scholarly journals Experimental and Modeling Studies of Stress Wave Propagation and Energy Dissipation Mechanism in Layered Composite Structures

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Youchun Zou ◽  
Chao Xiong ◽  
Junhui Yin ◽  
Huiyong Deng ◽  
Kaibo Cui ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Stress Wave ◽  
Composite Structures ◽  
Split Hopkinson Pressure Bar ◽  
Impact Resistance ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Stress Wave Propagation ◽  
Hopkinson Pressure Bar ◽  
Transmitted Waves ◽  
The Impact

Four composite structures (SiC/UHMWPE/TC4, SiC/TC4/UHMWPE, SiC/UHMWPE/MR/TC4, and SiC/TC4/MR/UHMWPE) were prepared using silicon carbide (SiC) ceramics, ultrahigh molecular weight polyethylene (UHMWPE), titanium alloy (TC4), and metal rubber (MR). The transmitted waves, failure forms, stress wave propagations, and energy dissipations of the composite structures were studied through Split Hopkinson Pressure Bar (SHPB) tests and numerical simulations. The results show that MR in composite structures can delay, attenuate, and smooth the stress wave, thereby reducing SiC damage. UHMWPE on the back of SiC provides cushioning for SiC, while TC4 on the back of SiC aggravates the damage of SiC. The composite structures with MR mainly dissipate the impact energy by reflecting energy, and the energy dissipation performance is better than that of composite structures without MR. A comprehensive comparison of transmitted waves, damage forms, stress wave propagations, and energy dissipations of the four composite structures shows that SiC/UHMWPE/MR/TC4 structure has the best impact resistance. Increasing the thickness of MR in the composite structures can improve the impact resistance, but there are also stress concentration and interface tensile stress.

Research on Dynamic Cumulative Damage Effect of Metal Rubber and Stress Wave Propagation Characteristics of Layered Composite Structure

2021 ◽  
Vol 13 (5) ◽  
pp. 981-990
Author(s):  
Youchun Zou ◽  
Chao Xiong ◽  
Junhui Yin ◽  
Kaibo Cui ◽  
Huiyong Deng ◽  
...  
Keyword(s):  
Stress Wave ◽  
Composite Structure ◽  
Composite Structures ◽  
Impact Resistance ◽  
Layered Composite ◽  
Damage Effect ◽  
Stress Wave Propagation ◽  
Metal Rubber ◽  
Layered Composite Structures ◽  
The Impact

The development of protective materials and structures is of great significance for improving the impact resistance, penetration resistance and spalling resistance of military equipment. At present, the layered composite structure has been widely used due to its good protective performance. In this paper, a special elastic porous material-metal rubber (MR) with excellent cushioning and damping properties was used to prepare high-performance layered composite structures. To begin with, the dynamic mechanical response and the dynamic cumulative damage effect of MR were studied through Split-Hopkinson Pressure Bar (SHPB) tests. Then, the failure form and stress wave propagation characteristics of the layered composite structures were investigated through SHPB tests and finite element method. The results show that repeated impacts can enhance the compactness of MR, thereby increasing the ultimate bearing capacity and energy absorption capacity, which is beneficial for MR to resist repeated impacts. The MR in composite structures can reduce ceramic damage, attenuate stress wave and smooth stress distribution. The titanium alloy on the back of the ceramic will aggravate the damage of the ceramic, and ultra-high molecular weight polyethylene on the back of the ceramic provides cushioning for the ceramic. Therefore, the impact resistance of the composite structure can be improved by adding MR and the reasonable arrangement of materials, and the SiC/UHMWPE/MR/TC4 composite structure has relatively reasonable stress distribution and better protection performance.

Improving the Impact Resistance of Reinforced Concrete

2014 ◽  
Vol 919-921 ◽  
pp. 1924-1929 ◽  
Author(s):  
Husain Abbas ◽  
Tarek Almusallam ◽  
Yousef Al-Salloum
Keyword(s):  
Reinforced Concrete ◽  
Split Hopkinson Pressure Bar ◽  
Impact Resistance ◽  
Concrete Structures ◽  
Material Behavior ◽  
Analytical Models ◽  
Impact Loads ◽  
Hopkinson Pressure Bar ◽  
Hybrid Fibers ◽  
The Impact

The strategic concrete structures are often required to resist impact loads arising from the projectile strike, falling weight, blast generated missile etc. The existing structures found deficient in resisting these loads are required to be retrofitted whereas the upcoming structures are required to be designed for expected impact loads. This paper explores the ways of strengthening existing reinforced concrete (RC) structures using externally bonded carbon fiber reinforced polymer (CFRP) sheets and improving the impact resistance of concrete by mixing hybrid fibers in its production. The impact response of concrete structures is assessed using experiments involving the impact of projectiles of different nose shapes on slab specimens. The material behavior at high strain rate is established using split Hopkinson pressure bar (SHPB) testing at varying strain rates. Analytical models are developed for predicting penetration depth, scabbing thickness, ballistic limit velocity and ejected mass. The experimental results were also validated through numerical modeling using LS-DYNA.

