Abstract
The continuous innovations in sheet metallic materials lead to the need of the development of new and innovative forming methodologies. The emergence of the near net shape technologies, with the aim to create a product as close as possible to the final component, is an answer to these recent progresses. The knowledge of the formability limits of a material, that define the capacity of a material to deform permanently without failure (by necking or fracture ) allows a better design of a near net shape manufacturing process. This chapter describes the methodology to determine experimentally the fracture limits by tension (fracture forming limit line—FFL) and in-plane shear (shear fracture forming limit line—SFFL). For this, commonly utilized laboratory test specimens for mechanical, fracture and formability characterization are used to determine gauge length strains at the post-testing cracked regions of the specimen and involves the determination of the gauge length strains at the cracked regions of the specimens.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Keeler SP (1968) Circular Grid System—a valuable aid for evaluating sheet metal formability. SAE technical paper 680092
Goodwin G (1968) Application of strain analysis to sheet metal forming problems in the press shop. SAE technical paper 680093
ISO 12004-2:2008 (2008) Metallic materials—sheet and strip—determination of forming-limit curves—Part 2: Determination of forming-limit curves in the laboratory. International Organization for Standardization
ASTM E2218-02 (2008) Standard test method for determining forming limit curves. ASTM International, West Conshohocken, PA
Vacher P, Dumoulin S, Morestin F, Mguil-Touchal S (1999) Bidimensional strain measurement using digital images. Proc IMechE Part C J Mech Eng Sci 213(8):811–817
Merklein M, Kuppert A, Geiger M (2010) Time dependent determination of forming limit diagrams. CIRP Ann Manuf Technol 59:295–298
Tan Z, Melin L, Magnusson C (1992) Application of an image processing technique in strain measurement in sheet metal forming. J Mater Process Technol 33:299–310
Martins PAF, Bay N, Tekkaya AE, Atkins AG (2014) Characterization of fracture loci in metal forming. Int J Mech Sci 83:112–123
Bao Y, Wierzbicki T (2004) A comparative study on various ductile crack formation criteria. J Eng Mater Technol Trans ASME 126:314–324
Wierzbicki T, Xue L (2005) On the effect of the third invariant of the stress deviator on ductile fracture. Technical Report, Impact and Crashworthiness Lab, MIT
McClintock FA (1966) Ductile fracture by hole growth in shear bands. Int J Fract Mech 2:614–627
Atkins AG (1997) Fracture mechanics and metalforming: damage mechanics and the local approach of yesterday and today. In: Rossmanith HP (ed) Fracture research in retrospect. AA Balkema, Rotterdam, pp 327–350
Hill R (1948) A theory of yielding and plastic flow of anisotropic materials. Proc R Soc Lond (SER A) 193:281–297
Atkins AG, Mai YW (1985) Elastic & plastic fracture. Ellis Horwood, Chichester
Embury JD, LeRoy (1977) Failure maps applied to metal deformation processes. Fracture 1977, ICF4, Waterloo, Canada, 1:15–42
Gurson A (1977) Continuum theory of ductile rupture by void nucleation and growth. I. Yield criteria and flow rules for porous ductile media. J Eng Mater Technol Trans ASME 99:2–15
Tvergaard V, Needleman A (1984) Analysis of the cup-cone fracture in a round tensile bar. Acta Metall 32:157–169
Nahshon K, Hutchinson J (2008) Modification of the Gurson model for shear failure. Eur J Mech A/Solid 27:1–17
McClintock FA (1968) A criterion for ductile fracture by the growth of holes. J Appl Mech Trans ASME 35:363–371
ASTM Standard E8/E8M—13 (2013) Standard test methods for tension testing of metallic materials. ASTM International, West Conshohocken, PA
Rossard C (1976) Mise en forme des métaux et alliages. CNRS, Paris, France
ISO Standard 120004-2 (2008) Metallic materials—sheet and strip—determination of forming-limit curves—Part 2: Determination of forming—limit curves in the laboratory, Geneva, Switzerland
Cristino VA, Silva MB, Wong PK, Martins PAF (2017) Determining the fracture forming limits in sheet metal forming: a technical note. J Strain Anal Eng Des 52(8):467–471
Cotterell B, Reddel JK (1977) The essential work of plane stress ductile fracture. Int J Fract 13(3):267–277
ASTM Standard B831-05 (2005) Standard test method for shear testing of thin aluminum alloy products. ASTM International, West Conshohocken, PA
Isik K, Silva MB, Tekkaya AE, Martins PAF (2014) Formability limits by fracture in sheet metal forming. J Mat Process Technol 214:1557–1565
Cotterell B, Lee E, Mai YW (1982) Mixed mode plane stress ductile fracture. Int J Fract 20:243–250
Atkins AG (1996) Fracture in forming. J Mater Process Technol 56:609–618
Acknowledgements
The authors acknowledge the provided support by Fundação para a Ciência e a Tecnologia of Portugal and IDMEC under LAETA-UID/EMS/50022/2013, PDTC/EMS-TEC/0626/2014 and the support by the project MODSEAT.: Modular Light-Rail Seat, P2020 LISBOA-01-0247-FEDER-017247.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2019 Springer Nature Switzerland AG
About this chapter
Cite this chapter
Magrinho, J.P., Silva, M.B., Martins, P.A.F. (2019). Fracture Forming Limits for Near Net Shape Forming of Sheet Metals. In: Gupta, K. (eds) Near Net Shape Manufacturing Processes. Materials Forming, Machining and Tribology. Springer, Cham. https://doi.org/10.1007/978-3-030-10579-2_7
Download citation
DOI: https://doi.org/10.1007/978-3-030-10579-2_7
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-030-10578-5
Online ISBN: 978-3-030-10579-2
eBook Packages: EngineeringEngineering (R0)