Author: Sherman A. Clevenson
Publisher:
ISBN:
Category : Aluminum alloys
Languages : en
Pages : 36
Book Description
Each of a number of aluminum-alloy test specimens was loaded by random forces at a constant root-mean-square stress level until rupture occurred. The forces were statistically stationary and Gaussian with a zero mean value. The fatigue life (to rupture) was determined for various values of the following statistical parameters: (a) root-mean-square nominal applied stress, (b) power spectral shape, (c) mean number of zero crossings per unit time, and (d) mean number of peak loads per unit time. The power spectra were varied over a passband of frequency for three spectral shapes either by holding the power constant with frequency or by varying it either directly or inversely proportional to the square of the frequency. The results indicate that the fatigue life was determined principally by the root-mean-square nominal applied stress level. The effects of spectral shape, average number of zero crossings, and average number of peak loads were insignificant in the ranges investigated. The fatigue life, based on the number of effective cycles, of the specimens under random loading was lower by at least an order of magnitude at all stress levels than that of the specimens loaded sinusoidally. A linear cumulative damage theory overestimated the fatigue life, especially at low stress levels. The fracture characteristics of the specimens which failed under random loading were similar to those which failed under sinusoidal loads.
Fatigue Life Under Random Loading for Several Power Spectral Shapes
Author: Sherman A. Clevenson
Publisher:
ISBN:
Category : Aluminum alloys
Languages : en
Pages : 36
Book Description
Each of a number of aluminum-alloy test specimens was loaded by random forces at a constant root-mean-square stress level until rupture occurred. The forces were statistically stationary and Gaussian with a zero mean value. The fatigue life (to rupture) was determined for various values of the following statistical parameters: (a) root-mean-square nominal applied stress, (b) power spectral shape, (c) mean number of zero crossings per unit time, and (d) mean number of peak loads per unit time. The power spectra were varied over a passband of frequency for three spectral shapes either by holding the power constant with frequency or by varying it either directly or inversely proportional to the square of the frequency. The results indicate that the fatigue life was determined principally by the root-mean-square nominal applied stress level. The effects of spectral shape, average number of zero crossings, and average number of peak loads were insignificant in the ranges investigated. The fatigue life, based on the number of effective cycles, of the specimens under random loading was lower by at least an order of magnitude at all stress levels than that of the specimens loaded sinusoidally. A linear cumulative damage theory overestimated the fatigue life, especially at low stress levels. The fracture characteristics of the specimens which failed under random loading were similar to those which failed under sinusoidal loads.
Publisher:
ISBN:
Category : Aluminum alloys
Languages : en
Pages : 36
Book Description
Each of a number of aluminum-alloy test specimens was loaded by random forces at a constant root-mean-square stress level until rupture occurred. The forces were statistically stationary and Gaussian with a zero mean value. The fatigue life (to rupture) was determined for various values of the following statistical parameters: (a) root-mean-square nominal applied stress, (b) power spectral shape, (c) mean number of zero crossings per unit time, and (d) mean number of peak loads per unit time. The power spectra were varied over a passband of frequency for three spectral shapes either by holding the power constant with frequency or by varying it either directly or inversely proportional to the square of the frequency. The results indicate that the fatigue life was determined principally by the root-mean-square nominal applied stress level. The effects of spectral shape, average number of zero crossings, and average number of peak loads were insignificant in the ranges investigated. The fatigue life, based on the number of effective cycles, of the specimens under random loading was lower by at least an order of magnitude at all stress levels than that of the specimens loaded sinusoidally. A linear cumulative damage theory overestimated the fatigue life, especially at low stress levels. The fracture characteristics of the specimens which failed under random loading were similar to those which failed under sinusoidal loads.
Fatigue life under random loading for several power spectral shapes
Fatigue Life Under Random Loading for Several Power Spectral Shapes [with List of References]
Spectral Method in Multiaxial Random Fatigue
Author: Adam Nieslony
Publisher: Springer Science & Business Media
ISBN: 3540738231
Category : Technology & Engineering
Languages : en
Pages : 148
Book Description
This monograph examines the theoretical foundations of the spectral method for fatigue life determination. The authors discuss a rule of description of random loading states with the matrix of power spectral density functions of the stress/strain tensor components. Some chosen criteria of multiaxial fatigue failure are analyzed. The formula proposed in this book enables readers to determine power spectral density of the equivalent history directly from the components of the power spectral density matrix of the multidimensional stochastic process.
Publisher: Springer Science & Business Media
ISBN: 3540738231
Category : Technology & Engineering
Languages : en
Pages : 148
Book Description
This monograph examines the theoretical foundations of the spectral method for fatigue life determination. The authors discuss a rule of description of random loading states with the matrix of power spectral density functions of the stress/strain tensor components. Some chosen criteria of multiaxial fatigue failure are analyzed. The formula proposed in this book enables readers to determine power spectral density of the equivalent history directly from the components of the power spectral density matrix of the multidimensional stochastic process.
Monthly Catalog of United States Government Publications
Semiannual Report to the Congress
Author: United States. National Aeronautics and Space Administration
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1106
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1106
Book Description
Reports and Documents
Author: United States. Congress
Publisher:
ISBN:
Category :
Languages : en
Pages : 1416
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 1416
Book Description
Report to the Congress
Author: United States. National Aeronautics and Space Administration
Publisher:
ISBN:
Category :
Languages : en
Pages : 556
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 556
Book Description
Scientific and Technical Aerospace Reports
Mechanical Vibration & Shock: Fatigue damage
Author: Christian Lalanne
Publisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages : 376
Book Description
Publisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages : 376
Book Description