Ductile Fracture from Spot Weld and Flange Edge in Advanced High Strength Steels

2017 ◽  
Vol 10 (2) ◽  
pp. 373-381 ◽  
Author(s):  
Kentaro Sato ◽  
Takayuki Futatsuka ◽  
Jiro Hiramoto ◽  
Kei Nagasaka ◽  
Akira Akita ◽  
...  
Keyword(s):  
Ductile Fracture ◽  
High Strength Steels ◽  
High Strength ◽  
Spot Weld ◽  
Advanced High Strength Steels

scholarly journals Spot Weld Strength Determination Using the Wedge Test: In Situ Observations and Coupled Simulations

2010 ◽  
Vol 24-25 ◽  
pp. 299-304 ◽  
Author(s):  
Rémi Lacroix ◽  
Joël Monatte ◽  
Arnaud Lens ◽  
Guillaume Kermouche ◽  
J.M. Bergheau ◽  
...  
Keyword(s):  
Energy Analysis ◽  
High Strength Steels ◽  
High Strength ◽  
Spot Weld ◽  
Weld Strength ◽  
Spot Welds ◽  
Local Loading ◽  
Advanced High Strength Steels ◽  
Strength Determination

This paper describes an innovative way to characterize the strength of spot welds. A wedge test has been developed to generate interfacial failures in weldments and observe in-situ the crack propagation. An energy analysis quantifies the spot weld crack resistance. Finite Element calculations investigate the stresses and strains along the crack front. A comparison of the local loading state with experimentally observed crack fronts provides the necessary data for a failure criterion in spot weld fusion zones. The method is applied to spot welds of Advanced High Strength steels.

Evaluation and Validation of Methods to Determine Limit Strain States with Focus on Modeling Ductile Fracture

2014 ◽  
Vol 622-623 ◽  
pp. 265-272
Author(s):  
Andreas Sabathil ◽  
Ingo Heinle ◽  
A. Lipp ◽  
J. Meinhardt ◽  
M. Merklein
Keyword(s):  
Ductile Fracture ◽  
Sheet Metal ◽  
High Strength Steels ◽  
High Strength ◽  
Limit Strain ◽  
Model Parameters ◽  
Element Analysis ◽  
Advanced High Strength Steels ◽  
Validation Experiment ◽  
Body In White

In the manufacturing process of body in white components made from sheet metal it is state of the art to accompany the process by means of finite element analysis. A main criterion for determining a feasible tool design and production process parameters is the prediction of material failure, which can be categorized in instability and ductile fracture. The ductile fracture failure mode is more likely to occur, as more advanced high strength steels and aluminum alloys are used for body in white components. Therefore different approaches have been presented to model ductile fracture over the past years. This task is more challenging when the material is exposed to arbitrary loading paths that can occur in deep drawing processes. However there is no guideline for sheet metal forming applications to determine which models for predicting ductile fracture are suitable, which experiments are necessary and how calibration of model parameters and validation of model prediction can be performed. Additionally there is no standard established that prescribes the evaluation of limit strain states from experiments. Suitable limit strain states are a basic requirement for prediction of ductile fracture as they are used for calibration of fracture models. In this paper, two methods for evaluation of limit strains are discussed and applied to tensile specimens with circular hole and circular cut outs made from aluminum alloy AlSi0.6Mg0.5. One validation experiment is used to investigate failure prediction that is based on limit strain states from different evaluation methods.

Numerical modeling of stress-strain relationships for advanced high strength steels

2021 ◽  
Vol 182 ◽  
pp. 106687
Author(s):  
Yu Xia ◽  
Chu Ding ◽  
Zhanjie Li ◽  
Benjamin W. Schafer ◽  
Hannah B. Blum
Keyword(s):  
Numerical Modeling ◽  
High Strength Steels ◽  
High Strength ◽  
Stress Strain ◽  
Advanced High Strength Steels

scholarly journals Heat Treatment Design for a QP Steel: Effect of Partitioning Temperature

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1136
Author(s):  
Marcel Carpio ◽  
Jessica Calvo ◽  
Omar García ◽  
Juan Pablo Pedraza ◽  
José María Cabrera
Keyword(s):  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
Tensile Tests ◽  
Quenching Temperature ◽  
Advanced High Strength Steels ◽  
New Family ◽  
Automotive Parts ◽  
Fresh Martensite ◽  
Industry Needs

Designing a new family of advanced high-strength steels (AHSSs) to develop automotive parts that cover early industry needs is the aim of many investigations. One of the candidates in the 3rd family of AHSS are the quenching and partitioning (QP) steels. These steels display an excellent relationship between strength and formability, making them able to fulfill the requirements of safety, while reducing automobile weight to enhance the performance during service. The main attribute of QP steels is the TRIP effect that retained austenite possesses, which allows a significant energy absorption during deformation. The present study is focused on evaluating some process parameters, especially the partitioning temperature, in the microstructures and mechanical properties attained during a QP process. An experimental steel (0.2C-3.5Mn-1.5Si (wt%)) was selected and heated according to the theoretical optimum quenching temperature. For this purpose, heat treatments in a quenching dilatometry and further microstructural and mechanical characterization were carried out by SEM, XRD, EBSD, and hardness and tensile tests, respectively. The samples showed a significant increment in the retained austenite at an increasing partitioning temperature, but with strong penalization on the final ductility due to the large amount of fresh martensite obtained as well.

Selection and use of coated advanced high-strength steels for automotive applications

2004 ◽  
Vol 101 (7-8) ◽  
pp. 551-558 ◽  
Author(s):  
R. Bode ◽  
M. Meurer ◽  
T. W. Schaumann ◽  
W. Warnecke
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Automotive Applications ◽  
Advanced High Strength Steels

Influence of the contact with friction on the deformation behavior of advanced high strength steels in the Nakajima test

2021 ◽  
pp. 030932472110212
Author(s):  
Mohammad Mehdi Kasaei ◽  
Marta C Oliveira
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Strain Rate ◽  
Contact Pressure ◽  
Deformation Behaviour ◽  
High Strength Steels ◽  
High Strength ◽  
Advanced High Strength Steels ◽  
Deformation Mechanics ◽  
Nakajima Test

This work presents a new understanding on the deformation mechanics involved in the Nakajima test, which is commonly used to determine the forming limit curve of sheet metals, and is focused on the interaction between the friction conditions and the deformation behaviour of a dual phase steel. The methodology is based on the finite element analysis of the Nakajima test, considering different values of the classic Coulomb friction coefficient, including a pressure-dependent model. The validity of the finite element model is examined through a comparison with experimental data. The results show that friction affects the location and strain path of the necking point by changing the strain rate distribution in the specimen. The strain localization alters the contact status from slip to stick at a portion of the contact area from the pole to the necking zone. This leads to the sharp increase of the strain rate at the necking point, as the punch rises further. The influence of the pressure-dependent friction coefficient on the deformation behaviour is very small, due to the uniform distribution of the contact pressure in the Nakajima test. Moreover, the low contact pressure range attained cannot properly replicate real contact condition in sheet metal forming processes of advanced high strength steels.

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