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.

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.

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 Development of a True-Biaxial Split Hopkinson Pressure Bar Device and Its Application

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7298
Author(s):  
Shumeng Pang ◽  
Weijun Tao ◽  
Yingjing Liang ◽  
Shi Huan ◽  
Yijie Liu ◽  
...  
Keyword(s):  
Stress Wave ◽  
Impact Loading ◽  
Split Hopkinson Pressure Bar ◽  
Axial Stress ◽  
Dynamic Mechanical Properties ◽  
Stress Waves ◽  
Hopkinson Pressure Bar ◽  
Dynamic Mechanical ◽  
Split Hopkinson ◽  
Pressure Bar

Although highly desirable, the experimental technology of the dynamic mechanical properties of materials under multiaxial impact loading is rarely explored. In this study, a true-biaxial split Hopkinson pressure bar device is developed to achieve the biaxial synchronous impact loading of a specimen. A symmetrical wedge-shaped, dual-wave bar is designed to decompose a single stress wave into two independent and symmetric stress waves that eventually form an orthogonal system and load the specimen synchronously. Furthermore, a combination of ground gaskets and lubricant is employed to eliminate the shear stress wave and separate the coupling of the shear and axial stress waves propagating in bars. Some confirmatory and applied tests are carried out, and the results show not only the feasibility of this modified device but also the dynamic mechanical characteristics of specimens under biaxial impact loading. This novel technique is readily implementable and also has good application potential in material mechanics testing.

scholarly journals Influence of Imperfect Position of a Striker and Input Bar on Wave Propagation in a Split Hopkinson Pressure Bar (SHPB) Setup with a Pulse-Shape Technique

2020 ◽  
Vol 10 (7) ◽  
pp. 2423 ◽  
Author(s):  
Robert Panowicz ◽  
Marcin Konarzewski
Keyword(s):  
Wave Propagation ◽  
Inclination Angle ◽  
High Frequency ◽  
Pulse Shape ◽  
Split Hopkinson Pressure Bar ◽  
Hopkinson Pressure Bar ◽  
Pulse Shaper ◽  
Split Hopkinson ◽  
Pressure Bar

The effect of using a pulse shaper technique, such as rounding a striker or applying a pulse shaper on the signals recorded with the split Hopkinson pressure bar (SHPB) technique, when the striker and the input bar are in an imperfect position, was investigated. Two of the most common cases have been analyzed: an offset of the symmetry axes of the striker and the input bar; and an inclination angle between the striker and the input bar. LS-Dyna software was used to examine this problem numerically. The inclination angle imperfection has a significant impact on signal disturbances, whereas the use of a rounded striker significantly affects the limitation of the vibration flexural modes. In all considered cases, a slight imperfection causes a reduction in the high-frequency Pochhammer–Chree oscillations.

An improved method for compressive stress-strain measurements at very high strain rates

1992 ◽  
Vol 438 (1902) ◽  
pp. 153-170 ◽  
Keyword(s):  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Pure Copper ◽  
High Strength ◽  
Tungsten Alloy ◽  
High Speed Photography ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Split Hopkinson ◽  
Pressure Bar

This paper describes a modification of the split Hopkinson pressure bar, to allow compression testing of high strength metals at a strain rate of up to about 10 5 s –1 . All dimensions are minimized to reduce effects of dispersion and inertia, with specimens of the order of 1 mm diameter. Strain is calculated from the stress record and calibrated with high-speed photography. Particular attention has been paid to the accuracy of the technique, and errors arising from nonlinearity in the instrumentation, dispersion, frictional restraint and inertia have all been quantitatively assessed. Stress–strain results are presented of Ti 6A14V alloy, a high strength tungsten alloy, and pure copper.

Dynamic Response and Fracture of High Strength Boride/Alumina Ceramic Composite

2006 ◽  
Vol 326-328 ◽  
pp. 1573-1576
Author(s):  
Dong Feng Cao ◽  
Li Sheng Liu ◽  
Jiang Tao Zhang
Keyword(s):  
Dynamic Response ◽  
Ceramic Composite ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
High Strength ◽  
Alumina Ceramic ◽  
Hopkinson Pressure Bar ◽  
Dynamic Loadings ◽  
Split Hopkinson ◽  
Pressure Bar

Dynamic response and fracture of high strength boride/alumina ceramic composite were investigated by split Hopkinson pressure bar (SHPB) experiment in this paper. The compressive stress–strain curves and dynamic compression strength of the composites were tested. The surface’s microstructure of fractured composites were examined by using scanning electron microscope (SEM) to investigate the fracture mechanism. The results show that boride/alumina has high dynamic compressive strength and high Young’s modulus. The main fracture mode of the material is the fracture of the ceramic grains. The micro-voids and flaws, generated during the sintering and manufacturing of material and mechanical process of specimen, decrease the strength of the material because they provide the source of crack expansion when the material undergoes the dynamic loadings.

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