Measurement on Strain Rate Sensitivity Properties of Rice Husk (Rh)/Linear Low Density Polyethylene (Lldpe) Composites under Various Loading Rates

2015 ◽  
Vol 754-755 ◽  
pp. 77-82
Author(s):  
Mohd Firdaus Omar ◽  
Nur Suhaili Abdul Wahab ◽  
Hazizan Md. Akil ◽  
Zainal Arifin Ahmad ◽  
N.Z. Noriman
Keyword(s):  
Strain Rate ◽  
Thermal Activation ◽  
Testing Machine ◽  
Rate Sensitivity ◽  
Applied Strain ◽  
Strain Rates ◽  
Static Compression ◽  
Loading Rates ◽  
Compression Properties ◽  
Great Dependency

In this study, LLDPE/RH composites were tested under various strain rate loadings (0.001/s, 0.01/s and 0.1/s) using the universal testing machine. Static compression properties of LLDPE/RH composites with different filler contents of 5 wt%, 10 wt%, 15 wt%,20 wt% and, 30 wt% RH were investigated. Results show that the yield stress, ultimate compressive strength and the rigidity properties of LLDPE/RH composites were strongly affected by both filler contents and strain rate loadings. Apart from that, the rate of sensitivity of LLDPE/RH show great dependency towards applied strain rate, where it was increased with increasing strain rates. Unfortunately, the thermal activation values show contrary trend. Visually, from the post damage analysis, the results show that applied strain rates affected the deformation behavior of tested LLDPE/RH composites.

Mechanical Properties of High Density Polyethylene (HDPE)/Sawdust Composites under Wide Range of Strain Rate

2015 ◽  
Vol 754-755 ◽  
pp. 83-88 ◽  
Author(s):  
Mohd Firdaus Omar ◽  
Haliza Jaya ◽  
Hazizan Md. Akil ◽  
Zainal Arifin Ahmad ◽  
N.Z. Noriman
Keyword(s):  
Strain Rate ◽  
Static Loading ◽  
Experimental Approach ◽  
Testing Machine ◽  
Damage Analysis ◽  
Static Compression ◽  
Compression Properties ◽  
Wide Range ◽  
Strain Rate Loading ◽  
Low Strain Rate

An experimental approach based on the conventional universal testing machine (UTM) was employed to perform low strain rate loading (0.001/s, 0.01/s and 0.1/s) in this research, to examine the reliance of natural filler contents towards HDPE/sawdust composites. By following to the low strain rate loading, static compression properties of HDPE/sawdust composites with varies filler contents of 5 wt% SD, 10 wt% SD, 15 wt% SD, 20 wt% SD and 30 wt: % SD were successfully studied. The results show that the yields stress, ultimate compression strength and the rigidity properties of HDPE/sawdust composites were sturdily affected by both filler contents and strain rate loadings. Moreover, for the post damage analysis, the results clearly show that different static loading employed to the specimens gives significant effects towards deformation behavior of HDPE/sawdust composites. The increasing of static loading employed caused the specimens to experience severe deformation.

Tensile Behavior of Unidirectional Carbon Reinforced Composites for Aerospace Structures under Varying Strain Rates

2015 ◽  
Vol 798 ◽  
pp. 357-361 ◽  
Author(s):  
Haris A. Khan ◽  
Mehr Nigar ◽  
Imran Ali Chaudhry
Keyword(s):  
Strain Rate ◽  
Volume Fraction ◽  
Testing Machine ◽  
Tensile Modulus ◽  
Failure Behavior ◽  
Strain Rates ◽  
Loading Rates ◽  
Matrix Volume ◽  
Versus Strain ◽  
Fiber Reinforced Laminates