scholarly journals Solid–Liquid Composites with High Impact Resistance

2021 ◽  
Author(s):  
Miao Yu ◽  
Xiying Li ◽  
Pengyu Lv ◽  
Huiling Duan
Keyword(s):  
Energy Dissipation ◽  
High Speed ◽  
Volume Fraction ◽  
Split Hopkinson Pressure Bar ◽  
Impact Resistance ◽  
High Impact ◽  
Strain Rates ◽  
Dynamic Impact ◽  
Solid Liquid ◽  
The Impact

AbstractSolid–liquid composites (SLCs) with novel thermal/electronic/mechanical properties imparted by programmable and functional liquid inclusions have attracted considerable research interest in recent years, and are widely used in smart electronics and soft robotics. The feasible application of SLCs requires that they exhibit excellent static physical properties as well as dynamic impact resistance to satisfy complex service conditions, such as drops and impacts. This paper examined the impact resistance of SLCs fabricated by using microfluidic 3D printing. The results of dynamic split-Hopkinson pressure bar (SHPB) tests showed that the performance of the fabricated SLCs improved in terms of energy dissipation and impact resistance compared with pristine materials. In case of dynamic impact in the strain rates ranging from 100 to $$400\,\hbox {s}^{-1}$$ 400 s - 1 , the SLC specimen deformed without fracture, and its energy dissipation was dominated by the viscosity of the liquid inclusions. For dynamic impact in the strain rates ranging from 500 to $$800\,\hbox {s}^{-1}$$ 800 s - 1 , the SLC specimen fractured and its energy dissipation was determined by the volume fraction of the liquid inclusions. Thus, the energy dissipation of the SLCs could be tuned by regulating the viscosity and volume fraction of the liquid inclusions to satisfy the requirements of protection against different strain rates. Furthermore, the process of fracture of the SLCs under the dynamic SHPB tests was recorded and analyzed by using a high-speed camera. The results showed that distributed liquid inclusions changed the paths of crack propagation to enhance energy dissipation in the SLCs. This study experimentally verified the enhancement in the energy dissipation of SLCs, and provided design strategies for developing multifunctional SLCs with high impact resistance.

Strain Rate Effects in Porous Materials

1998 ◽  
Vol 521 ◽  
Author(s):  
J. Lankford ◽  
K. A. Dannemann
Keyword(s):  
Strain Rate ◽  
Gas Flow ◽  
Split Hopkinson Pressure Bar ◽  
Impact Resistance ◽  
Hopkinson Pressure Bar ◽  
Porous Metals ◽  
Strain Rate Effects ◽  
Open Cell ◽  
Rate Dependent ◽  
The Impact

ABSTRACTThe behavior of metal foams under rapid loading conditions is assessed. Dynamic loading experiments were conducted in our laboratory using a split Hopkinson pressure bar apparatus and a drop weight tester; strain rates ranged from 45 s−1 to 1200 s−1. The implications of these experiments on open-cell, porous metals, and closed- and open-cell polymer foams are described. It is shown that there are two possible strain-rate dependent contributors to the impact resistance of cellular metals: (i) elastic-plastic resistance of the cellular metal “skeleton,” and (ii) the gas pressure generated by gas flow within distorted open cells. A theoretical basis for these implications is 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 Size Effect in the Split Hopkinson Pressure Bar Experiment

2022 ◽  
Vol 2160 (1) ◽  
pp. 012065
Author(s):  
Hailiang Nie ◽  
Weifeng Ma ◽  
Junjie Ren ◽  
Ke Wang ◽  
Jun Cao ◽  
...  
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Dynamic Testing ◽  
Impact Resistance ◽  
Dynamic Mechanical Properties ◽  
Experimental Results ◽  
Hopkinson Pressure Bar ◽  
Practical Engineering ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
The Impact

Abstract For many structures, their service environment is very strict, and the requirements for the impact resistance of materials are very high. Therefore, the dynamic testing method has important scientific significance and application value for practical engineering. Split Hopkinson pressure bar (SHPB) is one of the most common experimental methods for obtaining dynamic mechanical properties of materials. However, there is no uniform standard for the size of the bars and specimens used in the test. Theoretically, the size has little influence on the experimental results, but it has not been proved by experiments. This paper mainly studies the influence of device/specimen sizes of split Hopkinson pressure bar through experiments, it is demonstrated that the sizes of bars and specimen have little effect on experimental results.

SHPB Dynamic Experiment on Silica Fume Concrete

2013 ◽  
Vol 631-632 ◽  
pp. 771-775 ◽  
Author(s):  
Rong Jun Chen ◽  
Hong Wei Liu ◽  
Rui Zeng
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Silica Fume ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Impact Resistance ◽  
Dynamic Mechanical Properties ◽  
Hopkinson Pressure Bar ◽  
The Impact

Dynamic mechanical properties of silica fume concrete in a number of strain rate under the conditions of dynamic compression mechanical properties subjected to various strain rates were studied, and gained the stress versus strain curves, details of an experimental investigation using 74 mm-diameter split Hopkinson pressure bar(SHPB) apparatus were presented. The results showed that: The admixture of silica fume concrete impact resistance, especially under the impact of the performance of high-speed has a very important influence, with the impact velocity increased, the strain rate increase, and its impact more obvious.

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.

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