STRAIN RATE EFFECTS ON COMPRESSIVE PROPERTIES OF A BIODEGRADABLE PLASTIC

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1177-1182 ◽  
Author(s):  
MASAHIRO NISHIDA ◽  
KOICHI TANAKA ◽  
NORIOMI ITO
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Biodegradable Plastic ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Compressive Properties ◽  
Strain Rate Effects ◽  
Wide Range ◽  
Pressure Bar

The compressive properties of a biodegradable plastic were measured over a wide range of strain rates from 10−5 to 104 s −1, using a universal testing machine and a split Hopkinson pressure bar method. The yield stress of the biodegradable plastic increased with increasing strain rate and decreased with temperature and water absorption. Empirical equations for the yield stresses were derived for the strain rates from 10−5 to 103 s −1 and from 103 to 104 s −1, respectively.

Studies on the Dynamic Compressive Properties of Open-Celled Aluminum Alloy Foams

2006 ◽  
Vol 306-308 ◽  
pp. 905-910 ◽  
Author(s):  
Zhi Hua Wang ◽  
Hong Wei Ma ◽  
Long Mao Zhao ◽  
Gui Tong Yang
Keyword(s):  
Yield Strength ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Aluminum Foams ◽  
Wide Range ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
Dynamic Loading Conditions

The compressive deformation behavior of open-cell aluminum foams with different densities and morphologies was assessed under quasi-static and dynamic loading conditions. High strain rate experiments were conducted using a split Hopkinson pressure bar technique at strain rates ranging from 500 to 1 2000 − s . The experimental results shown that the compressive stress-strain curves of aluminum foams also have the “ three regions” character appeared in general foam materials, namely elastic region, collapse region and densification regions. It is found that density is the primary variable characterizing the modulus and yield strength of foams and the cell appears to have a negligible effect on the strength of foams. It also is found that yield strength and energy absorption is almost insensitive to strain rate and deformation is spatially uniform for the open-celled aluminum foams, over a wide range of strain rates.

High-Strain-Rate Failure of a Porous Heterogeneous Composite: Balsa Wood

2001 ◽  
Author(s):  
M. Vural ◽  
G. Ravichandran
Keyword(s):  
Strain Rate ◽  
Mechanical Response ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Balsa Wood ◽  
Split Hopkinson ◽  
Pressure Bar

Abstract The compression behavior of a naturally occurring porous and heterogeneous biocomposite, balsa wood, along the grain direction is investigated at strain rates 10−3 to 104 s−1. Specimens with different densities, ranging from 55 to 380 kg/m3, were loaded by a modified Kolsky (split Hopkinson) pressure bar apparatus at varying high strain rates and by a screw-driven testing machine at quasi-static strain rates. The mechanical response of balsa wood is documented and the variation of compressive strength, crushing stress and densification strain as a function of density and strain rate is presented. Results show that characteristics of mechanical response for balsa wood are significantly affected by the strain rate and density.

scholarly journals Study on the dynamic properties of AM-SLM AlSi10Mg alloy using the Split Hopkinson Pressure Bar (SHPB) technique

2018 ◽  
Vol 183 ◽  
pp. 04005 ◽  
Author(s):  
Bar Nurel ◽  
Moshe Nahmany ◽  
Adin Stern ◽  
Nahum Frage ◽  
Oren Sadot
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Rate Sensitivity ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Static Mechanical ◽  
Split Hopkinson ◽  
Pressure Bar

Additive manufacturing by Selective Laser Melting of metals is attracting substantial attention, due to its advantages, such as short-time production of customized structures. This technique is useful for building complex components using a metallic pre-alloyed powder. One of the most used materials in AMSLM is AlSi10Mg powder. Additively manufactured AlSi10Mg may be used as a structural material and it static mechanical properties were widely investigated. Properties in the strain rates of 5×102–1.6×103 s-1 and at higher strain rates of 5×103 –105 s-1 have been also reported. The aim of this study is investigation of dynamic properties in the 7×102–8×103 s-1 strain rate range, using the split Hopkinson pressure bar technique. It was found that the dynamic properties at strain-rates of 1×103–3×103 s-1 depend on a build direction and affected by heat treatment. At higher and lower strain-rates the effect of build direction is limited. The anisotropic nature of the material was determined by the ellipticity of samples after the SHPB test. No strain rate sensitivity was observed.

