Minimization of Energy in the Multipass Rolling Process

1999 ◽  
Vol 123 (1) ◽  
pp. 135-141 ◽  
Author(s):  
M. Abdul Samad ◽  
Ravi S. Rao
Keyword(s):  
Process Model ◽  
Rolling Process ◽  
Design Parameters ◽  
Optimum Number ◽  
Frictional Stress ◽  
Total Load ◽  
Design Variables ◽  
Roll Flattening ◽  
Flat Rolling ◽  
Point Pressure

This research focuses on the optimization of the flat rolling process. In order to optimize the process effectively, the existing process model has been especially enhanced—in the neutral zone where the friction changes sign over a region rather than at a point. Pressure and frictional stress distributions as well as total load and torque are thereby estimated as functions of the various rolling parameters. Roll flattening has also been taken into account. The main problem of determining the optimum design parameters of multipass rolling has been considered. The problem has been formulated and solved as a constrained nonlinear programming problem by considering the radius of the rolls, the front and back tensions as design variables. Optimum number of passes have been found, so that the total energy consumed by the tandem mill is minimized. Constraints are placed on the induced stresses, the neutral angle, the angle of bite and the deflections of the rolls, for both cold and hot rolling processes.

scholarly journals A Comparative Evaluation of Predictive Models of the Flat Rolling Process

2018 ◽  
Author(s):  
Máté Szűcs ◽  
György Krállics ◽  
John Lenard
Keyword(s):  
Element Model ◽  
Rolling Process ◽  
Dimensional Model ◽  
Rigid Plastic ◽  
One Dimensional ◽  
Inverse Approach ◽  
Friction Factors ◽  
Roll Flattening ◽  
The Coefficient Of Friction ◽  
Flat Rolling

The predictive abilities of several mathematical models of the cold, flat rolling process are tested by comparing their predictions to experimental measurements. The models include an empirical model, a one-dimensional model, a finite element model and an upper bound model. The coefficient of friction and the friction factor are first determined by the inverse approach, using the model deemed to be the most comprehensive. The effects of including or excluding an account of roll flattening, using elastic-plastic or rigid-plastic strips, and constant or velocity dependent coefficients of friction or friction factors are examined.

A unified framework for the design of low-complexity wavelet filters

2017 ◽  
Vol 15 (06) ◽  
pp. 1750054 ◽  
Author(s):  
Ameya K. Naik ◽  
Raghunath S. Holambe
Keyword(s):  
Feature Extraction ◽  
Compact Support ◽  
Low Complexity ◽  
Design Parameters ◽  
Unified Framework ◽  
Vanishing Moments ◽  
Wavelet Filters ◽  
Design Variables ◽  
Optimum Filter ◽  
Simulation Results

An outline is presented for construction of wavelet filters with compact support. Our approach does not require any extensive simulations for obtaining the values of design variables like other methods. A unified framework is proposed for designing halfband polynomials with varying vanishing moments. Optimum filter pairs can then be generated by factorization of the halfband polynomial. Although these optimum wavelets have characteristics close to that of CDF 9/7 (Cohen-Daubechies-Feauveau), a compact support may not be guaranteed. Subsequently, we show that by proper choice of design parameters finite wordlength wavelet construction can be achieved. These hardware friendly wavelets are analyzed for their possible applications in image compression and feature extraction. Simulation results show that the designed wavelets give better performances as compared to standard wavelets. Moreover, the designed wavelets can be implemented with significantly reduced hardware as compared to the existing wavelets.

CAD and Optimization of Helical Torsion Springs

1994 ◽  
Author(s):  
Sayed M. Metwalli ◽  
M. Alaa Radwan ◽  
Abdel Aziz M. Elmeligy
Keyword(s):  
Iterative Process ◽  
Minimum Weight ◽  
Design Parameters ◽  
Optimal Parameters ◽  
Direct Evaluation ◽  
Torsion Spring ◽  
Performance Requirements ◽  
Design Variables ◽  
Method Of Lagrange Multipliers ◽  
Torsion Springs

Abstract The convensional procedure of helical torsion spring design is an iterative process because of large number of requirements and relations that are to be attained once at a time. The design parameters are varied at random until the spring design satisfies performance requirements. A CAD of the spring for minimum weight is formulated with and without the variation of the maximum normal stress with the wire diameter. The CAD program solves by employing the method of Lagrange-Multipliers. The optimal parameters, in a closed form are obtained, normalized and plotted. These explicit relations of design variables allow direct evaluation of optimal design objective and hence, an absolute optimum could be achieved. The comparison of optimum results with those previously published, shows a pronounced achievement in the reduction of torsion spring weight.

