Failure Analysis of Metallic Materials in Sheet Metal Forming Using Finite Element Method

2008 ◽  
Vol 587-588 ◽  
pp. 736-740
Author(s):  
Pedro Teixeira ◽  
Abel D. Santos ◽  
J. César de Sá ◽  
Augusto Barata da Rocha
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Damage Mechanics ◽  
Damage Model ◽  
High Strength Steels ◽  
High Strength ◽  
Continuum Damage Mechanics ◽  
Traditional Use

The optimisation of sheet metal processes by using numerical simulations has become a key factor to a continuously increasing requirement for time and cost efficiency, for quality improvement and materials saving, in many manufacturing areas such as automotive, aerospace, building, packaging and electronic industries. The introduction of new materials brought new challenges to sheet metal forming processes. The behaviour observed with conventional steels may not be applied when using high-strength steels or aluminium alloys. Numerical codes need to model correctly the material and different constitutive equations must be considered to describe with greater accuracy its behaviour. This enhancement of material description may provide a better prediction of the forming limits, enabling an assessment of the influence of each forming parameter on the necking occurrence and the improvement of press performance. This paper presents two numerical approaches for failure prediction in sheet metal forming operations: one is the implementation of the Lemaitre’s ductile damage model in the Abaqus/Explicit code in accordance with the theory of Continuum Damage Mechanics and the other is the traditional use of FLDs, usually employed as an analysis of the finite element solution in which the necking phenomenon is carried out in the framework of Marciniak-Kuczinsky (M-K) analysis coupled with the conventional theory of plasticity. The previous strategies and corresponding results are compared with two experimental failure cases, in order to test and validate each of these strategies.

An Investigation of Springback in U-Channel Sheet Metal by Finite Element Analysis

2012 ◽  
Vol 548 ◽  
pp. 456-460 ◽  
Author(s):  
Gopi Alagappan ◽  
Syed H. Masood ◽  
Xuan Zhi Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
High Strength Steels ◽  
High Strength ◽  
Element Analysis ◽  
Advanced High Strength Steels ◽  
Forming Tools

In sheet metal forming, springback is defined as an elastic material recovery after unloading of the forming tools. Springback causes variations and inconsistencies of final part dimensions. Therefore prediction of springback is very important for production of precise products used in automobile and aerospace industries. There are various parameters involved in the process of sheet metal forming, including Young’s modulus, coefficient of friction, Poisson’s ratio, blank thickness, blank length, die radius, punch radius and blank holder force. The aim of this paper is to investigate the springback of a U-channel part by finite element analysis (FEA) and to identify the influences of important parameters on the springback of advanced high strength steels (AHSS) using numerical simulation.

An Enhanced Hybrid Springback Compensation Approach: Springback Path – Displacement Adjustment Method For Complex Shaped Products of Sheet Metal Forming

2021 ◽  
Author(s):  
Zhihui Gong ◽  
Mandeep Singh ◽  
Bohao Fang ◽  
Dongbin Wei
Keyword(s):  
Sheet Metal ◽  
Automobile Industry ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
High Strength Steels ◽  
Fem Analysis ◽  
High Strength ◽  
Design Stage ◽  
Springback Compensation ◽  
Compensation Approach

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.

scholarly journals Simulation of Sheet Metal Forming Processes Using a Fully Rheological-Damage Constitutive Model Coupling and a Specific 3D Remeshing Method

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 991 ◽  
Author(s):  
Abel Cherouat ◽  
Houman Borouchaki ◽  
Zhang Jie
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Constitutive Equations ◽  
Metal Forming ◽  
Damage Mechanics ◽  
Three Dimensions ◽  
Automatic Process ◽  
Adaptive Remeshing ◽  
Fully Coupled

Automatic process modeling has become an effective tool in reducing the lead-time and the cost for designing forming processes. The numerical modeling process is performed on a fully coupled damage constitutive equations and the advanced 3D adaptive remeshing procedure. Based on continuum damage mechanics, an isotropic damage model coupled with the Johnson–Cook flow law is proposed to satisfy the thermodynamic and damage requirements in metals. The Lemaitre damage potential was chosen to control the damage evolution process and the effective configuration. These fully coupled constitutive equations have been implemented into a Dynamic Explicit finite element code Abaqus using user subroutine. On the other hand, an adaptive remeshing scheme in three dimensions is established to constantly update the deformed mesh to enable tracking of the large plastic deformations. The quantitative effects of coupled ductile damage and adaptive remeshing on the sheet metal forming are studied, and qualitative comparison with some available experimental data are given. As illustrated in the presented examples this overall strategy ensures a robust and efficient remeshing scheme for finite element simulation of sheet metal‐forming processes.

