Fast numerical simulation of sheet metal forming using the program QuickForm

Yidong Bao,Junwei Chen,Zhiguo Wang,Wenliang Chen,Wing Lee 한국소성가공학회 2010 기타자료 Vol.2010 No.6

The fast numerical simulation system QuickForm has been self-developed specially for sheet metal forming with complex geometries. In order to resolve the convergence problem of static implicit method due to the change of contact state, the uncoupling solution method of the non-linear differential equations is used in QucikForm program. The bending effect and drawing effect during forming procedure are treated into two separate processes in QuickForm system, so this uncoupling solution has two basic steps. Firstly an approximate method named pre-stressed membrane element is used to achieve the intermediate configuration of sheet in this incremental step before incremental step iteration. The sheet shape of intermediate configuration depends on the current tooling position. Secondly the nonlinear material flow within this intermediate configuration is carried out, which means the nodes of deformed sheet can only slide on this form. The highly efficient iterative solver can be used to the solution of linear equations since the improved conditioning of the linear equations resulting from the uncoupling solution. Numerical simulation results of complex parts demonstrate the higher efficiency and accuracy of the proposed special purpose program.

QuickForm Simulation System of Sheet Metal Forming with Trial-and-error Contact Algorithm

Bao Yidong,Liu Lei,Lu Yu,Chen Wenliang 한국소성가공학회 2011 기타자료 Vol.2011 No.8

The QuickForm numerical simulation system has been self-developed specially for sheet metal forming with complex geometries. In order to resolve the convergence problem of static implicit method due to the change of contact state, the uncoupling solution method of the non-linear differential equations is used in QucikForm system. The bending effect and drawing effect during forming procedure are separated into two independent processes in QuickForm system. During bending effect solution, the contact state between the blank nodes and rigid tools should be determined by accurate contact algorithm. A trial-and-error contact algorithm is used in the bending effect calculation process of QuickForm system. The contact procedure is carried out before the solving of bending effect FEM equations, and the contact conditions are treated as the boundary conditions of FEM equations. Numerical simulation results of complex part demonstrate the higher efficiency and accuracy of this contact algorithm and the proposed special purpose program.

Mesh Generation Based on Virtual Geometry

Peng Wei,Chen Wenliang,Bao Yidong 한국소성가공학회 2010 기타자료 Vol.2010 No.6

Finite element mesh generation algorithm often requires the ability to abstract and modify the topology of a boundary representation model. A method based on virtual geometry for mesh generation is proposed to modify the model topology without changing the geometry of the model. By this method, a tool is given to adjust the model topology for optimal meshing, while leaving the geometry or shape of the model, and the accuracy of the resulting mesh in representing the model, unchanged. Our practical examples show that the proposed method is effective and reliable for mesh generation in molding analysis field.

Study on Ship Safety Pilotage in Shanghai Harbour by Way of FSA

FANG Quangen,CHEN Zhenghua,HU Shenping,XUE Yidong 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.2006 No.-

Ship Pilotage is one of the most important parts in the construction and development of Shanghai International Shipping Center as it has the fundamental function for the promotion and speed-up of the ship navigation and cargo operation. Recently, Shanghai Maritime University and Shanghai Harbour Pilotage Administration Station had carried out a research project of “Study on Ship Safety Pilotage in thε Shanghai Harbour by Way of FSA (Formal Safety Assessment)". The aim of this project is to put out some proposes of the decision-making for the improvement of the safety pilotage in Shanghai habour through the way of the FSA. Now these proposes of the decision-making have been adopted and conducted in practice and satisfactory results have been achieved. In the paper, some detailed information, methods and ideas about this research project have been introduced and explained for improving the safety pilotage in Shanghai Harbour.

An Improved Artificial Fish Swarm Algorithm based on Hybrid Behavior Selection

Zhehuang Huang,Yidong Chen 보안공학연구지원센터 2013 International Journal of Control and Automation Vol.6 No.5

A Sense Embedding of Deep Convolutional Neural Networks for Sentiment Classification

Zhijian Cui,Xiaodong Shi,Yidong Chen,Yinmei Guo 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.11

Sentiment classification task has attracted considerable interest as sentiment information is crucial for many natural language processing (NLP) applications. The goal of sentiment classification is to predict the overall emotional polarity of a given text. Previous work has demonstrate the remarkable performance of Convolutional Neural Network (CNN). However, nearly all this work assumes a single word embedding for each word type, ignoring polysemy and thus inevitably casting negative impact on the downstream tasks. We extend the Skip-gram model to learn multiple sense embeddings for the word types, catering to introduce sense-based embeddings for CNN during sentiment classification. Instead of using the pipeline method to learn multiple sense embeddings of a word type, the sense discrimination and sense embedding learning for each word type are performed jointly based upon the semantics of its contextual words. We validate the effectiveness of the method on the commonly used datasets. Experiment results show that our method are able to improve the quality of sentiment classification when comparing with several competitive baselines.