This paper focuses on progressive damage investigation and failure analysis of carbon fiber reinforced laminates under varying strain rates in tensile mode. Samples specimen prepared for experiments were made from unidirectional ply with 70/30 fiber-matrix volume fraction and cross-ply (0°-90°) balanced stacking. These laminates were subjected to uniaxial longitudinal tensile loading in a Universal Testing Machine (UTM) with varying strain rates. Results acquired from the experiments were used to plot stress versus strain curves for different strain rates. These plots were subsequently analyzed to investigate the effect of varying loading rates on the mechanical properties and failure behavior of these composites. Experimental data revealed a considerable increase in the tensile strength with increasing strain rate. The tensile modulus and strain to failure were also found to exhibit slight increase with the increasing strain rate.

scholarly journals On the Strain Rate Sensitivity of Fused Filament Fabrication (FFF) Processed PLA, ABS, PETG, PA6, and PP Thermoplastic Polymers

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2924
Author(s):  
Nectarios Vidakis ◽  
Markos Petousis ◽  
Emmanouil Velidakis ◽  
Marco Liebscher ◽  
Viktor Mechtcherine ◽  
...  
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Mechanical Response ◽  
Rate Sensitivity ◽  
Polymeric Materials ◽  
Applied Strain ◽  
Sensitivity Index ◽  
Strain Rates ◽  
Thermoplastic Polymers ◽  
Fused Filament Fabrication

In this study, the strain rate sensitivity of five different thermoplastic polymers processed via Fused Filament Fabrication (FFF) Additive Manufacturing (AM) is reported. Namely, Polylactic Acid (PLA), Acrylonitrile-Butadiene-Styrene (ABS), Polyethylene Terephthalate Glycol (PETG), Polyamide 6 (PA6), and Polypropylene (PP) were thoroughly investigated under static tensile loading conditions at different strain rates. Strain rates have been selected representing the most common applications of polymeric materials manufactured by Three-Dimensional (3D) Printing. Each polymer was exposed to five different strain rates in order to elucidate the dependency and sensitivity of the tensile properties, i.e., stiffness, strength, and toughness on the applied strain rate. Scanning Electron Microscopy (SEM) was employed to investigate the 3D printed samples’ fractured surfaces, as a means to derive important information regarding the fracture process, the type of fracture (brittle or ductile), as well as correlate the fractured surface characteristics with the mechanical response under certain strain rate conditions. An Expectation–Maximization (EM) analysis was carried out. Finally, a comparison is presented calculating the strain rate sensitivity index “m” and toughness of all materials at the different applied strain rates.

scholarly journals Strain rate sensitivity of the aluminium-magnesium-scandium alloy - Scalmalloy®

2021 ◽  
Vol 250 ◽  
pp. 05014
Author(s):  
Puneeth Jakkula ◽  
Georg Ganzenmüller ◽  
Florian Gutmann ◽  
Stefan Hiermaier
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Testing Machine ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Image Correlation ◽  
Strain Rates ◽  
Rate Dependency ◽  
Strain Rate Dependency ◽  
Scandium Alloy

This work investigates the strain rate sensitivity of the aluminiummagnesium-scandium alloy Scalmalloy, which is used extensively for additive manufacturing of lightweight structures. This high strength aluminium alloy combines very good weldability, machinability and mechanical strength: it can be heat-treated to reach nominal ultimate tensile strengths in excess of 500 MPa. We report tensile tests at strain rates ranging from 10−3 /s to 103 /s at room temperature. It is well known that Al-Mg alloys exhibit a negative strain rate dependency in combination with serrated flow caused by the Portevin-Le Chatelier effect, which describes the interaction of Mg solutes with dislocation propagations. In contrast, in Al-Sc alloys, the flow stress increases with increasing strain rate and displays positive strain rate dependency. Additionally, the presence of Sc in the form of Al3-Sc provides a fine-grained microstructure which allows higher tensile and fatigue strength. This research shows how these combined effects interact in the case of Scalmalloy, which contains both Mg and Sc. Tests are performed at quasi-static, intermediate and high strain rates with a servohydraulic testing machine and a Split-Hopkinson tension bar. Local specimen strain was performed using 2D Digital Image Correlation.

