作者机构：
[Zhang Yong-zhong] Cent S Univ Forestry & Technol, Coll Elect & Informat Engn, Changsha 410004, Hunan, Peoples R China.;[Luo Ying-she; Zhang Liang; Yang Zhan-yu; Ma Min-wei] Cent S Univ Forestry & Technol, Inst Rheol Mech & Mat Engn, Changsha 410004, Hunan, Peoples R China.;[Su Jian-xin] Xiangtan Univ, Coll Informat Engn, Xiangtan 411105, Peoples R China.
通讯机构：
[Zhang Yong-zhong] C;Cent S Univ Forestry & Technol, Coll Elect & Informat Engn, Changsha 410004, Hunan, Peoples R China.
会议名称：
The 9th National Conference on Rheology
会议时间：
2008-01-01
会议地点：
中国湖南长沙
会议论文集名称：
Proceedings of the 9th National Conference on Rheology
关键词：
pyromagnetic effect;high polymer;global magnetic field;sensor array
摘要：
The measurement system is the main equipment of the project. Based on the characteristic of experiment system, a sensor array is designed, and used to continually acquire the global magnetic field. A scientific scheme is developed to get the signal processing and temperature compensation for nondirective weak magnetic field. The software of sampling control system is given, which is complied using C language in Labwindows/CVI. Taking computer as main engine, the system can acquire the nondirective weak magnetic field automatically and continuously use the sensor array, the change of magnetic field can be shown in real-time and intuitively.
作者机构：
[Peng Xiang-hua] Cent S Univ Forestry & Technol, Swan Coll, Changsha 410004, Hunan, Peoples R China.;[Luo Ying-she; Yu Min; Luo Tao] Cent S Univ Forestry & Technol, Inst Rheol Mech & Mat Engn, Changsha 410004, Hunan, Peoples R China.;[Wang Zhi-chao] Xiangtan Univ, Coll Civil Engn & Mech, Xiangtan 411105, Peoples R China.
通讯机构：
[Yu Min] C;Cent S Univ Forestry & Technol, Inst Rheol Mech & Mat Engn, Changsha 410004, Hunan, Peoples R China.
会议名称：
第九届全国流变学学术会议
会议时间：
2008-09-28
会议地点：
长沙
会议论文集名称：
第九届全国流变学学术会议论文集
关键词：
elasto-plastic constitutive model;artificial neural network;BC-RBFNN (based on clustering radial basis function neural network);moderate sandy clay
摘要：
Application research of neural networks to geotechnical engineering has become a hotspot nowadays. General model may not reach the predicting precision in practical application due to different characteristics in different fields. In allusion to this, an elasto-plastic constitutive model based on clustering radial basis function neural network(BC-RBFNN) was proposed for moderate sandy clay according to its properties. Firstly, knowledge base was established on triaxial compression testing data; then the model was trained, learned and emulated using knowledge base; finally, predicting results of the BC-RBFNN model were compared and analyzed with those of other intelligent model. The results show that the BC-RBFNN model can alter the training and learning velocity and improve the predicting precision, which provides possibility for engineering practice on demanding high precision.
作者机构：
[Luo Ying-she; Yu Min] Cent S Univ Forestry & Technol, Inst Rheol Mech & Mat Engn, Changsha 410004, Hunan, Peoples R China.;[Peng Xiang-hua] Cent S Univ Forestry & Technol, Swan Coll, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Luo Ying-she] C;Cent S Univ Forestry & Technol, Inst Rheol Mech & Mat Engn, Changsha 410004, Hunan, Peoples R China.
