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Ren H.,State Key Laboratory of Construction Machinery | Ren H.,Zoomlion Heavy Industry Science and Technology Co. | Wang C.,State Key Laboratory of Construction Machinery | Wang C.,Zoomlion Heavy Industry Science and Technology Co. | And 6 more authors.
Jixie Qiangdu/Journal of Mechanical Strength | Year: 2014

Mathematic optimal model of parameters inversion in Y-U constitutive model was established. According to complex iterative process of Y-U constitutive model, a modified particle swarm optimization algorithm was adopted, which employed a mutation method of genetic algorithm and was improved on the aspects of parameters setting and initial group generation. A group of seven parameters was inversed based on tension-compression experimental data of high strength steel WELDOX1100. The accuracy of inversion parameters was verified through bending experiment and finite element analysis. The inversion results show refined convergent behavior and high precision, and are significant to increase the simulation accuracy of high strength steel forming.

Liu J.,State Key Laboratory of Construction Machinery | Liu J.,Hunan University | Sun X.,Hunan University | Meng X.,Hunan University | And 3 more authors.
International Journal of Mechanics and Materials in Design | Year: 2015

Aiming at uncertain structures, a computational inverse approach is proposed to identify the dynamic load on the basis of the shape function method and interval analysis. The forward model for an uncertain structure is established through the relationship between the uncertain load vector and the assembly matrix of the uncertain responses of the shape function loads in each discrete element in time domain. The uncertainty is characterized by the interval with a closed bounded set of uncertain parameters. On the basis of interval analysis method, the load identification for uncertain structures can be transformed into two kinds of deterministic inverse problems, namely the deterministic dynamic load identification and the first order derivatives of the unknown load to each parameter both at the midpoints of the uncertain parameters. In order to eliminate the ill-posedness of inversion, the regularization method is adopted to solve the deterministic equations. Two numerical examples demonstrates the effectiveness of the proposed method, and example one also gives the identified result using Monte Carlo method to compare with that using the proposed method. © 2015 Springer Science+Business Media Dordrecht

Chen X.-K.,State Key Laboratory of Construction Machinery | Chen X.-K.,Central South University
Gongcheng Kexue Xuebao/Chinese Journal of Engineering | Year: 2016

The viscosity of epoxy resin was tested by viscometer, and an engineering viscosity model was constructed by the fitting method. In this simulation, the viscosity model was applied to predict the flow process of epoxy resin with different initial temperatures by using PAM-RTM. The influence of the viscosity change of epoxy resin on resin transfer molding (RTM) was discussed in detail. The results show that the filling time of RTM decreases first and then increases as the initial temperature increases, and the shortest filling time is acquired at 40℃. The viscosity change of epoxy resin has remarkable influence on the RTM of large scale structure. © All right reserved.

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