Effect of stress frequency on fatigue crack propagation in Titanium
The effect of stress frequency on the fatigue crack propagation rate in 99.5 percent pure titanium, which has a strong strain rate dependency in the plastic region, was studied. Fatigue crack propagation tests were carried out under three stress frequencies (0.02Hz, 0.2Hz, 20Hz). An elasto/visco-plastic analysis of fatigue crack propagation was performed by the finite element method (FEM), and an analysis of the dependency of crack propagation rate on frequency and strain behavior at the crack tip. It was found from the experiments that the crack propagation rate, dl/dN, was approximately in inverse proportion to f'' (ngreater than or equal toO), where f is the frequency. A parameter closely related to the fatigue crack growth rate is the strain range, ..delta..EPSILON /SUB y/ , or visco-plastic strain range, ..delta..EPSILON /SUB y/ /SUP up/ at the crack tip. The effect of stress frequency on the fatigue crack propagation rate may be explained by variations of ..delta..EPSILON /SUB y/ or ..delta..EPSILON /SUB y/ /SUP up/ based on the strain rate dependency of the material.
- Research Organization:
- Department of Mechanical Engineering, Kumamoto University, Kurokami, Kumamoto 860
- OSTI ID:
- 5994889
- Journal Information:
- J. Eng. Mater. Technol.; (United States), Journal Name: J. Eng. Mater. Technol.; (United States) Vol. 104:4; ISSN JEMTA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360103* -- Metals & Alloys-- Mechanical Properties
CRACK PROPAGATION
DATA
ELEMENTS
EXPERIMENTAL DATA
FATIGUE
FREQUENCY DEPENDENCE
INFORMATION
MATERIALS TESTING
MECHANICAL PROPERTIES
MECHANICAL TESTS
METALS
NUMERICAL DATA
PARAMETRIC ANALYSIS
STRAINS
STRESSES
TESTING
TITANIUM
TRANSITION ELEMENTS