Fibre-reinforced plastics. Determination of fatigue properties under cyclic loading conditions

For investigating the twinning and detwinning behaviour under cyclic loading conditions in-situ stress measurements with different applied strain amplitudes were performed at the beamline 7T-MPW at BESSY II. Intensity measurements of the (10-10), (11-20) and (0002) reflections served for the determination of the twinned volume fraction. The measurements of the (hkil) dependent strains and stresses gave information on the load partitioning between different grain orientations. The intensity measurements performed in the compression regime showed that the evolution of the (0002) reflection intensity depends on the strain amplitude. For strain amplitudes ≥ 0.75 % an increase in intensity is observed whereas for smaller strain amplitudes the (0002) intensity decreases with increasing cycle numbers. In the tensile regime an increase in the (0002) reflection intensity is found for the whole range of applied strain amplitudes.

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Determination of the Cyclic Properties of Silty Sands

Advances in Civil and Industrial Engineering - Handbook of Research on Trends and Digital Advances in Engineering Geology ◽

10.4018/978-1-5225-2709-1.ch012 ◽

2018 ◽

pp. 416-445

Author(s):

Eyyüb Karakan ◽

Selim Altun

Keyword(s):

Cyclic Loading ◽

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Triaxial Tests ◽

Loading Conditions ◽

Systematic Testing ◽

Geotechnical Problems ◽

Insight Into

Liquefaction may be triggered by cyclic loading on saturated silty sands, which is responsible of severe geotechnical problems. Development of excess pore water pressure in soil results in a liquid-like behavior and may be the reason of unavoidable superstructural damage. In this study, in order to investigate the behavior of saturated silty sands exposed to cyclic loading under undrained conditions, a systematic testing program of stress-controlled cyclic triaxial tests was performed on specimens of different silt contents, under different loading conditions and environment. The effect of parameters such as silt content on the liquefaction behavior of specimens was studied. Pore water pressure and shear strain curves were obtained for the silty sands. Furthermore, the boundaries existing in the literature on sands are compared with the results current research, on silty sands. Conclusively, the outcomes of this study were useful to develop insight into the behavior of clean and silty sands under seismic loading conditions.

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