An Engineering Approach to Improve the Stamping Robustness of High Strength Steels

Author(s):  
Wu-rong Wang ◽  
Bo Hou ◽  
Zhong-qin Lin ◽  
Z. Cedric Xia

High strength steels (HSSs) are one of the light-weight sheet metals well suited for reducing vehicle weight due to their higher strength-to-weight ratio. However, HSS tend to have bigger variations in their mechanical properties due to more complex rolling techniques involved in the steel-making process. Such uncertainties, when combined with variations in the process parameters such as friction and blank holder force, pose a significant challenge in maintaining the robustness of HSS sheet metal stamping. The paper presents a systematic and robust approach, combining the power of the finite element method and stochastic statistics to decrease the sensitivity of HSS stamping in the presence of above-mentioned uncertainties. First, the statistical distribution of sheet metal properties of selected HSS is characterized from a material sampling database. Then a separate interval adaptive response surface methodology (RSM) is applied in modeling sheet metal stamping. The new method significantly improves the model accuracy when compared with the conventional RSM within a single interval. Finally, the Monte Carlo method is employed to simulate the stochastic response of material/process variations to stamping quality and to provide optimal process parameter designs to reduce the sensitivity of these effects. The experiment with the obtained optimal process design demonstrates the improvements of stamping robustness using small-batch experiments.

2011 ◽  
Vol 337 ◽  
pp. 350-353 ◽  
Author(s):  
Xuan Zhi Wang ◽  
S.H. Masood

Advanced high strength steels (AHSS) are increasingly utilised in sheet metal stamping in the automotive manufacture. In comparison with conventional steels, AHSS stampings produce higher contact pressures at the interface between the tool-workpiece interface, leading to more severe wear conditions, particularly at the draw die radius. To minimise tool wear using this approach it would be necessary to optimise the shape for a particular combination of circular and high elliptical profiles. This paper presents a methodology to optimise a die radius profile. For this, a specialised software routine is developed and compiled for optimisation of die radius profiles to minimise or achieve uniform contact pressure (wear distribution) using Python computer programming language supported by Abaqus software. A detailed algorithm for the optimisation is explained. A case study based on the algorithm is also discussed.


2010 ◽  
Vol 654-656 ◽  
pp. 346-349
Author(s):  
Xuan Zhi Wang ◽  
Syed H. Masood

Advanced high strength steels (AHSS) are increasingly used in sheet metal stamping in the automotive industry. In comparison with conventional steels, advanced high strength steel (AHSS) stampings produce higher contact pressures at the interface between draw die and sheet metal blank, resulting in more severe wear conditions, particularly at the draw die radius. The prediction of tool wear patterns for sheet metal stamping die is a highly challenging task as there are many control parameters involved in the production. This paper presents a numerical simulation methodology to analyse the influences of various control parameters on tool wear patterns of a sheet metal stamping die with different die radius arc profiles. The results of tool wear patterns provide informative guidelines for on-site production.


Author(s):  
Xiaobing Dang ◽  
Ruxu Du ◽  
Kai He ◽  
Qiyang Zuo

As a light-weight material with high stiffness and strength, cellular metal has attracted a lot of attentions in the past two decades. In this paper, the structure and mechanical properties of aluminum cellular metal with periodic cubic cells are studied. The aluminum cellular metal is fabricated by sheet metal stamping and simple adhesion. Two sizes of specimens with cell sizes of 3mm and 5mm are fabricated. Their relative density and mechanical properties are tested by means of experiments. The results show that the cubic-cell cellular metal has high and predictable strength and hence, can be used for many practical applications.


2021 ◽  
Author(s):  
Zhihui Gong ◽  
Mandeep Singh ◽  
Bohao Fang ◽  
Dongbin Wei

Abstract Springback compensation is critical in sheet metal forming. Advanced techniques have been adopted in the design stage of various sheet metal forming processes, e.g. stamping, some of which are for complex shaped products. However, the currently available numerical approaches are not always sufficiently accurate and reliable. To improve the accuracy of springback compensation, an enhanced hybrid springback compensation method named Springback Path – Displacement Adjustment (SP-DA) method has been developed in this study based on the well-known conventional displacement adjustment (DA) method. Its effectiveness is demonstrated using FEM analysis of low, medium and high strength steels adopted in automobile industry, in which a symmetrical model owning geometry complexity similar to an auto body panel was established. The results show this new enhanced SP-DA method is able to significantly improve the accuracy of springback compensation comparing to conventional displacement adjustment technique.


Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 631 ◽  
Author(s):  
Hamid Bayat ◽  
Sayantan Sarkar ◽  
Bharath Anantharamaiah ◽  
Francesco Italiano ◽  
Aleksandar Bach ◽  
...  

Increased passenger safety and emission control are two of the main driving forces in the automotive industry for the development of light weight constructions. For increased strength to weight ratio, ultra-high-strength steels (UHSSs) are used in car body structures. Prediction of failure in such sheet metals is of high significance in the simulation of car crashes to avoid additional costs and fatalities. However, a disadvantage of this class of metals is a pronounced scatter in their material properties due to e.g., the manufacturing processes. In this work, a robust numerical model is developed in order to take the scatter into account in the prediction of the failure in manganese boron steel (22MnB5). To this end, the underlying material properties which determine the shapes of forming limit curves (FLCs) are obtained from experiments. A modified Marciniak–Kuczynski model is applied to determine the failure limits. By using a statistical approach, the material scatter is quantified in terms of two limiting hardening relations. Finally, the numerical solution obtained from simulations is verified experimentally. By generation of the so called forming limit bands (FLBs), the dispersion of limit strains is captured within the bounds of forming limits instead of a single FLC. In this way, the FLBs separate the whole region into safe, necking and failed zones.


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