Deformation Mode Dependency on Strain Rate Sensitivity of Volume Resistivity in TRIP Steel

2013 ◽  
Vol 535-536 ◽  
pp. 473-476 ◽  
Author(s):  
Takeshi Iwamoto ◽  
Shiro Yamanaka ◽  
Alexis Rusinek
Keyword(s):  
Trip Steel ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Rate Sensitivity ◽  
Volume Resistivity ◽  
Deformation Mode ◽  
Absorption Characteristic ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Pressure Bar

With a phenomenon of strain-induced martensitic transformation, TRIP steel is expected to show excellent impact energy absorption characteristic. It is important for an improvement of a reliability of TRIP steel to evaluate an amount of martensite. In this study, AISI304, which is a kind of TRIP steel, is deformed plastically by a conventional material testing machine and the split Hopkinson pressure bar apparatus. During the deformation of TRIP steel, a circuit based on the Kevin double bridge measures change in volume resistivity which has a correlation with the amount of martensite. Experimental results show that the change in volume resistivity during the process of deformation at various strain rates.

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.

Using Split Hopkinson Pressure Bars to Perform Large Strain Compression Tests on Neoprene at Intermediate and High Strain Rates

2013 ◽  
Vol 631-632 ◽  
pp. 458-462 ◽  
Author(s):  
Peng Duo Zhao ◽  
Yu Wang ◽  
Jian Ye Du ◽  
Lei Zhang ◽  
Zhi Peng Du ◽  
...  
Keyword(s):  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Large Strain ◽  
Rate Sensitivity ◽  
Strain Rates ◽  
Compression Tests ◽  
Hopkinson Pressure Bar ◽  
High Strain Rates ◽  
Split Hopkinson ◽  
Pressure Bar

The strain rate sensitivity of neoprene is characterized using a modified split Hopkinson pressure bar (SHPB) system at intermediate (50 s-1, 100 s-1) and high (500 s-1, 1000 s-1) strain rates. We used two quartz piezoelectric force transducers that were sandwiched between the specimen and experimental bars respectively to directly measure the weak wave signals. A laser gap gage was employed to monitor the deformation of the sample directly. Three kinds of neoprene rubbers (Shore hardness: SHA60, SHA65, and SHA70) were tested using the modified split Hopkinson pressure bar. Experimental results show that the modified apparatus is effective and reliable for determining the compressive stress-strain responses of neoprene at intermediate and high strain rates.

Effect of Surface Modification on Strain Rate Sensitivity of Polypropylene/Muscovite Layered Silicate Composites

2014 ◽  
Vol 803 ◽  
pp. 343-347
Author(s):  
M.F. Omar ◽  
Nur Suhaili Abd Wahab ◽  
Hazizan Md Akil ◽  
Zainal Arifin Ahmad ◽  
Mohd Fadli Ahmad Rasyid ◽  
...  
Keyword(s):  
Surface Modification ◽  
Ion Exchange ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Split Hopkinson Pressure Bar ◽  
Layered Silicate ◽  
Rate Sensitivity ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Pressure Bar

Surface modification is one of the treatment methods that can be implemented to improve the strain rate sensitivity of composite materials. In this study, both untreated and treated polypropylene/muscovite layered silicate composites were tested under static and dynamic loading up to 1100 s-1 using the universal testing machine and the split Hopkinson pressure bar apparatus, respectively. Muscovite particles were treated with lithium nitrate and cetyltrimethylammonium bromide as a surfactant through ion exchange treatment. Results show that the treated polypropylene/muscovite specimens with fine state of dispersion level shows better rate of sensitivity as compared to untreated polypropylene/muscovite specimens under a wide range of strain rate investigated. Apart from that, the rate of sensitivity of both tested polypropylene/muscovite layered silicate composites also show great dependency on the strain rate sensitivity was steadily increased with increasing strain rate. Unfortunately, the thermal activation values show contrary trend. Key words: Ion exchange treatment; Strain rate sensitivity; Muscovite particles; Split Hopkinson pressure bar apparatus; Strain rates

scholarly journals Epoxy-glass Microballoon Syntactic Foams for Blast Mitigating Applications

2018 ◽  
Vol 68 (2) ◽  
pp. 210 ◽  
Author(s):  
A.V. Ullas ◽  
P. K. Sharma ◽  
P. Chandel ◽  
P. Sharma ◽  
D. Kumar ◽  
...  
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Hollow Spheres ◽  
Rate Sensitivity ◽  
Syntactic Foams ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Static Regime ◽  
Pressure Bar ◽  
Blast Loadings

Polymeric syntactic foams refer to a class of cellular material created using preformed hollow spheres bound together with a polymeric matrix. These cellular materials possess exceptional ability to respond against high impact dynamic loads. This paper is an attempt to fabricate polymeric syntactic foams of epoxy containing hollow glass microballoon at varying loading (40 % - 60 %) and explore their potential towards blast mitigation. The tensile, compressive and flexural strength were found to be inversely proportional to the microballoon loading in the quasi-static regime. The strain rate sensitivity of the foams was confirmed by performing high strain rate studies using split hopkinson pressure bar. The flow stress of these foams was found to increase with increasing strain rates. The syntactic foams were subjected to controlled transient blast loadings using a shock tube. The samples remained intact and no strain was observed on the strain gauge, even under a blast load of ~ 90 psi, which clearly highlight their potential as core materials for blast mitigating applications.

