scholarly journals Improving Ballistic Performance of Polyurethane Foam by Nanoparticle Reinforcement

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
M. F. Uddin ◽  
H. Mahfuz ◽  
S. Zainuddin ◽  
S. Jeelani
Keyword(s):  
Energy Absorption ◽  
Polyurethane Foam ◽  
High Speed ◽  
Failure Modes ◽  
High Speed Camera ◽  
Test Results ◽  
Ballistic Performance ◽  
Gas Gun ◽  
Set Up ◽  
Control Samples

We report improving ballistic performance of polyurethane foam by reinforcing it with nanoscaleTiO2particles. Particles were dispersed through a sonic cavitation process and the loading of particles was 3 wt% of the total polymer. Once foams were reinforced, sandwich panels were made and impacted with fragment simulating projectiles (FSPs) in a 1.5-inch gas gun. Projectile speed was set up to have complete penetration of the target in each experiment. Test results have indicated that sandwich with nanophased cores absorbed about 20% more kinetic energy than their neat counterpart. The corresponding increase in ballistic limit was around 12% over the neat control samples. The penetration phenomenon was also monitored using a high-speed camera. Analyses of digital images showed that FSP remained inside the nanophased sandwich for about 7 microseconds longer than that of a neat sandwich demonstrating improved energy absorption capability of the nanoparticle reinforced core. Failure modes for energy absorption have been investigated through a microscope and high-speed images.

Heterogeneous lightweight configuration for protection against 7.62 × 39 mm bullet impact

2019 ◽  
Vol 10 (3) ◽  
pp. 289-305
Author(s):  
Khurshid Ahmed ◽  
Abdul Qadeer Malik ◽  
Iram Raza Ahmad
Keyword(s):  
Polyurethane Foam ◽  
High Speed ◽  
Close Agreement ◽  
Body Armor ◽  
Critical Infrastructures ◽  
High Speed Camera ◽  
Fiber Glass ◽  
Steel Core ◽  
Blunt Force Trauma ◽  
Average Impact

Configuration of a heterogeneous lightweight material is investigated numerically and experimentally, for protection against 7.62 × 39 mm mild steel core bullet impact. The configuration consists of alumina (Al2O3) tile followed by fiber glass and polyurethane foam, all covered with kev-epoxy layer. Numerical simulations were performed using ANSYS AUTODYN. The 10-mm thick alumina completely disrupts the impacting bullet through blunting and erosion. The fiber glass and polyurethane foam disperse and absorb the propagation of shock wave, respectively. The kev-epoxy cladding seizes any scattering of brittle alumina fragments. The average impact velocity of the bullet was measured to be 710 m/s using high-speed camera. A 10-mm depth of depression spread over a wider area of 3.92 sq in of torso was recorded in blunt force trauma test, which was well within the European, German, and British standards that allow a 20–25 mm backface signature. Due to these characteristics it can be employed as body armor, vehicle armor, and for the safety and security of other critical infrastructures against this bullet and fragment impact. The residual mushroom-shaped bullet and its length of 9.3 mm in numerical simulation is in close agreement with the measured value of the 8.0 mm recovered bullet size and shape.

Experimental study on the effect of pressure and flow rate on cavitation in a poppet throttle valve

2019 ◽  
Vol 72 (5) ◽  
pp. 629-636
Author(s):  
Jian Zhang ◽  
Tingting Luo
Keyword(s):  
Flow Rate ◽  
Pressure Difference ◽  
High Speed ◽  
High Speed Camera ◽  
Experimental Conditions ◽  
Content Type ◽  
Experimental Support ◽  
Throttle Valve ◽  
Set Up

Purpose The purpose of this paper is to study the variation of cavitation scale with pressure and flow in poppet throttle valve, to obtain the cavitation scale under pressure and flow conditions and to provide experimental support for the research of suppressing throttle valve cavitation and cavitation theory. Design/methodology/approach A hydraulic cavitation platform was set up, a valve was manufactured with highly transparent PMMA material and a high-speed camera was used to observe the change in cavitation scale. Findings Through experiments, it is found that the pressure difference between inlet and outlet of throttle valve affects the cavitation scale, and the more the pressure difference is, the easier the cavitation will be formed. Under the condition of small pressure difference, the cavitation is not obvious and reducing the pressure difference can effectively suppress the cavitation; the flow rate also affects the cavitation scale, the smaller the flow rate, the more difficult the cavitation will be formed and the lower the flow rate, the more the cavitation will be suppressed. Research limitations/implications Because of the magnification factor of the high-speed camera lens, the morphology of smaller bubbles cannot be observed in this study, and the experimental conditions need to be improved in the follow-up study. Originality/value This study can provide experimental support for the study of throttle valve cavitation suppression methods and cavitation theory.

