Investigation and comparison of three noval strain rate-dependent fracture criteria

Current industrial trends bring new challenges in energy absorbing systems. Polymer materials as the traditional packaging materials seem to be promising due to their low weight, structure, and production price. Based on the review, the linear low-density polyethylene (LLDPE) material was identified as the most promising material for absorbing impact energy. The current paper addresses the identification of the material parameters and the development of a constitutive material model to be used in future designs by virtual prototyping. The paper deals with the experimental measurement of the stress-strain relations of linear low-density polyethylene under static and dynamic loading. The quasi-static measurement was realized in two perpendicular principal directions and was supplemented by a test measurement in the 45° direction, i.e., exactly between the principal directions. The quasi-static stress-strain curves were analyzed as an initial step for dynamic strain rate-dependent material behavior. The dynamic response was tested in a drop tower using a spherical impactor hitting a flat material multi-layered specimen at two different energy levels. The strain rate-dependent material model was identified by optimizing the static material response obtained in the dynamic experiments. The material model was validated by the virtual reconstruction of the experiments and by comparing the numerical results to the experimental ones.

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A Modified Peric Model for Al-Mg Alloy Sheet with Rate-Independent Initial Yield Stress at Warm Temperatures

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.287.3 ◽

2019 ◽

Vol 287 ◽

pp. 3-7

Author(s):

Yong Zhang ◽

Qing Zhang ◽

Yuan Tao Sun ◽

Xian Rong Qin

Keyword(s):

Flow Stress ◽

Plastic Strain ◽

Strain Rate ◽

Yield Stress ◽

Constitutive Models ◽

Mg Alloy ◽

Initial Yield Stress ◽

Initial Yield ◽

Rate Dependent ◽

Dependent Flow

The constitutive modeling of aluminum alloy under warm forming conditions generally considers the influence of temperature and strain rate. It has been shown by published flow stress curves of Al-Mg alloy that there is nearly no effect of strain rate on initial yield stress at various temperatures. However, most constitutive models ignored this phenomenon and may lead to inaccurate description. In order to capture the rate-independent initial yield stress, Peric model is modified via introducing plastic strain to multiply the strain rate, for eliminating the effect of strain rate when the plastic strain is zero. Other constitutive models including the Wagoner, modified Hockett–Sherby and Peric are also considered and compared. The results show that the modified Peric model could not only describe the temperature-and rate-dependent flow stress, but also capture the rate-independent initial yield stress, while the Wagoner, modified Hockett–Sherby and Peric model can only describe the temperature-and rate-dependent flow stress. Moreover, the modified Peric model could obtain proper static yield stress more naturally, and this property may have potential applications in rate-dependent simulations.

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A Study of Strain and Strain-Rate Dependent Properties of a Superplastic Zn-Al Alloy Under Biaxial Stresses

Journal of Engineering Materials and Technology ◽

10.1115/1.3225034 ◽

1982 ◽

Vol 104 (1) ◽

pp. 41-46

Author(s):

T. C. Hsu ◽

I. M. Bidhendi

Keyword(s):

Strain Rate ◽

Stress Ratio ◽

Local Stress ◽

Biaxial Stress ◽

Al Alloy ◽

Local Geometry ◽

Forming Process ◽

Rate Dependent ◽

Strain And Strain Rate ◽

Liquid Behavior

A superplastic Zn-Al alloy in sheet form is formed into a bulge over a circular hole by pneumatic pressure. The geometry, the stress, the strain, and the strain-rate are determined at various points covering the whole specimen and at various stages of the forming process. The complicated shape, and its complicated changes, are represented by introducing an index for the local geometry, called “prolateness,” which is also related to the local stress ratio in a simple way. The biaxial stress is analyzed into a strain-proportional and a strain-rate-proportional component, which represent, respectively, the quasi-solid and the quasi-liquid behavior of the superplastic material.

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Strain Rate Dependent Ductility and Strain Hardening in Q&P Steels

Metallurgical and Materials Transactions A ◽

10.1007/s11661-020-06127-y ◽

2021 ◽

Author(s):

Christopher B. Finfrock ◽

Melissa M. Thrun ◽

Diptak Bhattacharya ◽

Trevor J. Ballard ◽

Amy J. Clarke ◽

...

Keyword(s):

Strain Rate ◽

Strain Hardening ◽

Rate Dependent

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Molecular Dynamics Study of Grain Size and Strain Rate Dependent Tensile Properties of Nanocrystalline Copper

Journal of Computational and Theoretical Nanoscience ◽

10.1166/jctn.2013.2831 ◽

2013 ◽

Vol 10 (5) ◽

pp. 1215-1221 ◽

Cited By ~ 3

Author(s):

Meizhen Xiang ◽

Junzhi Cui ◽

Xia Tian ◽

Jun Chen

Keyword(s):

Molecular Dynamics ◽

Grain Size ◽

Strain Rate ◽

Tensile Properties ◽

Nanocrystalline Copper ◽

Rate Dependent

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Applicability of power law for describing the rheology of soils of different origins and characteristics

Canadian Geotechnical Journal ◽

10.1139/t09-031 ◽

2009 ◽

Vol 46 (9) ◽

pp. 1011-1023 ◽

Cited By ~ 41

Author(s):

Sueng Won Jeong ◽

Serge Leroueil ◽

Jacques Locat

Keyword(s):

Strain Rate ◽

Power Law ◽

Debris Flows ◽

Rheological Behaviour ◽

Strain Rate Range ◽

Rate Dependent ◽

Different Origins ◽

Power Law Index ◽

Soil Behaviour ◽

Low Activity

The rate-dependent rheological behaviour of soils of different origins and characteristics was studied and the applicability of the power law model was examined. The studied soils were divided into three groups: (i) low-activity soils, (ii) high-activity soils, and (iii) silt-rich soils. The results show that the power law applies to all these soils and is representative of soil behaviour in a strain rate range corresponding to debris flows, which is generally not the case with the Bingham model. For low-activity clays, the power law index, n, is typically equal to 0.12 and seems to increase with the plasticity index; it is larger (i.e., in the range of 0.2–0.6) for silt-rich soils. Comparison of n values for tests performed on intact and remoulded low-activity clay specimens indicates that the power law index is possibly strain-rate dependent.

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