Refine Search

New Search

Results: 17

(searched for: doi:10.4271/2011-01-1058)
Save to Scifeed
Page of 1
Articles per Page
by
Show export options
  Select all
Published: 17 December 2021
by MDPI
Materials, Volume 14; https://doi.org/10.3390/ma14247821

Abstract:
This article discusses the fracture modelling accuracy of strain-driven ductile fracture models when introducing damage of high strength sheet steel. Numerical modelling of well-known fracture mechanical tests was conducted using a failure and damage model to control damage and fracture evolution. A thorough validation of the simulation results was conducted against results from laboratory testing. Such validations show that the damage and failure model is suited for modelling of material failure and fracture evolution of specimens without damage. However, pre-damaged specimens show less correlation as the damage and failure model over-predicts the displacement at crack initiation with an average of 28%. Consequently, the results in this article show the need for an extension of the damage and failure model that accounts for the fracture mechanisms at the crack tip. Such extension would aid in the improvement of fracture mechanical testing procedures and the modelling of high strength sheet metal manufacturing, as several sheet manufacturing processes are defined by material fracture.
, Leo Kiawi, Iman S. Sarraf, Eugene Ryzer, Daniel E. Green
Published: 11 July 2021
Superalloys 2020 pp 1573-1583; https://doi.org/10.1007/978-3-030-75381-8_131

The publisher has not yet granted permission to display this abstract.
, Jie Xiong, Zhijiang Zuo, Wen Tan, Junlin Wang, Wuxin Yu
Published: 4 September 2020
Procedia Manufacturing, Volume 50, pp 761-764; https://doi.org/10.1016/j.promfg.2020.08.137

Abstract:
Two different types of dual phase steels DP780 were manufactured and investigated. Steel A contained higher carbon, the other one B had lower carbon with Nb added. The mechanical properties and microstructures were analyzed and compared. The hole expansion test were conducted to evaluate stretch-flangeability. An Ultra Micro-Indentation System (UMIS) were employed to carry out the nano-hardness test to check the nano-hardness of ferrite and martensite. The result showed that for DP steel A, higher over-aging temperature during manufacturing would result in lower ultimate tensile strength with martensite partly resolved, which would lead to higher stretch-flangeability. In comparison with A, steel B with lower carbon and Nb added exhibited higher stretch-flangeability, which was related to the refined grain size of ferrite. It could be concluded that for dual phase steel stretch-flangeability was mainly affected by the strength difference between ferrite and martensite. Generally the bigger the strength difference is, the lower the stretch-flangeability is. Either decreasing martensite strength by increasing over-aging temperature or increasing ferrite strength by adding Nb could improve the stretch-flangeability. The same parts formed from the two different dual phase steel were compared. There was crack in some edge area during forming for steel A, while the part formed from Steel B showed good quality without crack, which verified the stretch-flangeability improvement was very effective. However, increasing over-aging temperature during manufacturing is not easy to be implemented and it could result in lower ultimate tensile strength, which may not meet the strength requirement. Adding Nb is considered to be a more feasible and effective way to improve ferrite strength and stretch-flangeability for dual phase steel DP780.
, J. Adrien, C. Butcher, E. Maire, M. Worswick
International Journal of Mechanical Sciences, Volume 179; https://doi.org/10.1016/j.ijmecsci.2020.105661

The publisher has not yet granted permission to display this abstract.
, , S. Parareda, D. Casellas
PROCEEDINGS OF THE 22ND INTERNATIONAL ESAFORM CONFERENCE ON MATERIAL FORMING: ESAFORM 2019, Volume 2113; https://doi.org/10.1063/1.5112704