Numerical Prediction of Failure within Small Curvature Bending of Advanced High Strength Steels

2015 ◽  
Vol 639 ◽  
pp. 419-426
Author(s):  
Ioannis Tsoupis ◽  
Marion Merklein
Keyword(s):  
Crack Initiation ◽  
Damage Mechanics ◽  
Numerical Study ◽  
Damage Model ◽  
High Strength Steels ◽  
High Strength ◽  
Continuum Damage Mechanics ◽  
Calibration Method ◽  
Damage Parameter ◽  
Small Curvature

Within this paper a numerical study of the Continuum Damage Mechanics based damage model Lemaitre in commercial software LS-DYNA is performed in order to correctly predict failure in terms of crack occurrence within small curvature bending of AHSS steels. A strain based calibration method is used for the effective adaption of the Lemaitre model to the bending operation, which is based on the comparison and adaption of the numerically calculated and the experimentally measured deformation field on the outer surface of the bent specimen. Within this method the material dependent damage parameter S is systematically varied in the simulation in order to represent maximum major strain. The new method is proved by numerical simulation of experiments provoking crack initiation using smaller bending radii. It can be shown that failure in terms of crack initiation can be correctly predicted by the model with the damage parameters, which were determined by the method of strain based calibration and an additional optimisation of the parameter Dc. Thus, within this study a user friendly and effective way for the application of Lemaitre damage model to small curvature bending processes of AHSS steels is developed.

Advanced Materials in Sheet Metal Forming

2013 ◽  
Vol 581 ◽  
pp. 137-142 ◽  
Author(s):  
Miklós Tisza
Keyword(s):  
Sheet Metal ◽  
Automotive Industry ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Driving Forces ◽  
High Strength Steels ◽  
High Strength ◽  
Advanced Materials ◽  
Harmful Emission ◽  
Application Fields

In this paper, some recent developments in materials applied in sheet metal forming processes will be overviewed mainly from the viewpoint of automotive industry as one of the most important application fields. If we consider the main requirements in the automotive industry we can state that there are very contradictory demands on developments. Better performance with lower consumption and lower harmful emission, more safety and comfort are hardly available simultaneously with conventional materials and conventional manufacturing processes. These requirements are the main driving forces behind the material and technological developments in sheet metal forming: application of high strength steels, low weight light alloys and the appropriate non-conventional forming processes are the main target fields of developments summarized in this paper.

Experimental Study on Galling Behavior of Advanced High Strength Steel in Sheet Metal Forming

2012 ◽  
Vol 502 ◽  
pp. 36-40
Author(s):  
Ying Ke Hou ◽  
Shu Hui Li ◽  
Yi Xi Zhao ◽  
Zhong Qi Yu
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Sheet Material ◽  
High Strength Steels ◽  
High Strength ◽  
Forming Process ◽  
Advanced High Strength Steels ◽  
Sheet Materials ◽  
Materials Used

Galling is a known failure mechanism in many sheet metal forming processes. It limits the lifetime of tools and the quality of the products is affected. In this study, U-channel stamping experiments are performed to investigate the galling behavior of the advanced high strength steels in sheet metal forming . The sheet materials used in the tests are DP590 and DP780. In addition to the DP steels, the mild steel B170P1 is tested as a reference material in this study. Experimental results indicate that galling problem becomes severe in the forming process and the galling tendency can be divided into three different stages. The results also show that sheet material and tool hardness have crucial effects on galling performance in the forming of advanced high strength steels. In this study, DP780 results in the most heaviest galling among the three types of sheet materials. Galling performance are improved with increased hardness of the forming tool.

