Dependence of micro-hardness on deformation of deep-drawing steel sheets

Cotterell, M.; Schambergerova, J; Ziegelheim, J.; Janovec, Jiří

doi:10.1016/s0924-0136(02)00203-0

Cited by 17 publications

(14 citation statements)

References 2 publications

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“…The hardness value at O point is equal to the hardness value in elastic field. The above findings are also confirmed by Cotterell et al 8 He reported significantly higher hardness values in the region close to the crack tip, where localized deformation is occurred.…”

Section: Calculation For the Plastic Part (δ Pl )supporting

confidence: 83%

Study of influence of notch root radius on fracture behaviour of extra deep drawn steel sheets

Chaudhari

Kulkarni

Prakash

2009

Fatigue Fract Eng Mat Struct

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A B S T R A C T Fracture tests are carried out on extra deep drawn steel CT specimens containing notches with different values of notch root radius (ρ = 0.07-0.75 mm). Experimental findings clearly show a critical notch root radius (ρ c ) below which the fracture toughness remains independent of ρ and above which it varies linearly with ρ. The 3D finite element analysis shows that the location of maximum stress level causing crack initiation is in the vicinity of notch tip. The maximum stress level is independent of ρ; however, its location is shifted away from notch tip along unbroken ligament length with increase in ρ. I N T R O D U C T I O NFatigue pre-cracking is always preferred for pre-cracking process on test samples for fracture test. However, it is observed that specimens are damaged during fatigue precracking process as crack direction is changed because of vibrations in machine and in fixture holding the specimen. It is also observed that the fatigue pre-cracking induces residual plastic stresses. Such samples may produce wrong results on fracture toughness. The fatigue pre-crackingis a time consuming process as well. The other option 'wire electric discharge machine' (WEDM) is extensively used with least wire diameter for pre-cracking. WEDM produces notched specimens with finite notch radius. In the early 1960s, many studies have been made to see how the apparent fracture toughness was dependent on notch root radius. At that time, the discussions were mainly devoted to linear elastic fracture mechanics (LEFM). The present work is devoted on a thin sheet steel material in which the LEFM conditions do not apply. In this study, an experimental and finite element investigation of influence of notch radius on fracture toughness is presented.

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Section: Calculation For the Plastic Part (δ Pl )supporting

confidence: 83%

Study of influence of notch root radius on fracture behaviour of extra deep drawn steel sheets

Chaudhari

Kulkarni

Prakash

2009

Fatigue Fract Eng Mat Struct

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“…A relationship between Vickers hardness and the yield stress of non-strain hardening and strain hardening materials metal was described by Tabor [3]. Other researchers have also found variations in hardness in different parts of components that connected with different deformations during processing [6][7][8][9]. Those studies revealed that plastic strain is related closely to hardness.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Relationship between Hardness and Principal Strain in Tube Hydroforming Process

Wang¹,

Chan²,

Segui³

2009

AIP Conference Proceedings

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Numerical and experimental study of sheet metal hydroforming AIP Conf.Abstract. In order to find a feasible method to evaluate the deformation of tubes during the Tube Hydroforming (THF) process, the hardness and the strain in two selected deformation areas of hydro formed copper tubes (CI 1000) were measured and tested, and an instinct relationship was found between the hardness and the principal strains of the tubes. The major strain of the surface of tubes had the strongest linear relationship with hardness. A regression formula was used to describe the relationship between hardness and the sensitive strain which is defined in the present work as a dependent variable of major strain and thickness strain.

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“…This method is also well accepted for measuring the mechanical properties such as flow stress, fracture stress, elastic modulus and fracture toughness. Cotterell et al (2002) and Guelorget et al (2007) observed an increase in the micro-hardness of material after tensile testing and showed that it was due to work hardening. They also concluded that the micro-hardness in the surface of the specimen was higher than in its center and in addition, higher hardness values were recorded in the region close to the fracture surface.…”

Section: Introductionmentioning

confidence: 99%

Identification of damage parameters and plastic properties of an anisotropic damage model by micro-hardness measurements

Ganjiani

2013

International Journal of Damage Mechanics

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In this paper, an elastoplastic-anisotropic damage constitutive model is proposed for the identification of damage parameters of Al2024-T3 by micro-hardness measurements. For this purpose, micro-hardness experiments are conducted on the surface of the specimens after the standard tensile tests. A procedure for the identification of the damage as a tensor variable is followed and then, the parameters of the model are calibrated. Also, the constitutive equations are implemented in a finite element explicit code to simulate the double-edge-notched specimen under shear loads and the tensile test. The results of the simulations are in a good agreement with those obtained in the experiments.

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Dependence of micro-hardness on deformation of deep-drawing steel sheets

Cited by 17 publications

References 2 publications

Study of influence of notch root radius on fracture behaviour of extra deep drawn steel sheets

Study of influence of notch root radius on fracture behaviour of extra deep drawn steel sheets

Experimental Study on the Relationship between Hardness and Principal Strain in Tube Hydroforming Process

Identification of damage parameters and plastic properties of an anisotropic damage model by micro-hardness measurements

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