A Study on Warm Hydroforming of Al and Mg Sheet Materials: Mechanism and Proper Temperature Conditions

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Ho Choi ◽  
Muammer Koç ◽  
Jun Ni
Keyword(s):  
Process Parameters ◽  
Control Process ◽  
Hydraulic Pressure ◽  
Element Analysis ◽  
Lightweight Materials ◽  
Blank Holder ◽  
Warm Hydroforming ◽  
Temperature Levels ◽  
Fully Coupled

Hydroforming of lightweight materials at elevated temperature is a relatively new process with promises of increased formability at low internal pressure levels. In this study, the mechanism of warm hydroforming processes is presented in terms of its formability by comparison with warm forming, and cold hydroforming processes. Additionally, a strategy is proposed to control process parameters, such as temperature, hydraulic pressure, blank holder force, and forming speed. As a part of this strategy, the proper temperature condition is determined by adaptive-isothermal finite element analysis (FEA) and a design of experiment (DOE) approach. The adaptive-isothermal FEA determines the temperature levels of the blank material, which is selectively heated, by checking position of the blank material and adopting temperature level of the neighboring tooling. The proposed adaptive-isothermal FEA/DOE approach leads to the optimal temperature condition in a warm hydroforming system accurately and rapidly as opposed to costly and lengthy experimental trial and errors and/or fully coupled thermo-mechanical simulations. Other process parameters are also optimized in a continued study (Choi et al., 2007, “Determination of Optimal Loading Profiles in Warm Hydroforming of Lightweight Materials,” J. Mater. Process. Techn., 190(1–3), pp. 230–242.).

scholarly journals Some Studies on Forming Optimization with Genetic Algorithm

2012 ◽  
Vol 2 (2) ◽  
pp. 105-112
Author(s):  
Ganesh Marotrao KAKANDIKAR ◽  
Vilas M. NANDEDKAR
Keyword(s):  
Genetic Algorithm ◽  
Process Parameters ◽  
Wide Spectrum ◽  
Simulation Software ◽  
Flow Conditions ◽  
Element Analysis ◽  
Blank Holder ◽  
New Approach ◽  
Finite Element Analysis Simulation ◽  
Selection Of

Forming is a compression-tension process involving wide spectrum of operations and flow conditions. The result of the process depends on the large number of parameters and their interdependence. The selection of various parameters is still based on trial and error methods. In this paper the authors presents a new approach to optimize the geometry parameters of circular components, process parameters such as blank holder pressure and coefficient of friction etc. The optimization problem has been formulated with the objective of optimizing the maximum forming load required in Forming. Genetic algorithm is used for the optimization purpose to minimize the drawing load and to optimize the process parameters. A finite element analysis simulation software Fast Form Advanced is used for the validations of the results after optimization.

Application of FEM Simulation and Abductive Network to Predict the Springback of U-Shaped Bending Process with Counter Force

2012 ◽  
Vol 579 ◽  
pp. 32-41
Author(s):  
Tung Sheng Yang ◽  
Jen Chuan Yeh ◽  
Sheng Yi Chang
Keyword(s):  
Finite Element ◽  
Process Parameters ◽  
Fem Simulation ◽  
Data Sets ◽  
The Finite Element Method ◽  
Blank Holder Force ◽  
Element Analysis ◽  
Blank Holder ◽  
Bending Process ◽  
Abductive Network

This study applies the finite element method (FEM) in con-junction with an abductive network to predict springback’s angle during the U-shaped bending process with counter force. To verify the prediction of FEM simulation for springback, the experimental data are compared with the results of current simulation. Bending force, effective stress distribution and springback are investigated for different process parameters, such as profile radius of die, blank holder force and counter force of U-shaped bending process, by finite element analysis. The abductive network is then utilized to synthesize the data sets obtained from numerical simulations. Finally, prediction model is established for predicting springback’s angle under a suitable range of process parameters.

scholarly journals Optimization of Process Parameters during Hydroforming of Tank Bottom using NSGA-III Algorithm

2021 ◽  
Author(s):  
Zaifang Zhang ◽  
Feng Xu ◽  
Xiwu Sun
Keyword(s):  
Process Parameters ◽  
Quality Criteria ◽  
Pso Algorithm ◽  
Hydraulic Pressure ◽  
Blank Holder Force ◽  
Technological Parameters ◽  
Blank Holder ◽  
Optimization Of Process Parameters ◽  
Element Simulation ◽  
Thickness Variations