A Study on Optimum Design Using Fuzzy Numbers As Design Variables

1995 ◽  
Author(s):  
Masao Arakawa ◽  
Hiroshi Yamakawa
Keyword(s):  
Fuzzy Sets ◽  
Optimum Design ◽  
Fuzzy Numbers ◽  
Fuzzy Optimization ◽  
Design Parameters ◽  
Numerical Examples ◽  
Design Variables ◽  
Conventional Methods

Abstract In this study, we summerize the method of fuzzy optimization using fuzzy numbers as design variables. In order to detect flaw in fuzzy calculation, we use LR-fuzzy numbers, which is known as its simplicity in calculation. We also use simple fuzzy numbers’ operations, which was proposed in the previous papers. The proposed method has unique characteristics that we can obtain fuzzy sets in design variables (results of the design) directly from single numerical optimizing process. Which takes a large number of numerical optimizing processes when we try to obtain similar results in the conventional methods. In the numerical examples, we compare the proposed method with several other methods taking imprecision in design parameters into account, and demonstrate the effectiveness of the proposed method.

Design Sensitivity Analysis of Nonlinear Multidisciplinary Multibody Systems in the MIXEDMODELS Platform

2007 ◽  
Author(s):  
Shilpa A. Vaze ◽  
Prakash Krishnaswami ◽  
James DeVault
Keyword(s):  
Sensitivity Analysis ◽  
Multibody Systems ◽  
Design Sensitivity ◽  
Differential Algebraic Equations ◽  
The State ◽  
Design Sensitivity Analysis ◽  
Design Parameters ◽  
State Variables ◽  
Sensitivity Coefficients ◽  
Design Variables

Most state-of-the-art multibody systems are multidisciplinary and encompass a wide range of components from various domains such as electrical, mechanical, hydraulic, pneumatic, etc. The design considerations and design parameters of the system can come from any of these domains or from a combination of these domains. In order to perform analytical design sensitivity analysis on a multidisciplinary system (MDS), we first need a uniform modeling approach for this class of systems to obtain a unified mathematical model of the system. Based on this model, we can derive a unified formulation for design sensitivity analysis. In this paper, we present a modeling and design sensitivity formulation for MDS that has been successfully implemented in the MIXEDMODELS (Multidisciplinary Integrated eXtensible Engine for Driving Metamodeling, Optimization and DEsign of Large-scale Systems) platform. MIXEDMODELS is a unified analysis and design tool for MDS that is based on a procedural, symbolic-numeric architecture. This architecture allows any engineer to add components in his/her domain of expertise to the platform in a modular fashion. The symbolic engine in the MIXEDMODELS platform synthesizes the system governing equations as a unified set of non-linear differential-algebraic equations (DAE’s). These equations can then be differentiated with respect to design to obtain an additional set of DAE’s in the sensitivity coefficients of the system state variables with respect to the system’s design variables. This combined set of DAE’s can be solved numerically to obtain the solution for the state variables and state sensitivity coefficients of the system. Finally, knowing the system performance functions, we can calculate the design sensitivity coefficients of these performance functions by using the values of the state variables and state sensitivity coefficients obtained from the DAE’s. In this work we use the direct differentiation approach for sensitivity analysis, as opposed to the adjoint variable approach, for ease in error control and software implementation. The capabilities and performance of the proposed design sensitivity analysis formulation are demonstrated through a numerical example consisting of an AC rectified DC power supply driving a slider crank mechanism. In this case, the performance functions and design variables come from both electrical and mechanical domains. The results obtained were verified by perturbation analysis, and the method was shown to be very accurate and computationally viable.

