scholarly journals Investigation on the Durability of E-Glass/Epoxy Composite Exposed to Seawater at Elevated Temperature

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2182
Author(s):  
Amir Hussain Idrisi ◽  
Abdel-Hamid I. Mourad ◽  
Beckry M. Abdel-Magid ◽  
B. Shivamurty
Keyword(s):  
Elastic Modulus ◽  
Elevated Temperature ◽  
Epoxy Composite ◽  
Degradation Mechanism ◽  
Shift Factor ◽  
Time Shift ◽  
Slight Variation ◽  
Seawater Environment ◽  
Prediction Approach ◽  
Strength Retention

In this manuscript, the durability of the E-glass/epoxy composite was determined under a seawater environment. The effect of harsh environment was investigated in terms of seawater absorption, microstructure and degradation in mechanical properties. E-glass epoxy composite specimens were conditioned in gulf seawater at 23 °C, 65 °C and 90 °C for the period of 12 months. It was observed that the mass of the samples increased after the immersion of 12 months at 23 °C and 65 °C whereas it reduced at 90 °C. The salt deposition was observed at the surface of specimens without any crack for the seawater conditioning at 23 °C and 65 °C. The swelling and crack formation were significantly visible on the surface of the specimen immersed for 12 months at 90 °C. It indicates that the degradation mechanism accelerated at elevated temperature results fiber/matrix debonding. The tensile test indicates slight variation in the elastic modulus and reduction in strength of E-glass epoxy composite by 1% and 9% for specimens immersed at 23 °C and 65 °C respectively. However, at 90 °C, the tensile strength sharply decreased to 7% and elastic modulus significantly increased in the exposure of 12 months. A prediction approach based on a time-shift factor (TSF) was used. This model predicted that the strength retention of E-glass/Epoxy composite will be reduced to 7% in 450 years after immersion in seawater at 23 °C. Lastly, the activation energy for the degradation of the composite was calculated.

Kinetics of Network Re-Formation in Hydrolytic Degraded AFR700B Polyimide Resin

1996 ◽  
Vol 8 (4) ◽  
pp. 475-489 ◽  
Author(s):  
Andre Lee
Keyword(s):  
Elastic Modulus ◽  
High Temperature ◽  
Network Formation ◽  
Physical And Mechanical Properties ◽  
Shift Factor ◽  
Time Shift ◽  
Formation Processes ◽  
Curing Time ◽  
Controlling Mechanism ◽  
Kinetics Of

Dynamic mechanical spectrometry was used to investigate the network formation processes during the high-temperature isothermal post-cure of virgin and hydrolytic degraded AFR700B resin. Upon exposure to hydrolytic conditions, a significant degradation in physical and mechanical properties of newly developed high-temperature PMR type polyimide resins (AFR700B) was observed. In this study we are particularly interested in the kinetics and the controlling mechanism of the network formation and re-formation processes at the high-temperature post-cure stage. In situ viscoelastic experiments were performed at a temperature of 400 °C. At this temperature the curing of polymer resin continues, thus the isochronal elastic modulus increases as the curing time increases. Furthermore, it was possible to perform a time–curing time superposition using these isothermal elastic modulus curves. This time–curing time shift-rate is then used as a direct measure of the kinetics of polyimide network formation. Interestingly, in this study we found that the time–curing time shift-rate for the hydrolytic degraded samples was identical to the time–curing time shift-factor of virgin ‘ascured’ formulated samples. This observation does not necessarily imply that the chemistry of polyimide network formation is the same, but instead that the controlling mechanism of network formation must be identical.

Prediction of the elastic modulus of SWCNT/epoxy composite based on the micromechanics

2015 ◽  
Vol 57 (7-8) ◽  
pp. 690-696 ◽  
Author(s):  
Hassan S. Hedia ◽  
Saad M. Aldousari ◽  
Ahmed K. Abdellatif ◽  
Gamal S. Abdelhafeez
Keyword(s):  
Elastic Modulus ◽  
Epoxy Composite

Assessment of Mechanical Properties of Cold Formed Steel Material at Elevated Temperature

2016 ◽  
Vol 846 ◽  
pp. 27-36
Author(s):  
Fadhluhartini Muftah ◽  
Mohd Syahrul Hisyam Mohd Sani ◽  
Ahmad Rasidi Osman ◽  
Mohd Azran Razlan ◽  
Shahrin Mohammad
Keyword(s):  
Elastic Modulus ◽  
Elevated Temperature ◽  
Ambient Temperature ◽  
Yield Stress ◽  
Material Properties ◽  
High Efficiency ◽  
Strain Curve ◽  
Ultimate Stress ◽  
Fire Incident ◽  
Cold Formed Steel