Constitutive Equation of an Al-12.7Si-0.7Mg Alloy in Superplastic Deformation

2011 ◽  
Vol 415-417 ◽  
pp. 1147-1152 ◽  
Author(s):  
Yin Ben Han ◽  
Zhuo Liang Li ◽  
Ge Zhou ◽  
Fu Rong Cao ◽  
Hua Ding ◽  
...  
Keyword(s):  
Flow Stress ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Testing Machine ◽  
Rate Sensitivity ◽  
Strain Rates ◽  
Deformation Parameters ◽  
Deformation Activation Energy ◽  
Deformation Features

The hot deformation characteristics of Al-12.7Si-0.7Mg alloy were investigated on an Instron5500 electronic universal testing machine at strain rates ranging from 1.67×10-4 s-1 to 1.67×10-3 s-1 and testing temperatures ranging from 460 °C to 520 °C. The results show that strain rate had a great effect on the flow stress. The flow stress increased with increasing the strain rate. The true stress-strain curves of the Al-12.7Si-0.7Mg alloy were obtained, and the strain rate sensitivity and hot deformation parameters of deformation activation energy were calculated. The hot deformation constitutive equation with hyperbolic sine form was also obtained. The test calculations demonstrate that the constitutive equation describes the deformation features of the Al-12.7Si-0.7Mg alloy well.

MECHANICAL BEHAVIOR OF COPPER THIN FILMS SUBJECTED TO VARIOUS STRAIN RATE LOADINGS

2013 ◽  
Vol 37 (3) ◽  
pp. 861-871 ◽  
Author(s):  
Kuan-Jung Chung ◽  
Chi-Feng Lin ◽  
Wei-Cheng Chiang
Keyword(s):  
Strain Rate ◽  
Brittle Failure ◽  
Testing Machine ◽  
Rate Sensitivity ◽  
Maximum Tensile Stress ◽  
Stress And Strain ◽  
Strain Rates ◽  
Strongly Correlated ◽  
Tensile Testing Machine ◽  
Cu Films

In this study, a micro-force tensile testing machine (MTS Tytron 250) was applied to test the polyimide samples coated with different thicknesses of copper (500–1500 nm). The experiments using different strain rates (1.6 × 10−4 to 1.6 × 10−2 s−1) were conducted to the test vehicles. The results showed that the stress and strain of Cu films were strongly correlated with the strain rate and film thickness. The mechanical strength, yield stress, Young’s modulus, and maximum tensile stress, increase as the strain rate increases or the thickness decreases. Strain rate sensitivity rapidly increases as the thickness decreases from 750 to 500 nm to imply that the workhardening rate increases while the thickness decreases, resulting in a higher probability of brittle failure.

Effect of Strain Rates on the Mechanical Behavior of Cu Thin Films of Various Thicknesses

2013 ◽  
Vol 284-287 ◽  
pp. 94-97
Author(s):  
Kuan Jung Chung ◽  
Chi Feng Lin ◽  
W. C. Chiang
Keyword(s):  
Thin Film ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Strain Rate Sensitivity ◽  
Testing Machine ◽  
Rate Sensitivity ◽  
Strain Rates ◽  
Tensile Testing Machine ◽  
Cu Film ◽  
Cu Thin Film

The objective of this study is to investigate the mechanical behavior of copper thin film with different thicknesses subjected to varying strain rates. A micro-force tensile testing machine (MTS Tytron 250) was used to test the polyimide samples coated with different thicknesses of copper (500 nm, 750 nm, 1000 nm, and 1500 nm). The experiments were conducted by applying test vehicles to different strain rates (1.6×10-4s-1, 1.6×10-3s-1, and 1.6×10-2s-1). The experimental results showed the strain rate and the thickness have obvious influence upon the mechanical properties of Cu thin film. The yield stress increases as increasing the strain rate or decreasing the thickness of Cu film. For considering the strain rate sensitivity m, the strain rate sensitivity m is found that it increases as decreasing the thickness to imply that Cu film has high strain-rate response at low thickness.