Assessment of Damage Models in Sheet Metal Forming for Industrial Applications

2011 ◽  
Vol 473 ◽  
pp. 482-489
Author(s):  
Maria Doig ◽  
Karl Roll
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Damage Model ◽  
High Strength ◽  
Industrial Applications ◽  
Production Costs ◽  
Model Parameters ◽  
Damage Prediction ◽  
Damage Models

Due to increasing demands to reduce C02-emission and to augment occupant’s safety new modern materials are developed ongoing. Because of relatively low production costs, high strength and simultaneously good formability the advanced high strength steels (AHSS) are applied among others for the lightweight design of body-in-white components in the automotive industry. Their already mentioned properties follow from the presence of mixed mild and hard ferrous phases. Due to this multiphase microstructure of the most AHSS steels, a complex material and damage behavior is observed during forming. The damage grows in a ductile manner during plastic flow and the cracks appear without necking. They are often characterized as the so called shear cracks. The damage predictions with standard methods like the forming limit curve (FLC) lack accuracy and reliability. These methods are based on the measurement of linear strain paths. On the other hand ductile damage models are generally used in the bulk forming and crash analysis. The goal is to prove if these models can be applied for the damage prediction in sheet metal forming and which troubles have to be overcome. This paper demonstrates the capability of the Gurson-Tvergaard-Needleman (GTN) model within commercial codes to treat industrial applications. The GTN damage model describes the existence of voids and they evolution (nucleation, growth and coalescence). After a short introduction of the model the finite element aspects of the simulative damage prediction have been investigated. Finally, the determination of the damage model parameters is discussed for a test part.

Numerical Prediction of Forming Limit in Hemispherical Punch Bulging by Lemaitre's Ductile Damage Model

2011 ◽  
Vol 110-116 ◽  
pp. 1437-1441 ◽  
Author(s):  
Farhad Haji Aboutalebi ◽  
Mehdi Nasresfahani
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Damage Mechanics ◽  
Thin Sheet ◽  
Damage Model ◽  
Ductile Damage ◽  
Forming Limit ◽  
St14 Steel ◽  
Hemispherical Punch

Prediction of sheet metal forming limits or analysis of forming failures is a very sensitive problem for design engineers of sheet forming industries. In this paper, first, damage behaviour of St14 steel (DIN 1623) is studied in order to be used in complex forming conditions with the goal of reducing the number of costly trials. Mechanical properties and Lemaitre's ductile damage parameters of the material are determined by using standard tensile and Vickers micro-hardness tests. A fully coupled elastic-plastic-damage model is developed and implemented into an explicit code. Using this model, damage propagation and crack initiation, and ductile fracture behaviour of hemispherical punch bulging process are predicted. The model can quickly predict both deformation and damage behaviour of the part because of using plane stress algorithm, which is valid for thin sheet metals. Experiments are also carried out to validate the results. Comparison of the numerical and experimental results shows good adaptation. Hence, it is concluded that finite element analysis in conjunction with continuum damage mechanics can be used as a reliable tool to predict ductile damage and forming limit in sheet metal forming processes.

Formability of High Strength Sheet Metals with Special Regard to the Effect of the Influential Factors on the Forming Limit Diagrams

2015 ◽  
Vol 812 ◽  
pp. 271-275 ◽  
Author(s):  
Miklós Tisza ◽  
Péter Zoltán Kovács ◽  
Zsolt Lukács ◽  
Antal Kiss ◽  
Gaszton Gál
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
High Strength Steels ◽  
High Strength ◽  
Forming Limit ◽  
Experimental Investigations ◽  
Sheet Metals ◽  
Forming Limit Diagrams ◽  
Research Activities

Car manufacturing is one of the main target fields of sheet metal forming: thus sheet metal forming is exposed to the same challenges as the automotive industry. The continuously increasing demand on lower consumption and lower CO2 emission means the highest challenges on materials developments besides design and construction. As a general requirement, the weight reduction and light weight construction principles should be mentioned together with the increased safety prescriptions which require the application of high strength steels. However, the application of high strength steels often leads to formability problems. Forming Limit Diagrams (FLD) are the most appropriate tools to characterize the formability of sheet metals. Theoretical and experimental investigations of forming limit diagrams are in the forefront of todays’ research activities.

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