A Comparative Study of the Seismic Performances and Failure Mechanisms of Slopes Using Dynamic Centrifuge Modeling

During service, TBC can suffer degradation by CMAS, FOD, erosion or spallation. Whereas the first three are due to foreign particles, the last one is related to thermal cycling. When subjected to high temperature exposures followed by rapid coolings under oxidizing conditions, a TBC system undergoes morphological changes and stress development. This will initiate cracks which propagate and finally lead to failure by spallation. Consequently, the aim of the present study is to understand better the mechanisms responsible for such spallation events. Two kinds of TBC systems with different bond coatings (NiCoCrAlYTa or Pt-modified nickel aluminide bond coatings) are thermally cycled. Subsequently, SEM investigations on TBC systems after spallation concentrate on failure path, defect, morphological and microstructural changes to propose way for improving TBC system lifetime.

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Comparative study of fiber reinforced PP composites: Effect of fiber type, coupling and failure mechanisms

Composites Part A Applied Science and Manufacturing ◽

10.1016/j.compositesa.2020.105895 ◽

2020 ◽

Vol 133 ◽

pp. 105895 ◽

Cited By ~ 4

Author(s):

R. Várdai ◽

T. Lummerstorfer ◽

C. Pretschuh ◽

M. Jerabek ◽

M. Gahleitner ◽

...

Keyword(s):

Comparative Study ◽

Fiber Type ◽

Failure Mechanisms ◽

Fiber Reinforced ◽

Type Coupling ◽

Pp Composites

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Plausible failure mechanisms of wildlife-damaged earth levees: insights from centrifuge modeling and numerical analysis

Canadian Geotechnical Journal ◽

10.1139/cgj-2016-0484 ◽

2017 ◽

Vol 54 (10) ◽

pp. 1496-1508 ◽

Cited By ~ 5

Author(s):

Gholamreza Saghaee ◽

Ahmad A. Mousa ◽

Mohamed A. Meguid

Keyword(s):

Pore Pressure ◽

Failure Mechanisms ◽

Hydraulic Gradient ◽

The Body ◽

Centrifuge Modeling ◽

Silty Sand ◽

Failure Patterns ◽

Animal Burrows ◽

Wide Range ◽

The Impact

Earth levees are subject to a wide range of wildlife intrusion patterns that cause mass removal and subsequent serious deformations. Such invasive activities leave the body of an earth embankment with burrow systems too complex to map and model using conventional techniques. This study investigates the impact of different idealized configurations of animal burrows on the geotechnical performance of levees. For this purpose, centrifuge testing was conducted on homogenous scaled-down 1 horizontal : 1 vertical (1H:1V) levee models built from silty sand material. Modeling involved introducing horizontal cylinder-shaped waterside and landside burrows at different elevations within the levee section. The reference (intact) and deteriorated levee models were subject to a centrifugal acceleration of 35g, which was kept constant as the water level behind the levee model was gradually increased. The deformation profile of the model was tracked, and the crest displacements were concurrently measured. Miniature pore pressure transducers (PPTs) embedded within the levee body provided pore pressure measurements. A three-dimensional finite element model was developed to investigate the hydraulic performance and verify the failure patterns of the deteriorated levees. Compared with an intact levee, the presence of animal intrusions was found to increase the exit hydraulic gradient for both waterside and landside intrusions. Lower animal burrows appeared to cause larger exit gradients than higher ones. Similarly, waterside burrows exhibited a notably higher pore pressure and larger hydraulic gradient. Waterside damage resulted in a quicker and more violent failure than landside burrows. The failure mechanisms for both the waterside and landside burrows are dissimilar despite their similarly abrupt nature.

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