Abstract The hydroforming technology can realize overall forming of large storage tank’s bottom, but the quality is affected by many technological parameters. In view of wrinkling and cracking defects of integral storage tank’s bottom in hydroforming, a multi-objective optimization model is established for process parameters include pre-expansion pressure, hydraulic pressure, blank holder force and fillet radius of blank holder. Based on finite element simulation, the surrogate model between process parameters and quality criteria is established using Kriging technique. NSGA-III is used to determine optimal process parameters when storage tank’s bottom reaches targets include minimum wall thickness variations, minimum fracture trend, minimum flange wrinkle and minimum wrinkle trend. Compared with Particle swarm optimization (PSO) algorithm, NSGA-III algorithm is more suitable to solve this optimization problem. The validity of this method and accuracy of the results are verified by simulation experiments.

scholarly journals Surrogate model–based inverse parameter estimation in deep drawing using automatic knowledge acquisition

2021 ◽  
Author(s):  
Matthias Ryser ◽  
Felix M. Neuhauser ◽  
Christoph Hein ◽  
Pavel Hora ◽  
Markus Bambach
Keyword(s):  
Knowledge Acquisition ◽  
Process Parameters ◽  
Deep Drawing ◽  
Blank Holder ◽  
Target Values ◽  
Simulation Based ◽  
Column Subset Selection ◽  
Automatic Knowledge Acquisition ◽  
Sensor Signals

AbstractIn this paper, we propose a new approach for the simulation-based support of tryout operations in deep drawing which can be schematically classified as automatic knowledge acquisition. The central idea is to identify information maximising sensor positions for draw-in as well as local blank holder force sensors by solving the column subset selection problem with respect to the sensor sensitivities. Inverse surrogate models are then trained using the selected sensor signals as predictors and the material and process parameters as targets. The final models are able to observe the drawing process by estimating current material and process parameters, which can then be compared to the target values to identify process corrections. The methodology is examined on an Audi A8L side panel frame using a set of 635 simulations, where 20 out of 21 material and process parameters can be estimated with an R2 value greater than 0.9. The result shows that the observational models are not only capable of estimating all but one process parameters with high accuracy, but also allow the determination of material parameters at the same time. Since no assumptions are made about the type of process, sensors, material or process parameters, the methodology proposed can also be applied to other manufacturing processes and use cases.

Evaluation of web reinforcements in prestressed concrete box girders through shear-transverse bending domains

2020 ◽  
pp. 136943322098170
Author(s):  
Michele Fabio Granata ◽  
Antonino Recupero
Keyword(s):  
Analytical Model ◽  
Prestressed Concrete ◽  
3D Analysis ◽  
Box Girders ◽  
Element Analysis ◽  
Cross Sectional ◽  
Interaction Domains ◽  
Global And Local ◽  
Resultant Forces

In concrete box girders, the amount and distribution of reinforcements in the webs have to be estimated considering the local effects due to eccentric external loads and cross-sectional distortion and not only the global effect due to the resultant forces of a longitudinal analysis: shear, torsion and bending. This work presents an analytical model that allows designers to take into account the interaction of all these effects, global and local, for the determination of the reinforcements. The model is based on the theory of stress fields and it has been compared to a 3D finite element analysis, in order to validate the interaction domains. The results show how the proposed analytical model allows an easy and reliable reinforcement evaluation, in agreement with a more refined 3D analysis but with a reduced computational burden.

Determination of collapse moment of different angled pipe bends with initial geometric imperfection subjected to in-plane bending moments

2021 ◽  
pp. 095440622199640
Author(s):  
Manish Kumar ◽  
Pronab Roy ◽  
Kallol Khan
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Circular Cross Section ◽  
Initial Imperfection ◽  
Bend Angle ◽  
Bending Moments ◽  
Element Analysis ◽  
Geometric Imperfection ◽  
Initial Geometric Imperfection

From the recent literature, it is revealed that pipe bend geometry deviates from the circular cross-section due to pipe bending process for any bend angle, and this deviation in the cross-section is defined as the initial geometric imperfection. This paper focuses on the determination of collapse moment of different angled pipe bends incorporated with initial geometric imperfection subjected to in-plane closing and opening bending moments. The three-dimensional finite element analysis is accounted for geometric as well as material nonlinearities. Python scripting is implemented for modeling the pipe bends with initial geometry imperfection. The twice-elastic-slope method is adopted to determine the collapse moments. From the results, it is observed that initial imperfection has significant impact on the collapse moment of pipe bends. It can be concluded that the effect of initial imperfection decreases with the decrease in bend angle from 150∘ to 45∘. Based on the finite element results, a simple collapse moment equation is proposed to predict the collapse moment for more accurate cross-section of the different angled pipe bends.

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