Experimental Study of Energy Absorption of Fluid-Filled Honeycomb Structure

2014 ◽  
Author(s):  
S. Jenson ◽  
M. Ali ◽  
K. Alam ◽  
J. Hoffman
Keyword(s):  
Energy Absorption ◽  
High Speed ◽  
Honeycomb Structure ◽  
High Speed Camera ◽  
Damage Area ◽  
Impact Forces ◽  
Aluminum Honeycomb ◽  
Energy Absorbing ◽  
The Impact ◽  
Absorption Characteristics

The work presented here is a continuation of the study performed in exploring the energy absorption characteristics of non-Newtonian fluid-filled regular hexagonal aluminum honeycomb structures. In the previous study, energy absorbing properties were investigated by using an air powered pneumatic ram, dynamic load cell, and a high speed camera. This study was conducted using a pneumatic ram which was designed to exploit only its kinetic energy during the impact. Experimental samples included an empty honeycomb sample and a filled sample as the filled samples showed the largest difference in energy absorption with respect to the empty samples in the previous study. Therefore, the filled samples were further investigated in this study by measuring the impact forces at the distal end as well as the damage on the impact end. Upon impact, the filled samples were able to reduce the damage area on impact end and were able to lower average and peak forces by 71.9% and 77.4% at the distal end as compared to the empty sample.

Experimental investigation of the quasi-static and impact tests on the energy absorption characteristics of coupler rubber buffers used in railway vehicles

2018 ◽  
Vol 233 (9) ◽  
pp. 937-950 ◽  
Author(s):  
Shuguang Yao ◽  
Zhixiang Li ◽  
Wen Ma ◽  
Ping Xu ◽  
Quanwei Che
Keyword(s):  
Energy Absorption ◽  
Impact Velocity ◽  
High Speed ◽  
Compression Tests ◽  
Static Compression ◽  
Static Tests ◽  
Impact Tests ◽  
High Speed Trains ◽  
The Impact ◽  
Absorption Characteristics

Coupler rubber buffers are widely used in high-speed trains, to dissipate the impact energy between vehicles. The rubber buffer consists of two groups of rubbers, which are pre-compressed and then installed into the frame body. This paper specifically focuses on the energy absorption characteristics of the rubber buffers. Firstly, quasi-static compression tests were carried out for one and three pairs of rubber sheets, and the relationship between the energy absorption responses, i.e. Eabn  =  n ×  Eab1, Edissn =  n ×  Ediss1, and Ean =  Ea1, was obtained. Next, a series of quasi-static tests were performed for one pair of rubber sheet to investigate the energy absorption performance with different compression ratios of the rubber buffers. Then, impact tests with five impact velocities were conducted, and the coupler knuckle was destroyed when the impact velocity was 10.807 km/h. The results of the impact tests showed that with the increase of the impact velocity, the Eab, Ediss, and Ea of the rear buffer increased significantly, but the three responses of the front buffer did not increase much. Finally, the results of the impact tests and quasi-static tests were contrastively analyzed, which showed that with the increase of the stroke, the values of Eab, Ediss, and Ea increased. However, the increasing rates of the impact tests were higher than that of the quasi-static tests. The maximum value of Ea was 68.76% in the impact tests, which was relatively a high value for the vehicle coupler buffer. The energy capacity of the rear buffer for dynamic loading was determined as 22.98 kJ.

scholarly journals Energy Absorption and Crush Behavior of the Layered Aluminum Honeycomb

2017 ◽  
Vol 11 (1) ◽  
pp. 33-42
Author(s):  
Weiming Luo ◽  
Shaoqing Shi ◽  
Zipeng Chen ◽  
Jianhu Sun
Keyword(s):  
Energy Absorption ◽  
Surface Density ◽  
Static Load ◽  
Single Layer ◽  
Honeycomb Structure ◽  
Soft Layer ◽  
Aluminum Honeycomb ◽  
The Mean ◽  
Absorption Characteristics ◽  
Better Than

To investigate the energy absorption characteristics and crush behavior of layered aluminum honeycomb, the experiments of layered aluminum honeycomb structure under quasi-static load had been carried out, mainly includes single, double, triple, four layer combinations. The results showed that: the peak force and the mean plateau force of single-layer aluminum honeycomb structure are proportional to the surface density, however they decline slightly with increase of the height; unequal height double layered aluminum honeycomb structure has more advantage in cushion performance; with the increase of layers, the MP ratio will decrease; the combination of placing soft layer between hard layers is better than the others.

