Theoretical Study on the Dynamic Compression and Energy Absorption of Porous Materials Filled with Magneto-Rheological Fluid

2021 ◽  
pp. 104105
Author(s):  
X.W. Zhang ◽  
Q.M. Zhang ◽  
X.J. Ren
Keyword(s):  
Porous Materials ◽  
Energy Absorption ◽  
Theoretical Study ◽  
Dynamic Compression ◽  
Magneto Rheological

Analysis of a Liquid Filled Poroelastic Cylinder Exposed to a Time Varying Pressure Load

2017 ◽  
Author(s):  
Tyler L. Ceste ◽  
Sridhar Santhanam ◽  
Gerard F. Jones
Keyword(s):  
Finite Element ◽  
Porous Materials ◽  
Energy Absorption ◽  
Solid Phase ◽  
Dynamic Compression ◽  
Analytical Models ◽  
Finite Element Models ◽  
Porous Cylinder ◽  
Linear Effect ◽  
Non Linear

Porous materials are of interest for a number of applications one of them being energy absorption. These materials offer the ability to absorb more energy than a typical metallic solid and thus provide an opportunity to improve the performance of structures that endure blast loads. These structures undergo very large loads in very short periods of time and therefore maximizing energy absorption is paramount. This study seeks to improve the understanding of the response of porous materials by developing both analytical and finite element models for a liquid filled porous cylinder exposed to a dynamic compression loading. The poroelastic cylinder consists of a porous metallic solid phase and a viscous liquid phase. These two phases provide for two mechanisms of energy dissipation which are that of the deformation of the solid and the viscous flow of the liquid. The theories of elasticity and porous media were used to formulate the governing equations for the liquid filled porous cylinder. These equations describe the coupling between the displacements of the solid cylinder and the pressure distribution of the liquid. Analytical and finite element models were developed to predict the cylinders response in order to determine the amount of energy absorbed when the cylinder is exposed to a dynamic compression load. Analytical models were developed to validate the finite element results. As more complexity is added to this problem an analytical approach becomes unviable and a finite element approach must be used. One such complexity that can be considered is the effect of utilizing a non-constant liquid viscosity, which requires developing a non-linear finite element model to account for the viscositys dependence on strain rate. This added non-linear effect should allow for additional viscous energy to be absorbed and thus can further enhance the performance of the system.

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.

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 and Numerical Analysis of Qinling Mountain Engineered Rocks during Pulse-Shaped SHPB Test

2015 ◽  
Vol 16 (3-4) ◽  
pp. 165-171
Author(s):  
Shi Liu ◽  
Jinyu Xu
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Strain Rate ◽  
Energy Absorption ◽  
Absorption Rate ◽  
Failure Modes ◽  
Dynamic Compression ◽  
Peak Strain ◽  
Compression Stress ◽  
Dynamic Compressive Strength

AbstractIn order to study the dynamic compression mechanical properties of engineering rock under high strain rate （100~102 S−1）loads, dynamic compression tests of three common engineering rocks (marble, sandstone and granite) taken from the Qinling Mountain are studied subjected to five different kinds of shock air pressure using Φ 100 mm split Hopkinson pressure bar test system improved with purple copper waveform shaper. The dynamic compression stress-strain curves, dynamic compressive strength, peak strain, energy absorption rate and elastic modulus of three rocks variation with strain rate are researched. The dynamic compression failure modes under different strain rates are analyzed. Then the three-dimensional numerical simulations of waveform shaper shaping effects and stress wave propagation in the SHPB tests are carried out to reproduce the test results. The research results show that the dynamic compression stress-strain curves show certain discreteness, and there is an obvious rebound phenomenon after the peak. With the increase in strain rate, the dynamic compressive strength, peak strain and energy absorption rate are all in a certain degree of increase, but the elastic modulus have no obvious change trend. Under the same strain rate, the dynamic compressive strength of granite is greatest while of sandstone is least. With the increase in strain rate, the margin of increase in peak strain and energy absorption rate of granite is greatest while of sandstone is least. The failure modes of the sample experience a developing process from outside to inside with the increase of strain rate.

scholarly journals An Experimental Study on Mechanical Properties for the Static and Dynamic Compression of Concrete Eroded by Sulfate Solution

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5387
Author(s):  
Ao Yao ◽  
Jinyu Xu ◽  
Wei Xia
Keyword(s):  
Mechanical Properties ◽  
Longitudinal Wave ◽  
Energy Absorption ◽  
Wave Velocity ◽  
Concrete Structure ◽  
Mechanical Performance ◽  
Dynamic Compression ◽  
Sulfate Solution ◽  
Static Strength ◽  
Longitudinal Wave Velocity

The mechanical properties of the static and dynamic compression of concrete eroded by a 15% sodium sulfate solution were explored with a 70-mm-diameter true triaxial static-dynamic comprehensive loading test system, and an analysis of the weakening mechanisms for the degree of macroscopic damage and microscopic surface changes of eroded concrete were conducted in combination with damage testing based on relevant acoustic characteristics and SEM scanning. The experience obtained in this paper is used to analyze and solve the problem that the bearing capacity of concrete buildings is weakened due to the decrease in durability under the special conditions of sulfate erosion. The results showed that, in a short time, the properties of concrete corroded by sulfate solution were improved to a certain extent due to continuous hydration. When the corrosion time was prolonged, the internal concrete structure was destroyed after it was eroded by sulfate, and its dynamic and static strength, deformability, and energy absorption were reduced to differing degrees, thus greatly inhibiting the overall mechanical performance of concrete; the dynamic compressive strength changed with strain that exhibited a significant strain rate effect; and, under the influence of sulfate erosion and hydration, the longitudinal wave velocity increased first and then decreased. The longitudinal wave velocity was slower than that of concrete under normal environment and distilled water immersion condition. SEM and acoustic wave analysis indicated that the internal concrete structure was destroyed after it was eroded by sulfate, and its dynamic and static strength, deformability, and energy absorption were reduced to differing degrees, thus greatly inhibiting the overall mechanical performance of concrete.

scholarly journals Effect of CNTs Additives on the Energy Balance of Carbon/Epoxy Nanocomposites during Dynamic Compression Test

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 194 ◽  
Author(s):  
Manel Chihi ◽  
Mostapha Tarfaoui ◽  
Chokri Bouraoui ◽  
Ahmed El Moumen
Keyword(s):  
Carbon Fiber ◽  
Energy Absorption ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Dynamic Compression ◽  
Fiber Reinforced Polymers ◽  
Strain Rates ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Carbon Fiber Reinforced

Previous research has shown that nanocomposites show not only enhancements in mechanical properties (stiffness, fracture toughness) but also possess remarkable energy absorption characteristics. However, the potential of carbon nanotubes (CNTs) as nanofiller in reinforced epoxy composites like glass fiber-reinforced polymers (GFRP) or carbon fiber-reinforced polymers (CFRP) under dynamic testing is still underdeveloped. The goal of this study is to investigate the effect of integrating nanofillers such as CNTs into the epoxy matrix of carbon fiber reinforced polymer composites (CFRP) on their dynamic energy absorption potential under impact. An out-of-plane compressive test at high strain rates was performed using a Split Hopkinson Pressure Bar (SHPB), and the results were analyzed to study the effect of changing the concentration of CNTs on the energy absorption properties of the nanocomposites. A strong correlation between strain rates and CNT mass fractions was found out, showing that an increase in percentage of CNTs could enhance the dynamic properties and energy absorption capabilities of fiber-reinforced composites.

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