Specimen type and size effects on lithium hydride tensile strength distributions
Weibull's two-parameter statistical-distribution function is used to account for the effects of specimen size and loading differences on strength distributions of lithium hydride. Three distinctly differing uniaxial specimen types (i.e., an elliptical-transition pure tensile specimen, an internally pressurized ring tensile, and two sizes of four-point-flexure specimens) are shown to provide different strength distributions as expected, because of their differing sizes and modes of loading. After separation of strengths into volumetric- and surface-initiated failure distributions, the Weibull characteristic strength parameters for the higher-strength tests associated with internal fracture initiations are shown to vary as predicted by the effective specimen volume Weibull relationship. Lower-strength results correlate with the effective area to much lesser degree, probably because of the limited number of surface-related failures and the different machining methods used to prepare the specimen. The strength distribution from the fourth specimen type, the predominantly equibiaxially stressed disk-flexure specimen, is well below that predicted by the two-parameter Weibull-derived effective volume or surface area relations. The two-parameter Weibull model cannot account for the increased failure probability associated with multiaxial stress fields. Derivations of effective volume and area relationships for those specimens for which none were found in the literature, the elliptical-transition tensile, the ring tensile, and the disk flexure (including the outer region), are also included.
- Research Organization:
- Oak Ridge Y-12 Plant (Y-12), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OS21400
- OSTI ID:
- 5930848
- Report Number(s):
- Y-2440; ON: DE92008200
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
42 ENGINEERING
LITHIUM HYDRIDES
TENSILE PROPERTIES
BRITTLENESS
FRACTURES
GRAIN SIZE
SIZE
ALKALI METAL COMPOUNDS
CRYSTAL STRUCTURE
FAILURES
HYDRIDES
HYDROGEN COMPOUNDS
LITHIUM COMPOUNDS
MECHANICAL PROPERTIES
MICROSTRUCTURE
360203* - Ceramics
Cermets
& Refractories- Mechanical Properties
420500 - Engineering- Materials Testing