Improvement in Mechanical Properties of Clay Filled Carbon-Epoxy Composite

2006 ◽  
Author(s):  
Yuanxin Zhou ◽  
Farhana Pervin ◽  
Jamese Hamilton ◽  
Shaik Jeelani
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
High Speed ◽  
High Vacuum ◽  
Test Results ◽  
Trapped Air ◽  
Set Up ◽  
Flexural Tests ◽  
Mechanical Agitator ◽  
Mmt Clay

In the present investigation, a high intensity ultrasonic liquid processor was used to obtain a homogeneous molecular mixture of epoxy resin and K-10 MMT clay. The clay were infused into the part A of SC-15 (Diglycidylether of Bisphenol A) through sonic cavitations and then mixed with part B of SC-15 (cycloaliphatic amine hardener) using a high speed mechanical agitator. The trapped air and reaction volatiles were removed from the mixture using high vacuum. Flexural tests were performed on unfilled, 1wt. %, 2wt. %, 3 wt. % and 4 wt.% clay filled SC-15 epoxy to identify the loading effect on mechanical properties of the composites. The flexural test results indicate that 2.0 wt% loading of clay in epoxy resin showed the highest improvement in strength as compared to the neat systems. After that, the nanophased matrix with 2 wt.% clay is then utilized in a Vacuum Assisted Resin Transfer Molding (VARTM) set up with satin weave carbon preforms to fabricate laminated composites. The resulting structural composites have been tested under flexural and tensile loads to evaluate mechanical properties. 13.5% improvement in flexural strength and 5.8% improvement in tensile strength were observed in carbon/epoxy nanocomposite. TGA and DMA tests were also conducted to observe the thermal stability of the structural composite.

Energy absorption capability of origami automobile bumper system

2019 ◽  
Vol 233 (18) ◽  
pp. 6577-6587
Author(s):  
Lin Yuan ◽  
Jiayao Ma ◽  
Zhong You
Keyword(s):  
Energy Absorption ◽  
High Speed ◽  
Failure Modes ◽  
Absorption Efficiency ◽  
Vital Role ◽  
Vehicle Safety ◽  
Energy Absorption Efficiency ◽  
Stable Performance ◽  
Absorption Performance ◽  
Bumper System

The crashworthiness of an automobile bumper plays a vital role in overall vehicle safety. Energy absorption efficiency, as well as predictable and stable performance, are the most demanding features in the design of the bumper system. To this end, this paper presents a series of innovative bumper designs using built-in origami patterns. Also, we outline a numerical framework for evaluating the energy absorption performance of a bumper when subjected to an impact loading. Comparative analyses on full frontal and 40% offset frontal impact tests are conducted numerically for both low and high-speed scenarios. It is found that the designed failure modes are successfully triggered and followed during the collision process for the combined origami beam-origami crash box design. Most importantly, this optimal design could absorb 31.5% more energy than the conventional bumper.

A Performance Study on Self-Piercing Riveting and Adhesive Hybrid Joints of Different Adhesive

2014 ◽  
Vol 887-888 ◽  
pp. 1261-1264
Author(s):  
Fu Long Liu ◽  
Xiao Cong He ◽  
Yu Qi Wang
Keyword(s):  
Failure Mechanism ◽  
Energy Absorption ◽  
Failure Mode ◽  
Failure Modes ◽  
Test Results ◽  
Performance Study ◽  
Strength Capacity ◽  
Hybrid Joints ◽  
Overall Performance ◽  
Tension Loading

This paper studied the performance of self-piercing riveting (SPR) and adhesive hybrid joints of different adhesive, including strength, capacity of energy absorption, failure mode and failure mechanism of the hybrid joints. The performances of SPR-adhesive hybrid joints were compared with SPR joints. SPR-adhesive hybrid joints and SPR joints were tested under a tension loading. The test results showed that adhesive have a function of improving the strength of SPR joints; however, the capacity of energy absorption of SPR joints was weakened. While the adhesive have no effect on the failure modes of SPR joints. When appropriate adhesive was selected, the overall performance of SPR-adhesive hybrid joints was superior to SPR joints. In a word, the combination of SPR and adhesive could get a well jointing structure.