Optimum Design of Anti-Siphon Device used to Prevent Cerebrospinal Fluid from Overdraining

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1374-1380
Author(s):  
Jong Yun Jang ◽  
Chong Sun Lee ◽  
Chang Min Suh
Keyword(s):  
Cerebrospinal Fluid ◽  
Numerical Simulations ◽  
Optimum Design ◽  
Upright Position ◽  
Design Parameters ◽  
Design Variables

The present study investigated design parameters of an anti-siphon device used with shunt valves to treat patients with hydrocephalus. Structural analyses were performed to understand roles of design variables and optimize performance of the diaphragm-type anti-siphon device (hereafter referred to as the ASD). Experiments were performed on the lab-made product and showed good agreements with the numerical simulations. Using the simulations, we were able to design a more physiological ASD which gave equal opening pressures in both supine and upright postures. Tissue encapsulization phenomenon was also simulated and the results indicated underdrainage of CSF in the upright position of the patient.

Optimal design of a parallel robotic gripper using enhanced multi-objective ant lion optimizer with a sensitivity analysis approach

2020 ◽  
Vol 40 (5) ◽  
pp. 703-721
Author(s):  
Golak Bihari Mahanta ◽  
Deepak BBVL ◽  
Bibhuti B. Biswal ◽  
Amruta Rout
Keyword(s):  
Sensitivity Analysis ◽  
Distribution Function ◽  
Design Parameters ◽  
Objective Functions ◽  
Content Type ◽  
Multi Objective ◽  
The Past ◽  
Design Variables ◽  
Pick And Place ◽  
Ant Lion

Purpose From the past few decades, parallel grippers are used successfully in the automation industries for performing various pick and place jobs due to their simple design, reliable nature and its economic feasibility. So, the purpose of this paperis to design a suitable gripper with appropriate design parameters for better performance in the robotic production systems. Design/methodology/approach In this paper, an enhanced multi-objective ant lion algorithm is introduced to find the optimal geometric and design variables of a parallel gripper. The considered robotic gripper systems are evaluated by considering three objective functions while satisfying eight constraint equations. The beta distribution function is introduced for generating the initial random number at the initialization phase of the proposed algorithm as a replacement of uniform distribution function. A local search algorithm, namely, achievement scalarizing function with multi-criteria decision-making technique and beta distribution are used to enhance the existing optimizer to evaluate the optimal gripper design problem. In this study, the newly proposed enhanced optimizer to obtain the optimum design condition of the design variables is called enhanced multi-objective ant lion optimizer. Findings This study aims to obtain optimal design parameters of the parallel gripper with the help of the developed algorithms. The acquired results are investigated with the past research paper conducted in that field for comparison. It is observed that the suggested method to get the best gripper arrangement and variables of the parallel gripper mechanism outperform its counterparts. The effects of the design variables are needed to be studied for a better design approach concerning the objective functions, which is achieved by sensitivity analysis. Practical implications The developed gripper is feasible to use in the assembly operation, as well as in other pick and place operations in different industries. Originality/value In this study, the problem to find the optimum design parameter (i.e. geometric parameters such as length of the link and parallel gripper joint angles) is addressed as a multi-objective optimization. The obtained results from the execution of the algorithm are evaluated using the performance indicator algorithm and a sensitivity analysis is introduced to validate the effects of the design variables. The obtained optimal parameters are used to develop a gripper prototype, which will be used for the assembly process.

scholarly journals Tuning the Properties of PNIPAm-Based Hydrogel Scaffolds for Cartilage Tissue Engineering

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3154
Author(s):  
Md Mohosin Rana ◽  
Hector De la Hoz Siegler
Keyword(s):  
Tissue Engineering ◽  
Physical Properties ◽  
Tissue Regeneration ◽  
Structural Integrity ◽  
Cartilage Tissue ◽  
Design Parameters ◽  
Comprehensive Overview ◽  
Hydrogel Scaffolds ◽  
Design Variables

