Measuring and testing – Specimen stress or strain – or testing by stress or strain... – Specified electrical sensor or system
Patent
1992-12-09
1994-10-18
Raevis, Robert
Measuring and testing
Specimen stress or strain, or testing by stress or strain...
Specified electrical sensor or system
73787, G01B 716
Patent
active
053557344
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a gauge for predicting a useful life of a structure subjected to a varying load, such as a frame of a constructional large size dump truck and so forth.
BACKGROUND OF THE INVENTION
A constructional large size dump track is formed by mounting a frame on front and further rear wheels and defines a driver's compartment and a vessel for transporting earth, sand or so forth. The frame is subject bending load and a torsional load to possibly cause breakage due to fatigue.
On the other hand, the bending and torsional loads acting on the frame can be significantly differentiated depending upon load weight on the vessel, road surface condition, vehicle speed and so forth. Therefore, it is practically not possible to predict the timing for breakage by fatigue, i.e. a useful life of the frame.
Therefore, in the prior art, a strain gauge is fitted on the frame for measuring a distortion of the strain gauge as an actual strain by means of a measuring equipment during operation for a long period. Based on the measured value, fatigue damage of the frame is calculated through a cumbersome calculation, such as by frequency processing and so forth to predict the useful life.
In such method of for predicting the useful life, of a member it becomes necessary to perform a cumbersome calculation, such as frequency processing and so forth, on the basis of the measured values. Also, only data, representative of an operational condition while the measurement is performed by means of the measuring equipment, can be obtained.
SUMMARY OF THE INVENTION
In view of the problems set forth above, it is an object of the present invention to provide a novel gauge for predicting a life of a structure which facilitates prediction of the life of the structure without requiring a cumbersome calculation as required in the prior art, and to provide a method for predicting the life employing the same.
In order to accomplish the above-mentioned objects, there is provided, in accordance with the first aspect of the invention, a gauge for predicting a life of a structure comprising a gauge main body of thin plate form having annular ring portions of substantially the same configuration at both ends and a strip-like connecting portion integrally connecting the annular ring portions and formed with V-shaped cut-outs at an intermediate portion in opposition to each other, the gauge main body having a shorter life than the life of the structure to be predicted and a crack gauge fitted between the mutually opposing cut-outs.
Also, in order to accomplish the above-mentioned object, there is provided, in accordance with the present invention, a method for predicting a life of a structure comprising the steps of rigidly fixing a gauge as defined to a predetermined portion of the structure, obtaining a breaking period of the gauge on the basis of a variation of a resistance, and predicting a life of the structure on the basis of the breaking period thus obtained.
As set forth above, according to the present invention, since the life of the structure can be predicted by mounting the gauge having a shorter fatigue life than the structure on the structure, by detecting the cracking condition of this gauge based on a variation of the resistance of the crack gauge and thus deriving a breaking period, the life of the structure can be easily predicted without requiring cumbersome calculations as required in the prior art.
The above-mentioned and other objects, aspects and advantages of the present invention will become clear to those skilled in the art from the discussion described and illustrated in connection with the accompanying drawings which illustrate preferred embodiments meeting with the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic side elevation showing a gauge for predicting a life according to the present invention mounted on a structure, a life of which is to be predicted;
FIG. 2 is a plan view of a main body of the gauge;
FIG. 3 is a front elevatio
REFERENCES:
patent: 2920480 (1960-01-01), Haas
patent: 3136154 (1964-06-01), Christensen
patent: 3272003 (1966-09-01), Harting
patent: 3602041 (1971-08-01), Weinert
patent: 3786679 (1974-01-01), Crites
patent: 3979949 (1976-09-01), Smith
Kabushiki Kaisha Komatsu Seisakusho
Kananen Ronald P.
Raevis Robert
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