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Methodology to improve design of accelerated life tests in civil engineering projects.

Lin J, Yuan Y, Zhou J, Gao J - PLoS ONE (2014)

Bottom Line: As an example, the methods are applied to the pipe in subsea pipeline.However, they can be widely used in other civil engineering industries as well.The proposed method is compared with current methods.

View Article: PubMed Central - PubMed

Affiliation: Department of Construction Management, Dalian University of Technology, Dalian, China.

ABSTRACT
For reliability testing an Energy Expansion Tree (EET) and a companion Energy Function Model (EFM) are proposed and described in this paper. Different from conventional approaches, the EET provides a more comprehensive and objective way to systematically identify external energy factors affecting reliability. The EFM introduces energy loss into a traditional Function Model to identify internal energy sources affecting reliability. The combination creates a sound way to enumerate the energies to which a system may be exposed during its lifetime. We input these energies into planning an accelerated life test, a Multi Environment Over Stress Test. The test objective is to discover weak links and interactions among the system and the energies to which it is exposed, and design them out. As an example, the methods are applied to the pipe in subsea pipeline. However, they can be widely used in other civil engineering industries as well. The proposed method is compared with current methods.

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Related in: MedlinePlus

Energy Expansion Tree as applied to piping in a subsea pipeline.Boxes with bold font represent the energies to be fed into MEOST. Boxes with various shaded backgrounds and borders are used to distinguish the corresponding branch development underneath it. Numbers to the right of bolded boxes are used for linking the energies into the subsequent MEOST table.
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pone-0103937-g003: Energy Expansion Tree as applied to piping in a subsea pipeline.Boxes with bold font represent the energies to be fed into MEOST. Boxes with various shaded backgrounds and borders are used to distinguish the corresponding branch development underneath it. Numbers to the right of bolded boxes are used for linking the energies into the subsequent MEOST table.

Mentions: Following the above principles, we develop the Expansion Tree for energies related to the piping in a subsea pipeline as shown in Fig. 3. The nomenclature, “Energy Expansion Tree” (EET) is chosen because this logic tree is concerned solely with energy, regardless of the reliability regime. Three general categories are identified which cover all the energy sources related to a subsea pipeline: (a) “External energy sources” outside the system (the environment), (b) “Operational energy” for energies employed in and used by the system itself, and (c) “Internal-External Differences” resulting from the 2nd law of thermodynamics which gives rise to equilibration forces whenever two regions of space have different energy levels. The external and internal-external difference branches are split into sublevels using the “basis of split” shown in the leftmost column according to expansion tree principles, while the internal (operational) branch is derived below from a newly proposed energy function model. The reason different approaches are needed is that external to the system the environment is unstructured, while the system itself is designed with very specific laws of physics in mind in order to achieve the system primary functions. The later can be enumerated by design; the former cannot.


Methodology to improve design of accelerated life tests in civil engineering projects.

Lin J, Yuan Y, Zhou J, Gao J - PLoS ONE (2014)

Energy Expansion Tree as applied to piping in a subsea pipeline.Boxes with bold font represent the energies to be fed into MEOST. Boxes with various shaded backgrounds and borders are used to distinguish the corresponding branch development underneath it. Numbers to the right of bolded boxes are used for linking the energies into the subsequent MEOST table.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4128810&req=5

pone-0103937-g003: Energy Expansion Tree as applied to piping in a subsea pipeline.Boxes with bold font represent the energies to be fed into MEOST. Boxes with various shaded backgrounds and borders are used to distinguish the corresponding branch development underneath it. Numbers to the right of bolded boxes are used for linking the energies into the subsequent MEOST table.
Mentions: Following the above principles, we develop the Expansion Tree for energies related to the piping in a subsea pipeline as shown in Fig. 3. The nomenclature, “Energy Expansion Tree” (EET) is chosen because this logic tree is concerned solely with energy, regardless of the reliability regime. Three general categories are identified which cover all the energy sources related to a subsea pipeline: (a) “External energy sources” outside the system (the environment), (b) “Operational energy” for energies employed in and used by the system itself, and (c) “Internal-External Differences” resulting from the 2nd law of thermodynamics which gives rise to equilibration forces whenever two regions of space have different energy levels. The external and internal-external difference branches are split into sublevels using the “basis of split” shown in the leftmost column according to expansion tree principles, while the internal (operational) branch is derived below from a newly proposed energy function model. The reason different approaches are needed is that external to the system the environment is unstructured, while the system itself is designed with very specific laws of physics in mind in order to achieve the system primary functions. The later can be enumerated by design; the former cannot.

Bottom Line: As an example, the methods are applied to the pipe in subsea pipeline.However, they can be widely used in other civil engineering industries as well.The proposed method is compared with current methods.

View Article: PubMed Central - PubMed

Affiliation: Department of Construction Management, Dalian University of Technology, Dalian, China.

ABSTRACT
For reliability testing an Energy Expansion Tree (EET) and a companion Energy Function Model (EFM) are proposed and described in this paper. Different from conventional approaches, the EET provides a more comprehensive and objective way to systematically identify external energy factors affecting reliability. The EFM introduces energy loss into a traditional Function Model to identify internal energy sources affecting reliability. The combination creates a sound way to enumerate the energies to which a system may be exposed during its lifetime. We input these energies into planning an accelerated life test, a Multi Environment Over Stress Test. The test objective is to discover weak links and interactions among the system and the energies to which it is exposed, and design them out. As an example, the methods are applied to the pipe in subsea pipeline. However, they can be widely used in other civil engineering industries as well. The proposed method is compared with current methods.

Show MeSH
Related in: MedlinePlus