Back to results
US 7,889,840 B2Granted
System and method for predicting material fatigue and damage
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsAsuri K. Vasudevan, Kuntimaddi Sadananda, Grzegorz Glinka, Daniel Kujawski
Life of this patent
Estimating the term…
Abstract
A method and system for determining damage prediction of a component. The component may be critical component used in an aircraft or other vehicle experiencing cyclic loading. The method and system determines the ΔK, Kmax and Kinternal values for the component and utilizes these values in order to predict damage and/or failure of the component.
Claims15
A method for component damage prediction in real world service environments comprising:
- determining ΔKappl and Kmax,appl of the component from service life load data, said service life having varying maximum loads and environmental conditions;
- experimentally determining Kint and ΔKint of the component by measuring crack tip displacements as a function of distance from crack tip;
- determining ΔKtotal as a sum of the ΔKappl and the ΔKint of the component;
- and
- predicting crack growth rate da/dN according to
- ⅆ
- a
- ⅆ
- N
- =
- C
-
- {
- Δ
-
-
- K
- total
- 1
- -
- p
-
- K
- max
- ,
- total
- P
- }
- γ
- ,
- wherein p is a driving force constant, γ a fatigue growth equation exponent, and p and γ are empirically determined from fitting a Coffin-Manson curve to strain-controlled fatigue test data of the component, C is a fatigue crack growth constant computed from the Coffin-Manson curve and the strain-controlled fatigue test data, ΔKappl is applied stress intensity range, Kmax,appl is a maximum applied stress intensity factor, Kint and ΔKint are internal stress intensity factors due to internal stresses, and Kmax,total is a total maximum stress intensity factor calculated as a sum of Kint and Kmax,appl.
28 more elements
A system for component crack growth prediction comprising:
- a sensor enabled to determine empirical data related to the component;
- a receiver operably connected to a computer;
- a database operably connected to the computer, wherein material data related to the component is stored;
- wherein the computer is programmed to receive and use the empirical data and the material data related to the component in order to
- predict crack growth rate da/dN according to
- ⅆ
- a
- ⅆ
- N
- =
- C
-
- {
- Δ
-
-
- K
- total
- 1
- -
- p
-
- K
- max
- ,
- total
- P
- }
- γ
- ,
- wherein p is a driving force constant, γ is a fatigue growth equation exponent, and p and γ are empirically determined from fitting a Coffin-Manson curve to strain-controlled fatigue test data of the component,
- wherein C is a fatigue crack growth constant computed from the Coffin-Manson curve and the strain-controlled fatigue test data, ΔKtotal is a sum of ΔKappl and ΔKint of the component, ΔKappl is applied stress intensity range, Kmax,appl is a maximum applied stress intensity factor, and ΔKappl and Kmax,appl of the component are determined based on service life load data, said service life having varying maximum loads and environmental conditions.
29 more elements
Dependencies are inferred from the claim text.