Control of Failure Evolution in 3D Cellular Woven Composite Systems

2000 ◽  
Author(s):  
Jared N. Baucom ◽  
Mohammed A. Zikry ◽  
Yiping Qiu
Keyword(s):  
Areal Density ◽  
Textile Composites ◽  
Woven Composite ◽  
Ballistic Performance ◽  
Composite Systems ◽  
Matrix Cracks ◽  
Failure Evolution ◽  
Undesirable Property ◽  
Highly Porous

Abstract This investigation examines the role of porosity in the perforation resistance of 3-D woven fiber reinforced epoxy panels under impact by rigid projectiles at velocities of 100 to 200 m/s. Incident and residual velocities are measured to determine the energy absorption by the target. To compare samples of different areal density, the energy is normalized by the target areal density. The sample responses segregate by porosity, and the more highly porous samples absorb a greater amount of specific energy. The reason for this is unclear but may be due to the deflection of matrix cracks by pores or due to the greater flexibility of the fibers to absorb energy through tensile straining. Although porosity is generally an undesirable property in textile composites, the induction of porosity may result in reduced panel weight without degradation of ballistic performance, a clear advantage for weight minimization.

Dynamic Failure Mechanisms in 3D Cellular Woven Composite Systems

2001 ◽  
Author(s):  
Jared N. Baucom ◽  
Mohammed A. Zikry ◽  
Yiping Qiu
Keyword(s):  
Target Material ◽  
Textile Composites ◽  
Material Behavior ◽  
Woven Composite ◽  
Ballistic Performance ◽  
Matrix Cracks ◽  
Dynamic Loading Condition ◽  
Undesirable Property ◽  
Highly Porous

Abstract The role of porosity on failure resistance of 3-D woven fiber reinforced epoxy panels under dynamic loading condition is investigated. Incident and residual velocities are measured to determine the energy absorption by the target. Material behavior segregates by porosity, and the more highly porous samples absorb a greater amount of specific energy. The reason for this may be due to the deflection of matrix cracks by pores or due to the greater flexibility of the fibers to absorb energy through tensile straining. Although porosity is generally an undesirable property in textile composites, the induction of porosity may result in reduced panel weight without degradation of ballistic performance, which is a clear advantage for weight minimization.

Study of the Water-Glass Role in the Foam Glass Synthesis Using Glycerol Foaming Agent

2021 ◽  
Vol 316 ◽  
pp. 153-158
Author(s):  
Boris M. Goltsman ◽  
Lyubov A. Yatsenko ◽  
Natalia S. Goltsman
Keyword(s):  
Porous Structure ◽  
Structure Formation ◽  
Water Glass ◽  
Glass Batch ◽  
Foam Glass ◽  
Foaming Agent ◽  
Additive Type ◽  
Highly Porous ◽  
Material Porosity

The article discusses the peculiarities of the "water-glass – glycerol" foaming mixture components interaction during foam glass synthesis. The important role of the foaming additive type in the foam glass porous structure formation was described, the main foaming substances were listed. The obtaining and researching technology of the samples was described, the compositions of the initial batches using the "water-glass – glycerol" mixture were developed. It was shown that a material with a highly porous structure and density below 500 kg/m3 can be obtained only with the combined introduction of water-glass and glycerol. In this case, mixtures with a predominance of water-glass in the foaming mixture possess optimal properties. Using DSC, it was shown that the addition of water-glass to the mixture completely eliminates the evaporation of glycerol at lower temperatures and intensifies its combustion at higher temperatures. Thus, the addition of water-glass to the glycerol-based foam glass batch allows glycerol to be saved up to higher temperatures that increases the resulting material porosity.

Effect of Varied Layer-Content/Thickness on Ballistic Performance of a Functionally Graded Al2O3/ZrO2 Material

2018 ◽  
Vol 928 ◽  
pp. 243-248 ◽  
Author(s):  
Yu Liang Chen ◽  
Chin Yu Huang
Keyword(s):  
Energy Absorption ◽  
Ceramic Composite ◽  
Single Layer ◽  
Areal Density ◽  
Wave Impedance ◽  
Functionally Graded ◽  
Ballistic Performance ◽  
Graded Material ◽  
Stress Damage ◽  
Transmission And Reflection

This study compared the ballistic performance of alumina (Al2O3)/ zirconia (ZrO2) functionally graded material (FGM) specimens with various levels of thickness and ZrO2 content and a pure Al2O3 single-layer ceramic composite (PCM). Ballistic tests were conducted with 0.3-inch armor-piercing (AP) projectiles, and finite element code LS-DYNA was used to examine energy absorption, stress distribution, and ceramic cone failure in the specimens. The findings are as follows: First, regarding energy absorption per unit of areal density, the 5% FGMs had the highest ballistic performance, which increased by up to 8%. By contrast, the ballistic performance of the 15% FGMs declined significantly to lower than that of the PCM. Second, the capability of the ceramic cone to withstand stress damage and projectiles was significantly greater in the 5% FGMs than in the 15% FGMs. Third, the wave impedance variations increased with the ZrO2 content in each layer, thereby enhancing the interactions between impact waves and aggravating ceramic damage. Thus, the intensities of transmission and reflection waves in the 15% FGMs increased, thereby causing reductions in its ballistic performance.

