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.

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.

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 Research on energy absorption properties of open-cell copper foam for current collector of Li-ions

2019 ◽  
Vol 37 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Jian Chen ◽  
Xiongfei Li ◽  
Wei Li ◽  
Cong Li ◽  
Baoshan Xie ◽  
...  
Keyword(s):  
Strain Rate ◽  
Pore Size ◽  
Energy Absorption ◽  
Testing Machine ◽  
Young Modulus ◽  
Current Collector ◽  
Absorption Efficiency ◽  
Absorption Capacity ◽  
Absorption Mechanism ◽  
Open Cell

AbstractQuasi-static uniaxial compressive tests of open-cell copper (Cu) foams (OCCF) were carried out on an in-situ bi-direction tension/compress testing machine (IBTC 2000). The effects of strain rate, porosity and pore size on the energy absorption of open-cell copper foams were investigated to reveal the energy absorption mechanism. The results show that three performance parameters of open-cell copper foams (OCCF), involving compressive strength, Young modulus and yield stress, increase simultaneously with an increase of strain rate and reduce with increasing porosity and pore size. Furthermore, the energy absorption capacity of OCCF increases with an increase of porosity and pore size. However, energy absorption efficiency increases with increasing porosity and decreasing pore size. The finite element simulation results show that the two-dimensional stochastic model can predict the energy absorption performance of the foam during the compressive process. The large permanent plastic deformation at the weak edge hole is the main factor that affects the energy absorption.

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.

Bending Behavior of Simply-Supported Sandwich Beams Subjected to Large Deflection

2018 ◽  
Vol 777 ◽  
pp. 569-574
Author(s):  
Zhong You Xie
Keyword(s):  
Energy Absorption ◽  
Large Deflection ◽  
Absorption Efficiency ◽  
Sandwich Beams ◽  
Element Simulation ◽  
Energy Absorption Efficiency ◽  
Load Carrying ◽  
Absorption Performance ◽  
Bending Behavior ◽  
The Moment

Due to thin skins and soft core, it is apt to local indentation inducing the concurrence of geometrical and material nonlinearity in sandwich structures. In the paper, finite element simulation is used to investigate the bending behavior of lightweight sandwich beams under large deflection. A modified formulation for the moment at mid-span section of sandwich beams under large deflection is presented, and energy absorption performance is assessed based on energy absorption efficiency. In addition, it is found that no local indentation arises initially, while later that increases gradually with loading displacement increasing. The height of the mid-span section as well as load-carrying capacity decreases significantly with local indentation depth increasing.

Compressive Properties of Electroless Ni-P Coating Reinforced Magnesium Alloy Foams

2021 ◽  
Vol 889 ◽  
pp. 123-128
Author(s):  
Sheng Jun Liu ◽  
Zhi Qiang Dong ◽  
Ren Zhong Cao ◽  
Da Song ◽  
Jia An Liu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Energy Absorption ◽  
Absorption Efficiency ◽  
Absorption Capacity ◽  
Compressive Properties ◽  
Compressive Test ◽  
Energy Absorption Capacity ◽  
Energy Absorption Efficiency ◽  
Hybrid Foams ◽  
Electroless Ni

In this study, the open-cell Mg-2Zn-0.4Y foams were prepared by infiltration casting method. The Ni/Mg hybrid foams were prepared by electroless Ni-P coating on the foam struts to improve the compressive strength and energy absorption capacity. The compressive properties of the Mg alloy foams and Ni/Mg hybrid foams were studied by quasi-static compressive test. The experimental results show that the Ni-P coating is composed of crystallites. The Ni-P coating can significantly enhance the compressive strength, energy absorption capacity and energy absorption efficiency of the foams.

scholarly journals Energy Absorption of Different Cell Structures for Closed-Cell Foam-Filled Tubes Subject to Uniaxial Compression

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1579 ◽  
Author(s):  
Yang Yu ◽  
Zhuokun Cao ◽  
Ganfeng Tu ◽  
Yongliang Mu
Keyword(s):  
Energy Absorption ◽  
Absorption Efficiency ◽  
Foam Core ◽  
Aluminum Foams ◽  
Static Compression ◽  
Cell Structures ◽  
Closed Cell ◽  
Energy Absorption Efficiency ◽  
Foam Filled ◽  
Quasi Static Compression

The energy absorption of different cell structures for closed-cell aluminum foam-filled Al tubes are investigated through quasi-static compression testing. Aluminum foams are fabricated under different pressures, obtaining aluminum foams with different cell sizes. It is found that the deformation of the foam core is close to the overall deformation, and the deformation band is seriously expanded when the cell size is fined, which leads to the increase of interaction. Results confirm that the foam-filled tubes absorb more energy due to the increase of interaction between the foam core and tube wall when the foaming pressure increases. The energy absorption efficiency of foam-filled tubes can reach a maximum value of 90% when the foam core is fabricated under 0.30 MPa, which demonstrates that aluminum foams fabricated under increased pressure give a new way for the applications of foam-filled tubes in the automotive industry.

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