On the Assessment of the Failure Strains in Conventional and Incremental Forming of Polymer Sheets

Abstract:

This article presents an experimental research carried out on polymer sheet deformed by conventional forming, i.e. tensile and Nakajima tests, as well as by single point incremental forming (SPIF). The analysis is performed for polycarbonate (PC) polymer sheet material within the framework developed in previous recent papers of the authors, which the aim of defining a complete testing methodology for assessing formability and failure by necking and fracture of polymeric sheets. In the case of SPIF, truncated pyramid and cone test geometries are selected, enabling a variety of strain states from plane to biaxial strains. The results obtained allow an accurate evaluation and assessment of the forming limits by necking and fracture within the material forming limit diagram (FLD), and also include an analysis of the influence of the process parameters on the formability and failure modes attained in the case of incremental forming.

• Periodical: Key Engineering Materials (Volume 957)
• Pages: 41-50
• DOI: https://doi.org/10.4028/p-1ljolN
• Online since: October 2023
• Authors: Ana Rosa-Sainz, Gabriel Centeno Báez*, Maria Beatriz Silva, Carpoforo Vallellano
• Keywords: Failure, Formability, Incremental Sheet Forming, Polymer Sheet Forming

References

[1] Zhang W, Xu Y. Mechanical properties of polycarbonate: Experiment and modeling for aeronautical and aerospace applications. 2019.

DOI: 10.1016/C2019-0-02488-0

[2] Legrand DG, Bendler JT. Handbook of Polycarbonate Science and Technology. 1st ed. New York: CRC Press (Marcel Dekker Inc); 1999.

DOI: 10.1201/9781482273694

[3] Wohlers T. History of Additive Manufacturing. WohlersassociatesCom 2017:1–24.

DOI: 10.4018/978-1-5225-2289-8.ch001

[4] Parashar BSN, Mittal RK. Elements of manufacturing processes. New Delhi, India: Prentice-Hall of India; 2003.

[5] Lenard JG. Metal Forming Science and Practice. Exeter, United Kingdom: Elsevier science; 2002.

[6] Ajay, Mittal RK. Incremental Sheet Forming Technologies : Principles, Merits, Limitations and Applications. Chennai, India: CRC Press; 2020.

DOI: 10.1201/9780429298905

[7] Silva MB, Alves LM, Martins PAF. Single point incremental forming of PVC: Experimental findings and theoretical interpretation. Eur J Mech A/Solids 2010;29:557–66.

DOI: 10.1016/j.euromechsol.2010.03.008

[8] Alkas Yonan S, Silva MB, Martins PAF, Tekkaya AE. Plastic flow and failure in single point incremental forming of PVC sheets. Express Polym Lett 2014;8:301–11.

DOI: 10.3144/expresspolymlett.2014.34

[9] Bagudanch I, Centeno G, Vallellano C, Garcia-Romeu ML. Revisiting formability and failure of polymeric sheets deformed by Single Point Incremental Forming. Polym Degrad Stab 2017;144:366–77.

DOI: 10.1016/j.polymdegradstab.2017.08.021

[10] Franzen V, Kwiatkowski L, Martins PAF, Tekkaya AE. Single point incremental forming of PVC. J Mater Process Technol 2009;209:462–9.

DOI: 10.1016/j.jmatprotec.2008.02.013

[11] Martins PAF, Kwiatkowski L, Franzen V, Tekkaya AE, Kleiner M. Single point incremental forming of polymers. CIRP Ann - Manuf Technol 2009;58:229–32.

DOI: 10.1016/j.cirp.2009.03.095

[12] Le VS, Ghiotti A, Lucchetta G. Preliminary studies on single point incremental forming for thermoplastic materials. Int J Mater Form 2008;1:1179–82.

DOI: 10.1007/s12289-008-0191-0

[13] Bagudanch I, Garcia-Romeu ML, Centeno G, Elías-Zúñiga A, Ciurana J. Forming force and temperature effects on single point incremental forming of polyvinylchloride. J Mater Process Technol 2015;219:221–9.

DOI: 10.1016/j.jmatprotec.2014.12.004

[14] Davarpanah MA, Mirkouei A, Yu X, Malhotra R, Pilla S. Effects of incremental depth and tool rotation on failure modes and microstructural properties in Single Point Incremental Forming of polymers. J Mater Process Technol 2015;222:287–300.

DOI: 10.1016/j.jmatprotec.2015.03.014

[15] Durante M, Formisano A, Lambiase F. Incremental forming of polycarbonate sheets. J Mater Process Technol 2018;253:57–63.

DOI: 10.1016/j.jmatprotec.2017.11.005

[16] Marques TA, Silva MB, Martins PAF. On the potential of single point incremental forming of sheet polymer parts. Int J Adv Manuf Technol 2012;60:75–86.

DOI: 10.1007/s00170-011-3585-y

[17] Centeno G, Martínez-Donaire AJ, Morales-Palma D, Vallellano C, Silva MB, Martins PAF. Novel experimental techniques for the determination of the forming limits at necking and fracture. Mater Form Mach Res Dev 2015:1–24.

DOI: 10.1016/B978-0-85709-483-4.00001-6

[18] Carothers WH, Hill JW. Studies of polymerization and ring formation. XV. Artificial fibers from synthetic linear condensation superpolymers. J Am Chem Soc 1932;54:1579–87.

DOI: 10.1021/ja01343a051

[19] Rosa-Sainz A, Centeno G, Silva MB, López-Fernández JA, Martínez-Donaire AJ, Vallellano C. On the Determination of Forming Limits in Polycarbonate Sheets. Materials (Basel) 2020;13:1–17.

DOI: 10.3390/ma13040928

[20] Martínez-Donaire AJ, García-Lomas FJ, Vallellano C. New approaches to detect the onset of localised necking in sheets under through-thickness strain gradients. Mater Des 2014; 57: 135-45.

DOI: 10.1016/j.matdes.2014.01.012

[21] ASTM-D638-14. Standard Test Method for Tensile Properties of Plastics. ASTM Stand 2014.

[22] Lampman S. Characterization and failure analysis of plastics. vol. 41. United States: 2004.

[23] Rosa-Sainz A, Centeno G, Silva MB, Vallellano C. Experimental failure analysis in polycarbonate sheet deformed by spif. J Manuf Process 2021;64:1153–68.

DOI: 10.1016/j.jmapro.2021.01.047

[24] Legrand DG. Crazing, yielding, and fracture of polymers. I. Ductile brittle transition in polycarbonate. J Appl Polym Sci 1969;13:2129–47.

DOI: 10.1002/app.1969.070131010

[25] Morgan RJ, O'Neal JE. Modes of deformation and failure of polycarbonate. Polymer (Guildf) 1979; 20: 375–87.

[26] Yan C, Han J, Zhang J, Zhao F, Liu C, Shen C. The influence of sub-Tg annealing on environmental stress cracking resistance of polycarbonate. Polym Test 2016;56:364–8.

DOI: 10.1016/j.polymertesting.2016.09.010

[27] Bagudanch I, Garcia-Romeu ML, Sabater M. Incremental forming of polymers: Process parameters selection from the perspective of electric energy consumption and cost. J Clean Prod 2016;112:1013–24.

DOI: 10.1016/j.jclepro.2015.08.087