Hardware Implementation of Two-level Scheduling Algorithm in μC/OS-II

Guangwu Zhang,Yan Li,Yidong Chen,Huaiguo Dong,Huanhuan Chi,Min Shi,Junfeng Gao 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.4

Aiming at the problem that μC/OS-II does not support round-robin scheduling of the same priority task, a two-level hybrid task scheduling strategy was proposed. In the first level, by putting the task priority as criterion for task scheduling, a preemptive scheduling of different priority task was implemented. And in the second level, adopting time slice circulars scheduling strategy, round-robin scheduling of same priority task was implemented. The waiting list of tasks was designed by on-chip registers of FPGA and the ready list of tasks was designed by RAM of FPGA, and to implement time slice circulars scheduling, hardware circuit for finding successor of task was designed. The system adopted VHDL, and simulated by the software ISE10.1. The simulation results show that the hardware implementation of the system is well-worked.

Corrosion Cracking Process of Reinforced Concrete under the Coupled Effects of Chloride and Fatigue Loading

Jiansheng Shen,Junzhe Liu,Yidong Xu,Kanghao Jia,Fangyu Wu,Wei Chen,Dayong Zhu 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.9

To study the corrosion cracking process of reinforced concrete under the combined effects of chloride and fatigue loading, the constan-current and dry-wet cycle accelerated corrosion method was used to corrosion the specimens under different stress levels for different time. The quality loss of reinforcement, the composition of corrosion products and the cracking of concrete are analyzed from the macro, micro and micro scales, and to obtain the spatial distribution as well as microscopic characteristics of corrosion products of the reinforcement bar under coupling conditions. Additionally, a model of steel rust cracking under the coupled action of chloride and fatigue loading is established. The results show that: under the same corrosion time, the concrete cracking and steel corrosion degree become more serious with the increase of stress level. The greater the stress level, the earlier corrosion occurs and the more corrosion products are, Moreover, due to the fatigue load, the concrete on the upper side of the steel bar has rust expansion cracks earlier than the lower side.

A Novel Distributed Clustering-based MDS Algorithm for Nodes Localization in WSNs

Guoyong Dai,Chunyu Miao,Yidong Li,Keji Mao,Qingzhang Chen 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.2

Localization of sensors nodes is a key and fundamental issue in wireless sensor networks due to random deployment. In this paper, we propose a tree based clustering (TBC) multidimensional scaling algorithm for wireless sensor networks with the purpose of overcoming the shortage of classical MDS algorithms in its localization accuracy and computing complexity. Clustering is adopted to degrade the problem scale in our approach and a moderate number of common nodes between clusters are kept during clustering. Inner cluster local coordinates are calculated and then mapped into global coordinates according to the tree structure formed by clustering. Simulations on MATLAB are conducted and the results show that the proposed algorithm has better localization coverage and higher accuracy than the traditional MDS based algorithms.

Development of novel hybrid 2D-3D graphene oxide diamond micro composite polyimide films to ameliorate electrical & thermal conduction

Muhammad Shoaib Bhutta,Tang Xuebang,Shakeel Akram,Chen Yidong,Xiancheng Ren,Muhammad Fasehullah,Ghulam Rasool,Muhammad Tariq Nazir 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.114 No.-

Graphene and its oxides are the most extensively studied, fascinating 2-dimensional Sp2 carbon hybridizedmaterials. Due to its superior and excellent thermal conductivity, it is considered to be a practicalsolution for the thermal dissipation of electric machines electronic components. Furthermore, grapheneoxide invariably reduces electrical insulation capability, which is inappropriate for electrical machinesrequiring low electrical and high thermal conductivity. Therefore, we have created 2D-3D hybrid grapheneoxide (GO)-diamond (DM) micro-composite polyimide (PI) films for high temperature and electricallyinsulated environments of electric machines such as motors and generators. With a modest fillingcharge of 10 wt% GO with 10% diamond (DM), the maximum thermal conductivity of 1.83 Wm-1K1 isachieved for polyimide micro composite and is almost 11 times higher than that of pristine PI films. The 10% PI/GO/DM micro composite films also show lower electrical conductivity than other samples. Hybrid fillers with high thermal and low electrical conductivities are responsible for synergistic improvementsin experimental results.