investigate the asymmetries in the impacts of oil price changes.

In recent years, the application of blockchain in enterprise financing has become a hot topic in academic research. This study aims to review the existing literature, construct a knowledge framework for this research topic and propose an agenda for future research.

Based on 181 papers published from 2016 to 2020 in core journal databases in China and abroad, this study used bibliometric tools to identify and analyze an overview of literature publications, research hotspot trends and research theme clustering. This study also qualitatively analyzes literature from the dimensions of enabling mechanisms, multitechnology synergy, challenges, theoretical perspectives and research methods.

This study presents the research progress of blockchain applications in direct financing, bank credit, supply chain finance and other financing modes and analyzes the similarities and differences between domestic and international literature. This study also reveals enabling mechanisms of blockchain in enterprise financing, reflected as information quality improvement (data elements), trust mechanism innovation (business process) and collaboration structure enhancement (network structure). The study found several challenges (e.g. technological uncertainty, data security and organizational change) and trends (e.g. integrated innovation of multiple digital technologies). Additionally, the authors identified several gaps and opportunities for further research.

This study adopts a strict strategy of selecting search terms when retrieving the literature, leading to the exclusion of certain papers on this topic.

This study provides valuable insights into the innovative development of enterprise financing modes enabled by blockchain and emphasizes that managers should clarify the applicable boundaries and necessary conditions of blockchain innovation in different financing scenarios to match technological innovation with industrial expectations.

This study constructs a knowledge framework on this topic based on a comprehensive review of existing research and proposes several important issues for future research based on the identified research gaps.