Gasket Catastrophic Failure Modes

2018 ◽  
Author(s):  
Warren Brown ◽  
Nathan Knight
Keyword(s):  
Failure Modes ◽  
The Body ◽  
Bolted Joints ◽  
Test Results ◽  
Bolted Joint ◽  
Critical Factors ◽  
Test Set ◽  
Set Up ◽  
Industry Experience ◽  
Corrugated Metal

This paper outlines how, under certain scenarios, gaskets may catastrophically blow out of pressure boundary bolted joints. Supporting the observations on industry occurrences of such failures, attempts were made to re-create one of the failure modes in a test set-up. The tests managed to highlight critical factors for blow out of Corrugated Metal with Covering Layer (CMCL) gaskets. A summary of the known industry experience with gasket blow out and the CMCL test results are included in the body of this paper. Conclusions and recommendations for considering these failure modes in both pressure boundary bolted joint design and also risk assessment are made.

scholarly journals Nonlinear Analysis of Mineral Wool Fiberization Process

2015 ◽  
Vol 10 (2) ◽  
Author(s):  
Benjamin Bizjan ◽  
Brane Širok ◽  
Edvard Govekar
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
High Speed ◽  
Nonstationary Process ◽  
Mineral Wool ◽  
Nonlinear Time Series Analysis ◽  
High Speed Camera ◽  
Test Results ◽  
Computer Aided ◽  
Low Dimensional

In this paper, the mineral wool fiberization process on a spinner wheel was studied by means of the nonlinear time series analysis. Melt film velocity time series was calculated using computer-aided visualization of the process images recorded with a high speed camera. The time series was used to reconstruct the state space of the process and was tested for stationarity, determinism, chaos, and recurrent properties. Mineral wool fiberization was determined to be a low-dimensional and nonstationary process. The 0–1 chaos test results suggest that the process is chaotic, while the determinism test indicates weak determinism.

Effect of graphene nanoplatelets on the ballistic performance of hybrid Kevlar/Cocos nucifera sheath-reinforced epoxy composites

2019 ◽  
Vol 89 (21-22) ◽  
pp. 4349-4362 ◽  
Author(s):  
J Naveen ◽  
M Jawaid ◽  
ES Zainudin ◽  
Mohamed TH Sultan ◽  
R Yahaya
Keyword(s):  
Energy Absorption ◽  
Laminated Composites ◽  
Cocos Nucifera ◽  
Graphene Nanoplatelets ◽  
Epoxy Composites ◽  
Ballistic Limit ◽  
Ballistic Performance ◽  
Gas Gun ◽  
Significant Difference ◽  
Ballistic Properties

This study investigated the effect of graphene nanoplatelets (GnPs) on the ballistic performance of Kevlar/ Cocos nucifera sheath-reinforced epoxy composites. GnPs with different wt. % (0%, 0.25%, 0.50%) were integrated into epoxy resin through ultra-sonication. Laminated composites were fabricated by incorporating Kevlar and Cocos nucifera sheath layers into the epoxy/GnP mixture by the hand lay-up method followed by hot pressing. Nine- and 12-layered laminates were fabricated with different numbers of Kevlar and Cocos nucifera sheath plies. Ballistic tests were conducted using a single-stage gas gun experimental setup with an 8 mm hemispherical stainless steel projectile. The results showed that the addition of GnPs improved the energy absorption by 8.5% (nine plies) and 12.88% (12 plies) and the ballistic limit by 4.28% (nine plies) and 6.17% (12 plies), respectively of Kevlar/epoxy/GnP composites at 0.25 wt. %. However, hybrid Kevlar/ Cocos nucifera sheath/epoxy/GnP composites and Cocos nucifera sheath/epoxy/GnP laminated composites decreased the energy absorption and ballistic limit after the addition of GnPs. This is because the addition of GnPs improved the interfacial interactions between the fiber and GnP modified epoxy matrix, which is inappropriate to absorb and dissipate the kinetic energy of the projectile. Statistical analysis was carried out using one-way analysis of variance and it was shown that there is a statistically significant difference between the obtained ballistic properties of the laminates.

Experimental Investigation on the Crashworthiness of Braided Glass/Epoxy Tubes Subjected to Axial Impacting

2014 ◽  
Vol 23 (2) ◽  
pp. 096369351402300
Author(s):  
Ping Zhang ◽  
Liang-Jin Gui ◽  
Zi-Jie Fan ◽  
Jing-Yu Liu
Keyword(s):  
Energy Absorption ◽  
Specific Energy ◽  
Failure Modes ◽  
Impact Load ◽  
Peak Load ◽  
Low Velocity Impact ◽  
Test Results ◽  
Specific Energy Absorption ◽  
The Mean ◽  
The Impact

This paper presented an experimental study on the low-velocity impact response of triaxial braided composite circular tubes, which were fabricated with S-glass/epoxy composite. The impact responses were recorded and analyzed in terms of impact load-displacement curves and specific energy absorption. In addition, four basic failure modes called delaminating, splaying, fragmental fracture and progressive folding were founded. The levels of the mean impact load and specific energy absorption (SEA) are determined by the energy absorption mechanisms, which are related to the dominant failure modes of the tubes. In general, delamination which exhibits the poor energy absorbing performance is the dominant failure mode for all the specimens. Impact test results showed that all three types of tubes had almost the same SEA. Compared to the quasi-static test results, the first peak load and the mean load decrease at about 50% and 10% respectively, SEA generally decreases at an average level 10%.

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