An effective logarithmic formulation for piecewise linearization requiring no inequality constraint

Author(s):  
F. J. Hwang ◽  
Yao-Huei Huang
2020 ◽  
Vol 53 (2) ◽  
pp. 11181-11186
Author(s):  
Jelibeth Racedo-Gutiérrez ◽  
Fidel Torres-Delgado

2003 ◽  
Vol 125 (3) ◽  
pp. 267-273 ◽  
Author(s):  
W. Zhao ◽  
R. Seshadri ◽  
R. N. Dubey

A technique for elastic-plastic analysis of a thick-walled elastic-plastic cylinder under internal pressure is proposed. It involves two parametric functions and piecewise linearization of the stress-strain curve. A deformation type of relationship is combined with Hooke’s law in such a way that stress-strain law has the same form in all linear segments, but each segment involves different material parameters. Elastic values are used to describe elastic part of deformation during loading and also during unloading. The technique involves the use of deformed geometry to satisfy the boundary and other relevant conditions. The value of strain energy required for deformation is found to depend on whether initial or final geometry is used to satisfy the boundary conditions. In the case of low work-hardening solid, the difference is significant and cannot be ignored. As well, it is shown that the new formulation is appropriate for elastic-plastic fracture calculations.


Author(s):  
Hemavathy P.R. ◽  
Mohamed Shuaib Y ◽  
S.K. Lakshmanaprabu

In this paper, an Internal model Controller (IMC) based PID with fractional filter for a first order plus time delay process is proposed. The structure of the controller has two parts, one is integer PID controller part cascaded with fractional filter. The proposed controller has two tuning factors λ, filter time constant and a, fractional order of the filter. In this work, the two factors are decided in order to obtain low Integral Time Absolute Error (ITAE). The effectiveness of the proposed controller is studied by considering a non linear (hopper tank) process. The experimental set up is fabricated in the laboratory and then data driven model is developed from the experimental data. The non linear process model is linearised using piecewise linearization and two linear regions are obtained. At each operating point, linear first order plus dead time model is obtained and the controller is designed for the same. To show the practical applicability, the proposed controller is implemented for the proposed experimental laboratory prototype.


2010 ◽  
Vol 428-429 ◽  
pp. 487-492
Author(s):  
Xi Yin ◽  
Xiao Jun Wang ◽  
Yong Que Xie

This thesis introduces a low cost and high precision temperature cycle measurement system with adoption of PT100 as temperature sensor, with single chip computer as the core. The method of sub-three-wire connection is proposed for engineering practice, then, can eliminate the effects of lead wire resistance and simplify the external cable connection. We discuss and research circuit component selection, circuit design, improving system reliability, and a software method of piecewise linearization process is adopted, thus we ensure exact and reliable measure and the system characteristic of low cost and high precision.


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