An improved constrained inverse optimization method for mechanical draft cooling towers

2017 ◽  
Vol 114 ◽  
pp. 573-582 ◽  
Author(s):  
Kuljeet Singh ◽  
Ranjan Das
2017 ◽  
Vol 8 (2) ◽  
pp. 86
Author(s):  
Lili Zhang ◽  
Wenwen Yang ◽  
Dejun Teng

The research collects competence items of informal questionnaire by expert interview method, analyzes the results qualitatively and quantitatively and forms formal questionnaire. Through statistical analysis and AMOS modeling, the research obtains workers’ competence model and validates competence model. An identification method of individual advantage characters according competency indicator system is built up relying on programming analysis and parameter optimization. We build the optimization model and its inverse optimization model, starting from the original optimization model, adjusting parameter value as small as possible, the conventional optimization model translated into the inverse model by the principle of duality. A calculation example is used to make sure the method is reliability and feasibility.


1997 ◽  
Vol 34 (2) ◽  
pp. 255-257 ◽  
Author(s):  
Shigeru Obayashi ◽  
Shinkyu Jeong ◽  
Yuichi Matsuo

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2216
Author(s):  
Xuewen Chen ◽  
Tingting Lian ◽  
Bo Zhang ◽  
Yuqing Du ◽  
Kexue Du ◽  
...  

As a novel kind of cold roller steel, Cr8 alloy steel has the characteristics of high hardness, high wear resistance and good toughness, which can effectively prolong the service life of the roller that is an important part of the steel rolling mill. How to accurately define the constitutive model parameters of metal materials is the major problem, because it seriously affects the accuracy of numerical simulation results of the roller hot forming process. In the study of Cr8 alloy steel’s thermal deformation behavior of the present paper, the high temperature compression test was done on a Gleebel-1500D thermal/force simulation testing machine. A novel method of parameter identification was proposed based on inverse optimization. The Hansel–Spittel constitutive model was established by using the inverse optimization method. To carry out the verification on the accuracy of the established constitutive model, the predicted flow-stress of constitutive model was made a contrast to the experimental flow-stress, and the standard statistical parameters were also applied to further evaluation. The results showed a relatively high prediction accuracy of the Hansel–Spittel constitutive model based on the inverse optimization algorithm. Meanwhile, to obtain optimal parameters of Cr8 alloy steel in the thermal processing, 3D thermal processing maps concerning strain-rate, strain and temperature were built based on the dynamic material model. According to the 3D processing map, the most adequate thermal processing parameters of Cr8 alloy steel were obtianed as follows: strain 0.2–0.4, strain-rate 0.05–0.005 s−1, temperature 1100–1150 °C.


1997 ◽  
Author(s):  
Hyoung-Jin Kim ◽  
Oh-Hyun Rho ◽  
Hyoung-Jin Kim ◽  
Oh-Hyun Rho

Author(s):  
Yujiang Xiang ◽  
Benjamin Ramirez ◽  
Sarah Hoffman ◽  
Tonoy Chowdhury

Foot-ground interaction is modeled for a human gait simulation by using a 2D skeletal model with 12 degrees of freedom (DOF). Three contacting elements are attached to the heel, phalangeal, and toe sections respectively. The contacting process is modeled using an inverse optimization approach, in which the contacting force due to the penetration deformation and velocity is equal to the balanced ground reaction force (GRF). This is set as an equality constraint in the walking optimization formulation. A predictive dynamics approach is used to predict the walking motion and to optimize the contacting process. The results indicated that the contacting model can realistically match the GRF, and the resulting gait motion, contacting penetration, and contacting parameters are all optimized simultaneously. The optimal solution is obtained in seconds. This demonstrates an efficient way to model the foot-ground contacting deformation process using an inverse optimization method and eliminates the need for integrating equations of motion (EOM).


2019 ◽  
Vol 64 (20) ◽  
pp. 205001 ◽  
Author(s):  
Yuting Lin ◽  
Benjamin Clasie ◽  
Tian Liu ◽  
Mark McDonald ◽  
Katja M Langen ◽  
...  

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