Fire accident is considered as the one of most severe environmental hazards to building and infrastructure. Cold formed steel (CFS) beam has been used extensively as primary load bearing structural member in many applications in the building construction due to high efficiency in term of production, fabrication, and assembling in construction. This material must be well perform in fire incident in term of its integrity and stability of structural for a period of time. Hence, the assessment of the material properties of this material is greatly important in order to predict the performance of this structure under fire incident. The tensile coupon tests of CFS are according to BS EN 10002-1:2001. The CFS material G450 with 1.9 mm thickness is used in this study. The elastic modulus, yield stress, correspondent percentage strain at yield stress, ultimate stress, and correspondent percentage strain of ultimate stress was 200.3 GPa, 540.5 MPa, 0.478 %, 618.8 MPa, and 8.701 % respectively. The results of the ambient temperature test have been used to assess the mechanical strength of CFS at elevated temperature. The discussion of material properties is based on EC3-1-2 and proposed model from other researchers. The main material properties discussed is the stress-strain curve, elastic modulus, yield strength at elevated temperature was determined. The actual elastic region is slightly lower than the prediction of EC3-1.2 at ambient temperature, but well fit with two other studies. Besides that, the actual material properties experience strain hardening after yielding and reach a maximum stress up to 618 MPa while EC3-1.2 predict the constant value of the yield stress after yield until 15 % strain,other two study was fit the ambient tensile test up to ultimate stress, and fit until 2 % strain level.

scholarly journals Study on Tensile Properties of CFRP Plates under Elevated Temperature Exposure

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1995 ◽  
Author(s):  
Yongxin Yang ◽  
Yanju Jiang ◽  
Hongjun Liang ◽  
Xiaosan Yin ◽  
Yue Huang
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Elevated Temperature ◽  
Tensile Properties ◽  
Failure Mode ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Effect Of Temperature ◽  
Temperature Exposure ◽  
The Impact

Elevated temperature exposure has a negative effect on the performance of the matrix resin in Carbon Fiber Reinforced Plastics (CFRP) plates, whereas limited quantitative research focuses on the deteriorations. Therefore, 30 CFRP specimens were designed and tested under elevated temperatures (10, 30, 50, 70, and 90 °C) to explore the degradations in tensile properties. The effect of temperature on the failure mode, stress-strain curve, tensile strength, elastic modulus and elongation of CFRP plates were investigated. The results showed that elevated temperature exposure significantly changed the failure characteristics. When the exposed temperature increased from 10 °C to 90 °C, the failure mode changed from the global factures in the whole CFRP plate to the successive fractures in carbon fibers. Moreover, with temperatures increasing, tensile strength and elongation of CFRP plates decreases gradually while the elastic modulus shows negligible change. Finally, the results of One-Way Analysis of Variance (ANOVA) show that the degradation of the tensile strength of CFRP plates was due to the impact of elevated temperature exposure, rather than the test error.

Determining Elastic Modulus of Ceramic Coatings at Elevated Temperature Using Impulse Excitation Technology

2016 ◽  
Vol 680 ◽  
pp. 13-16 ◽  
Author(s):  
Chen Guang Wei ◽  
Yi Wang Bao ◽  
Xue Qiang Cao ◽  
Zhao Liu ◽  
Yuan Tian
Keyword(s):  
Elastic Modulus ◽  
Elevated Temperature ◽  
Single Layer ◽  
Ceramic Coatings ◽  
Coated Sample ◽  
Multilayer Coatings ◽  
Relative Method ◽  
Impulse Excitation ◽  
Novel Method ◽  
Layer Coating

Although elastic modulus of ceramic coatings at elevated temperature is difficult to measure, it was evaluated in this work simply by impulse excitation tests based on the relative method that need only the measured moduli of coated sample and substrate. This novel method was demonstrated to be valid not only for the single layer coating but also for multilayer coatings.

scholarly journals Elastic Modulus of Ceramics at Elevated Temperature (Part 3)

1995 ◽  
Vol 103 (1198) ◽  
pp. 598-602 ◽  
Author(s):  
Takakazu YOSHIOKA ◽  
Ichiro TAKAHASHI
Keyword(s):  
Elastic Modulus ◽  
Elevated Temperature
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