Impact damage assessment of carbon fiber reinforced composite with different stacking sequence

2019 ◽  
Vol 54 (2) ◽  
pp. 193-203
Author(s):  
Rahul S Sikarwar ◽  
R Velmurugan
Keyword(s):  
High Speed ◽  
Stacking Sequence ◽  
High Speed Camera ◽  
Ballistic Limit ◽  
Limit Velocity ◽  
Post Impact ◽  
Damage Extent ◽  
Ballistic Limit Velocity ◽  
Energy Absorbing ◽  
The Impact

This work examines the experimental and analytical investigation of impact on the carbon/epoxy laminates of various stacking sequence. The impact tests were carried out by using gas gun equipped with high-speed camera. Projectile velocities selected were 80 m/s and 30 m/s where 80 m/s was above ballistic limit velocity and 30 m/s was below ballistic limit velocity. The impact process was recorded with high-speed camera which facilitated to identify different energy absorbing mechanisms. High-speed images were also used to measure pre-impact and post-impact velocities of the projectile accompanied by photo diode and aluminum foil method. Total energy absorbed by the laminates, which is the difference between pre-impact and post-impact kinetic energy of the projectile, was calculated for the laminates with different stacking sequences. Damage extent in the laminates of different stacking sequences were also assessed by C-Scan of the laminates. Then effect of stacking sequences on damage extent and energy absorbing capacity was established. An analytical model was proposed to predict the residual velocity of the projectile at above ballistic limit velocity, which was based on the total energy absorbed by different energy absorption mechanisms. The analytical model was validated with experimental results for different stacking sequences. Additionally, effect of fiber orientation on damage shape at below ballistic limit velocity was also studied.

Optimization of Honeycomb Cellular Meso-Structures for High Speed Impact Energy Absorption

2011 ◽  
Author(s):  
Jesse Schultz ◽  
David Griese ◽  
Prabhu Shankar ◽  
Joshua D. Summers ◽  
Jaehyung Ju ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Wall Thickness ◽  
High Speed ◽  
Honeycomb Structure ◽  
Maximum Energy ◽  
Geometric Parameters ◽  
Absorption Properties ◽  
High Speed Impact ◽  
High Degree ◽  
The Impact

This paper presents the energy absorption properties of hexagonal honeycomb structures of varying cellular geometries to high speed in-plane impact. While the impact responses in terms of energy absorption and densification strains have been extensively researched and reported, a gap is identified in the generalization of honeycombs with controlled and varying geometric parameters. This paper attempts to address this gap through a series of finite element (FE) simulations where cell angle and angled wall thickness are varied while maintaining a constant mass of the honeycomb structure. A randomly filled, non-repeating Design of Experiments (DOE) is generated to determine the effects of these geometric parameters on the output of energy absorbed, and a statistical sensitivity analysis is used to determine the parameters significant for optimization. A high degree of variation in the impact response of varying cellular geometries has shown the potential for the forward design into lightweight crushing regions in many applications, particularly the automotive and aerospace industries. It is found that while an increase in angled wall thickness enhances the energy absorption of the structure, increases in either the cell angle or ratio of cell angle to angled wall thickness have adverse effects on the output. Finally, optimization results present that a slightly auxetic cellular geometry with maximum angled wall thickness provides for maximum energy absorption, which is verified with an 8% error when compared to a final FE simulation.

scholarly journals Full-Field Operational Modal Analysis of an Aircraft Composite Panel from the Dynamic Response in Multi-Impact Test

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1602
Author(s):  
Ángel Molina-Viedma ◽  
Elías López-Alba ◽  
Luis Felipe-Sesé ◽  
Francisco Díaz
Keyword(s):  
Modal Analysis ◽  
Energy Absorption ◽  
High Speed ◽  
Operational Modal Analysis ◽  
Modal Identification ◽  
Image Correlation ◽  
Composite Panel ◽  
Impact Excitation ◽  
Full Field ◽  
The Impact

Experimental characterization and validation of skin components in aircraft entails multiple evaluations (structural, aerodynamic, acoustic, etc.) and expensive campaigns. They require different rigs and equipment to perform the necessary tests. Two of the main dynamic characterizations include the energy absorption under impact forcing and the identification of modal parameters through the vibration response under any broadband excitation, which also includes impacts. This work exploits the response of a stiffened aircraft composite panel submitted to a multi-impact excitation, which is intended for impact and energy absorption analysis. Based on the high stiffness of composite materials, the study worked under the assumption that the global response to the multi-impact excitation is linear with small strains, neglecting the nonlinear behavior produced by local damage generation. Then, modal identification could be performed. The vibration after the impact was measured by high-speed 3D digital image correlation and employed for full-field operational modal analysis. Multiple modes were characterized in a wide spectrum, exploiting the advantages of the full-field noninvasive techniques. These results described a consistent modal behavior of the panel along with good indicators of mode separation given by the auto modal assurance criterion (Auto-MAC). Hence, it illustrates the possibility of performing these dynamic characterizations in a single test, offering additional information while reducing time and investment during the validation of these structures.

