Detecting fatigue from magnetic characteristics
AssigneeTanaka Systems Incorporated
InventorKiyoshi Inoue
Life of this patent
Estimating the term…
Abstract
Fatigue in a magnetically sensitive detector element (20, 172) can be evaluated using the expression H∞ log(N). Employing this method, measuring changes in magnetization of the detector element (20, 172) permit predicting fatigue with many practical applications.
Claims13
A method for assessing fatigue in a basic material being subjected to external stresses and strain using a magnetically permeable detector element, said method comprising the steps of:
- attaching at least a portion of said detector element to any basic material while the basic material and said detector element are subjected to external stress or strain;
- and
- for assessing fatigue in said basic material, analyzing, using a digital computer, changes in magnetic characteristics of said detector element due to internal change in magnetic domain and crystal deformation thereof caused by said external stress or strain.
A method for detecting fatigue in a magnetically permeable machining workpiece being subjected to external stresses and strain, said method comprising:
- positioning adjacent to the machining workpiece a movable magnetic sensing means adapted for magnetically scanning the machining contour of the machining workpiece;
- and
- for assessing fatigue in the machining workpiece, analyzing, using a digital computer, changes in magnetic characteristics of the machining workpiece due to domain and crystal deformation thereof caused by said external stress or strain.
A machine-tool fatigue detections apparatus comprising:
- a magnetically permeable machining tool adapted for being moved during machining of a workpiece, which movement during machining subjects said tool to external stressing and strain, before commencing machining said tool being conditioned magnetically for detecting fatigue;
- and
- sensing means adapted for and positioned for measuring changes in magnetic characteristics of the moving tool whereby tool fatigue is evaluated from measured changes in tool magnetization.
Dependencies are inferred from the claim text.