Narrow Results

Due to the error between the strain measured by the fiber grating sensor pasted on the surface of the substrate and the real strain of the substrate, the analysis of the relationship between the strain measured by the fiber and the actual strain of the substrate is the focus of this research. Since structures are subjected to various harsh conditions in actual service, such as temperature changes, fatigue, corrosion, aging, cracks and other external factors, when using surface-adhesive fiber Bragg grating (FBG) sensors for structural health monitoring, all external factors may affect the measurement accuracy of the sensors and cause measurement errors, so it is necessary to consider some specific factors in a comprehensive manner. In this paper, we theoretically study the average strain transfer rate of the three-layer strain transfer model of a surface-adhesive fiber grating sensor under the effects of temperature change and fatigue load, derive the formula for the average dynamic strain transfer rate under the combined effects of two external factors using the shear-lag method and analyze the parameters of the fiber-optic sensor to correct the error and optimize the measurement accuracy of the sensor in order to better monitor the structure under temperature change and fatigue load. The shear hysteresis method is also used to analyze the parameters of the fiber-optic sensor to correct the errors and optimize the measurement accuracy of the sensor in order to better monitor the real dynamic strain of the substrate under temperature and fatigue loads and provide theoretical guidance for its measurement.

In this research, intestinal anastomosis was compared in hand and automatic suturing. This work is based on two different experiments: The first one is the tensile test with the aim of finding the maximum breaking strength with the elongation rate of 5mm/min; and the second one is the fatigue test with a frequency of 0.2Hz and the amplitude of 16, 24 and 32mm of stretch in each phase to discover the total number of cycles to failure. For this purpose, 42 fresh bovine intestines were used; 21 specimens for the tensile and 21 for the fatigue test. These two tests were compared by two hand sewing techniques: simple continuous and ford interlocking stitches, and one automatic technique, i.e., the lock stitches. Seven samples were examined for each particular technique. The results of the tensile test indicated that the breaking strength of automatic sutured specimens is significantly greater than those of hand sutured specimens ($p=1.31\mathrm{\text{e}}-5$). That might be due to the regularity, as the suturing lines by machines are more regular than suturing by hand. In addition, results showed that automatic sutured specimens failed in greater number of cycles than hand sutured specimens in the fatigue test ($p=2.86\mathrm{\text{e}}-6$).