Determination of strain rate dependent material data for FEA crash simulation of polymers using digital image correlation

Hopmann, Christian; Klein, Jan

doi:10.1016/j.commatsci.2015.01.021

Cited by 12 publications

(1 citation statement)

References 15 publications

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“…The model, which is used to simulate thermal softening, is LCID-D in MAT_SAMP-1. Material data measurement was performed as presented in former research by the authors [14]. The simulations were performed with and without the presented softening model (FIGURE 5).…”

Section: Validationmentioning

confidence: 99%

Determination of the strain rate dependent thermal softening behavior of thermoplastic materials for crash simulations

Hopmann¹,

Klein²,

Schöngart³

2016

AIP Conference Proceedings

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Abstract. Thermoplastic materials are increasingly used as a light weight replacement for metal, especially in automotive applications. Typical examples are frontends and bumpers. The loads on these structures are very often impulsive, for example in a crash situation. A high rate of loading causes a high strain rate in the material which has a major impact on the mechanical behavior of thermoplastic materials. The stiffness as well as the rigidity of polymers increases to higher strain rates. The increase of the mechanical properties is superimposed at higher rates of loading by another effect which works reducing on stiffness and rigidity, the increase of temperature caused by plastic deformation. The mechanical behavior of thermoplastic materials is influenced by temperature opposing to strain rate. The stiffness and rigidity are decreased to higher values of temperature. The effect of thermal softening on thermoplastic materials is investigated at IKV. For this purpose high-speed tensile tests are performed on a blend, consisting of Polybutylenterephthalate (PBT) and Polycarbonate (PC). In preliminary investigations the effects of strain rate on the thermomechanical behavior of thermoplastic materials was studied by different authors. Tensile impact as well as split Hopkinson pressure bar (SHPB) tests were conducted in combination with high-speed temperature measurement, though, the authors struggled especially with temperature measurement. This paper presents an approach which uses high-speed strain measurement to transpire the link between strain, strain rate and thermal softening as well as the interdependency between strain hardening and thermal softening. The results show a superimposition of strain hardening and thermal softening, which is consistent to preliminary investigations. The advantage of the presented research is that the results can be used to calibrate damage and material models to perform mechanical simulations using Finite Element Analysis.

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Section: Validationmentioning

confidence: 99%

Determination of the strain rate dependent thermal softening behavior of thermoplastic materials for crash simulations

Hopmann¹,

Klein²,

Schöngart³

2016

AIP Conference Proceedings

Self Cite

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Drop Test Simulation of Packaging for Dangerous Goods: An Investigation of Appropriate Drop Height Adjustment in Case of Deviating Packaging Gross Mass

Lengas,

Müller,

Schlick‐Hasper

et al. 2024

Packag Technol Sci

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In the approval process of dangerous goods packagings, drop tests onto a flat, essentially unyielding surface are used to assess resistance against mechanical damage. International adopted regulations like ADR and RID define filling good dependent drop heights and filling degrees whilst the user needs to define the maximum gross mass to be tested and approved. Maximum packaging gross mass is defined conservatively and not reached in practice. To meet the defined gross mass in testing, using additives is permitted. However, in some cases, additives are not desirable due to packaging design or filling substance properties. This leads to deviations from the initial gross mass definition. Hence, a certain drop height adjustment is necessary to achieve the required impact loading. Laboratories frequently adjust drop height assuming a perfectly elastic collision that is inaccurate. Appropriate adjustment is not trivial due to energy conversion processes, for example, plastic deformation. In this work, a test stand is developed for measuring the change in kinetic energy of different packaging designs and filling substances in regulative drop tests. The experimental results are used to validate finite‐element (FE) models so that packaging properties can be varied in simulated drop test scenarios. The findings intend to describe the appropriate drop height adjustment of the respective packaging with same design but deviating gross mass to produce comparable mechanical response. The results are highly beneficial for testing laboratories, approval issuing authorities and packaging institutes confronted with the problem of testing packages with gross masses other than those to be approved.

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Multi-technology Products

Bobzin

Bührig–Polaczek

Hopmann

et al. 2017

Integrative Production Technology

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Determination of strain rate dependent material data for FEA crash simulation of polymers using digital image correlation

Cited by 12 publications

References 15 publications

Determination of the strain rate dependent thermal softening behavior of thermoplastic materials for crash simulations

Determination of the strain rate dependent thermal softening behavior of thermoplastic materials for crash simulations

Drop Test Simulation of Packaging for Dangerous Goods: An Investigation of Appropriate Drop Height Adjustment in Case of Deviating Packaging Gross Mass

Multi-technology Products

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