Inverse Finite Element Approach to Identify the Post-Necking Hardening Behavior of Polyamide 12 under Uniaxial Tension.

Amstutz, Cornelia; Weisse, Bernhard; Haeberlin, Andreas; Burger, Jürgen; Zurbuchen, Adrian (2022). Inverse Finite Element Approach to Identify the Post-Necking Hardening Behavior of Polyamide 12 under Uniaxial Tension. Polymers, 14(17) MDPI 10.3390/polym14173476

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Finite-element (FE) simulations that go beyond the linear elastic limit of materials can aid the development of polymeric products such as stretch blow molded angioplasty balloons. The FE model requires the input of an appropriate elastoplastic material model. Up to the onset of necking, the identification of the hardening curve is well established. Subsequently, additional information such as the cross-section and the triaxial stress state inside the specimen is required. The present study aims to inversely identify the post-necking hardening behavior of the semi-crystalline polymer polyamide 12 (PA12) at different temperatures. Our approach uses structural FE simulations of a dog-bone tensile specimen in LS-DYNA with mesh sizes of 1 mm and 2 mm, respectively. The FE simulations are coupled with an optimization routine defined in LS-OPT to identify material properties matching the experimental behavior. A Von Mises yield criterion coupled with a user-defined hardening curve (HC) were considered. Up to the beginning of necking, the Hockett-Sherby hardening law achieved the best fit to the experimental HC. To fit the entire HC until fracture, an extension of the Hockett-Sherby law with power-law functions achieved an excellent fit. Comparing the simulation and the experiment, the following coefficient of determination R2 could be achieved: Group I: R2 > 0.9743; Group II: R2 > 0.9653; Group III: R2 > 0.9927. Using an inverse approach, we were able to determine the deformation behavior of PA12 under uniaxial tension for different temperatures and mathematically describe the HC.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Department of Cardiovascular Disorders (DHGE) > Clinic of Cardiology
08 Faculty of Science > School of Biomedical and Precision Engineering (SBPE)

UniBE Contributor:

Amstutz, Cornelia Doreen, Häberlin, Andreas David Heinrich, Burger, Jürgen, Zurbuchen, Adrian


600 Technology > 610 Medicine & health








Pubmed Import

Date Deposited:

15 Sep 2022 08:48

Last Modified:

05 Dec 2022 16:24

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Uncontrolled Keywords:

PA12 inverse identification mechanical properties modeling plasticity post-necking




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