Optimum design of middle stage tool geometry and addendum surfaces in sheet metal stamping processes using a new isogeometric-based framework

2021 ◽  
pp. 095440542110410
Author(s):  
Mansoor Shamloofard ◽  
Amir Reza Isazadeh ◽  
Mehdi Bostan Shirin ◽  
Ahmad Assempour
Keyword(s):  
Sheet Metal ◽  
Optimum Design ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Computation Time ◽  
Objective Functions ◽  
Acceptable Accuracy ◽  
Design Variables ◽  
One Step

An efficient isogeometric-based framework is presented to integrate optimum design and formability analysis of sheet metal forming processes. To assess the quality of the formed parts, several objective functions such as fracture, wrinkling, thickness variation, and stretching are studied. In this framework, geometric parameters of addendum surfaces and middle tools are considered as design variables, the objective functions are calculated using the recently developed one-step and multi-step inverse isogeometric methods, and the optimum design variables are obtained using the genetic global optimization algorithm. The major advantage of employing the inverse methods is to analyze the formability of the parts with a low computation time. In this research, the effects of altering addendum surfaces and/or middle tools on the quality of the formed parts are simultaneously observed since modeling, formability analysis, and optimization stages of sheet metal forming simulation are integrated using the NURBS functions. To evaluate the performance of the inverse isogeometric models in calculation of the studied objective functions, the results obtained by these models are compared to those of experiment and forward FEM. Comparisons of the results indicate that these models predict the objective functions with acceptable accuracy at a low computation time. For instance, in sheet metal forming analysis of a rectangular box with three different addendum surfaces, the maximum error in prediction of minimum thickness using the one-step inverse model is approximately 4.65% more than forward FEM, while the solution time of forward FEM is around 40 times greater. Finally, the presented optimization procedure is applied to design addendum surfaces in forming of a rectangular box and the middle tools in a two-stage drawing of a square box. The results of these problems confirm the credibility of the present approach in rapid optimum design of addendum surfaces and intermediate tools with acceptable accuracy.

A Contribution to the Optimisation of a Simple Shear Test

2009 ◽  
Vol 410-411 ◽  
pp. 467-472 ◽  
Author(s):  
Marion Merklein ◽  
M. Biasutti
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Shear Test ◽  
The Finite Element Method ◽  
Simple Shear Test ◽  
Material Parameters

The finite element method is a widely used tool in sheet metal forming. The quality of the results of such an analysis depends largely on the applied constitutive model and its material parameters, which have to be determined experimentally. These data are relevant on the choice of the yield criterion among the wide range of options available in the commercial applications implementing the finite element method. Since the accuracy of material parameters estimation is therefore crucial, investigations were performed with an Al-Mg sheet alloy and a mild steel sheet to optimize a Miyauchi-based simple shear test. This method is one of the basic ways to investigate the plastic properties of a sheet metal up to large strains, which is very important for numerical analysis of sheet metal forming processes. Aim of the test is to determine the shear stress-strain correlation. In order to enhance the quality of the experimental results the detection of the deformation’s field, trough an optical measurement system, and the methodology for its evaluation are focus of the present study.

Numerical Simulation of the Effect of Punch Paths on the Quality of Sheet Metal Stretch Forming

2012 ◽  
Vol 217-219 ◽  
pp. 2002-2005
Author(s):  
Chang Jiang Wang ◽  
Diane J Mynors ◽  
Tarsem Sihra
Keyword(s):  
Numerical Simulation ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Finite Element Modelling ◽  
Metal Strip ◽  
Stretch Forming ◽  
Forming Quality ◽  
Element Modelling

Presented here is the simulation of uniaxial stretch forming using two punches in a sheet metal forming operation. In the finite element modelling, the sheet metal strip was held by two bank holders and two punches are able to move in two directions to stretch the sheet metal. Due to the friction between the punch and sheet metal, it was found that friction affects the sheet metal forming quality, however by adopting an optimal punch path the effect of friction in sheet metal forming can be reduced. The effect of punch paths on the quality of the sheet metal are also reported in this paper.

scholarly journals Blank shape optimization considering 3D space targets for external and internal boundaries in sheet metal forming processes

