Shear properties and load-deflection response of cross-ply glass-epoxy composite short-beams subjected to three-point-bending tests, and the effect of moisture absorption

2013 ◽  
Vol 129 (4) ◽  
pp. 2244-2252 ◽  
Author(s):  
Emilio P. Sideridis ◽  
George S. Bikakis
2012 ◽  
Vol 450-451 ◽  
pp. 482-485 ◽  
Author(s):  
A Ying Zhang ◽  
Di Hong Li ◽  
Dong Xing Zhang

The effects of moisture content on the bending strength of T300/914 composite laminates that immersed in water for 7 days and 14 days was discussed in this paper. The three-point bending tests were conducted on the composite laminates. Experimental results reveal that the moisture content in the laminates increased with immersion time and that moisture absorption accelerated damage propagation in the composite laminates. The bending strength of the unaged, aged specimens were characterized and analyzed. Compared to the unaged specimens, the bending strength of the composite laminates immersed for 7 and 14 days decreased by 6.62% and 16.98%, respectively. The results revealed that the bending strength of the aged specimens decreased with the increasing immersion time.


2008 ◽  
Vol 47-50 ◽  
pp. 536-539 ◽  
Author(s):  
H. Ku ◽  
F. Cardona ◽  
D. Rogers ◽  
A. Vandenbroucke

Low cost composite materials are widely used in civil and structural engineering applications. This project uses EPON to plasticize a commonly used resin, epoxy resin to lower the cost of the composite and to find out the mechanical and thermal properties of the plasticized epoxy resin to see if it is suitable for the said applications. Three point bending tests were carried out to evaluate the flexural properties of the plasticized resins. Differential scanning calorimetry and dynamic mechanical thermal analysis are used to evaluate the thermal properties of the plasticized epoxy resin. The study with epoxy and EPON showed that the mechanical properties of the epoxy composite were lowered but its ability to dissipate energy increased because of its improved thermal properties. As EPON is much cheaper that epoxy resin, the composite produced is therefore cheaper and provided the service requirements were not so demanding, it can be used in the said applications.


2014 ◽  
Vol 911 ◽  
pp. 18-22
Author(s):  
Abdul Hakim Abdullah ◽  
Mohd Ridzuan Mohd Razali ◽  
Muhd Azimin A. Ghani

This paper presents the effect of moisture absorption towards thermal modulus evaluation of Arenga Pinnata fibre reinforced epoxy composite. The specimens are produced by hand lay-up method for practically with the ratio of combination of fibre with epoxy and hardener. The fibres were treated with sodium hydroxide (NaOH) prior the composites fabrication. Then, it were submerged in the water for moisture absorption and left for 8 days, 16 days and 30 days. The flexural modulus indicates there is reduction of elastic modulus values over the submerged period. Thermal analysis depicted by storage modulus curve showed the submerged specimens were not affected too much as compared to the control specimens. In fact, their performances were remaining the same across the temperature across from-10°C to 100°C. It is suggested from the experimental result that Arenga Pinnata fibres have a potential prospect as fibre reinforcement composites in many application.


2020 ◽  
Vol 837 ◽  
pp. 41-45
Author(s):  
Shuai Sun ◽  
Kai Hua Liu

In order to determine the evolution features of deformation twins for TA2 commercial pure titanium (cp-TA2), the TA2 samples were bent under different bending angles in three-point bending tests via a universal testing machine. The electron backscatter diffraction (EBSD) technique was applied to identify the grain boundaries (GBs) and twin boundaries (TBs) in the bending areas. The results reveal that the type of deformation area would effect the evolution of different deformation twins. It is inferred that the state of stress would promote the multiplication of the same type of deformation twins.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3522
Author(s):  
Marta Caballero-Jorna ◽  
Marta Roig-Flores ◽  
Pedro Serna

The use of synthetic fibers in fiber-reinforced concretes (FRCs) is often avoided due to the mistrust of lower performance at changing temperatures. This work examines the effect of moderate temperatures on the flexural strengths of FRCs. Two types of polypropylene fibers were tested, and one steel fiber was employed as a reference. Three-point bending tests were carried out following an adapted methodology based on the standard EN 14651. This adapted procedure included an insulation system that allowed the assessment of FRC flexural behavior after being exposed for two months at temperatures of 5, 20, 35 and 50 °C. In addition, the interaction of temperature with a pre-cracked state was also analyzed. To do this, several specimens were pre-cracked to 0.5 mm after 28 days and conditioned in their respective temperature until testing. The findings suggest that this range of moderate temperatures did not degrade the behavior of FRCs to a great extent since the analysis of variances showed that temperature is not always a significant factor; however, it did have an influence on the pre-cracked specimens at 35 and 50 °C.


1991 ◽  
Vol 227 ◽  
Author(s):  
Rajeevi Subramanian ◽  
Michael T. Pottiger ◽  
Jacqueline H. Morris ◽  
Joseph P. Curilla

ABSTRACTMoisture absorption and its effect on electrical properties were measured for several polyimides. A Quartz Crystal Microbalance (QCM) was used to investigate the moisture absorption in BPDA/PPD, PMDA/ODA, and BTDA//ODA/MPD polyimides. The steady-state moisture uptake in polyimides as a function of relative humidity (RH) was determined by exposing film samples to successively higher RH values ranging from 10 to 85% at 25°C. The isothermal moisture absorption as a function of percent RH was found to be nearly linear for all of the polyimides studied. The effect of moisture on the electrical properties of a BPDA/PPD polyimide was also investigated. The relative dielectric constant at 25 °C was found to be a linear function of the moisture absorbed.


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