Print Velocity Effects on Strain-Rate Sensitivity of Acrylonitrile-Butadiene-Styrene Using Material Extrusion Additive Manufacturing

The strain-rate sensitivity of the yield stress for Acrylonitrile-Butadiene-Styrene (ABS) tensile samples processed via material extrusion additive manufacturing (ME-AM) was investigated. Such specimens show molecular orientation and interstitial voids that affect the mechanical properties. Apparent densities were measured to compensate for the interstitial voids. Three different printing speeds were used to generate ME-AM tensile test samples with different molecular orientation. Printing velocities influenced molecular orientation and stretch, as determined from thermal shrinkage measurements. Likewise, infill velocity affected the strain-rate dependence of the yield stress. The ABS material manifests thermorheollogically simple behavior that can correctly be described by an Eyring flow rule. The changing activation volume, as a result of a varying print velocity, scales linearly with the molecular orientation, as captured in an estimated processing-induced pre-strain. Therefore, it is suggested that ME-AM processed ABS shows a deformation-dependent activation volume. This paper can be seen as initial work that can help to improve quantitative predictive numerical tools for ME-AM, taking into account the effects that the processing step has on the mechanical properties.

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Strain Rate Sensitivity of the Additive Manufacturing Material Scalmalloy®

Journal of Dynamic Behavior of Materials ◽

10.1007/s40870-021-00298-4 ◽

2021 ◽

Author(s):

P. Jakkula ◽

G. Ganzenmüller ◽

F. Gutmann ◽

A. Pfaff ◽

J. Mermagen ◽

...

Keyword(s):

Additive Manufacturing ◽

Strain Rate ◽

Yield Stress ◽

Strain Rate Sensitivity ◽

Mass Density ◽

Rate Sensitivity ◽

Heat Treating ◽

Tensile Tests ◽

Strain Rates ◽

Interesting Candidate

AbstractThis work investigates the influence of strain rate on the stress/strain behaviour of Scalmalloy. This material is an aluminium–scandium–magnesium alloy, specifically developed for additive manufacturing. The bulk yield stress of the material processed by Selective Laser Melting is approximately 340 MPa which can be increased by heat-treating to approximately 530 MPa. These numbers, combined with the low mass density of 2.7 g/cm3, make Scalmalloy an interesting candidate for lightweight crash-absorbing structures. As this application is inherently dynamic, it is of interest to study the loading rate sensitivity, which is difficult to predict: Al–Sc alloys exhibit classic strain rate sensitivity with an increased yield stress at elevated strain rates. However, Al–Mg alloys are known to show the contrary effect, they exhibit less strength as strain rate is increased. To answer the question how these effects combine, we study the dynamic behaviour at four different strain rates ranging from 10−3 to 1000 /s using servo-hydraulic and split-Hopkinson testing methods. The resulting data is analysed in terms of strain rate sensitivity of tensile strength and failure strain. A constitutive model based on a simplified Johnson–Cook approach is employed to simulate the tensile tests and provides good agreement with the experimental observations.

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Strain Rate Sensitivity of the Additive Manufacturing Material Scalmalloy®

10.20944/preprints202101.0271.v1 ◽

2021 ◽

Author(s):

Puneeth Jakkula ◽

Georg Ganzenmüller ◽

Florian Gutmann ◽

Aron Pfaff ◽

Jörg Mermagen ◽

...

Keyword(s):

Additive Manufacturing ◽

Strain Rate ◽

Yield Stress ◽

Strain Rate Sensitivity ◽

Mass Density ◽

Rate Sensitivity ◽

Heat Treating ◽

Tensile Tests ◽

Strain Rates ◽

Interesting Candidate

This work investigates the influence of strain rate on the stress/strain behaviour of Scalmalloy. This material is an aluminium-scandium-magnesium alloy, specifically developed for additive manufacturing. The bulk yield stress of the material processed by Selective Laser Melting is approximately 340 MPa which can be increased by heat-treating to approximately 530 MPa. These numbers, combined with the low mass density of 2.7 g/cm3, make Scalmalloy an interesting candidate for lightweight crash-absorbing structures. As this application is inherently dynamic, it is of interest to study the loading rate sensitivity, which is difficult to predict: Al-Sc alloys exhibit classic strain rate sensitivity with an increased yield stress at elevated strain rates. However, Al-Mg alloys are known to show the contrary effect, they exhibit less strength as strain rate is increased. To answer the question how these effects combine, we study the dynamic behaviour at four different strain rates ranging from 10−3 /s to 1000 /s using servo-hydraulic and Split-Hopkinson testing methods. The resulting data is analysed in terms of strain rate sensitivity of tensile strength and failure strain. A constitutive model based on a simplified Johnson-Cook approach is employed to simulate the tensile tests and provides good agreement with the experimental observations.

