Fatigue Life Progression Characterization
AssigneeBoard of Supervisors of Louisiana State University and Agricultural and Mechanical College
InventorsMichael Khonsari, Ali Mahmoudi
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Abstract
Methods of evaluating mechanical damage are disclosed relating to fatigue life progression that include the evaluation of temperature differentials against stress dependent damage parameters for mechanical objects. Evaluation of the remaining useful life of such mechanical objects may be conducted by comparing a stabilized stressed temperature to a reference temperature for the mechanical object. The methods may be used to determine remaining useful life without benefit of a prior fatigue history.
Claims11
A method of evaluating mechanical damage comprising:
- a. applying a repeated stress having a stress magnitude to a mechanical object until the repeated stress results in a stabilized stressed temperature in a region of greatest temperature elevation within the mechanical object caused by the repeated stress at a time;
- b. measuring the stabilized stressed temperature at the time;
- c. measuring a reference temperature associated with the time;
- d. calculating a temperature differential associated with the time from the stabilized stressed temperature and the reference temperature associated with the time;
- e. calculating a fatigue life progression characterization utilizing the temperature differential associated with the time and two or more stress dependent damage parameters for the mechanical object;
- f. wherein the measuring of the stabilized stressed temperature is under a set of prevailing conditions;
- g. wherein the stabilized stressed temperature is a non-accelerating temperature;
- h. wherein the reference temperature is associated with the mechanical object and representative of a stabilized unstressed temperature of the mechanical object within the region of greatest temperature elevation under an equivalent resting condition.
A machine for evaluating damage comprising:
- a. a first temperature measurement device attached to a region of greatest temperature elevation on a mechanical object;
- b. a second temperature measurement device attached at a location remote from the region of greatest temperature elevation;
- c. a data acquisition system capable of receiving an input representative of the stress magnitude;
- d. a data storage component storing stress dependent damage parameters for the mechanical object;
- e. a processing system capable of identifying a stabilized stressed temperature from data obtained from the first temperature measurement device and data obtained from the second temperature measurement device;
- f. wherein the processing system is arranged and configured to evaluate and communicate a fatigue life progression characterization.
Dependencies are inferred from the claim text.