会议名称：
第九届全国流变学学术会议
会议时间：
2008-09-28
会议地点：
长沙
会议论文集名称：
第九届全国流变学学术会议论文集
关键词：
carbon constructional quality steel;creep under high temperature;constitutive equation;integral core function;viscosity
摘要：
Creep tests under at a certain temperature and different stress levels were performed on two carbon constructional quality steels at a certain stress level and different temperatures, and their creep curves at high temperature were obtained based on analyzing the testing data. Taking 45 steel at a certain temperature and stress as the example, the integral creep constitutive equation and the differential stress-strain constitutive relationship were established based on the relevant rheological model, and the integral core function was also obtained. Simultaneously, the viscous coefficients denoting the viscous behavior in visco-plastic constitutive equation were determined by taking use of the creep testing data. Then the viscous coefficients of three carbon steels (20 steel, 35 steel and 45 steel) were compared and analyzed. The results show that the viscosity is different due to different materials at the same temperature and stress.
摘要：
The paper is aimed to exploit a creep constitutive mode of TC11 titanium alloy based on RBF neural network. Creep testing data of TC11 titanium alloy obtained under the same temperature and different stress are considered as knowledge base and the characteristics of rheological forming of materials and radial basis function neural network (RBFNN) are also combined when exploiting the model. A part of data extracted from knowledge base is divided into two groups: one is learning sample and the other testing sample, which are being performed training, learning and simulating. Then predicting value is compared with the creep testing value and the theoretical value deduced by primary model, which validates that the RBFNN model has higher precision and generalizing ability.
摘要：
The element-free method is a new numerical technique presented in recent years. It uses the moving least square(MLS) approximation as its shape function, and it is determined by the basic function and weight function. The weight function is the mainly determining factor, so it greatly affects the accuracy of the computational results. The element-free Galerkin method(EFGM) was applied for the solution to plastic large deformation. The simulation of metal rheological forming was successfully done by programming and its results were visualized by using the plotting and data analyses software Tecplot. Then plastic strain under different stages during rheological forming and the three principal stresses at the last deformation were obtained. The example shows the feasibility of EFGM used for metal rheological forming and provides a new method for numerical simulation of rheological forming of complex parts.
摘要：
Thermomechanical coupling of PVC sheet with defects under uniaxial loading at different rates and different sizes of microbores was studied. The local temperature field of the dynamic damage-rupture process zone at crack tip was surveyed with infrared thermographic sensor. Based on the irreversible thermomechanics theory, the dissipation law of deformation-heat effect during the whole process was found. Furthermore, the effect of thermoelasticity in the initial stage of extension was explained.
关键词：
rheological stress;strain rate effect;temperature effect;constitutive model
摘要：
The basic factors relating to the rheological stress in the constitutive equations were introduced. Carbon constructional quality steels were regarded as a kind of elastic-viscoplastic materials under high temperature and the elastic-viscoplastic constitutive models were summarized. A series of tension experiments under the same temperature and different strain rates, and the same strain rate and different temperatures were done on 20 steel, 35 steel and 45 steel. 52 groups of rheological stress—strain curves were obtained. The experimental results were analyzed theoretically. The rheological stress constitutive models of carbon steels were built combining the strong points of the Perzyna model and Johnson-Cook model. Comparing the calculation results conducted from the model with the experiment results, the results proves that the model can reflect the temperature effect and strain rate effect of carbon constructional quality steels better.
摘要：
The non-linear equations of strings under a concentrated load were derived. The formulae of the linear frequency and the governing equation of the primary resonance were obtained by Galerkin and Multiple-dimensioned method. The reason of the loss of load in practical engineering was addressed. The bifurcation graphics and the relationship graphics of bifurcate point with concentrated load and the span length of the cable were obtained by calculating example. The results show that formula of the linear frequency of the suspended cable is different from that of the string.
摘要：
The meshless method is a new numerical technology presented in recent years. It uses the moving least square (MLS) approximation as its shape function, and it is determined by the basic function and weight function. The weight function is the mainly determining factor, so it greatly affects the accuracy of the computational results. The process of cylinder compression was analyzed by using rigid-plastic meshless variational principle and programming reproducing kernel partial method (RKPM), the influence of node number, weight functions and size factor on the solution was discussed and the suitable range of size factor was obtained. Compared with the finite element method (FEM), the feasibility and validity of the method were verified, which proves a good supplement of FEM in this field and provides a good guidance for the application of meshless in actual engineering.