scholarly journals Energy Absorption Characteristics of PVC Coarse Aggregate Concrete under Impact Load

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Shi Hu ◽  
Huaming Tang ◽  
Shenyao Han
Keyword(s):  
Compressive Strength ◽  
Energy Absorption ◽  
High Speed ◽  
Coarse Aggregate ◽  
Specific Energy Absorption ◽  
Low Speed ◽  
High Speed Impact ◽  
Aggregate Content ◽  
Dynamic Compressive Strength ◽  
Absorption Characteristics

AbstractIn this paper, polyvinyl chloride (PVC) coarse aggregate with different mixing contents is used to solve the problems of plastic pollution, low energy absorption capacity and poor damage integrity, which provides an important reference for PVC plastic concrete used in the initial support structures of highway tunnels and coal mine roadway. At the same time, the energy absorption characteristics and their relationship under different impact loads are studied, which provides an important reference for predicting the energy absorption characteristics of concrete under other PVC aggregate content or higher impact speed. This study replaced natural coarse aggregate in concrete with different contents and equal volume of well-graded flaky PVC particles obtained by crushing PVC soft board. Also, slump, compression, and splitting strength tests, a free falling low-speed impact test of steel balls and a high-speed impact compression test of split Hopkinson pressure bar (SHPB) were carried out. Results demonstrate that the static and dynamic compressive strength decreases substantially, and the elastic modulus and slump decrease slowly with the increase of the mixing amount of PVC aggregate (0–30%). However, the energy absorption rate under low-speed impact and the specific energy absorption per MPa under high-speed impact increase obviously, indicating that the energy absorption capacity is significantly enhanced. Regardless of the mixing amount of PVC aggregate, greater strain rate can significantly enhance the dynamic compressive strength and the specific energy absorption per MPa. After the uniaxial compression test or the SHPB impact test, the relative integrity of the specimen is positively correlated with the mixing amount of PVC aggregate. In addition, the specimens are seriously damaged with the increase of the impact strain rate. When the PVC aggregate content is 20%, the compressive strength and splitting strength of concrete are 33.8 MPa and 3.26 MPa, respectively, the slump is 165 mm, the energy absorption rate under low-speed impact is 89.5%, the dynamic compressive strength under 0.65 Mpa impact air pressure is 58.77 mpa, and the specific energy absorption value per MPa is 13.33, which meets the requirements of shotcrete used in tunnel, roadway support and other impact loads. There is a linear relationship between the energy absorption characteristics under low-speed impact and high-speed impact. The greater the impact pressure, the larger the slope of the fitting straight line. The slope and intercept of the fitting line also show a good linear relationship with the increase of impact pressure. The conclusions can be used to predict the energy absorption characteristics under different PVC aggregate content or higher-speed impact pressure, which can provide important reference for safer, more economical, and environmental protection engineering structure design.

Experimental assessment of adding carbon nanotubes on the impact properties of Kevlar-ultrahigh molecular weight polyethylene fibers hybrid composites

2020 ◽  
pp. 152808372092148 ◽  
Author(s):  
Mansour B Bigdilou ◽  
Reza Eslami-Farsani ◽  
Hossein Ebrahimnezhad-Khaljiri ◽  
Mohammad A Mohammadi
Keyword(s):  
Carbon Nanotubes ◽  
Molecular Weight ◽  
Energy Absorption ◽  
Hybrid Composites ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Absorbed Energy ◽  
Impact Properties ◽  
Damage Area ◽  
Ultrahigh Molecular Weight ◽  
The Impact

In the present study, the effect of adding various percentage (0.1, 0.3, 0.5, and 0.9 wt.%) of carbon nanotubes on the impact properties of hybrid composites reinforced with the different stacking sequence of Kevlar fibers and ultrahigh molecular weight polyethylene was investigated. The obtained results showed that the composite with the configuration of sandwiched ultrahigh molecular weight polyethylene layers by Kevlar layers had the higher impact properties as compared with other hybrid configurations. Adding 0.1 wt.% carbon nanotubes in this configuration was caused to increase the normalized absorbed energy more than 6.5 times. The fracture surface of this configuration showed that the branching and expanding the damage area were the dominant mechanisms for the energy absorption of impactor. Also, the field emission scanning electron microscope illustrated that the carbon nanotubes by bridging, pulling out, and fracturing mechanisms increased the capability of energy absorption in the hybrid composites.

