scholarly journals A SHPB Experimental Study on Dynamic Mechanical Property of High-Damping Rubber

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Xiudi Li ◽  
Huaiyuan Mao ◽  
Ke Xu ◽  
Chaoyang Miao
Keyword(s):  
Strain Rate ◽  
Energy Absorption ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Absorption Efficiency ◽  
Stress Strain ◽  
Dynamic Mechanical ◽  
Energy Absorption Efficiency ◽  
High Damping Rubber ◽  
The Ideal

A split Hopkinson pressure bar (SHPB) experiment was done to examine the feasibility and explosion resistance of high-damping rubber materials developed for use in the area of antiexplosion applications. Through the experiment, the dynamic mechanical properties of the high-damping rubber were determined. The existence of dynamic compressive stress-strain curves at various strain rates of the high-damping rubber have been confirmed from the SHPB experiment. The variation law of the dynamic compression performance with the strain rate is studied, and the energy absorption characteristics of high-damping rubber materials are analyzed. To study the microstructural changes of the high-damping rubber before and after impact, a scanning electron microscopy (SEM) test was done. The results indicated that the stress-strain curve and dynamic modulus of high-damping rubber has an obvious strain rate effect, and the strength and energy absorption ability of high-damping rubber material increases with an increase in the strain rate; the ideal energy absorption efficiency of high-damping rubber can reach 0.8 at a high strain rate and the ideal energy absorption efficiency is more than 0.5 in a wide deformation range; when compared with aluminum foam, the energy absorption effect for high-damping rubber is more apparent. In the event of a compressed deformation or the creation of holes, there may be a change in the main internal mechanism of the high buffering and energy absorption capacity of the high-damping rubber.

Energy Absorption Efficiency of Open-Cell Carbon Foams

2018 ◽  
Vol 933 ◽  
pp. 323-329
Author(s):  
Fumi Asai ◽  
Hiroshi Fukazawa ◽  
Koichi Kitazono
Keyword(s):  
Strain Rate ◽  
Energy Absorption ◽  
Dynamic Compression ◽  
Indentation Test ◽  
Absorption Efficiency ◽  
Plateau Region ◽  
Open Cell ◽  
Energy Absorption Efficiency ◽  
Carbon Foams ◽  
Cell Carbon

Energy absorbing properties of open-cell carbon foams were evaluated by quasi-static and dynamic compression tests. Though carbon foams show brittle deformation behaviors, they have wide plateau region. The plateau stress linearly increases with increasing the relative density. Furthermore, the strain rate sensitivity is 0.03 and 0.15 at low and high strain rate region, respectively. Indentation tests were performed on cylindrical sample having porosity of 92.3 to 92.8% with different impact speeds. No plateau region is observed and macro cracks occur in the high speed indentation test. The energy absorption efficiency of carbon foams is higher than that of conventional aluminum foams because of their wide plateau regions.

Experimental Investigation on Liquid Infiltration Speed in Liquid Nanofoam

2016 ◽  
Author(s):  
Mingzhe Li ◽  
Weiyi Lu
Keyword(s):  
Strain Rate ◽  
Energy Absorption ◽  
Liquid Flow ◽  
Flow Speed ◽  
Absorption Efficiency ◽  
Strain Rates ◽  
Liquid Infiltration ◽  
Infiltration Pressure ◽  
Energy Absorption Efficiency ◽  
Nanoporous Particles

Liquid nanofoam (LN) as a novel material for energy absorption applications exhibits superior properties, including high energy absorption efficiency, ultra-fast energy dissipation, light weight and small size, over existing options. It is a liquid suspension of nanoporous particles, whose nanopore surface is non-wettable to the liquid molecules. Past studies on LN have focused on quasi-static responses, and the actual system performance under dynamic loadings has remained unclear. In this study, the mechanical behavior of two types of LN samples at various strain rates and the liquid flow speed in the nanopores have been experimentally investigated. The quasi-static behavior of LN is rigorously characterized by an Instron 5982 universal tester, from which we find that large amount of energy is dissipated into heat due to the effective excess solid-liquid interfacial tension, and confirm that the energy absorption efficiency of the LN is determined by the liquid infiltration pressure and the total deformability. The dynamic behavior of the LN is investigated by impacting it with a lab-customized drop tower apparatus at intermediate strain rates (around 102 s−1), from which the measured strain-stress curves are highly hysteretic. By comparing with the quasi-static sorption isotherm curve, we show that the liquid infiltration pressure as well as the total deformability of the LN sample in liquid marble form is not affected by the increased strain rate. This suggests that the dynamic behavior of LN can be characterized by quasi-static compressive tests. In the dynamic tests, the ultra-fast energy dissipation rate of LN indicates that the real liquid flow speed in nanopores is much higher than that predicted by the continuum theory. The flow speed can be directly measured from the strain rate by considering the total surface area of the nanoporous particles exposed to the liquid phase. The flow speed is related to the external remote pressure and the 3D porous structure of nanoporous particles. We have examined for the first time the dynamic behaviors of LN, and demonstrated the energy absorption capacity of LN can be activated at desired pressure range by virtue of the strain rate-independent liquid infiltration behavior. This is the first experimental approach to characterize the liquid flow speed in nano-environment. These findings provide strong evidence supporting the potential application of LNs to mitigate energy in blunt impact scenarios such as head to head and head to shoulder collisions in sports, traffic accidents and ballistic impact.

