International Journal of Engineering Systems Modelling and Simulation (5 papers in press)
Research on Lifetime Distribution and Reliability of IGBT Module Based on Accelerated Life Test and K-S Test
by Huawei Wu, Congjin Ye, Yuanjin Zhang, Fei Hou, Jingquan Nie
Abstract: To realize lifetime distribution and reliability analysis of IGBT, a new research method for IGBT module lifetime was proposed based on double stress accelerated life test and K-S test. In this method, the lifetime of IGBT module was assumed to be logarithmic normal distribution.Then the K-S test was used to test the distribution of the logarithmic normal and Weibull on a set of the junction temperature and vibration double stress constant stress accelerated life test data of IGBT module for electric vehicle.And another set of IGBT accelerated life data was simulated and analyzed by using the accelerated life test data analysis software. The results show that the lifetime of IGBT modules under ALTA accelerated life simulation is still confirmed to the lognormal distribution, which further validates the correctness of the proposed assumption.This method has certain guiding significance to the life distribution and reliability analysis of IGBT module.
Keywords: insulated gate bipolar transistor; logarithmic normal distribution; Kolmogorov-Smirnov test; accelerated life test analysis; acceleration factor.
Three-dimensional Visual Modeling of Geological Information of Hydraulic Engineering Based on Surface Constraint Reconstruction
by Jing Wei, Xuejuan Wang, Xiaolong Wen
Abstract: In order to solve the problems of big errors in results and weak spatial expression ability of the existing three-dimensional visual modeling methods for geological information of hydraulic engineering, a three-dimensional visual modeling method of geological information of hydraulic engineering based on surface constraint reconstruction is proposed. Geological information of large-scale hydraulic engineering is loaded into an expert image processing system through the sparse scatterplot analysis method to construct a spatial scatterplot model for geological information distribution; adaptive feature matching is performed to the geological information through the template matching method, and edge contour features of the three-dimensional visual image are extracted through surface interpolation and vector edge clipping method; information enhancement and local profile horizon reconstruction are performed for the three-dimensional reconstruction image about geological information of large-scale hydraulic engineering through the wavelet domain feature decomposition method. Simulation results show that the method proposed in this paper can provide high accuracy in visual modeling of large-scale hydraulic engineering geological information with error of only 0.04mm, strong spatial expression ability of three-dimensional visual modeling and relatively high matching of feature points, so it can provide good three-dimensional reconstruction effect of geological information.
Keywords: Hydraulic engineering; geological information; three-dimensional visual modeling; image.
Radial Basis Function for Non-Matching Mesh Interpolation in Parallel Solving FSI Problem
by Sergey Kopysov, Igor Kuzmin, Alexander Novikov, Nikita Nedozhogin, Leonid Tonkov
Abstract: In strongly coupled fluid-structure interaction simulations, the fluid dynamics and solid dynamics problems are solved independently on their own meshes. Therefore, it becomes necessary to interpolate physical properties (pressure, displacement) across two meshes.
In the present paper, we propose to accelerate the interpolation process by the method of radial basis functions using the matrix-free solution of the equation system on a GPU. Also, we reduce the number of equations in the system by using an adaptive algorithm for choosing interpolation points.
Keywords: parallel computing; hybrid HPC platforms; fluid-structure interaction; radial basis functions; layer-by-layer partitioning.
Experimental study and numerical analysis on the vertical bracket of the plate buckle
by Fengjian Zhang, Guoyao Li, Zheng Shi, Kelun Wei, Guangyao Zhang
Abstract: In this paper, a new type of rotary plate buckle bracket is introduced, and the static loading test of the single span four-step vertical bracket system is carried out. Research and analysis the internal force transmission ways and failure modes of different types of tubes of the whole vertical bracket, and plot of the load-displacement curve and load-strain curve. Using the ANSYS program, a numerical model is obtained which is consistent with the experimental results. The results of test and finite element analysis show that: The finite element calculation results are close to the ultimate bearing capacity of the new type of rotary plate buckle vertical bracket; Under the ultimate load, the failure mode and the force of each tube are basically the same. The new type of rotary plate buckle vertical bracket is higher than that of traditional steel tubular scaffold with couplers, and it has good economic benefit.
Keywords: new type of rotary plate buckle vertical bracket; static loading test; failure modes; finite element analysis.
Performance Improvement of Distributed System through Load Balancing & Task Scheduling Using Fuzzy Logic
by Abhijit A.Rajguru, Sulabha S. Apte
Abstract: Task scheduling & load balancing in distributed network are the most challenging research area in computer science. In distributed systems, scheduling mechanism has more issues as there is no centralized authority to allocate the workload among multiple processors. Further, handling both load balancing and scheduling at hand is a daunting task. In this paper, we propose a fuzzy based load balancing and task scheduling technique to optimize the performance of distributed system. Initially, clusters are formed and node with larger buffer availability and high CPU speed is elected as cluster head. Tasks are prioritized into flexible and non-flexible using task prioritizing strategy. Non-Flexible tasks are prioritized over flexible tasks. For non-flexible tasks, essential information of nodes such as CPU speed, work load and distance from cluster head are made pass through the fuzzy system. Node state is obtained as output. Based on states of node, non-flexible tasks are allocated. Our technique dynamically handles scheduling and load balancing at hand. We use simulation results to prove efficiency of our technique.
Keywords: Distributed Computing; Fuzzy Logic; Load Balancing; Task Scheduling.