Ballistic Performance Evaluation of Kevlar-Glass Fibre Hybrid Composite Laminate against Medium Velocity Impact

2021 ◽  
Vol 1165 ◽  
pp. 47-64
Author(s):  
Saurabh S. Kumar ◽  
Rajesh G. Babu ◽  
U. Magarajan
Keyword(s):  
Energy Absorption ◽  
Specific Energy ◽  
Glass Fibre ◽  
Hybrid Composite ◽  
Composite Laminates ◽  
Areal Density ◽  
Ballistic Performance ◽  
Performance Requirement ◽  
Specific Energy Absorption ◽  
Fabric Composite

In this paper, the post ballistic impact behaviour of kevlar-glass fibre hybrid composite laminates was investigated against 9×19 mm projectile. Eight different types of composite laminates with different ratios of kevlar woven fibre to glass fibre were fabricated using hand lay-up with epoxy matrix. Ballistic behaviour like ballistic Limit (V50), energy absorption, specific energy absorption and Back Face Signature (BFS) were studied after bullet impact. The results indicated that as the Percentage of glass fibre is increased there was a linear increment in the ballistic behaviour. Addition of 16% kevlar fabric, composite sample meets the performance requirement of NIJ0101.06 Level III-A. Since the maximum specific energy absorption was observed in Pure Kevlar samples and the adding of glass fibre increases the weight and Areal Density of the sample, further investigations need to be carried out to utilize the potential of glass fibre for ballistic applications.

scholarly journals Role of laminate fracture energy on ballistic performance of glass composite laminates

2019 ◽  
Vol 14 ◽  
pp. 676-683
Author(s):  
P Rama Subba Reddy ◽  
T Sreekantha Reddy ◽  
K Mogulanna ◽  
G Seshagiri Rao ◽  
Vemuri Madhu ◽  
...  
Keyword(s):  
Fracture Energy ◽  
Composite Laminates ◽  
Glass Composite ◽  
Ballistic Performance

scholarly journals The Role of Space Observations in The Calibration of Fundamental Stellar Quantities

1985 ◽  
Vol 111 ◽  
pp. 209-224
Author(s):  
Arthur D. Code
Keyword(s):  
Current Status ◽  
Ultraviolet Spectrophotometry ◽  
Data Bases ◽  
Future Directions ◽  
Composite Systems ◽  
Early Type Stars ◽  
Stellar Properties ◽  
Ultraviolet Observations ◽  
Space Observations

This paper summarizes the current status of ultraviolet spectrophotometry with emphasis on the instrumental characteristics unique to space observations and on the application of existing data to the calibration of stellar properties. The currently available data bases will be briefly reviewed. When combined with ground based data, ultraviolet observations provide information on effective temperatures and bolometric corrections for early type stars and on the nature of the intervening interstellar medium. The ultraviolet measurements are sensitive to chemical composition differences and provide a powerful tool in discussion of stellar evolution in composite systems. This review concludes with a brief discussion of future directions in instrumentation and analysis.

Detection and enumeration of microbial cells within highly porous calcareous reef sands

2006 ◽  
Vol 57 (4) ◽  
pp. 415 ◽  
Author(s):  
Christian Wild ◽  
Christian Laforsch ◽  
Markus Huettel
Keyword(s):  
Laser Scanning ◽  
Complex Surface ◽  
Porous Matrix ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Size Spectrum ◽  
Order Of Magnitude ◽  
Grain Surface ◽  
Highly Porous

In order to assess and to compare the abundances of prokaryotes in coral sands from three different areas in the Indo-Pacific, a technique was developed and evaluated for enumeration of prokaryotes living on and within calcareous grains. Propidium iodide labelling of prokaryotes and consecutive confocal laser scanning microscopy showed microbial colonisation within pores and small fissures of the coral sands. This embedded microbial colonisation required at least four extractions with weak acetic acid to dissolve the grain surface layer in order to detach 97% of the prokaryotic cells. Microbial enumeration based on this technique revealed that the abundance of prokaryotes in the carbonate sands were not significantly different among the three sites, but were about one order of magnitude higher than reported for silicate sands of a similar grain size spectrum. A possible reason for this high abundance of prokaryotes is the complex surface structure of the biogenic calcareous grains, their correspondingly highly porous matrix and the associated ability of prokaryotes to penetrate into carbonate grains. Our results highlight the role of calcareous reef sands as a substratum with a large specific surface area for prokaryotic colonisation and emphasise the contribution of calcium carbonate reef sands for element cycles in subtropical and tropical ecosystems.

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