Stress wave propagation effects in split Hopkinson pressure bar tests

1995 ◽  
Vol 449 (1936) ◽  
pp. 187-204 ◽  
Keyword(s):  
Wave Propagation ◽  
Strain Rate ◽  
Stress Wave ◽  
Split Hopkinson Pressure Bar ◽  
Rate Sensitivity ◽  
Stress Wave Propagation ◽  
Hopkinson Pressure Bar ◽  
Propagation Effects ◽  
Split Hopkinson ◽  
Pressure Bar

Studies of the properties of materials at high strain rates by the split Hopkinson pressure bar suggest that most materials show a sharp increase in strain rate sensitivity at high rates. In this paper, analytical and numerical evidence is presented which shows that his apparent increase in the strain rate sensitivity reported in the literature may result from stress wave propagation effects present in the test. A one-dimensional analytical solution has been developed for a rate independent bi-linear material tested in a split Hopkinson pressure bar apparatus. The solution, which is based on a stress wave reverberation model, shows that there is an apparent increase in the strain rate sensitivity of the material which can only be explained in terms of large propagating plastic wave fronts in the specimen. Numerical modelling of the same test geometry for the same input material model is in excellent agreement showing conclusively that stress wave propagation effects are inevitable at high impact velocities. The assumption of uniform stress and strain distribution within a split Hopkinson pressure bar specimen is therefore incorrect at high impact velocities. The formulation of the novel numerical code used in the present work, which is based on the finite volume technique, is also presented.

The Effect of Stress Wave on Dynamic Response of Square Thin-Walled Tube

2014 ◽  
Vol 590 ◽  
pp. 63-68 ◽  
Author(s):  
Zhu Hua Tan ◽  
Bo Zhang ◽  
Peng Cheng Zhai
Keyword(s):  
Wave Propagation ◽  
Dynamic Response ◽  
Stress Wave ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Stress Wave Propagation ◽  
Hopkinson Pressure Bar ◽  
Thin Walled Tube ◽  
Split Hopkinson ◽  
Pressure Bar

The effect of stress wave propagation on dynamic response of square tube was investigated by the experimental and numerical simulation methods in the present paper. The square tubes were subjected to the axial impact by split Hopkinson pressure bar. And the deformation process of each square tube was recorded by a high speed camera. Typical dynamic plastic buckling phenomena were observed in the experiments. And the numerical calculation of the experimental load case was conducted to analyze the effect of the stress wave propagation on the initial buckling of the square tube. The results show that there is obvious stress wave propagation in the square tube before the buckling of the square tube. And the initial buckling starts from the rear end of the tube due to the propagation of the stress wave. The relation between the stress wave propagation and initial buckling of the square tube was also discussed.

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.

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.

scholarly journals The effect of perforations on the stress wave propagation characteristics of multilayered materials

2016 ◽  
Vol 29 (12) ◽  
pp. 1680-1695 ◽  
Author(s):  
Alper Tasdemirci ◽  
Ali Kara
Keyword(s):  
Stress Wave ◽  
Split Hopkinson Pressure Bar ◽  
Stress Wave Propagation ◽  
Large Strains ◽  
Hopkinson Pressure Bar ◽  
Multilayered Structures ◽  
Backing Plate ◽  
Split Hopkinson ◽  
Multilayered Materials ◽  
Pressure Bar

The effect of perforated interlayers on the stress wave transmission of multilayered materials was investigated both experimentally and numerically using the Split Hopkinson pressure bar (SHPB) testing. The multilayer combinations consisted of a ceramic face plate and a glass/epoxy backing plate with a laterally constrained low modulus solid or perforated rubber and Teflon interlayer. The perforations on rubber interlayer delayed the stress rise time and reduced the magnitude of the transmitted stress wave at low strains, while the perforations allowed the passage of relatively high transmitted stresses at large strains similar to the solid rubber interlayer. It was concluded that the effect of perforations were somewhat less pronounced in Teflon interlayer configuration, arising from its relatively low Poisson’s ratio. It was finally shown that SHPB testing accompanied with the numerical simulations can be used to analyze the effect of compliant interlayer insertion in the multilayered structures.

scholarly journals Experimental Study on Stress Wave Propagation Crossing the Jointed Specimen with Different JRCs

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
S.N. Hong ◽  
H.B. Li ◽  
L.F. Rong
Keyword(s):  
Wave Propagation ◽  
Stress Wave ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Three Dimensional ◽  
Stress Wave Propagation ◽  
Roughness Coefficient ◽  
Rock Masses ◽  
Hopkinson Pressure Bar ◽  
Pressure Bar

Most of the rock masses in the outer crust of the Earth are discontinuous. They are divided by joints, faults, fractures, etc. And those discontinuities, generally referred to as joints, greatly affect the property of the rock masses. The paper experimentally investigates the stress wave propagation crossing the jointed specimens. The tests were conducted on the split Hopkinson pressure bar (SHPB). The test specimens consist of two parts cast by cement mortar. Both parts have an irregular surface, and they were designed to match each other completely. The surfaces where two parts meet make an artificial joint. The surfaces of the joints were scanned by a three-dimensional scanner to obtain its actual topography and then to calculate the roughness of the surface, i.e., the joint roughness coefficient (JRC). A set of jointed specimens with JRC ranging from 0 to 20 were made and used in dynamic compression experiments. During the tests, signals were captured by strain gauges stuck on the incident and transmitted bars of the SHPB apparatus. The incident, reflected, and transmitted waves across the jointed specimens were obtained from the test records. We found out that more stress wave would transmit through the jointed specimen with larger JRC. Besides, collected data were processed to get the dynamic stress-strain relation of jointed specimens and the stress-closure curves of the joints. The results show that the joint increases the deformation of the specimen, and the stiffness of the jointed specimen would increase slightly when the joint is rougher.

scholarly journals High strain-rate dynamic compressive behavior and energy absorption of distiller’s dried grains and soluble composites with paulownia and pine wood using a split Hopkinson pressure bar technique

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9444-9461
Author(s):  
Damian Stoddard ◽  
Suman Babu Ukyam ◽  
Brent Tisserat ◽  
Ivy Turner ◽  
Rowan Baird ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Energy Absorption ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Rate Sensitivity ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Pressure Bar

Novel bio-based composite wood panels (CWPs) that consisted of distiller’s dried grains and solubles (DDGS) flour adhesive bound to a wood filler/reinforcement were subjected to high strain-rate compression loading, and their behavior was investigated. Specimens of DDGS-Paulownia wood (PW) or DDGS-pinewood (Pine) composites made using DDGS with fractions of 10%, 15%, 25%, and 50% were tested at high strain-rates using a modified compression Split Hopkinson Pressure Bar (SHPB). Both DDGS-PW and DDGS-Pine composites displayed strain-rate sensitivity, and DDGS-PW had a 25% fraction, which showed the highest ultimate compressive strength of 655 MPa at approximately 1600/s. The 90%-PW had the highest specific energy of 19.24 kJ/kg at approximately 1600/s when loaded via dynamic compression. The CWPs constructed of DDGS-PW had higher strength and energy absorption than DDGS-Pine with the exception of the 50% DDGS composites.

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