2021 ◽  
Author(s):  
Hamidreza Gharehchahi ◽  
Mohammad Javad Kazemzadeh-Parsi ◽  
Ahmad Afsari ◽  
Mehrdad Mohammadi
Keyword(s):  
Sheet Metal ◽  
Optimum Design ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Production Costs ◽  
Internal Boundary ◽  
Optimum Shape ◽  
Plastic Behavior ◽  
3D Space ◽  
Blank Shape

Abstract The optimum design of an initial blank shape in sheet metal forming processes is an important step in many industries, especially automobile manufacturers because it reduces production costs and material waste. To the best of our knowledge, no research has been conducted on the blank shape designs based on 3D space target contours. Moreover, the present study considers parts with internal boundaries and optimum design of the internal boundary, which are among the innovations of this research. By following the iterative simulation-based optimization process, a special updating algorithm was proposed to modify the blank geometry in each iteration and reach the optimum shape. The sheet forming was severely nonlinear, due to plastic behavior, large deformations, and frictional contact surfaces. Therefore, the updating formula should be robust enough to be insensitive to the initial guess for the blank. To evaluate the proposed updating formula, some numerical examples were solved and the results were presented. Finally, the robustness of the proposed algorithm was investigated in these numerical experiences, by considering different geometries, target contours, internal boundaries, and initial guesses. The present study reveals that the proposed algorithm can be effectively used to solve blank optimization problems for the deep drawing process.

Study on Parameters for Affecting SCI of Sheet Metal Forming

2010 ◽  
Vol 44-47 ◽  
pp. 2862-2866
Author(s):  
Ji Tao Du
Keyword(s):  
Mechanical Property ◽  
Surface Quality ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Friction Condition ◽  
Experimental Results ◽  
Forming Defect ◽  
Punch Radius

The surface contact impression(SCI) is the neglected forming defect and seriously affects surface quality and mechanical property of stamping parts. The technology parameters and affective degree which alleviate or eliminate SCI are researched , four factors including die radius(DR) , die clearance(DC), punch radius(PR) and friction condition(FC) , which each factor chooses three levels are designed and constitute a L9（34）orthogonal table. The experimental results indicate that the significances order of technology parameters affecting SCI is DR> PR > DC >FC. The analyzed result shows that the superior parameter affecting SCI is DR ,the inferior is FC, adapted DC greatly removes SCI. the research puts forward a reference for improving surface quality of stamping parts.

Deep Drawing Process Design: A Multi Objective Optimization Approach

2009 ◽  
Vol 410-411 ◽  
pp. 601-608 ◽  
Author(s):  
Rosanna Di Lorenzo ◽  
Giuseppe Ingarao ◽  
Laura Marretta ◽  
Fabrizio Micari
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Optimal Solution ◽  
Optimization Procedure ◽  
Pareto Optimal Solution ◽  
Pareto Optimal ◽  
Drawing Process ◽  
Deep Drawing Process ◽  
Design Variables

In sheet metal forming most of the problems are multi objective problems, generally characterized by conflicting objectives. The definition of proper parameters aimed to prevent both wrinkles and fracture is a typical example of an optimization problem in sheet metal forming characterized by conflicting goals. What is more, nowadays, a great interest would be focused on the availability of a cluster of possible optimal solutions instead of a single one, particularly in an industrial environment. Thus, the design parameters calibration, accomplishing all the objectives, is difficult and sometimes unsuccessful. In order to overcome this drawback a multi-objectives optimization procedure based on Pareto optimal solution search techniques seems a very attractive approach to deal with sheet metal forming processes design. In this paper, an integration between numerical simulations, response surface methodology and Pareto optimal solution search techniques was applied in order to design a rectangular deep drawing process. In particular, the initial blank shape and the blank holder force history were optimized as design variables in order to accomplish two different objectives: reduce excessive thinning and avoid wrinkling occurrence. The steps of the optimization procedure include: 1) application of Central Composite Design (CCD) for the identification of the necessary data over the domain of variation of the design variables; 2) numerical simulations of the samples identified by CCD; 3) development of a response surface model to interpret the final objectives as functions of the design variables; 4) Pareto optimal solution analysis to reach the most performing design variables. The final aim is to develop a predictive tool able to identify a sort of process window for the analyzed process also minimizing the computational effort in particular with respect to mono-objective optimization techniques or traditional trial and error methods. Many possible technological scenarios were investigated by the implemented procedure and a set of reliable solutions, i.e. able to satisfy different design requirements, were obtained.

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