Study on Stress Relaxation Properties of GFRP Rebars/Bolts

2010 ◽  
Vol 168-170 ◽  
pp. 1821-1826
Author(s):  
Guo Qing Yuan ◽  
Guo Hua Dong ◽  
Jian Ma
Keyword(s):  
Stress Relaxation ◽  
Relaxation Rate ◽  
Construction Projects ◽  
Test Time ◽  
Relaxation Properties ◽  
Reinforced Plastics ◽  
Glass Fiber Reinforced ◽  
Fiber Reinforced Plastics ◽  
Superior Corrosion Resistance ◽  
Gfrp Rebars

Glass fiber reinforced plastics (GFRP) rebars / bolts are more and more being applied in construction projects with its superior corrosion resistance. To improve the economical efficiency of their application it is very significant to develop the prestressed GFRP rebars/bolts structure system. Therefore it is very valuable to probe the stress relaxation properties of GFRP rebars/bolts. With an innovation ends anchoring method for stress relaxation specimens of GFRP rebars/bolts, the stress relaxation properties has been tested in this paper. Results show that the relaxation rate of GFRP rebars/bolts increases with the initial stress increasing and with test time prolonging. It is increasing more rapidly at the beginning stage and it becomes slow after 24 hours. The relaxation law of GFRP rebars/bolts is similar to the law of CFRP and AFRP rebars/bolts. The relation between the relaxation rate and the logarithm of test time in hour follows also better linear law. The relaxation rate of GFRP rebars/bolts is bigger than CFRP ones and smaller than AFRP ones. The mechanical properties do not change obviously after 120h relaxation test.

scholarly journals The Effects of Weathering on Mechanical Properties of Glass Fiber Reinforced Plastics (Grp) Materials

1970 ◽  
Vol 1 (2) ◽  
Author(s):  
H. Abdullah ◽  
S. Al Araimi and R. A. Siddiqui
Keyword(s):  
Mechanical Properties ◽  
Relative Humidity ◽  
Ultraviolet Radiation ◽  
Glass Fiber ◽  
Exposure Time ◽  
Atmospheric Conditions ◽  
Fiber Reinforced ◽  
Reinforced Plastics ◽  
Glass Fiber Reinforced ◽  
Fiber Reinforced Plastics

Glass fiber reinforced plastics composite is extensively used as a structural material for pools, oil pipes and tanks because it has good corrosion resistance properties.  The effects of weathering on the mechanical properties of glass fiber reinforced plastics (GRP) in the Sultanate of Oman have been studied.  The tensile and three point bend specimens were exposed to outdoor conditions (open atmosphere) in sunlight and tested for various intervals of time.  It was observed that as the exposure time to sunlight, ultraviolet radiation and dust increases the mechanical properties of GRP materials decrease.  The effects of relative humidity (%RH) on the mechanical properties were also studied. It was found that as the relative humidity increased in the atmosphere during the exposure time, the tensile strength, flexural strength and modulus of elasticity are lowered. This work has revealed that the decrease in the mechanical properties of GRP under weathering conditions is subjected to atmospheric conditions such as humidity, temperature, ultraviolet radiation and pollutant.Key Words: Weathering, Glass-Fiber Reinforced Plastics, Degradation

Study on the Fabrication and Cutting Performance of HFCVD Diamond Coated Silicon Nitride Inserts

2010 ◽  
Vol 431-432 ◽  
pp. 515-518
Author(s):  
Guo Dong Yang ◽  
Bin Shen ◽  
Fang Hong Sun ◽  
Zhi Ming Zhang ◽  
Ming Chen
Keyword(s):  
Silicon Nitride ◽  
Chemical Vapor ◽  
Cutting Performance ◽  
Work Piece ◽  
X Ray Diffraction ◽  
Fine Grained ◽  
Reinforced Plastics ◽  
Glass Fiber Reinforced ◽  
Fiber Reinforced Plastics ◽  
Hot Filament

Microcrystalline diamond (MCD) and fine-grained diamond (FGD) films are deposited on silicon nitride (Si3N4) inserts using the hot filament chemical vapor deposition (HFCVD) method. Scanning electron microscope (SEM), X –ray diffraction (XRD) and Raman spectrum are employed to characterize these as-deposited diamond films. Cutting performance of as-fabricated CVD diamond coated Si3N4 inserts is examined in dry turning glass fiber reinforced plastics (GFRP) material, comparing with the uncoated Si3N4 inserts. The results indicate that the tool failure is mainly attributed to its severe flank wear, which is caused by continuous friction and impact brought by many hard SiO2 particles distributed in the GFPR work piece. The lifetime of Si3N4 inserts can be prolonged by depositing MCD or FGD films on them and the FGD coated insert shows better wear resistance than the MCD coated one.

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