scholarly journals Experimental investigation of the impact response of novel steelbiocomposite hybrid materials

2018 ◽  
Vol 183 ◽  
pp. 02040
Author(s):  
KarthikRam Ramakrishnan ◽  
Mikko Hokka ◽  
Essi Sarlin ◽  
Mikko Kanerva ◽  
Reijo Kouhia ◽  
...  
Keyword(s):  
High Speed ◽  
Structural Integrity ◽  
Metal Layer ◽  
Rear Surface ◽  
Impact Resistance ◽  
Natural Fibre ◽  
Image Correlation ◽  
Impact Response ◽  
High Speed Camera ◽  
The Impact

Recent developments in the production of technical flax fabrics allow the use of sustainable natural fibres to replace synthetic fibres in the manufacture of structural composite parts. Natural fibre reinforced biocomposites have been proven to satisfy design and structural integrity requirements but impact strength has been identified as one of their limitations. In this paper, hybridisation of the biocomposite with a metal layer has been investigated as a potential method to improve the impact resistance of natural fibre composites. The impact response of biocomposites made of flax-epoxy is investigated experimentally using a high velocity particle impactor. A high-speed camera setup was used to observe the rear surface of the plates during impact. Digital Image Correlation (DIC) of the high speed camera images was used for full-field strain measurement and to study the initiation and propagation of damage during the impact. The different modes of damage in the hybrid laminate were identified by postimpact analysis of the section of the damaged composite plate using optical microscopy. The study shows the difference in impact response for different material combinations and configurations. The hybrid construction was shown to improve the impact resistance of the flax composite.

Impact performance of innovative corrugated polystyrene foam for bicycle helmets

2020 ◽  
pp. 0021955X2096521
Author(s):  
Somen K Bhudolia ◽  
Goram Gohel ◽  
Kah Fai Leong
Keyword(s):  
Energy Absorption ◽  
High Speed ◽  
Head Injuries ◽  
Expanded Polystyrene ◽  
The Novel ◽  
Comparison Study ◽  
Impact Performance ◽  
Bicycle Helmets ◽  
Weight Property ◽  
The Impact

Expanded Polystyrene (EPS) is a common material used to manufacture the inner foam liner of a bicycle helmet due to its outstanding energy absorption characteristics and light-weight property. The current research presents a novel corrugated expanded polystyrene (EPS) foam design concept which is used to enhance the impact dissipation of bicycle helmets from the safety standpoint to reduce head injuries and make them lighter. The baseline comparison study under impact for different foam configurations is compared with a conventional EPS foam sample without corrugation. Corrugated foam designs under current investigation are 12.5–20% lighter and provide up to 10% higher energy absorption. The details of the novel manufacturing concept, CPSC 1203 helmet impact tests, high-speed camera study to understand the differences in the failure mechanisms are deliberated in this paper.

Energy Absorption Mechanisms and Crash Analysis of Helicopter Seats

2018 ◽  
Author(s):  
Gülce Özturk ◽  
Altan Kayran
Keyword(s):  
Plastic Deformation ◽  
Energy Absorption ◽  
Strain Curve ◽  
Rigid Wall ◽  
Absorption Mechanism ◽  
Dynamic Simulations ◽  
Explicit Finite Element ◽  
Energy Absorbing ◽  
The Impact ◽  
Aluminum Material

In this paper, a crushable absorber system is designed to analyze the dynamic behavior and performance of a helicopter seat. The mechanism of the absorption system makes use of the crash energy to plastically deform the aluminum material of the seat legs. Seat structure is composed of a bucket, two legs and two sliding parts on each leg. Seat legs are made of aluminum and and the sliding parts of the seat are steel. During the impact event, the heavier sliding parts move down and crash the aluminum material for the purpose of deforming the aluminum material under the sliding parts and reduce the crash energy. The designed helicopter seat is analyzed using the explicit finite element method to evaluate how the seat energy absorbing mechanism works. Dynamic simulations are performed in ABAQUS by crashing the seat to a fixed rigid wall. To simulate the plastic deformation, true stress-strain curve of the aluminum material of the seat leg has been used. Time response results are filtered to calculate the meaningful g loads which incur damage to the occupants. Analyses are performed with and without the energy absorption mechanism in order to see the effectiveness of the energy absorption mechanism on the human survivability by comparing the g loads on the seat bucket with the acceptable loads specified by EASA. This study is a preliminary study intended to check the effectiveness of the damping mechanism based on the plastic deformation of the aluminum legs of the seat in the event of a crash.

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