Thermal stability and flammability characteristics of phenolic syntactic foam core sandwich composites

2020 ◽  
pp. 109963622092666
Author(s):  
SJ Amith Kumar ◽  
SJAjith Kumar ◽  
Bharath K Nagaraja
Keyword(s):  
Thermal Stability ◽  
Composite Structures ◽  
Syntactic Foam ◽  
Spherical Particles ◽  
Core Material ◽  
Foam Core ◽  
Sandwich Composites ◽  
Minimum Concentration ◽  
Polymeric Foam ◽  
Structural Applications

Polymeric foam core sandwich composites are the nascent materials used in marine and aerospace structural applications for its low-density characteristics. A special class of foam called syntactic foam is one of the promising core material having high specific properties. However, these polymeric foam core sandwich composite structures may encounter problems in correlation with temperature and fire. Damages that happen due to the variation in temperature and by the catch of fire are sometimes imperceptible which may lead to the deterioration of load carrying ability or catastrophic failure of these composite structures. Present investigation is focused on the possibilities of reducing the extent of damages due to variation in temperature and by the catch of fire by enhancing its thermal stability and flame resistance characteristics. This was achieved from the development of syntactic foam by embedding hollow micro-spherical particles in phenolic resin for fire containment or fire isolation. Result of the experimentation reveals that the phenolic syntactic foam core was thermally more stable than glass/epoxy face skins up to a temperature of 450°C. The minimum concentration of oxygen required for burning was found to be 30%, in which phenolic syntactic foam core helps in flame isolation, whereas E-glass/epoxy face skins contribute to flame spread in the event of burning of sandwich composites. Improved thermal stability and fire resistance characteristics of developed sandwich composites are attributed to the phenolic syntactic foam core and by its orientation.

Effect of Microballoon Radius Ratio on Syntactic Foam Core Sandwich Composites

2005 ◽  
Vol 7 (2) ◽  
pp. 95-111 ◽  
Author(s):  
Eyassu Woldesenbet ◽  
Nikhil Gupta ◽  
H. Dwayne Jerro
Keyword(s):  
Syntactic Foam ◽  
Radius Ratio ◽  
Foam Core ◽  
Sandwich Composites

Forming of Shape Memory Composite Structures

2013 ◽  
Vol 554-557 ◽  
pp. 1930-1937 ◽  
Author(s):  
Loredana Santo ◽  
Fabrizio Quadrini ◽  
Leonardo De Chiffre
Keyword(s):  
Shape Memory ◽  
Composite Structures ◽  
Room Temperature ◽  
Thermoplastic Composite ◽  
Bending Test ◽  
Core Material ◽  
Foam Core ◽  
Axial Tomography ◽  
Initial Shape ◽  
Shape Memory Composite

A new forming procedure was developed to produce shape memory composite structures having structural composite skins over a shape memory polymer core. Core material was obtained by solid state foaming of an epoxy polyester resin with remarkably shape memory properties. The composite skin consisted of a two-layer unidirectional thermoplastic composite (glass filled polypropylene). Skins were joined to the foamed core by hot compression without any adhesive: a very good adhesion was obtained as experimental tests confirmed. The structure of the foam core was investigated by means of computer axial tomography. Final shape memory composite panels were mechanically tested by three point bending before and after a shape memory step. This step consisted of a compression to reduce the panel thickness up to 60%. At the end of the bending test the panel shape was recovered by heating and a new memory step was performed with a higher thickness reduction. Memory steps were performed at room temperature and 120 °C so as to test the foam core in the glassy and rubbery state, respectively. Shape memory tests revealed the ability of the shape memory composite structures to recover the initial shape also after severe damaging (i.e. after room temperature compression). Compressing the panel at a temperature higher than the foam resin glass transition temperature minimally affects composite stiffness.

The Sensitivity of the Foam-Core Parameters under Impact Loading

2012 ◽  
Vol 525-526 ◽  
pp. 289-292
Author(s):  
Fei Xu ◽  
Min Ge Duan
Keyword(s):  
Impact Resistance ◽  
Low Velocity Impact ◽  
Core Material ◽  
Foam Core ◽  
Sandwich Composites ◽  
Low Velocity ◽  
Fea Model ◽  
The Face ◽  
Damage Process ◽  
The Impact

This study presents the numerical investigation of the low-velocity impact for the foam-cored sandwich composites. Firstly, the proposed FEA model is validated by comparing the results between simulation and test. The user subroutine VUMAT and the crushable foam model are chosen to describe the damage of the face sheets and the characteristics of the foam material, respectively. The detailed damage process of the sheets and the foam is clearly shown. The sensitivity of seven parameters related to foam-core material are studied. It is shown that the yield strength, the fracture strain and the fracture displacement have significant effects on the impact-resistance of the foam-cored sandwich composites.

Effects of Seawater and Low Temperatures on Polymeric Foam Core Material

2011 ◽  
Vol 52 (1) ◽  
pp. 25-36 ◽  
Author(s):  
A. Siriruk ◽  
D. Penumadu ◽  
A. Sharma
Keyword(s):  
Low Temperatures ◽  
Core Material ◽  
Foam Core ◽  
Polymeric Foam

Dynamic Impact Behavior of Syntactic Foam Core Sandwich Composites

2018 ◽  
Author(s):  
PETER BREUNIG ◽  
VINAY DAMODARAN ◽  
KIRAN SHAHAPURKAR ◽  
SUNIL WADDAR ◽  
MRITYUNJAY DODDAMANI ◽  
...  
Keyword(s):  
Syntactic Foam ◽  
Impact Behavior ◽  
Foam Core ◽  
Sandwich Composites ◽  
Dynamic Impact

Dynamic impact behavior of syntactic foam core sandwich composites

2019 ◽  
Vol 54 (4) ◽  
pp. 535-547 ◽  
Author(s):  
P Breunig ◽  
V Damodaran ◽  
K Shahapurkar ◽  
S Waddar ◽  
M Doddamani ◽  
...  
Keyword(s):  
Syntactic Foam ◽  
Impact Response ◽  
Sandwich Composite ◽  
Foam Core ◽  
Syntactic Foams ◽  
Sandwich Composites ◽  
Dynamic Impact ◽  
Damage Mechanisms ◽  
The Impact ◽  
Dynamic Impact Loading

Sandwich composites and syntactic foams independently have been used in many engineering applications. However, there has been minimal effort towards taking advantage of the weight saving ability of syntactic foams in the cores of sandwich composites, especially with respect to the impact response of structures. To that end, the goal of this study is to investigate the mechanical response and damage mechanisms associated with syntactic foam core sandwich composites subjected to dynamic impact loading. In particular, this study investigates the influence of varying cenosphere volume fraction in syntactic foam core sandwich composites subjected to varying dynamic impact loading and further elucidates the extent and diversity of corresponding damage mechanisms. The syntactic foam cores are first fabricated using epoxy resin as the matrix and cenospheres as the reinforcement with four cenosphere volume fractions of 0% (pure epoxy), 20%, 40%, and 60%. The sandwich composite panels are then manufactured using the vacuum assisted resin transfer molding process with carbon fiber/vinyl ester facesheets. Dynamic impact tests are performed on the sandwich composite specimens at two energy levels of 80 J and 160 J, upon which the data are post-processed to gain a quantitative understanding of the impact response and damage mechanisms incurred by the specimens. A qualitative understanding is obtained through micro-computed tomography scanning of the impacted specimens. In addition, a finite element model is developed to investigate the causes for different damage mechanisms observed in specimens with different volume fractions.

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