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Local Investigations of the Mechanical Properties of Ultrafine Grained Metals by Nanoindentations

Materials Science Forum ◽

10.4028/www.scientific.net/msf.503-504.31 ◽

2006 ◽

Vol 503-504 ◽

pp. 31-36 ◽

Cited By ~ 17

Author(s):

Johannes Mueller ◽

Karsten Durst ◽

Dorothea Amberger ◽

Matthias Göken

Keyword(s):

Mechanical Properties ◽

Strain Rate ◽

Strain Rate Sensitivity ◽

Room Temperature ◽

Rate Sensitivity ◽

Strain Rates ◽

Fcc Metals ◽

Angular Pressing ◽

Ultrafine Grained ◽

Indentation Strain

The mechanical properties of ultrafine-grained metals processed by equal channel angular pressing is investigated by nanoindentations in comparison with measurements on nanocrystalline nickel with a grain size between 20 and 400 nm produced by pulsed electrodeposition. Besides hardness and Young’s modulus measurements, the nanoindentation method allows also controlled experiments on the strain rate sensitivity, which are discussed in detail in this paper. Nanoindentation measurements can be performed at indentation strain rates between 10-3 s-1 and 0.1 s-1. Nanocrystalline and ultrafine-grained fcc metals as Al and Ni show a significant strain rate sensitivity at room temperature in comparison with conventional grain sized materials. In ultrafine-grained bcc Fe the strain rate sensitivity does not change significantly after severe plastic deformation. Inelastic effects are found during repeated unloading-loading experiments in nanoindentations.

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Advanced Nanoindentation Testing for Studying Strain-Rate Sensitivity and Activation Volume

JOM ◽

10.1007/s11837-017-2536-y ◽

2017 ◽

Vol 69 (11) ◽

pp. 2246-2255 ◽

Cited By ~ 27

Author(s):

Verena Maier-Kiener ◽

Karsten Durst

Keyword(s):

Strain Rate ◽

Strain Rate Sensitivity ◽

Activation Volume ◽

Rate Sensitivity ◽

Nanoindentation Testing

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Strain-Rate-Dependent Deformation Behavior and Mechanical Properties of a Multi-Phase Medium-Manganese Steel

Metals ◽

10.3390/met9030344 ◽

2019 ◽

Vol 9 (3) ◽

pp. 344 ◽

Cited By ~ 15

Author(s):

Simon Sevsek ◽

Christian Haase ◽

Wolfgang Bleck

Keyword(s):

Mechanical Properties ◽

Strain Rate ◽

Strain Rate Sensitivity ◽

Deformation Behavior ◽

Rate Sensitivity ◽

Manganese Steel ◽

Strain Rates ◽

Rate Dependent ◽

Medium Manganese Steel ◽

Multi Phase

The strain-rate-dependent deformation behavior of an intercritically annealed X6MnAl12-3 medium-manganese steel was analyzed with respect to the mechanical properties, activation of deformation-induced martensitic phase transformation, and strain localization behavior. Intercritical annealing at 675 °C for 2 h led to an ultrafine-grained multi-phase microstructure with 45% of mostly equiaxed, recrystallized austenite and 55% ferrite or recovered, lamellar martensite. In-situ digital image correlation methods during tensile tests revealed strain localization behavior during the discontinuous elastic-plastic transition, which was due to the localization of strain in the softer austenite in the early stages of plastic deformation. The dependence of the macroscopic mechanical properties on the strain rate is due to the strain-rate sensitivity of the microscopic deformation behavior. On the one hand, the deformation-induced phase transformation of austenite to martensite showed a clear strain-rate dependency and was partially suppressed at very low and very high strain rates. On the other hand, the strain-rate-dependent relative strength of ferrite and martensite compared to austenite influenced the strain partitioning during plastic deformation, and subsequently, the work-hardening rate. As a result, the tested X6MnAl12-3 medium-manganese steel showed a negative strain-rate sensitivity at very low to medium strain rates and a positive strain-rate sensitivity at medium to high strain rates.

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Development of a gripper for garment handling designed for additive manufacturing

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406219857763 ◽

2019 ◽

pp. 095440621985776

Author(s):

Michal Jilich ◽

Mattia Frascio ◽

Massimiliano Avalle ◽

Matteo Zoppi

Keyword(s):

Mechanical Properties ◽

Additive Manufacturing ◽

Acrylonitrile Butadiene Styrene ◽

Cost Effective ◽

Lower Number ◽

Polybutylene Terephthalate ◽

Design Validation ◽

Polymeric Additive ◽

Lower Complexity ◽

Butadiene Styrene

The paper presents how a robotic gripper specific for grasping and handling of textiles and soft flexible layers can be miniaturized and improved by polymeric additive manufacturing-oriented re-design. Advantages of polymeric additive manufacturing are to allow a re-design of components with integrated functions, to be cost-effective equipment for small batches production and the availability of suitable materials for many applications. The drawback is that for design validation extended testing is still necessary because of lacks in standardization and that the mechanical properties are building parameters dependent. The outcomes are a lower complexity of the design overall and lower number of components. These are pursued taking advantage of the anisotropy of the additive manufacturing processed polymer and assigning appropriate shapes and linkages in the mechanisms. Set of common materials (polylactide, polyethylene terephthalate, acrylonitrile butadiene styrene) and technical (acrylonitrile styrene acrylate, polycarbonate/polybutylene terephthalate blend) are tested to obtain data for the modelling.