scholarly journals Experimental and Constitutive Model Study on Dynamic Mechanical Behavior of Metal Rubber under High-Speed Impact Loading

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Youchun Zou ◽  
Chao Xiong ◽  
Junhui Yin ◽  
Kaibo Cui ◽  
Xiujie Zhu ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Mechanical Behavior ◽  
Energy Absorption ◽  
Split Hopkinson Pressure Bar ◽  
High Energy ◽  
Property A ◽  
Stress Strain ◽  
Dynamic Mechanical ◽  
Dynamic Mechanical Behavior ◽  
Metal Rubber

The development of lightweight, impact-resistant, and high energy-consuming materials is of great significance for improving the defense capabilities of military equipment. As a new type of damping material, metal rubber has demonstrated great potential for application in the field of impact protection. In this paper, the dynamic mechanical response of metal rubber under a high strain rate is studied, which provides a new idea for developing high-performance protective materials. The stress-strain curves, energy absorption performance, and wave transmission performance of metal rubber at various strain rates were investigated based on a split-Hopkinson pressure bar (SHPB) device. The dynamic stress-strain curve of metal rubber is divided into three stages: elastic stage, plastic stage, and failure stage. The optimal energy absorption efficiency is greater than 0.5, and the maximum value can reach 0.9. The wave transmittance is less than 0.01. The dynamic mechanical tests have proved that metal rubber has excellent energy absorption capacity and impact resistance property. A constitutive model based on Sherwood–Frost was established to predict the dynamic mechanical behavior of metal rubber. The results of comparison between the calculation and the experiment show that the constitutive model can accurately predict the dynamic mechanical performance of metal rubber.

An Experimental Investigation of the Dynamic Mechanical Behaviors of Hollow Spheres Filled Syntactic Foam

2012 ◽  
Vol 268-270 ◽  
pp. 67-73
Author(s):  
Ming Yu ◽  
Ping Zhu
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Failure Mechanisms ◽  
Hollow Spheres ◽  
Syntactic Foam ◽  
Mechanical Behaviors ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Dynamic Mechanical ◽  
Split Hopkinson

Dynamic mechanical behaviors are critical to the engineering applications of hollow spheres filled syntactic foams. The potential of such composites cannot be fully realized unless the effects of strain rate on their mechanical properties are fully understood. In this study, both the compressive and the tensile behaviors of an epoxy syntactic foam filled by ceramic microspheres were experimentally investigated over the strain rate range from 0.001 to 2000 s-1. The compressive and tensile tests at high strain rates were carried out by means of split Hopkinson pressure bar (SHPB) and split Hopkinson tensile bar (SHTB), respectively. The stress-strain responses and failure mechanisms were examined quantitatively and qualitatively. The experimental results indicate that both the compressive and the tensile behaviors of syntactic foam are highly sensitive to strain rate. Moreover, a comparison of the stress-strain curves suggests that the compressive and tensile behaviors are dominated by different failure mechanisms, which consequently lead to distinct effects of strain rate on the compressive and tensile behaviors of syntactic foam.

Compressive stress-strain properties of natural materials treated with aqueous NaOH

Holzforschung ◽  
2008 ◽  
Vol 62 (4) ◽  
Author(s):  
Yukiko Ishikura ◽  
Takato Nakano
Keyword(s):  
Compressive Stress ◽  
Energy Absorption ◽  
Shape Change ◽  
Absorption Efficiency ◽  
Threshold Concentration ◽  
Small Range ◽  
Stress Strain ◽  
Longitudinal Contraction ◽  
Energy Absorption Efficiency ◽  
Efficiency Parameter

Abstract Physical and cushioning properties of wood samples treated with various concentrations of NaOH aqueous solutions have been investigated based on compressive stress-strain curves. The shapes of curves changed essentially at NaOH concentrations above 10% as a threshold concentration. The stress-strain curves were analyzed based on the assumption that a rule of mixtures is applicable in the case of a very small range of displacement. The form factor n was also calculated. The values of n of the wood samples treated with NaOH whose concentration was higher than 10% were different from those of the wood samples treated with NaOH whose concentration was less than 10%. The shape changes, longitudinal contraction and twisting of the wood samples are related to NaOH concentration. The energy-absorption efficiency parameter E and ideality parameter I were calculated based on stress-strain curves according to the literature. Also, these parameters change above the threshold concentration of 10%. It was concluded that the cushioning properties of wood treated with alkali concentrations higher than 10% are improved. Due to the shape change of wood samples, the efficiency of energy-absorption properties is higher.