High Strain-Rate Compressive Characteristics of Carbon/Epoxy Laminated Composites in Through-Thickness Direction

2004 ◽  
Vol 1-2 ◽  
pp. 11-16 ◽  
Author(s):  
Takashi Yokoyama
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Laminated Composites ◽  
Fiber Direction ◽  
Strain Rates ◽  
Thickness Direction ◽  
Hopkinson Pressure Bar ◽  
Total Strain Energy ◽  
Split Hopkinson ◽  
Pressure Bar

Compressive stress-strain characteristics of carbon/epoxy laminated composites in the through-thickness direction at strain rates of over 1000/s were evaluated using the standard split Hopkinson pressure bar. Three carbon/epoxy laminated composites (i.e., unidirectional, cross-ply and woven) with almost the same thickness were tested at room temperature. Small solid cylindrical specimens were machined such that the direction of the compression loading was perpendicular to the fiber direction of the laminates. The effects of strain rate and reinforcement geometry on the secant modulus at 1% strain, ultimate compressive strength and strain, and total strain energy to failure were examined in detail.

Modelling of Micro-Concrete Behaviour under Static and Dynamic Loading

2014 ◽  
Vol 584-586 ◽  
pp. 1089-1096
Author(s):  
Remdane Boutemeur ◽  
Mustapha Demidem ◽  
Abderrahim Bali ◽  
El Hadi Benyoussef
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Dynamic Tests ◽  
Hopkinson Pressure Bar ◽  
Proposed Model ◽  
Wide Range ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
Static And Dynamic Loading

The aim of this study is to present a model for assessing the dynamic compression behaviour of a micro-concrete. This model is based on the results of numerous tests providing the developments of the mechanical characteristics of the material on a wide range of strain rate from 10-4s-1to 10+3s-1.The Split Hopkinson Pressure Bar (SHPB) dispositive, based on the wave propagation theory in materials, has-been adopted to carry out the dynamic tests on the investigated material. The proposed model is composed of two terms, each characterizing the different contributions noted in the two major explored areas of strain rate.

Measurement of Mechanical Properties of St 37 Material at High Strain Rates Using a Split Hopkinson Pressure Bar

2014 ◽  
Vol 660 ◽  
pp. 562-566 ◽  
Author(s):  
Akbar Afdhal ◽  
Leonardo Gunawan ◽  
Sigit P. Santosa ◽  
Ichsan Setya Putra ◽  
Hoon Huh
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Test Specimen ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Split Hopkinson ◽  
Pressure Bar

The dynamic mechanical properties of a material are important keys to investigate the impact characteristic of a structure such as a crash box. For some materials, the stress-strain relationships at high strain rate loadings are different than that at the static condition. These mechanical properties depend on the strain rate of the loadings, and hence an appropriate testing technique is required to measure them. To measure the mechanical properties of a material at high strain rates, ranging from 500 s-1 to 10000 s-1, a Split Hopkinson Pressure Bar is commonly used. In the measurements, strain pulses are generated in the bars system, and pulses being reflected and transmitted by a test specimen in the bar system are measured. The stress-strain curves as the material properties of the test specimen are obtained by processing the measured reflected and transmitted pulses. This paper presents the measurements of the mechanical properties of St 37 mild steel at several strain rates using a Split Hopkinson Pressure Bar. The stress-strain curves obtained in the measurement were curve fitted using the Power Law. The results show that the strength of St 37 material increases as the strain rate increases.