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Strain Rate Sensitivity of Epoxy Composites Reinforced with Varied Sizes of Bagasse Particles

Journal of Composites Science ◽

10.3390/jcs4030110 ◽

2020 ◽

Vol 4 (3) ◽

pp. 110

Author(s):

Sujan Debnath ◽

Tan Ke Khieng ◽

Mahmood Anwar ◽

Animesh Kumar Basak ◽

Alokesh Pramanik

Keyword(s):

Mechanical Properties ◽

Strain Rate ◽

Strain Rate Sensitivity ◽

Interfacial Strength ◽

Rate Sensitivity ◽

Natural Fibre ◽

Filler Loading ◽

Epoxy Composites ◽

Fibre Reinforced Polymer ◽

Filler Particles

Viscoelastic materials, such as natural fibre-reinforced polymer composites, are strain rate sensitive. In the present investigation, the low strain rate sensitivity (0.00028 s−1, 0.00085 s−1 and 0.0017 s−1) of different sized bagasse particle-reinforced (212 µm and 300 µm) epoxy composites was examined using the Weibull analysis method. The filler loading content was optimized at 2 wt.% to achieve better mechanical properties. Based on the experimental results, it was observed that composites with 212 µm filler particles had higher characteristic strengths, more consistent failure strengths and higher energy absorption properties with higher loading speeds, compared to that of 300 µm filler particles. Based on the mathematical models for particle–matrix interactions, improvements in mechanical properties are attributed to proper filler dispersion and a better fibre–matrix interfacial strength.

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Dynamic Mechanical Compression Impulse of Lithium-Ion Pouch Cells

Energies ◽

10.3390/en13082105 ◽

2020 ◽

Vol 13 (8) ◽

pp. 2105 ◽

Cited By ~ 2

Author(s):

Alon Ratner ◽

Richard Beaumont ◽

Iain Masters

Keyword(s):

Mechanical Properties ◽

Strain Rate ◽

Strain Rate Sensitivity ◽

Lithium Ion ◽

Rate Sensitivity ◽

Dynamic Mechanical Properties ◽

Impact Testing ◽

Significant Feature ◽

Dynamic Mechanical ◽

The Impact

Strain rate sensitivity has been widely recognized as a significant feature of the dynamic mechanical properties of lithium-ion cells, which are important for their accurate representation in automotive crash simulations. This research sought to improve the precision with which dynamic mechanical properties can be determined from drop tower impact testing through the use of a diaphragm to minimize transient shock loads and to constrain off-axis motion of the indenter, specialized impact absorbers to reduce noise, and observation of displacement with a high speed camera. Inert pouch cells showed strain rate sensitivity in an increased stiffness during impact tests that was consistent with the poromechanical interaction of the porous structure of the jellyroll with the liquid electrolyte. The impact behaviour of the inert pouch cells was similar to that of an Expanded Polypropylene foam (EPP), with the exception that the inert pouch cells did not show hysteretic recovery under the weight of the indenter. This suggests that the dynamic mechanical behaviour of the inert pouch cells is analogous to a highly damped foam.

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Strain Rate Dependence of the Flow Stress and Work-Hardening of Single Crystals of NI3(Al,Hf)B

MRS Proceedings ◽

10.1557/proc-364-695 ◽

1994 ◽

Vol 364 ◽

Author(s):

S. S. Ezz ◽

Y. Q. Sun ◽

P. B. Hirsch

Keyword(s):

Flow Stress ◽

Strain Rate ◽

Temperature Dependence ◽

Single Crystals ◽

Yield Stress ◽

Strain Rate Sensitivity ◽

Work Hardening ◽

Room Temperature ◽

Rate Sensitivity ◽

Controlling Mechanism

AbstractThe strain rate sensitivity ß of the flow stress τ is associated with workhardening and β=(δτ/δln ε) is proportional to the workhardening increment τh = τ - τy, where τy is the strain rate independent yield stress. The temperature dependence of β/τh reflects changes in the rate controlling mechanism. At intermediate and high temperatures, the hardening correlates with the density of [101] dislocations on (010). The nature of the local obstacles at room temperature is not established.

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