A Gradient Based Optimization Framework for the Design of Single and Multi-Stage Metal Forming Processes

2000 ◽  
Author(s):  
Akkaram Srikanth ◽  
Nicholas Zabaras
Keyword(s):  
Sensitivity Analysis ◽  
Metal Forming ◽  
Driving Forces ◽  
Single Stage ◽  
Lagrangian Analysis ◽  
Equilibrium Equations ◽  
Infinite Dimensional ◽  
Multi Stage ◽  
Gradient Based ◽  
Optimization Methodology

Abstract A gradient based optimization methodology is developed for the design of metal forming processes. A novel, efficient and mathematically rigorous scheme is proposed for a continuum based sensitivity analysis of metal forming processes that can be used to accurately evaluate gradients of the objective function and design constraints. In particular, a sensitivity analysis is being developed for the Lagrangian analysis of finite inelastic deformations of hyperelastic-viscoplastic materials involving frictional contact. A framework for shape as well as parameter optimization for single-stage metal forming processes was introduced in [1–4]. Weak sensitivity equilibrium equations were derived for the large deformation of the workpiece in a typical forming operation. This sensitivity kinematic problem was linearly coupled with the appropriate sensitivity constitutive and contact sub-problems. Thus a linear sensitivity problem with appropriate driving forces was identified and the analysis carried out in an infinite dimensional framework. This work on the design of single-stage forming processes is currently expanded to include the design of multi-stage forming processes which necessarily involve the computation of both shape as well as non-shape (parameter) sensitivities. The direct deformation and sensitivity deformation problems are implemented using the finite element method. The effectiveness of the proposed methodology is tested here with the solution of two practical design problems in single and two-stage forming processing.

Global sensitivity analysis approaches applied to parameter selection for numerical model-updating of structures

2019 ◽  
Vol 36 (4) ◽  
pp. 1282-1304 ◽  
Author(s):  
Marzieh Jafari ◽  
Khaled Akbari
Keyword(s):  
Sensitivity Analysis ◽  
Numerical Model ◽  
Model Updating ◽  
Parameter Selection ◽  
Design Parameters ◽  
Lagrangian Analysis ◽  
Data Set ◽  
Content Type ◽  
Global Sensitivity ◽  
Gradient Based

Purpose This paper aims to measure the sensitivity of the structure’s deformation numerical model (NM) related to the various types of the design parameters, which is a suitable method for parameter selection to increase the time of model-updating. Design/methodology/approach In this research, a variance-based sensitivity analysis (VBSA) approach is proposed to measure the sensitivity of NM of structures. In this way, the contribution of measurements of the structure (such as design parameter values and geometry) on the output of NM is studied using first-order and total-order sensitivity indices developed by Sobol’. In this way the generated data set of parameters by considering different distributions such as Gaussian or uniform distribution and different order as input along with, the resulted deformation variables of NM as output has been submitted to the Sobol’ indices estimation procedure. To the verification of VBSA results, a gradient-based sensitivity analysis (SA), which is developed as a global SA method has been developed to measure the global sensitivity of NM then implemented over the NM’s results of a tunnel. Findings Regarding the estimated indices, it has been concluded that the derived deformation functions from the tunnel’s NM usually are non-additive. Also, some parameters have been determined as most effective on the deformation functions, which can be selected for model-updating to avoid a time-consuming process, so those may better to be considered in the group of updating parameters. In this procedure for SA of the model, also some interactions between the selected parameters with other parameters, which are beneficial to be considered in the model-updating procedure, have been detected. In this study, some parameters approximately (27 per cent of the total) with no effect over the all objective functions have been determined to be excluded from the parameter candidates for model-updating. Also, the resulted indices of implemented VBSA were approved during validation by the gradient-based indices. Practical implications The introduced method has been implemented for a circular lined tunnel’s NM, which has been created by Fast Lagrangian Analysis of Continua software. Originality/value This paper plans to apply a statistical method, which is global on the results of the NM of a soil structure by a complex system for parameter selection to avoid the time-consuming model-updating process.

scholarly journals Extraction of tetracycline using the ionic liquid-based aqueous two phase systems: Single-stage versus multi-stage

2018 ◽  
Vol 24 (4) ◽  
pp. 387-397 ◽  
Author(s):  
Yi Liu ◽  
Li Chen ◽  
Jun Zhou ◽  
Zongcheng Yan
Keyword(s):  
Extraction Efficiency ◽  
Ph Value ◽  
Influence Factors ◽  
Volume Ratio ◽  
Line Length ◽  
Single Stage ◽  
Two Phase ◽  
Extraction Behavior ◽  
Multi Stage ◽  
Tie Line

Ionic liquids-based aqueous two-phase extraction (ILs-ATPE) offers an alternative approach to the extraction of tetracycline (TC) through their partitioning between two phases. Single-stage and multi-stage strategies have been evaluated and compared for the purification of TC using ATPE composed of 1-butyl-3-methylimidazolium halide ([Bmim]X(X=Cl,Br)) and K2HPO4. The influence factors on single-stage extraction behavior of TC were optimized systematically, including the pH value, tie line length, and volume ratio. The optimal extraction efficiency of TC could reach above 95% when the volume ratio is higher than 1.5 and the tie line length is 30.52%. The multi-stage ATPE was also investigated by simulating a three-stage crosscurrent operation in test tubes. According to the TC isotherm curve and respective McCabe?Thiele diagrams, a predicted optimized scheme of the countercurrent multi-stage ATPE was determined. TC can be purified in the IL-rich top phase with a final extraction efficiency of 99% and a final TC concentration of 0.25 mg/mL, if a three- -stage [Bmim]Cl-K2HPO4 ATPE with volume ratio of 0.5 and tie line length of 30.52% was employed. Thus, the multi-stage extraction with small volume ratio is necessary to achieve a higher recovery yield, resulting in the reduction of the IL consumption.

