Abstract: A method of brazing including melting a surface region (26) of a substrate (12, 14, 22) and contacting a braze material (10) with the melted surface region, the braze material including a plurality of braze fillers (16) and a plurality of carbon structures (18). The method further includes subjecting the braze material to an amount of energy effective to melt the braze fillers but not the carbon structures, and cooling the braze material to form a brazement (28, 32) including the carbon structures within at least a portion of the substrate. The brazement includes a gradient (30) of the carbon structures, wherein a concentration of the carbon structures increases in a direction away from an interior of the substrate.

Abstract: A method for estimating the crack length ãn+1 of at least one crack (2) in a component (1): At a first instant, the length ãn of the crack is determined and the length of the crack ãn+1=ãn+?ãn is estimated at a second instant by using the integration scheme a ~ n + 1 = a ~ n + d ? ? a ~ 1 6 + d ? ? a ~ 2 3 + d ? ? a ~ 3 3 + d ? ? a ~ 4 6 ( 17 ) d ? ? a ~ 1 = d ? ? Nf ? ( ? ? ? K n ) ( 18 ) d ? ? a ~ 2 = d ? ? Nf ? ( ? ? ? K n + 1 2 ? ? ? ? K n 2 ? ? a ~ n ? d ? ? a ~ 1 ) ( 19 ) d ? ? a ~ 3 = d ? ? Nf ? ( ? ? ? K n + 1 2 ? ? ? ? K n 2 ? ? a ~ n ? d ? ? a ~ 2 ) ( 20 ) d ? ? a ~ 4 = d ? ? Nf ? ( ? ? ? K n + ? ? ? K n 2 ? a ~ n ? d ? ? a ~ 3 ) , ( 21 ) with ?ãn designating the increase in the crack size, N design

Abstract: A method for probabilistic fatigue life prediction using nondestructive testing data considering uncertainties from nondestructive examination (NDE) data and fatigue model parameters. The method utilizes uncertainty quantification models for detection, sizing, fatigue model parameters and inputs. A probability of detection model is developed based on a log-linear model coupling an actual flaw size with a nondestructive examination (NDE) reported size. A distribution of the actual flaw size is derived for both NDE data without flaw indications and NDE data with flaw indications by using probabilistic modeling and Bayes theorem. A turbine rotor example with real world NDE inspection data is presented to demonstrate the overall methodology.

Abstract: A probabilistic estimation of fatigue crack life of a component is provided. A plurality of representations of the component is defined from material property scatter data and flaw-size scatter data, wherein each representation is defined by one possible material condition and flaw-size condition associated with the component. For each representation, a component location is selected and a determination is made whether said individual representation fails after a given number of cycles N, based on the calculation of a crack growth in the selected location. The crack growth is calculated on the basis of the material condition and the flaw-size condition in the selected location. Failure of the individual representation is determined if the crack growth is determined to be unstable. The sum total of the number of the representations that failed after N cycles is determined. A probability of failure of the component after N cycles is then determined.

Abstract: A method for probabilistically predicting fatigue life in materials includes sampling a random variable for an actual equivalent initial flaw size (EIFS), generating random variables for parameters (ln C, m) of a fatigue crack growth equation ? a ? N = C ? ( ? ? ? K ) m from a multivariate distribution, and solving the fatigue crack growth equation using these random variables. The reported EIFS data is obtained by ultrasonically scanning a target object, recording echo signals from the target object, and converting echo signal amplitudes to equivalent reflector sizes using previously recorded values from a scanned calibration block. The equivalent reflector sizes comprise the reported EIFS data.