Experimental and theoretical studies of smart composite structures.

摘要

The experimental aspect of this research includes embedding Fabry Perot sensors in glass fiber reinforced polymer (FRP) tendons during pultrusion. The smart FRP tendons are then used as reinforcements in civil engineering applications wherein they would act as concrete reinforcements, replacing steel. A comprehensive testing program is carried out for the laboratory designed concrete beams which included thermal exposure (during and after concrete curing phases), static loading and cyclic loading. The study shows that the response, in terms of internal mechanical strain, against applied mechanical and structural loads up to the failure of the concrete beams can be steadily obtained using embedded smart GFRP rebars. It is observed that the results obtained using Fabry Perot sensors are accurate. The last section of the experimental part of this thesis discusses issues related to the application of piezoelectric ceramic fibers and ribbons for strain monitoring in smart composite structures.; The second part of this thesis includes the application of asymptotic homogenization methodology to analyze smart composite plates with rapidly varying thickness and a periodic array of embedded actuators. It is shown that the original problem for the regularly non-homogeneous smart composite structures reduces to a system of simpler types of so-called unit-cell problems. These unit cell problems are used to calculate the effective elastic, piezoelectric, hygroscopic expansion, and thermal expansion coefficients for (a) three-layered shell with honeycomb filler and (b) ribbed shell with T-shaped ribs. As well (a) rib-reinforced plate and (b) wafer-reinforced plate are also considered. In the last section of this part of the thesis the effective elastic, piezoelectric, hygroscopic expansion, and thermal expansion coefficients for the four smart structures mentioned above are calculated and compared. (Abstract shortened by UMI.)