Mean Sojourn Time in Multi Stage Fork-Join Network

2015 ◽  
Vol 6 (3) ◽  
pp. 80-99 ◽  
Author(s):  
Yonit Barron
Keyword(s):  
Supply Chains ◽  
Sojourn Time ◽  
Computer Processing ◽  
Single Stage ◽  
Assembly Systems ◽  
Parallel Tasks ◽  
Multi Stage ◽  
Stage System ◽  
Major Factors ◽  
Performance Behavior

Fork-Join queue networks (F-J) have received increasing attention during the last Decade, due to their ability to model parallel and distributed computer processing, supply chains and assembly systems. However, most research is focused on a single stage processing, and only scant work exists on F-J with two or more stages. In this paper, the author investigates (through simulation) the performance behavior of a multi-stage system; in particular, the performance of a synchronized system is compared to an unsynchronized system regarding three major factors: (1) the number of parallel tasks; (2) the number of serial stages and (3) the utilization.

scholarly journals A New DEA Model for Evaluation of Supply Chains: A Case of Selection and Evaluation of Environmental Efficiency of Suppliers

Symmetry ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 565 ◽  
Author(s):  
Krmac ◽  
Djordjević
Keyword(s):  
Sensitivity Analysis ◽  
Complex Problem ◽  
Environmental Efficiency ◽  
Data Envelopment Analysis Model ◽  
Data Envelopment ◽  
Analysis Model ◽  
Chain Management ◽  
Dea Model ◽  
Multi Stage ◽  
Stage System

Supply Chain Management (SCM) represents an example of a complex multi-stage system. The SCM involves and connects different activities, from customer’s orders to received services, all with the aim of satisfying customers. The evaluation of a particular SCM is a complex problem because of the internally linked hierarchical activities and multiple entities. In this paper, the introduction of a non-radial DEA (Data Envelopment Analysis) model for the evaluation of different components of SCM, primarily in terms of sustainability, is the main contribution. However, in order to confirm the novelty and benefits of this new model in the field of SCM, a literature review of past applications of DEA-based models and methods are also presented. The non-radial DEA model was applied for the selection and evaluation of the environmental efficiency of suppliers considering undesirable inputs and outputs resulting in a better ranking of suppliers. Via perturbation of the data used, behavior, as well as the benefits and weaknesses of the introduced model are presented through sensitivity analysis.

scholarly journals Robust global sensitivity analysis of a river management model to assess nonlinear and interaction effects

2014 ◽  
Vol 18 (9) ◽  
pp. 3777-3785 ◽  
Author(s):  
L. J. M. Peeters ◽  
G. M. Podger ◽  
T. Smith ◽  
T. Pickett ◽  
R. H. Bark ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Driving Forces ◽  
Potential Evapotranspiration ◽  
Nonlinear Effects ◽  
River System ◽  
River Management ◽  
Interaction Effects ◽  
Regulated River ◽  
Management Model ◽  
Sensitivity Indices

Abstract. The simulation of routing and distribution of water through a regulated river system with a river management model will quickly result in complex and nonlinear model behaviour. A robust sensitivity analysis increases the transparency of the model and provides both the modeller and the system manager with a better understanding and insight on how the model simulates reality and management operations. In this study, a robust, density-based sensitivity analysis, developed by Plischke et al. (2013), is applied to an eWater Source river management model. This sensitivity analysis methodology is extended to not only account for main effects but also for interaction effects. The combination of sensitivity indices and scatter plots enables the identification of major linear effects as well as subtle minor and nonlinear effects. The case study is an idealized river management model representing typical conditions of the southern Murray–Darling Basin in Australia for which the sensitivity of a variety of model outcomes to variations in the driving forces, inflow to the system, rainfall and potential evapotranspiration, is examined. The model outcomes are most sensitive to the inflow to the system, but the sensitivity analysis identified minor effects of potential evapotranspiration and nonlinear interaction effects between inflow and potential evapotranspiration.

Comparative Simulation Study of Multi Stage Hybrid All Optical Fiber Amplifiers in Optical Communications

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
IS Amiri ◽  
Ahmed Nabih Zaki Rashed ◽  
P. Yupapin
Keyword(s):  
Optical Fiber ◽  
Communication Systems ◽  
Single Stage ◽  
Fiber Amplifiers ◽  
Multi Stage ◽  
Raman Amplifiers ◽  
All Optical ◽  
Optical Communication Systems ◽  
Optical Fiber Amplifiers ◽  
Hybrid Configuration

AbstractThis study clarifies the comparison between hybrid all optical fiber amplifiers in single-stage and multi-stage amplification. EDFA/Raman, Raman/EDFA/Raman, and EDFA/Raman/EDFA configurations are employed for upgrading optical communication systems. Single-stage Raman amplifiers clarifies very better performance than single-stage EDFA amplifier. Multi-stage Raman/EDFA/Raman also outlines very better performance than other hybrid configuration up to 475 km distance. Single-stage Raman amplification has outlined maxi. Q factor up to 218.392 for 250 km distance and 11.937 up to 475 km propagation range. So hybrid all optical amplifiers are essentially for upgrading optical system performance efficiency.

Sign in / Sign up

Export Citation Format

Share Document