Abstract:
Edge fracture prediction in high strength cold formed components still being a challenge for automotive part manufacturers. Even though several experimental methodologies have been proposed in the last years to assess edge formability, the material properties governing edge cracking sensitivity of high strength sheet materials are not clearly defined. This work investigates the correlation between the fracture toughness of various 1000 MPa Dual Phase and Complex Phase steel grades and their edge fracture resistance, evaluated by means of hole expansion tests according to ISO 16630. The good linear correlation observed between these parameters shows that fracture toughness is a reliable indicator of edge cracking resistance in advanced high strength steel sheets. However, it is well known that edge formability does not only depends on the material properties but also on the edge quality. In order to evaluate the effect of the edge condition on edge formability, additional hole tension tests are performed in some of the investigated steel grades with different punch to die clearances. It is shown that steels with greater fracture toughness present higher strain at fracture and lower cutting clearance sensitivity. According to these results, the fracture toughness is proposed as a relevant material property to understand the edge formability of high strength metal sheets.
Ji He, , Liang Dong
International Journal of Material Forming, Volume 13, pp 547-560; https://doi.org/10.1007/s12289-019-01491-6

The publisher has not yet granted permission to display this abstract.
Published: 28 March 2019
by MDPI
Materials, Volume 12; https://doi.org/10.3390/ma12071023

Abstract:
This research aims to characterize damage at the sheared edge caused by the blanking operation of magnesium alloy AZ31B sheets. Shearing tests were carried out on an in-house blanking die-set and mechanical press (universal testing machine) by varying punch⁻die clearance and temperature. Edge damage was distinguished by the geometrical features of the sheared edge and by the distribution of the edge strain hardening (ESH) index. In this account, optical microscopy and scanning electron microscopy were applied to examine the characteristic dimensions of the sheared edge, fracture profile, and sheared edge quality, while the Vickers hardness test was applied to observe the surface micro-hardness in the shear zone (SZ) and the shear affected zone (SAZ). It was concluded that the blanking of magnesium alloy sheets at room temperature results in sheared edge defects, due to premature fracture, referred to here as micro-cracks, loose particles, and a jagged-plus-curved fracture profile. However, such deformities were completely suppressed with the rise in temperature. In addition, based on optical morphology, micro-hardness tests, and microstructure evolution, the recommendation regarding blanking temperature for the magnesium alloy AZ31B has was proposed.
Yun Han, , Shuang Kuang, Tao Li, Chunqian Xie, Huaxiang Teng
Journal of Materials Engineering and Performance, Volume 28, pp 372-381; https://doi.org/10.1007/s11665-018-3774-z

The publisher has not yet granted permission to display this abstract.
, C. Butcher, M. Worswick
Journal of Materials Engineering and Performance, Volume 25, pp 4919-4932; https://doi.org/10.1007/s11665-016-2316-9

The publisher has not yet granted permission to display this abstract.
, Roland Golle,
Published: 1 January 2016
Procedia CIRP, Volume 41, pp 1078-1083; https://doi.org/10.1016/j.procir.2016.01.007

Abstract:
The usage of high-strength-steels allows for the reduction of a component's weight by reducing the sheet thickness. During the production process of such components, shear cutting is commonly used for the initial cutting process. One of the main challenges in the production process is imposed by the shearing operation, which yields high tensile loads on the parts’ edges. During the subsequent forming process, edge-cracks occur and therefore limit the forming potential of these materials. Studies at our institute focus on developing a new measuring method to investigate the formation of edge-cracks. This procedure called, an edge-fracture-tensile-test, helps to identify relevant parameters of the shearing process to avoid edge-cracks. The sample geometry resembles the shape of tensile-test-samples. The following test parameters can then be varied: die clearance, cutting edge geometry, and open or closed cutting line. The results show it is possible to influence the formability of cut edges by varying the process parameters.
, Tomasz Wierzbicki
International Journal of Fracture, Volume 194, pp 19-36; https://doi.org/10.1007/s10704-015-0034-1

The publisher has not yet granted permission to display this abstract.
Jody N. Hall, Jason Coryell, Bill Wendt, Donald Adamski
SAE International Journal of Materials and Manufacturing, Volume 8, pp 783-788; https://doi.org/10.4271/2015-01-0529

Page of 1
Articles per Page
by
Show export options
  Select all
Back to Top Top