Compressive Failure of Carbon/Epoxy Laminate Composites under High Impact Loading

2006 ◽  
Vol 324-325 ◽  
pp. 1237-1240 ◽  
Author(s):  
Wei Zhou ◽  
Mao Sheng Cao ◽  
Hai Bo Jin ◽  
Yi Long Lei ◽  
Ji Li Rong
Keyword(s):  
Strain Rate ◽  
Shear Failure ◽  
Split Hopkinson Pressure Bar ◽  
Interfacial Crack ◽  
Fracture Morphology ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Laminate Composites ◽  
Plane Direction ◽  
Pressure Bar

The effect of strain rate on the dynamic compressive of carbon/epoxy composite materials was investigated via the split Hopkinson pressure bar (SHPB) technique. The specimens were tested in the thickness, as well as in the in-plane direction at different high strain rates. The macro- and micro-fracture morphology of the damaged laminated specimens was obtained utilizing the scanning electron microscope (SEM). The experimental results showed that the compressive properties could be significantly affected by the strain rates. The compressive strength and the ultimate strain in the in-plane direction were obviously lower than that in the thickness direction. As the strain rate increased, the laminate had not enough time to respond, the splitting failure of 0° ply of laminates loaded in-plane along 0° was firstly found, then interfacial crack and delamination were induced, the specimens were crushed to fragments at the highest strain rate. No obvious damage of laminates loaded through the thickness could be observed at strain rate below 2000 s-1. The main way of the dynamic compressive failures through the thickness was shear failure due to the brittle fracture of the fiber at 2260 s-1.

scholarly journals Dynamic Behavior of Aluminum Alloy Aw 5005 Undergoing Interfacial Friction and Specimen Configuration in Split Hopkinson Pressure Bar System at High Strain Rates and Temperatures

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4614 ◽  
Author(s):  
Amine Bendarma ◽  
Tomasz Jankowiak ◽  
Alexis Rusinek ◽  
Tomasz Lodygowski ◽  
Bin Jia ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Split Hopkinson Pressure Bar ◽  
Strain Rates ◽  
Compression Tests ◽  
Hopkinson Pressure Bar ◽  
Element Analysis ◽  
Wide Range ◽  
Temperature Experiment ◽  
Split Hopkinson ◽  
Pressure Bar

In this paper, experimental and numerical results of an aluminum alloy’s mechanical behavior are discussed. Over a wide range of strain rates (10−4 s−1 ≤ έ ≤ 103 s−1) the influence of the loading impact, velocity and temperature on the dynamic response of the material was analyzed. The interface friction effect on the material’s dynamic response is examined using a split Hopkinson pressure bar (SHPB) in a high temperature experiment using finite element analysis (FEA). The effect of different friction conditions between the specimen and the transmitted/incident bars in the SHPB system was examined using cylinder bulk specimens and cylinder plates defined with four-layer configurations. The results of these tests alongside the presented numerical simulations allow a better understanding of the phenomenon and reduces (minimizes) errors during compression tests at high and low strain rates with temperatures ranging from 21 to 300 °C.

Effect of Foam Structure on Impact Compressive Properties in Foamed Polyethylene Film

2016 ◽  
Vol 715 ◽  
pp. 159-164 ◽  
Author(s):  
Kohei Tateyama ◽  
Hiroyuki Yamada ◽  
Nagahisa Ogasawara
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Polyethylene Film ◽  
Elastic Response ◽  
Hopkinson Pressure Bar ◽  
Compressive Properties ◽  
Foam Structure ◽  
The Impact

The purpose of this study is to elucidate the effect of foam structure on the impact compressive properties of foamed polyethylene film. Three types of foamed PE film were prepared, which have different foam structure: base type, spheral type and dense type. A quasi-static test was performed using a universal testing machine at the strain rate of 10-3~10-1s-1. Impact tests were carried out using a drop-weight testing machine at the strain rate of 101~102s-1 and using a split Hopkinson pressure bar method at the strain rate of approximately 103s-1. It was confirmed that the foamed PE film shows an increase of the flow stress with increasing of the strain rate, regardless of the specimen type. In the spheral type specimen, the elastic response is observed immediately after compression because the cell shape of this specimen has high bending resistance in comparison with the other two specimens. In addition, it is confirmed that the relative density and cell size affects the flow stress in the foamed PE film.

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