Type II and burst methods for ultrashort laser direct fabrication of high-strength Bragg grating waveguides inside bulk glasses: a comparison

An experimental investigation on square and circular high-strength concrete short columns confined with aramid fiber-reinforced polymer (AFRP) sheets was conducted in this study. Fiber Bragg grating sensors have been applied successfully in monitoring of the strains of the AFRP-confined square and circular concrete columns. The experimental results demonstrate that two types of axial force-strain curves were observed depending on the form of the column. Results show fiber Bragg grating sensors have good repeatability and the ultimate load of the circular concrete column is larger than that of the square concrete column. The interlaminar strains of AFRP and high-strength concrete have also been attained. It helps to analyze the constraint effect of the concrete column and compute the ultimate load of the square and circular concrete column.

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Metallurgical transformations of high strength low alloys steels 450 EMZ type II in the heat affected zone during multipass submerged arc welding

Revista de Metalurgia ◽

10.3989/revmetalm.2006.v42.i4.25 ◽

2006 ◽

Vol 42 (4) ◽

Author(s):

R. González-Palma ◽

J. C. Suárez-Bermejo ◽

F. J. Vicario ◽

A. Muñoz

Keyword(s):

Heat Affected Zone ◽

Arc Welding ◽

High Strength ◽

Submerged Arc Welding ◽

Type Ii ◽

Submerged Arc

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High Strain Monitoring during Fatigue Loading of Thermoplastic Composites Using Imbedded Draw Tower Fibre Bragg Grating Sensors

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.56.441 ◽

2008 ◽

Vol 56 ◽

pp. 441-446 ◽

Cited By ~ 1

Author(s):

Eli Voet ◽

Geert Luyckx ◽

Ives De Baere ◽

Joris Degrieck ◽

J. Vlekken ◽

...

Keyword(s):

Composite Laminates ◽

High Strength ◽

Fatigue Loading ◽

Strain Sensors ◽

Thermoplastic Composites ◽

Bragg Grating ◽

Fibre Bragg Grating ◽

Strain Measurements ◽

Strain Monitoring

This paper presents the experimental study of fibre Bragg grating sensors for measuring strain inside composite laminates during fatigue loading. The optical fibres are imbedded inside thermoplastic CFRP test-coupons which have an ultimate strain of about 1.1%. Tension – tension fatigue cycling at a rate of 5Hz is been carried out at 314MPa with a maximum strain of 0.51%. At such extreme strain levels the use of high strength sensors becomes inevitable. Neither the sensor nor the composite test-coupons showed any significant degradation even after more than 500000 cycles. Fibre optic Bragg grating sensors are known to be very accurate strain sensors but one should be very careful interpreting their response once they are imbedded inside composite materials. In this study high strength fibre Bragg grating sensors with coating are imbedded in composite test coupons and a pretty good correlation was found between the strain measurements of an electrical extensometer and the imbedded sensor during the complete cycling. The high strength sensor show to be very feasible for extreme and long term strain measurements.

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