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US 7,623,974 B2Granted
System and method for detecting onset of structural failure
AssigneePratt & Whitney Rocketdyne, Inc.
InventorDale O. Cipra
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AssigneePratt & Whitney Rocketdyne, Inc.
InventorDale O. Cipra
Estimating the term…
A system for detecting the onset of structural failure in a structural element subject to a mechanical load comprises a metering array, a signal processor, and an output processor. The metering array measures physical quantities associated with the structural element. The signal processor transforms the measured physical quantities into a series of sample mode spectra, and the output processor generates output as a function of the series of sample mode spectra. Methods are also disclosed for detecting the onset of failure in a structural element subject to a mechanical load, for structural testing, and for structural health monitoring.
A system for detecting onset of structural failure in a structural element subject to a mechanical load, the system comprising:
A method for detecting onset of structural failure in a structural element subject to a mechanical load, the method comprising:
A method for structural testing of a structural element subject to a mechanical load, the method comprising:
A method for structural health monitoring, the method comprising:
Dependencies are inferred from the claim text.
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Investigating strength properties of solid materials by application of mechanical stress: by applying repeated or pulsating forces
Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings: of elongated objects, e.g. pipes, masts, towers or railways
Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings: by determining damage, crack or wear
By applying repeated or pulsating forces: generated by mechanical means, e.g. hammer blows
About 6 months of term left · ends 20 Apr 2027 (estimated)
The present invention relates generally to structural testing and structural monitoring, and in particular to detecting the onset of structural failure by analysis of sample oscillation mode spectra.
Structural failure can be unpredictable and catastrophic, posing both financial risk and a threat to personal and public safety. Traditional destructive testing techniques are effective at determining a failure threshold, but cannot generally detect the onset of failure before it occurs. As a result, safety margins must be determined a priori or by trial and error.
This presents a significant problem for non-destructive testing, in which unanticipated structural failure can result in both economic loss and safety hazards. Post-testing failures (i.e., during construction or use) may be even more serious, but are even more difficult to predict.
FIG. 1 is a perspective view of a vertical cantilevered beam subject to a compressive load.
FIG. 2 is a plot of natural oscillation frequency as a function of cantilever length, neglecting the effect of load on frequency.
FIG. 3 is an enlarged view of FIG. 2, showing the effect of load on frequency near critical length.
FIG. 1 is a perspective view of vertical cantilevered beam 11 subject to compressive load 12. FIG. 1 shows cantilevered beam 11 of length L with transverse dimensions h and w, loading mass 12 with mass m, and immobile base 13. Beam 11 is vertically oriented, with lower end of beam 14 affixed to base 13 and upper end of beam 15 affixed to loading mass 12. Beam 11 has small mass as compared to mass m of loading mass 12, and loading mass 12 has small dimensions as compared to length L of beam 11.
In this arrangement, loading mass 12 and upper end 15 of beam 11 are susceptible to small-amplitude oscillations generally contained in a horizontal plane parallel to base 13. Arrows 16 indicate one possible sense of this oscillation, which is spring-like with natural frequency f determined by effective spring constant k and mass m:
f = 1 2 π k m . ( 1 )