scholarly journals Hygro-Thermo-Mechanical Responses of Balsa Wood Core Sandwich Composite Beam Exposed to Fire

Processes ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 103 ◽  
Author(s):  
Luan TranVan ◽  
Vincent Legrand ◽  
Pascal Casari ◽  
Revathy Sankaran ◽  
Pau Loke Show ◽  
...  
Keyword(s):  
Composite Beam ◽  
Cone Calorimeter ◽  
Mechanical Test ◽  
Sandwich Composite ◽  
Test Device ◽  
Balsa Wood ◽  
Three Point Bending ◽  
Mechanical Responses ◽  
Loss Kinetic ◽  
Composite Skins

In this study, the hygro–thermo–mechanical responses of balsa core sandwich structured composite was investigated by using experimental, analytical and numerical results. These investigations were performed on two types of specimen conditions: dry and moisture saturation sandwich composite specimens that are composed of E-glass/polyester skins bonded to a balsa core. The wet specimens were immersed in distilled water at 40 °C until saturated with water. The both dry and wet sandwich composite specimens were heated by fire. The mass loss kinetic and the mechanical properties were investigated by using a cone calorimeter following the ISO 5660 standard and three-point bending mechanical test device. Experimental data show that the permeability and fire resistance of the sandwich structure are controlled by two composite skins. Obtained results allow us to understand the Hygro–Thermo–Mechanical Responses of the sandwich structured composite under application conditions.

scholarly journals Multiscale Characterization of E-Glass/Epoxy Composite Exposed to Extreme Environmental Conditions

2021 ◽  
Vol 5 (3) ◽  
pp. 80
Author(s):  
George Youssef ◽  
Scott Newacheck ◽  
Nha Uyen Huynh ◽  
Carlos Gamez
Keyword(s):  
Power Distribution ◽  
Epoxy Composite ◽  
Fire Retardant ◽  
Sandwich Composite ◽  
Dynamic Mechanical Analyzer ◽  
Fire Event ◽  
Balsa Wood ◽  
X Ray ◽  
Dynamic Mechanical ◽  
Composite Skins

Fiber-reinforced polymer matrix composites continue to attract scientific and industrial interest since they offer superior strength-, stiffness-, and toughness-to-weight ratios. The research herein characterizes two sets of E-Glass/Epoxy composite skins: stressed and unstressed. The stressed samples were previously installed in an underground power distribution vault and were exposed to fire while the unstressed composite skins were newly fabricated and never-deployed samples. The mechanical, morphological, and elemental composition of the samples were methodically studied using a dynamic mechanical analyzer, a scanning electron microscope (SEM), and an x-ray diffractometer, respectively. Sandwich composite panels consisting of E-glass/Epoxy skin and balsa wood core were originally received, and the balsa wood was removed before any further investigations. Skin-only specimens with dimensions of ~12.5 mm wide, ~70 mm long, and ~6 mm thick were tested in a Dynamic Mechanical Analyzer in a dual-cantilever beam configuration at 5 Hz and 10 Hz from room temperature to 210 °C. Micrographic analysis using the SEM indicated a slight change in morphology due to the fire event but confirmed the effectiveness of the fire-retardant agents in quickly suppressing the fire. Accompanying Fourier transform infrared and energy dispersive X-ray spectroscopy studies corroborated the mechanical and morphological results. Finally, X-ray diffraction showed that the fire event consumed the surface level fire-retardant and the structural attributes of the E-Glass/Epoxy remained mainly intact. The results suggest the panels can continue field deployment, even after short fire incident.

Thermal decomposition of multilayer honeycomb core laminate sandwich composite panels in cone calorimeter apparatus – Effect of the top decomposed layer

2021 ◽  
pp. 002199832199087
Author(s):  
Hussain Najmi ◽  
Jocelyn Luche ◽  
Thomas Rogaume
Keyword(s):  
Cone Calorimeter ◽  
Single Layer ◽  
Heat Fluxes ◽  
Decomposition Process ◽  
Phase Iii ◽  
Sandwich Composite ◽  
Back Surface ◽  
Multilayer Composite ◽  
In Fire

