| Summary: | 碩士 === 建國科技大學 === 自動化工程系暨機電光系統研究所 === 96 === Abstract
The working stress analysis use finite element method or finite difference method to estimate the external deformation and the distribution of internal stress and/or strain of MSEW. The stress-strain curve for a geogrid material is nonlinear. In order to use working stress analysis reasonably, the stiffness of geogrid material at different strain level should be established. In this study, a series of monotonic and cyclic tensile loading tests are carried out using PET geogrid. Equipped with servomotor and highly resolution measurement system, the monotonic loading of geogrid is measured from axial strain = 0.01% to 10%. Cyclic tests are also performed at different strain level to understand the variation of stiffness and damping ratio. It is shown that the stiffness increased while the damping ratio decreased with increasing cyclic strain at higher strain level (ε= 3 and 5%). The increased damping ratio curve is not observed while stiffness curve increased atε= 1%.
Keywords: geogrid, small strain, fully stress-strain curve, stiffness, damping ratio.
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