Poly(N-isopropylacrylamide) (PNIPAm) is a three-dimensional (3D) crosslinked polymer that can interact with human cells and play an important role in the development of tissue morphogenesis in both in vitro and in vivo conditions. PNIPAm-based scaffolds possess many desirable structural and physical properties required for tissue regeneration, but insufficient mechanical strength, biocompatibility, and biomimicry for tissue development remain obstacles for their application in tissue engineering. The structural integrity and physical properties of the hydrogels depend on the crosslinks formed between polymer chains during synthesis. A variety of design variables including crosslinker content, the combination of natural and synthetic polymers, and solvent type have been explored over the past decade to develop PNIPAm-based scaffolds with optimized properties suitable for tissue engineering applications. These design parameters have been implemented to provide hydrogel scaffolds with dynamic and spatially patterned cues that mimic the biological environment and guide the required cellular functions for cartilage tissue regeneration. The current advances on tuning the properties of PNIPAm-based scaffolds were searched for on Google Scholar, PubMed, and Web of Science. This review provides a comprehensive overview of the scaffolding properties of PNIPAm-based hydrogels and the effects of synthesis-solvent and crosslinking density on tuning these properties. Finally, the challenges and perspectives of considering these two design variables for developing PNIPAm-based scaffolds are outlined.

scholarly journals New Numerical Solution of von Karman Equation of Lengthwise Rolling

2015 ◽  
Vol 2015 ◽  
pp. 1-20 ◽  
Author(s):  
Rudolf Pernis ◽  
Tibor Kvackaj
Keyword(s):  
Contact Stress ◽  
Rolling Force ◽  
Rolling Process ◽  
Normal Contact Stress ◽  
Normal Contact ◽  
Circular Arch ◽  
Relative Stress ◽  
Roll Flattening ◽  
Polygonal Curve ◽  
Rolling Torque

The calculation of average material contact pressure to rolls base on mathematical theory of rolling process given by Karman equation was solved by many authors. The solutions reported by authors are used simplifications for solution of Karman equation. The simplifications are based on two cases for approximation of the circular arch: (a) by polygonal curve and (b) by parabola. The contribution of the present paper for solution of two-dimensional differential equation of rolling is based on description of the circular arch by equation of a circle. The new term relative stress as nondimensional variable was defined. The result from derived mathematical models can be calculated following variables: normal contact stress distribution, front and back tensions, angle of neutral point, coefficient of the arm of rolling force, rolling force, and rolling torque during rolling process. Laboratory cold rolled experiment of CuZn30 brass material was performed. Work hardening during brass processing was calculated. Comparison of theoretical values of normal contact stress with values of normal contact stress obtained from cold rolling experiment was performed. The calculations were not concluded with roll flattening.

Numerical simulation of slab deformation process with different reduction values in vertical rolls of mill 2000 roughing stands

2021 ◽  
Vol 77 (6) ◽  
pp. 675-681
Author(s):  
N. L. Bolobanova ◽  
E. A. Garber
Keyword(s):  
Process Model ◽  
Surface Defects ◽  
Numerical Study ◽  
Rolling Process ◽  
Rolled Stock ◽  
Metal Consumption ◽  
Wide Face ◽  
Total Reduction ◽  
Hot Rolling Mill ◽  
Deform 3D

Perfection of rolled stock production processes at continuous wide-strip hot rolling mill (CWHRM) aimed at minimization of metal consumption, is an effective mean to decrease its cost. In the process of slabs rolling at CWHRM, the metal consumption is stipulated first of all by complicated workpiece forming in roughing stands during consecutive reduction by vertical and horizontal rolls. Results of the numerical study of slab deformation with different values of reduction in vertical rolls of roughing stands of mill 2000 are presented. The implementation of rolling process model based on application of DEFORM-3D program of finiteelement analysis described for evaluation of metal shifting from the edges of slab in the direction of the middle of the width. The convergence of the simulation results with the measurements data of workpiece forming during roughing rolling at Severstal mill 2000 was experimentally confirmed. It was found that an increase of reduction in vertical rolls has no significant effect on the metal shifting from a narrow edge to a wide one. Increase the total reduction in vertical rolls leads to an unfavorable stress-strain state of the edge region and the Cockcroft–Latham criterion rises by 20–30%. It was proposed to reduce the total reduction in the vertical rolls of the roughing stands of mill 2000 down to 40–50 mm. It was shown that increase of time of slab moving from the heating furnace to the scale breaker causes growth the Cockcroft-Latham criterion and does not affect the amount of metal shifting from a narrow face to a wide one. The proposed method of simulation the process of slab deformation in the roughing group of the mill 2000 proved by results of industrial rolling can to be used for further study of the effect of rolls profiling and forming of surface defects with the provision of minimal metal shifting onto a wide face.

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