Multilayer composite materials are frequently used in aircraft interiors. Even though they have high properties (such as physical, chemical and mechanical properties), their application is limited due to lack of knowledge of their decomposition process and on the interaction between different layers in fire. In the present work, two types of composites with 3 and 4 layers are studied. The fire characterization of multilayer composite is studied in 3 different phases using ISO-5660 cone calorimeter at two heat fluxes (35 and 50 kW.m−2). Phase-I mainly concentrates on the decomposition of single layer materials (paint, laminate and honeycomb) while in phase-II and phase-III, different assemblies are formed using a single layer material and studied in the same experimental configuration. In all the three phases, back surface temperatures of the materials or assemblies are measured and analyzed with different gas productions which allow to understand the dynamics of the decomposition process. The finding from the cone calorimeter study suggests that the ignition primarily depends on the top layer behavior of the composite. The permeability analysis on the top layer of the composite confirms that decomposed layer of paint offers more resistance to the volatile gases escaping from the composite. At the end of the study, thermal conductivity is determined and the ignition temperature of both the composite is determined.

scholarly journals Design and Analysis of Sandwich Composite Beam

2016 ◽  
Vol V5 (08) ◽  
Author(s):  
B Durga Prasad ◽  
R Pallavi Reddy ◽  
Keyword(s):  
Composite Beam ◽  
Sandwich Composite

Some Results and Issues in the Non-Destructive Evaluation of Sandwich Composite Structures

2001 ◽  
Author(s):  
Emmanuel O. Ayorinde ◽  
Ronald F. Gibson ◽  
Feizhong Deng
Keyword(s):  
Composite Structures ◽  
Failure Modes ◽  
Sandwich Beam ◽  
Sandwich Composite ◽  
Glass Composite ◽  
Transverse Loading ◽  
Three Point Bending ◽  
Damage States ◽  
Vibration Modal ◽  
Non Destructive

Abstract This paper focuses on the use of basic NDE methods like ultrasonics, imaging and vibration testing to assess the integrity of some sandwich composites which have been subjected to transverse loading. Samples of a foam core, glass composite facing sandwich beam of varying thicknesses and end notch lengths were tested in three point bending and assessed by these NDE methods. The results show that core shear and indentation failures appear to be the prominent failure modes for these geometries and materials, and that changes in the damping and vibration modal frequencies of the beams can indicate damage states.

Bio-Crude by Acidic Phenolation and Carbamation for the Preparation of Phenolic Thermosetting Resin and Its Application in Thermoresistant Laminates

2019 ◽  
Vol 17 (4) ◽  
Author(s):  
Huan Wang ◽  
Zhuo Wang ◽  
Penggang Ren ◽  
Mingcun Wang
Keyword(s):  
High Performance ◽  
Phenolic Resin ◽  
Mechanical Test ◽  
Chemical Reactivity ◽  
Cost Effective ◽  
Mechanical Analysis ◽  
Thermosetting Resin ◽  
Scanning Calorimetry ◽  
Three Point Bending ◽  
Mechanical Performances

Abstract Fir sawdust was liquefied in phenol solvent under acidic catalyst at 135, 150 and 165 °C, respectively; after neutralization, bio-crude was obtained where contained oil-like liquid and tiny powder-like residue. The bio-crude was chemically modified with urea at high temperature (e. g. > 130 °C) to form carbamate so as to improve chemical reactivity of bio-crude in phenolic resin synthesis. The carbamate-containing bio-crude was condensed with paraformaldehyde into thermosetting phenolic resin. Finally, this biomass-derived phenolic resin matrixed silica fabric laminates were processed. The uncured and thermally cured bio-based resins were characterized by the techniques of Differential Scanning Calorimetry (DSC), Fourier Transform Infrared spectrum (FT-IR), rheology and Thermogravimetric Analysis (TGA), and the laminates’ structure and mechanical performances were studied using the methods of Scanning Electron Microscopy (SEM), three point bending mechanical test and Dynamic Mechanical Analysis (DMA). The results showed: (1) the chemical reactivity of bio-crude was highly improved by carbamation; (2) biomass-derived thermosetting phenolic resin was thermally curable at 150–250 °C (with two exothermic peaks at 185 °C and 220 °C); (3) the char yield was about 47 %, which was not in apparent relationship with sawdust liquefaction temperatures; (4) flexural strength of silica fabric laminates at room temperature was around 357 MPa (similar with that of conventional phenolic laminate); (5) glass transition temperature of silica fabric laminate was above 270 °C (much higher than Tg of conventional phenolic resin laminate, which is normally at 215 °C). The biomass-derived phenolic resin is expected to be widely used as cost-effective and environment-friendly thermosetting resin in the application of high-performance composites.

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