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.

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.

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.

Biomechanics of Soft Tissues: The Role of the Mathematical Model on Material Behavior

2019 ◽  
pp. 301-311
Author(s):  
Carlos Bustamante-Orellana ◽  
Robinson Guachi ◽  
Lorena Guachi-Guachi ◽  
Simone Novelli ◽  
Francesca Campana ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Soft Tissues ◽  
Material Behavior ◽  
The Mathematical Model

scholarly journals The Contribution of Infrared Thermography in the Characterization of Glass/Epoxy Laminates through Remote Sensing of Thermal-Stress Coupled Effects

Proceedings ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 21
Author(s):  
Carosena Meola ◽  
Simone Boccardi ◽  
Giovanni Maria Carlomagno
Keyword(s):  
Cantilever Beam ◽  
Mechanical Stresses ◽  
Material Behavior ◽  
Low Velocity Impact ◽  
Imaging Device ◽  
Temperature Variations ◽  
Thermal Images ◽  
Damage Initiation ◽  
Matrix Cracks ◽  
The Impact

Mechanical stresses of materials are generally coupled with temperature variations and then, monitoring such variations can help gaining information about the material behavior under the applied loads. This can be accomplished with an infrared imaging device, which can be advantageously exploited to sense the thermal radiation associated with mechanical stresses and to obtain a legible explicative temperature map. In the present paper, glass/epoxy is used as material case study to show that thermal signatures visualized during the load application can be decoded into knowledge, which can contribute to the material characterization. In particular, glass/epoxy specimens are subjected to three types of tests: cantilever beam alternate bending, quasi-static bending and low velocity impact. Thermal images are acquired in time sequence during each test and after post-processed and analyzed. It is possible to get data about the damage initiation and its evolution under either quasi-static bending, or impact. In particular, a cute analysis of thermal images supplies information about damage types (matrix cracks, or fibers breakage) and extension of delamination, as well of the impact duration and the time to reach peak contact force. It is also possible to well depict the harmonic cantilever beam oscillations through the associated small temperature variations.

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

A Continued Evaluation of the Role of Material Hardening Behavior for the NeT TG1 and TG4 Specimens

2014 ◽  
Author(s):  
David J. Dewees ◽  
Phillip E. Prueter ◽  
Seetha Ramudu Kummari
Keyword(s):  
Structural Integrity ◽  
Plastic Material ◽  
Critical Factor ◽  
Material Model ◽  
Standard Test ◽  
Material Behavior ◽  
Weld Residual Stress ◽  
Hardening Models ◽  
Elastic Plastic Material

Modeling of cyclic elastic-plastic material behavior (hardening) has been widely identified as a critical factor in the finite element (FE) simulation of weld residual stresses. The European Network on Neutron Techniques Standardization for Structural Integrity (NeT) Project has provided in recent years both standard test cases for simulation and measurement, as well as comprehensive material characterization. This has allowed the role of hardening in simulation predictions to be isolated and critically evaluated as never before possible. The material testing information is reviewed, and isotropic, nonlinear kinematic and combined hardening models are formulated and tested. Particular emphasis is placed on material model selection for general fitness-for-service assessments, as it relates to the guidance for weld residual stress (WRS) in flaw assessments of in-service equipment in Annex E of the FFS standard, API 579-1/ASME FFS-1.

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.

Modeling of the Strain Rate Dependent Material Behavior of 3D-Textile Composites with Production and Operational Defects

2011 ◽  
Vol 403-408 ◽  
pp. 651-655
Author(s):  
W. Hufenbach ◽  
M. Gude ◽  
R. Protz
Keyword(s):  
Strain Rate ◽  
Damage Mechanics ◽  
Additive Model ◽  
Experimental Tests ◽  
Continuum Damage Mechanics ◽  
Textile Composites ◽  
Material Behavior ◽  
Rate Dependent ◽  
Dynamic Tensile Loading ◽  
Good Coincidence

This paper concerned with modeling of the strain rate dependent material behavior of 3D-textile composites with simultaneous consideration of production and operational (e.g. pores or fatigue damage) defects. Therefore an additive model in the sense of continuum damage mechanics was introduced. For the model validation extensive experimental tests on glass non-crimp fabrics reinforced epoxy (GF-NCF/EP) composites are performed. The focus is put on the influence of production and fatigue related pre-damage under subsequent highly-dynamic tensile loading. The theoretical studies shows a good coincidence with the experimentally results

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