Experimental Techniques for Dynamic Characterization of Composite Materials

1995 ◽  
Vol 117 (1) ◽  
pp. 94-100 ◽  
Author(s):  
Robert Greif ◽  
Benjamin Hebert

This research combines theoretical and experimental approaches for dynamic material characterization of composite materials. The samples studied include continuous fiber graphite/epoxy beams with various symmetric lay-up configurations. Included are laminated beams with the following lay-ups: [08/908]s, [908/08]s, [(45/0/−45)5]s and [(0/45/0/−45)3/90/0/01/2]s. The resonant dwell technique is used to determine the material damping and the real part of the dynamic flexural modulus of double cantilever beam specimens in the first mode of vibration over the frequency range 25 Hz to 300 Hz. The dynamic properties are determined as a function of the frequency of oscillation at room temperature. In addition, the Metravib Viscoanalyzer, based on off-resonance tests, is also used to provide another source of experimental data for comparison. Although the Viscoanalyzer was originally intended for testing viscoelastic polymers, the present research establishes the limits of applicability for composite materials, with particular emphasis on the three point bending test. Comparisons and limitations of both techniques are critically discussed.

2011 ◽  
Vol 391-392 ◽  
pp. 1445-1449
Author(s):  
Chun Hua Zhang ◽  
Shi Lin Luan ◽  
Xiu Song Qian ◽  
Bao Hua Sun ◽  
Wen Sheng Zhang

The influences of low temperature on the interlaminar properties for PBO fiber/epoxy composites have been studied at liquid nitrogen temperature (77 K) in terms of three point bending test. Results showed that the interlaminar shear strength at 77 K were significantly higher than those at room temperature (RT). For the analysis of the test results, the tensile behaviors of epoxy resin at both room temperature and liquid nitrogen temperature were investigated. The interface between fiber and matrix was observed using SEM images.


2006 ◽  
Vol 321-323 ◽  
pp. 913-916
Author(s):  
Sang Ll Lee ◽  
Yun Seok Shin ◽  
Jin Kyung Lee ◽  
Jong Baek Lee ◽  
Jun Young Park

The microstructure and the mechanical property of liquid phase sintered (LPS) SiC materials with oxide secondary phases have been investigated. The strength variation of LPS-SiC materials exposed at the elevated temperatures has been also examined. LPS-SiC materials were sintered at the different temperatures using two types of Al2O3/Y2O3 compositional ratio. The characterization of LPS-SiC materials was investigated by means of SEM with EDS, three point bending test and indentation test. The LPS-SiC material with a density of about 3.2 Mg/m3 represented a flexural strength of about 800 MPa and a fracture toughness of about 9.0 MPa⋅√m.


2018 ◽  
Vol 11 (4) ◽  
pp. 339-344 ◽  
Author(s):  
Yucheng Huang ◽  
Yanhua Guan ◽  
Linbing Wang ◽  
Jian Zhou ◽  
Zhi Ge ◽  
...  

2004 ◽  
Vol 261-263 ◽  
pp. 1635-1640 ◽  
Author(s):  
Seok Hwan Ahn ◽  
Ki Woo Nam ◽  
Kotoji Ando

Four kinds of brittle materials were used to evaluate the bending strength under three-point bending and the characteristics of the elastic wave signal by Vickers indentation. The bending test was carried out under room temperature and high temperature. A crack was made at the tension side of the specimen with a Vickers indenter to investigate fracture strength. Fracture wave detector was used to evaluate characteristics of waveform and frequency of the elastic wave signal.


2007 ◽  
Vol 14 (04) ◽  
pp. 817-820
Author(s):  
MIN HUANG ◽  
KE-ZHI LI ◽  
HE-JUN LI ◽  
QIAN-GANG FU ◽  
GUO-DONG SUN

SiC coating for carbon/carbon composites was prepared by pack cementation method. The effects of coating process on the microstructure and the mechanical properties of C / C composites were analyzed by SEM and three-point bending test, respectively. As the infiltrated Si improved the interfaces bonding during the coating process, the flexural strength and flexural modulus of SiC -coated carbon/carbon composites were both increased by about 10% than the naked C / C composites. In addition, the mechanism of the change of failure mode of SiC coated C / C composites and naked C / C composites was addressed.


2014 ◽  
Vol 580-583 ◽  
pp. 2213-2219 ◽  
Author(s):  
Lin Liao ◽  
Sergio Cavalaro ◽  
Albert de la Fuente ◽  
Antonio Aguado

Many researches have been conducted in past decades for promoting the application of steel fibre reinforced concrete (SFRC), either conventional or self-compacting. However, the differences of post-crack behaviour and the properties of these two types of concrete remains unclear. The objective of this paper is to analyse such differences in terms of flexural behaviour, fibre orientation and contribution as well as the fibre content. For that, an extensive experimental campaign was carried out. In total 3 mixes of self-compacting and 3 mixes with traditional concrete were produced with the nominal fibre contents of 30kg/m3, 45kg/m3 and 60kg/m3. In each series, specimens were produces and characterized by three point bending test (code EN 14651) and inductive test. The results illustrate how fibre orientation and distribution justify the differences in the mechanical behaviour of the materials and the scatter of the bending test results.


2015 ◽  
Vol 40 (2) ◽  
pp. 181-189 ◽  
Author(s):  
M D'Amario ◽  
F De Angelis ◽  
M Vadini ◽  
N Marchili ◽  
S Mummolo ◽  
...  

SUMMARY The aim of this study was to assess the flexural strength, flexural elastic modulus and Vickers microhardness of three resin composites prepared at room temperature or cured after one or repeated preheating cycles to a temperature of 39°C. Three resin composites were evaluated: Enamel Plus HFO (Micerium), Opallis (FGM), and Ceram X Duo (Dentsply DeTrey). For each trial, one group of specimens of each material was fabricated under ambient laboratory conditions, whereas in the other groups, the composites were cured after 1, 10, 20, 30, or 40 preheating cycles to a temperature of 39°C in a preheating device. Ten rectangular prismatic specimens (25 × 2 × 2 mm) were prepared for each group (N=180; n=10) and subjected to a three-point bending test for flexural strength and flexural modulus evaluation. Vickers microhardness was assessed on 10 cylindrical specimens from each group (N=180; n=10). Statistical analysis showed that, regardless of the material, the number of heating cycles was not a significant factor and was unable to influence the three mechanical properties tested. However, a significant main effect of the employed material on the marginal means of the three dependent variables was detected.


2017 ◽  
Vol 891 ◽  
pp. 542-546 ◽  
Author(s):  
Ladislav Fojtl ◽  
Soňa Rusnáková ◽  
Milan Žaludek ◽  
Alexander Čapka ◽  
Lukáš Maňas

Jute fabric is well-known reinforcing material in composite science, however, there is a necessity to treat these fabrics to reduce moisture uptake and improve properties. Nevertheless, every modification increases the cost and reduces the possible applications. Presented research deals with an investigation of possibility to use untreated jute in various fabric weight as a reinforcing material in sandwich structures facings. Untreated jute reinforcements and two types of cork cores were saturated in one step during vacuum infusion creating a lightweight sandwich composite. All samples were mechanically tested in three-point bending test. Experimental results showed the most appropriate material combination and produced sandwich structure are proposed for design applications.


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