Fatigue life prediction method based on CT test piece
A technology for fatigue life prediction and fatigue life, which is applied in measuring devices, using stable tension/pressure to test the strength of materials, and conducting material analysis through optical means, etc. question
Active Publication Date: 2021-01-05
NORTHWESTERN POLYTECHNICAL UNIV
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Problems solved by technology
However, the small crack stage takes a long time (generally 40-80% of the total fatigue life), and the growth rate and mechanism of the small crack stage are not different from those of the large crack stage, so there is no uniform and applicable formula
Therefore, it is not accurate to calculate the fatigue life of the small crack stage by integrating the crack growth rate in the small crack stage up and down.
[0004] At present, the fatigue life in the stage of small cracks is usually calculated by combining the test data and empirical formula, or obtained by subtracting the life in the stage of large cracks from the total life. Not only the calculation process is cumbersome, but also the calculation accuracy is not high enough
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[0060] Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided in order to give a thorough understanding of embodiments of the present disclosure.
[0061] The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided in order to give a thorough understanding of embodiments of the present disclosure. However, on...
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The invention relates to the technical field of fatigue life prediction, in particular to a fatigue life prediction method based on a CT test piece. The fatigue life prediction method comprises the following steps: deriving a critical crack length of a CT test piece by utilizing fracture toughness and a Kmax-a curve of the CT test piece; performing a fatigue test on the CT test piece to determinea curve and an equivalent initial crack length of the CT test piece; calculating correction parameters of the crack length in the CT test piece in combination with the Kmax-a curve and the crack tip plastic region size of the CT test piece; correcting the critical crack length, the equivalent initial crack length and the slope of the curve by using the correction parameters to obtain a critical crack correction length, an equivalent initial crack correction length and a correction slope of the curve of the CT test piece; and predicting the fatigue life of the CT test piece by combining the critical crack correction length, the equivalent initial crack correction length and the correction slope. The fatigue life prediction method is simple in calculation process and high in calculation precision.
Description
technical field [0001] The present disclosure relates to the technical field of fatigue life prediction, in particular to a fatigue life prediction method based on a CT specimen. Background technique [0002] Fatigue damage is a form of damage to engineering structures under cyclic / alternating loads, because fatigue damage needs to go through three stages, namely: initial crack initiation stage (small crack stage), crack stable growth stage (large crack stage) And crack instability fracture stage, correspondingly, the total fatigue life of the engineering structure is composed of the fatigue life of the above three stages. [0003] The prediction of fatigue life mainly considers the stage of large cracks, and integrates the upper and lower limits of crack growth through the fatigue crack growth model. However, the small crack stage takes a long time (generally 40-80% of the total fatigue life), and the growth rate and mechanism of the small crack stage are not different fro...
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Patent Timeline
Login to View More IPC IPC(8): G01N3/08G01N21/84
CPCG01N3/08G01N21/84G01N2203/0062G01N2203/0066G01N2203/0073G01N2203/0212G01N2203/0647G01N2203/0682
Inventor 温志勋李飞刘双博梁晨宵李萌岳珠峰
Owner NORTHWESTERN POLYTECHNICAL UNIV