Research of Compression and Energy Absorption Characteristics of Polyimide Foam

2014 ◽  
Vol 541-542 ◽  
pp. 30-34 ◽  
Author(s):  
Meng Qian Li ◽  
Gang Ma ◽  
Ji Jun Xiao
Keyword(s):  
Energy Absorption ◽  
Compressive Strain ◽  
Testing Machine ◽  
Absorption Efficiency ◽  
Absorption Characteristic ◽  
Stress Strain ◽  
Compression Properties ◽  
Universal Testing ◽  
Energy Absorption Efficiency ◽  
Compaction Stress

The compression and energy absorption characteristic of polyimide foams with three different densities were analyzed in this paper. The compression properties were characterized by CMT7104 Electronic Universal Testing Machine, and the results show that the compressive stress at the same compressive strain increases with the foam density, and the stress-strain curves of polyimide foams with different densities were all composed of elastic region, plateau region and compacted region. The foams ideal energy-absorption efficiency curves were obtained from their stress-strain curves, and all findings show that stress corresponding to at the peak of the energy-absorption efficiency was closed to the compaction stress of material, all their ideal energy-absorption efficiency can reach about 0.8. The polyimide foam is a kind of excellent energy-absorption material.

scholarly journals Effects of Strain Rate and Initial Density on the Dynamic Mechanical Behaviour of Dry Calcareous Sand

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Zhangyong Zhao ◽  
Yanyu Qiu ◽  
Mingyang Wang
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Initial Density ◽  
Strain Rate Range ◽  
Hopkinson Pressure Bar ◽  
Calcareous Sand ◽  
Dynamic Mechanical ◽  
Mechanical Behaviours ◽  
Pressure Bar

The dynamic compressive behaviour of dry calcareous sand under rigid confinement was characterised using a split-Hopkinson pressure bar (SHPB). Sand samples were confined inside a sleeve of hardened stainless steel and capped by a pair of aluminium cylindrical rods. This assembly was subjected to repeated dynamic compaction to attain precise bulk mass densities. It was then sandwiched between the incident and transmission bars of SHPB for dynamic compression testing. Sand specimens of three initial mass densities, namely, 1.26 g/cm3, 1.35 g/cm3, and 1.42 g/cm3, were loaded by incident pulses applying a stress of 35 MPa, 71 MPa, and 143 MPa, respectively. Experimental results show that in the strain rate range of 335 s−1 to 1253 s−1, the dynamic mechanical behaviours of dry calcareous sands exhibited no significant strain rate effect. The Lundborg model and the Murnaghan model could be used to describe the deviatoric and volumetric behaviours of calcareous sand with different initial densities, respectively.

The Dynamic Mechanical Constitutive Equation of Concrete under High Temperture

2011 ◽  
Vol 99-100 ◽  
pp. 782-785 ◽  
Author(s):  
Bin Jia ◽  
Zheng Liang Li ◽  
Jun Lin Tao ◽  
Chun Tao Zhang
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Dynamic Stress ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Mechanical Properties ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Dynamic Mechanical ◽  
Whole Process ◽  
Pressure Bar

Based on the test by the split Hopkinson Pressure Bar (SHPB), in this papaer the research on the dynamic mechanical properties of concrete under high temperture has been conducted, the influence law of temperature and strain rate on the mechanical peoperties has been analyzed, and the dynamic stress-strain curves of concrete under high temperature have been obtained. Analysis indicate that the concrete strain rate hardening effect is coupled with the high temperature weakening effect. Therefore, on the basis of classical damage theoretical model, in accordance with the concrete high-temperature dynamic mechanical characteristics, a unified equation is established to describe the whole process of concrete dynamic stress-strain relationship under high temperature, which is well coincided with the test results.

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.

Energy Absorption of Origami Crash Box: Numerical Simulation and Theoretical Analysis

2018 ◽  
Author(s):  
Mengyan Shi ◽  
Jiayao Ma ◽  
Yan Chen ◽  
Zhong You
Keyword(s):  
Energy Absorption ◽  
Theoretical Study ◽  
Low Cost ◽  
Deformation Mode ◽  
Absorption Efficiency ◽  
Great Promise ◽  
Good Match ◽  
Energy Absorption Efficiency ◽  
Thin Walled ◽  
Initial Peak

Thin-walled tubes as energy absorption devices are widely in use for their low cost and high manufacturability. Employing origami technique on a tube enables induction of a predetermined failure mode so as to improve its energy absorption efficiency. Here we study the energy absorption of a hexagonal tubular device named the origami crash box numerically and theoretically. Numerical simulations of the quasi-static axial crushing show that the pattern triggers a diamond-shaped mode, leading to a substantial increase in energy absorption and reduction in initial peak force. The effects of geometric parameters on the performance of the origami crash box are also investigated through a parametric study. Furthermore, a theoretical study on the deformation mode and energy absorption of the origami crash box is carried out, and a good match with numerical results is obtained. The origami crash box shows great promise in the design of energy absorption devices.

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