Strain Rate Sensitivity of Die Steel under Compressive Loads

2012 ◽  
Vol 585 ◽  
pp. 412-416
Author(s):  
Nilamber K. Singh ◽  
Maloy K. Singha ◽  
Ezio Cadoni ◽  
Narinder K. Gupta
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Rate Sensitivity ◽  
Gauge Length ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Static Tests ◽  
Die Steel

An experimental investigation on the strain rate sensitivity of die steel (D3) has been presented in this paper at different rates (0.001-2500s-1) of uni-axial compression. Quasi-static tests (0.001s-1) of the material are conducted on universal testing machine (UTM), whereas, the experiments at high strain rates are performed on split Hopkinson pressure bar (SHPB) apparatus. The effects of gauge length of the specimen on the material properties of the material are studied at different strain rates. The material parameters of existing Cowper-Symonds and Johnson-Cook material models are determined and the suitability of the models is examined.

scholarly journals Compressive Behaviour of Additively Manufactured Periodical Re-Entrant Tetrakaidecahedral Lattices at Low and High Strain-Rates

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1196
Author(s):  
Michaela Neuhäuserová ◽  
Tomáš Fíla ◽  
Petr Koudelka ◽  
Jan Falta ◽  
Václav Rada ◽  
...  
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
High Speed ◽  
Mechanical Response ◽  
Split Hopkinson Pressure Bar ◽  
Deformation Behaviour ◽  
Rate Sensitivity ◽  
Image Correlation ◽  
Strain Rates ◽  
Static Compression

Compressive deformation behaviour of additively manufactured lattice structures based on re-entrant tetrakaidecahedral unit-cell geometry were experimentally investigated under quasi-static and dynamic loading conditions. Specimens of four different structures formed by three-dimensional periodical assembly of selected unit-cells were produced by a laser powder bed fusion technique from a powdered austenitic stainless steel SS316L. Quasi-static compression as well as dynamic tests using split Hopkinson pressure bar (SHPB) apparatus at two strain-rates were conducted to evaluate the expected strain-rate sensitivity of the fundamental mechanical response of the structures. To evaluate the experiments, particularly the displacement fields of the deforming lattices, optical observation of the specimens using a high-resolution camera (quasi-static loading) and two synchronised high-speed cameras (SHPB experiments) was employed. An in-house digital image correlation algorithm was used in order to evaluate the anticipated auxetic nature of the investigated lattices. It was found that neither of the investigated structures exhibited auxetic behaviour although strain-rate sensitivity of the stress–strain characteristics was clearly identified for the majority of structures.

The effects of strain and strain rate on residual microstructures in copper

1986 ◽  
Vol 44 ◽  
pp. 420-421
Author(s):  
M. F. Stevens ◽  
P. S. Follansbee
Keyword(s):  
Strain Rate ◽  
Applied Stress ◽  
Threshold Stress ◽  
Rate Sensitivity ◽  
Viscous Drag ◽  
Strain Rates ◽  
Strain And Strain Rate ◽  
Threshold Strength ◽  
Mechanism Transition ◽  
Intrinsic Strength

The strain rate sensitivity of a variety of materials is known to increase rapidly at strain rates exceeding ∼103 sec-1. This transition has most often in the past been attributed to a transition from thermally activated guide to viscous drag control. An important condition for imposition of dislocation drag effects is that the applied stress, σ, must be on the order of or greater than the threshold stress, which is the flow stress at OK. From Fig. 1, it can be seen for OFE Cu that the ratio of the applied stress to threshold stress remains constant even at strain rates as high as 104 sec-1 suggesting that there is not a mechanism transition but that the intrinsic strength is increasing, since the threshold strength is a mechanical measure of intrinsic strength. These measurements were made at constant strain levels of 0.2, wnich is not a guarantee of constant microstructure. The increase in threshold stress at higher strain rates is a strong indication that the microstructural evolution is a function of strain rate and that the dependence becomes stronger at high strain rates.

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