Fatigue assessment
AssigneeBoard of Supervisors of Louisana State University and Agricultural and Mechanical College
InventorsMichael M. Khonsari, Behnam Hajshirmohamadi
Life of this patent
Estimating the term…
Abstract
Methods of evaluating mechanical fatigue using nondestructive techniques are described herein. Such techniques involve mechanically testing a component to establish a relationship between some measure of actuation and a temperature profile produced during the testing. Measurements from a separate external heating test that generates a similar temperature profile on the component may then be used to generate an estimate of a fatigue lifespan of the component by utilizing data from those tests.
Claims19
An evaluation method comprising:
- a. conducting a first cyclic mechanical test of a component thereby establishing a relationship between a measure of actuation during the first cyclic mechanical test and a first temperature profile of the component;
- b. conducting a first external heating test comprising externally heating the component generating a second temperature profile matching the first temperature profile;
- and
- c. estimating a fatigue lifespan of the component based on an observed surface temperature and an observed external heating power.
An evaluation method comprising:
- a. conducting a first cyclic mechanical test of a component thereby establishing a relationship between a measure of actuation during the first cyclic mechanical test and a first temperature profile of the component;
- b. conducting a first external heating test comprising externally heating the component generating a second temperature profile matching the first temperature profile;
- and
- c. estimating a fatigue lifespan of the component based on an observed surface temperature and an observed external heating power according to the equation:
- N
- f
- =
- FFE
-
- fT
- s
- β
-
- (
- P
- -
- P
- *
- )
- ;
- d. wherein FFE is fracture fatigue entropy;
- e. wherein f is frequency;
- f. wherein Ts is absolute surface temperature:
- g. wherein β is an experimentally determined parameter;
- h. wherein P is power consumed;
- i wherein P* is a non-damaging portion of the power consumed;
- and
- j. wherein Nf is a number of cycles to failure.
Dependencies are inferred from the claim text.