Strain monitoring

BE-1432 Fibre optic strain monitoring at elevated temperatures RoH Ouatavaaon Vattenfall AB... 

Worldwide Streptococcus pneumoniae % susceptibility to penicillin is decreasing. In some countries up to two-thirds of the clinical isolates have reduced susceptibility to penicillin or are highly resistant to this drug. Moreover, the rate of resistance to other drugs commonly used for RTI including erythromycin, tetracycline and trimethoprim-sulfamethoxazole is higher in penicillin-resistant than penicillin-susceptible strains. Monitoring local or hospital resistance patterns of pneumococci is, therefore, needed. 

For example, a delamination in a composite layup produces strain distribution in the surroimding area that is substantially different from that in a pristine zone [20]. Strain monitoring can be done with conventional electrical resistance strain gauges or with fiber optics. The latter offer the capability of having several measuring locations that can be individually addressed on the same fiber. Kesavan et al. [20] used conventional strain gauges to monitor delaminalion in a composite T-joint. The strain gauges were placed on the outside of the joint in zones deemed sensitive to strain redistribution due to delaminations. 

Key words fibre optic sensors (FOS), strain monitoring, damage detection, textiles. 

Figure 12. The strain monitoring of main arch ring.

For the measurement of tensile properties, dumb-bell specimens of the form shown in Fig. 2.13 are suggested. Tensile modulus. Poisson s ratio and elongation at failure may be measured with appropriate strain monitoring equipment and a set of stress/strain curves for a typical range of epoxies is given in Fig. 2.14. Similar... 

Tensile strength. The tensile strength of the hardened adhesive at 20 °C should be at least 12 MN m -. A dumb-bell specimen of dimensions according to BS 2782 Part 3 (5) (methods 320 B/C) and having a cross-section of 10 mm x 3 mm is recommended (see Fig. A.4) (3). The specimens should be east in polytetrafluoroethyl-ene-lined moulds. Adhesive ductility may also be measured with appropriate strain monitoring equipment. 

The safety of ship lock is related to the people s life and property in the downstream, so that the ship lock structure health monitoring is a critical issue to avoid its damages. The stress state of ship lock structure is dependent on its type and structural complexity. In addition, the temperature and construction methods have a great influence on the structural quality. Thus, strengthening the structural temperature and stress-strain monitoring during the construction plays a significant role to ensure the construction quality of the ship lock. 

Figure 6. Strain monitoring results of the slope mass under 12.5 kPa local loading.

In order to explore the relationship between strain monitoring data with the slope stability condition, the averaged maximum horizontal strain is introduced here, which is defined as... 

The model test study verifies the capability of the fiber optic sensing network to monitor the stability of slope with high accuracy. The distributed strain monitoring results may indicate the location of the potential slip surface in the slope. 

Johnson, T.M., Fullwood, D.T., Hansen, G., 2012. Strain monitoring of carbon fiber composite via embedded nickel nano-particles. Composites Part B Engineering 43 (3), 1155—1163. 

Papantoniou A, Rigas G, Alexopoulos ND. Comp. Stmct. 2011, 93, 2163-2172. Assessment of the strain monitoring reliability of fiber Bragg grating sensor (FBGs) in advanced composite stmctures. 

Lau K T, Chan C C, Zhou L M and Jin W (2001a), Strain monitoring in composite-strengthened concrete structures using optical fibre sensors . Compos Part B - Eng, 32(1), 33-45. 

Figure 6.6 Relaxation of the elastic strain generated in a poly(ethyl acrylate) film observed by a Mach-Zehnder interferometer at 25 °C. y the mean cross-link density dashed curve with open symbols the elastic strain observed during irradiation solid curves with closed symbols elastic strain monitored after stopping irradiation [45].

Meissner J, Nowak W, Slowik V et al., Strain monitoring at a prestressed concrete bridge . In Proc. 12th Int. Conf. Optical Fiber Sensors, Williamsburg, 48-51,1997. 

Zhao, X., et al. Strain monitoring in glass fiber reinforced composites embedded with carbon... 

Figure 18.25 Demonstration of remote strain sensing, using the sUicone-based integrated wireless strain sensor a) Wireless strain monitoring in an anechoic chamber, b) Remote strain sensing in ordinary office environment. The subplot shows the real-time recorded data at the PC-assisted RF receiver 5 m away.

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