Effect of Strain Rate on Mechanical Properties of Pure Iron

2013 ◽  
Vol 705 ◽  
pp. 21-25 ◽  
Author(s):  
Wei Ping Bao ◽  
Zhi Ping Xiong ◽  
Xue Ping Ren ◽  
Fu Ming Wang
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Work Hardening ◽  
Pure Iron ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Hopkinson Pressure Bar ◽  
Hardening Effect ◽  
Split Hopkinson ◽  
Pressure Bar

Effect of strain rate on mechanical properties of pure iron was studied by compression experiments using Gleebe-1500D thermal simulation testing machine and Split-Hopkinson Pressure Bar, indicating that pure iron only has strain rate hardening effect. Adiabatic temperature rise tends to increase with increasing the strain rate. Work hardening effect is also analyzed. It found that there are only two work hardening regions in static stage (10-3 to 1 s-1) while there are three work hardening regions in dynamic stage (650 to 8500 s-1). It is on account of onset of twining at high strain rates.

Study on Constitutive Relationship of Fe-36Ni Invar Alloy

2011 ◽  
Vol 291-294 ◽  
pp. 1131-1135
Author(s):  
Guo He Li ◽  
Yu Jun Cai ◽  
Hou Jun Qi
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Constitutive Relationship ◽  
Invar Alloy ◽  
Hopkinson Pressure Bar ◽  
Universal Testing ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
Relationship Of

By electronic universal testing machine and Split Hopkinson Pressure Bar, the mechanical properties data of Fe-36Ni invar alloy are gained at a range of temperature from 20°C to 800°C and strain rate from 10-3 /s to 104/s. An improved Johnson-Cook model is presented to describe the mechanical behavior of Fe-36Ni invar alloy at high temperature and high strain rate, and verified by experimental results.

Quasistatic and Dynamic Compressive Behavior of Gelatin

2010 ◽  
Author(s):  
Jiwoon Kwon ◽  
Ghatu Subhash
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Rate Sensitivity ◽  
Polymeric Materials ◽  
Soft Materials ◽  
High Rate ◽  
Constitutive Behavior ◽  
Hopkinson Pressure Bar ◽  
Property Data ◽  
Split Hopkinson ◽  
Pressure Bar

Gelatin has been extensively used as a tissue stimulant. Determination of properties and tits constitutive behavior is crucial to successful use of gelatin in these applications. In this study, ballistic gelatin was used because the recipe to prepare the gelatin and its quasi-static strength (250 bloom) of this particular type of gelatin is well known [1]. Although the study for high rate deformation is important to understand the damage from blast impact, majority of the currently available material property data is in quasi-static range [2,3]. Generally, polymeric materials (including human tissue) exhibit highly rate sensitive response [4]. Therefore, the understanding of the constitutive behavior for these materials at high rate loading is essential. This study will provide the rate sensitivity of gelatin by comparing the response under quasi-static and dynamic loading. In order to investigate the dynamic behavior of gelatin, the split Hopkinson pressure bar (SHPB) was used in this study. Because use of a solid metallic bar to test such soft materials does not provide an adequate transmitted signal, a polymer split Hopkinson pressure bar (PSHPB) was used to reduce the impedance mismatch between bar and soft gelatin specimen. The nature of dispersion and attenuation was corrected using an iterative scheme developed earlier [5].

Effect of Surface Modification on Rice Husk (RH)/Linear Low Density Polyethylene (LLDPE) Composites under Various Loading Rates

2016 ◽  
Vol 840 ◽  
pp. 3-7 ◽  
Author(s):  
Nur Suhaili Abdul Wahab ◽  
Mohd Firdaus Omar ◽  
Hazizan Md Akil ◽  
Zainal Arifin Ahmad ◽  
N.Z. Noimam
Keyword(s):  
Surface Modification ◽  
Dynamic Loading ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Hopkinson Pressure Bar ◽  
Silane Coupling Agents ◽  
Loading Rates ◽  
Silane Coupling ◽  
Split Hopkinson ◽  
Pressure Bar

The surface modification of RH filler was carried out using silane coupling agents in order to improve the adhesion between LLDPE and RH. RH was treated using silane coupling agent at four different concentrations (1, 3, 5 and 7 %) at room temperature. In this study, both untreated and treated RH/LLDPE composites were tested under static (0.001 s-1, 0.01 s-1 and 0.1 s-1) and dynamic loading rates (650 s-1, 900 s-1 and 1100 s-1) using universal testing machine and split Hopkinson pressure bar apparatus, respectively. Results show that the 5% treated LLDPE/RH composite shows the higher ultimate compressive strength (UCS) and rigidity as compared to untreated LLDPE/RH composites under various loading rates. Overall, it is proved that the surface treatment of RH gives significant contribution towards the UCS and rigidity of LLDPE/RH composites under both static and dynamic loading rates.

The Effect of Percentage of Primary α on Mechanical Properties of Bimodal Microstructure of TC4

2011 ◽  
Vol 418-420 ◽  
pp. 173-178
Author(s):  
Jing Min Yang ◽  
Yang Wei Wang ◽  
Ju Bin Gao ◽  
Pan Xiong
Keyword(s):  
Mechanical Properties ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Bimodal Microstructure ◽  
Hopkinson Pressure Bar ◽  
Different Temperatures ◽  
Split Hopkinson ◽  
Universal Material Testing Machine ◽  
Pressure Bar ◽  
Material Testing Machine

In order to discuss the effect of content of primary α on properties of bimodal microstructure, the TC4 sheet in rolling state was heat treated at different temperatures of 10~50°Cbelow the β-transus temperature, then a series of bimodal microstructures with different content of primary α were obtained by air-cooled procedure. Quasi-static and dynamic compress tests were carried out with universal material testing machine and Split Hopkinson Pressure Bar (SHPB) respectively. The results indicated that the relationship between mechanical properties and primary α is irregular, and that bimodal microstructure with 25% primary α shows a better combination of strength and ductility.

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