Development of a Device Compatible with Universal Testing Machine to Perform Hole Expansion and Erichsen Cupping Tests

Santos, Rafael Oliveira; Péreira, A.; Butuc, Marilena C.; Vincze, Gabriela; Festas, António; Moreira, Luciano Pessanha

doi:10.3390/machines8010002

Cited by 8 publications

(4 citation statements)

References 15 publications

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“…Anisotropy is one of the reasons that sheet metal demonstrates different mechanical behavior along different directions. Thus, Bakhshi-Jooybari et al chose CK 67 steel sheet and bent in different orientations to examine anisotropy factor [38]. To investigate anisotropy effect on spring-back behavior, sheet metal was bent in different rolling directions.…”

Section: Effect Of Die Angle and Rolling Direction On Spring-back Anglementioning

confidence: 99%

An experimental investigation of formability of inconel sheet plate for different die angles and rolling directions in press brake bending

HAYRAT

Kosa

DURMUŞOĞLU

2023

European Mechanical Science

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The formability of Inconel materials is important to be used in engineering applications such as in fields of aircraft and maritime. The aim of study is to investigate bending characteristic and formability of Inconel 625 material having a property of corrosion resistance and high strength. In the paper, spring-back phenomena of Inconel 625 sheets are focused on experimentally. The 4 specimens for each different die angle are prepared to be bent. The press brake is used for forming Inconel 625 sheets. The die angle is altered from 90˚ to 150˚. The different rolling direction such as 0˚ and 90˚ is chosen to investigate the effect of grain orientation on spring-back of Inconel sheets. The bending radius is constant and set as 2 mm for all bending tests. The spring-back angles and amounts are measured. Results show that as the bending angle is increased, the spring-back amount in units of angle is decreased averagely from 3.35˚ to 2.58˚ for 0˚ rolling direction and maximum spring-back angle is obtained at a die angle of 120˚ for rolling direction of 90˚. Finally, Erichsen cupping test is also applied to determine the deformability of Inconel sheets. It is demonstrated that cup height value has been found as 17.20 mm.

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Section: Effect Of Die Angle and Rolling Direction On Spring-back Anglementioning

confidence: 99%

An experimental investigation of formability of inconel sheet plate for different die angles and rolling directions in press brake bending

HAYRAT

Kosa

DURMUŞOĞLU

2023

European Mechanical Science

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“…The term "stretch-flangeability" refers to the ability of sheet metal materials to resist edge cracking when exposed to edge stretching deformation. This property is typically evaluated through hole punching and expansion tests [4].…”

Section: Introductionmentioning

confidence: 99%

Application of Digital Image Processing Techniques to Detect Through-Thickness Crack in Hole Expansion Test

Cruz

Amaral

Santos

et al. 2023

Metals

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Advanced high-strength steels (AHSS) have become increasingly popular in the automotive industry due to their high yield and ultimate tensile strengths, enabling the production of lighter car body structures while meeting safety standards. However, they have some setbacks compared to conventional steels, such as edge cracking through sheet thickness caused by forming components with shear-cut edges. When characterizing the formability of sheet metal materials, the hole expansion test is an industry-standard method used to evaluate the stretch-flangeability of their edges. However, accurately visualizing the first cracking is usually tricky and may be subjective, often leading to inconsistent results and low reproducibility with some impact of the operator on both direct and post-processing measurements. To address these issues, a novel digital image processing method is presented to reduce operator reliance and enhance the accuracy and efficiency of the hole expansion test results. By leveraging advanced image processing algorithms, the proposed approach detects the appearance of the first edge cracks, enabling a more precise determination of the hole expansion ratio (HER). Furthermore, it provides valuable insights into the evolution of the hole diameter, allowing for a comprehensive understanding of the material behavior during the test. The proposed method was evaluated for different materials, and the corresponding HER values were compared with the traditional method.

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“…Paul [22] carried out hole expansion tests with various kinds of AHSS sheets to evaluate the edge formability, but their HER measurement results have large deviations due to the inconsistent HER evaluation. Santos et al [23] developed a test machine for the hole expansion test to evaluate the HER in terms of various thicknesses. They utilized real-time image acquisition from a video camera, but there was a large deviation in the HER results due to the different material conditions such as light reflection.…”

Section: Introductionmentioning

confidence: 99%

Integrated Machine Vision System for Evaluating Hole Expansion Ratio of Advanced High-Strength Steels

et al. 2022

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In this paper, we propose a new method to estimate the hole expansion ratio (HER) using an integrated analysis system. To precisely measure the HER, three kinds of analysis methods (computer vision, punch load, and acoustic emission) were utilized to detect edge cracks during a hole expansion test. Cracks can be recognized by employing both computer vision and a punch load analysis system to determine the moment of crack initiation. However, the acoustic emission analysis system has difficulty detecting the instant of crack appearance since the magnitude of the audio signal is drowned out by noise from the press, which interrupts the differentiation of crack configuration. To enhance the accuracy for determining the HER, an integrated analysis system that combines computer vision with punch load analysis, and improves on the shortcomings of each analysis system, is newly suggested.

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Development of a Device Compatible with Universal Testing Machine to Perform Hole Expansion and Erichsen Cupping Tests

Cited by 8 publications

References 15 publications

An experimental investigation of formability of inconel sheet plate for different die angles and rolling directions in press brake bending

An experimental investigation of formability of inconel sheet plate for different die angles and rolling directions in press brake bending

Application of Digital Image Processing Techniques to Detect Through-Thickness Crack in Hole Expansion Test

Integrated Machine Vision System for Evaluating Hole Expansion Ratio of Advanced High-Strength Steels

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