"Crack Size Forecasting Servic" - Crack Size Forecast from Fatigue Calculations.

9) - Crack Inspection Efficiency.

Probable crack size and growth rate in a structural detail at the time of a sceduled inspection - predicted together with the chance of crack detection.

The calculations are based on the following input data:
- SN-curve parameters for the structural detail.
- Assumed mean values for initial defect size and laboratory specimen failure size.
- Stress concentration factor K with uncertainty.
- Statistical stress distribution parameter or nominal fatigue life.
- Average stress period with uncertainty.
- Probability of Detection (POD) curve parameters.

Input Data:

Time of Scheduled Inspection:
Year of the inspection (from eta=0):. . . .  years
Crack size of particular concern: . . . . .  cm
      
SN-curve Data:
Slope parameter, m: . . . . . . . . . . . . 
Mean value of log10 A:. . . . . . . . . . . 
Standard deviation sigma_log10 A: . . . . . 
    Alternatively give standard fatigue class notation,
    and set K=1.0 and dK=0.0 for stress concentration below:
    SN-curve (B,C,D,F,F2,G,H,S or X). . . . . . 
Stress concentration parameter, K:. . . . . 
Standard deviation dK of K: . . . . . . . . 
      
Assumed Crack Size Values:
Assumed mean of initial size (eta=0): . . .  cm
Assumed fatigue failure size (eta=1): . . .  cm

Weibull Stress and Concentration Data:
Weibull slope parameter, h: . . . . . . . . 
Average scale parameter, q: . . . . . . . .  N/mm^2
Standard deviation dq of q: . . . . . . . .  N/mm^2
    Alternatively to the stress range scale parameter q and 
    uncertaingy dq, one may also give the nominal fatigue life 
    in years as input. The standard deviation should then be given 
    as the relative uncertainty in q in percent, that is dq/q*100.
    Nominal fatigue life in years, q: . . . . .  years
    Relative uncertainty in stress, dq/q in %:.  percent

Average stress period, T: . . . . . . . . .  sec
Standard deviation dT of T: . . . . . . . .  sec

POD-Curve Parameters:
Size of 50% detection chance, a:. . . . . . 
Slope (dispersion) parameter, b:. . . . . . 
Chance of missing irresp.of size, P in %: .  percent
Repeated Calculations:
To perform successive calculations with an updated input variable, then click on the right-hand radio button at the variable to be updated. Give the step length and the number of repetitions in the fields below. Updated results caused by updated input will appear on additional lines in the output report. If spreadsheet variables are selected (see below) the successive variable values will appear in a separate table instead. 
Step length:      Repetitions:   No repeat:
Start the Calculation:
The data given so far are sufficient to perform a calculation. Give your name or signature if desired, and klick on the start bar to run the run. Klick on "Reset" will revert all new input to the default value.

Format: 

Your name:

Report Content and Layout:

Initial Comment:
Write a comment that will appear on the top of the report (HTML may be used):

Sections Included:

From the list below you may choose which possible sections to be included in the report. By choosing "Main data only" some less important data will be left out.
Nominal Fatigue Life Calculation. (Main data only: )
Strucural and Load Data. (Main data only: )
Status Report by Inspection. (Main data only: )

Numerical Accuracy:
For different purposes, you may choose the number of significant digits wanted in the results. Click on the desired number. Normally numbers greater than e+4 or less than e-4 will be given with an exponent. By pressing the button marked "e+00" ALL numbers will be given with exponent. Normally integer numbers are given with decimal point and one decimal. By pressing "Integer" integers will be given without decimal point.

2: 3: 4: 5: 6: 7: e+00: Integer:

Spreadsheet Result Format:

Alternatively to the repeated calculation results in the ordinary report listing, you may have such data in a spreadsheet-like table at the end of a report. Arrange updated variable, steplength and number of repetitions as explained for "Repeated Calculations" above. Then pick out the variables to be included in the table from the list below.

Spreadsheet Heading:
Write a heading that will appear above the table (HTML effects work):

Line Spaces in the Spreadsheet:
If the table is long, then introduce line space for convenience:

Space per 5.line: Per 10.line: Per 25.line: No spaces:

Variables Included in the Spreadsheet:
Select the variables desired to be included in the table:

Usage factor (Miner-sum eta).

Very smallest crack size (97.5% exceedance).

Growth rate of very smallest crack (97.5%).
Detection chance of very smallest crack (97.5%).

Small crack size estimate (84% exceedance).

Growth rate of small crack size (84%).
Detection chance small estimated crack (97.5%).

Expected Crack size (50%).

Growth rate of expected crack size (50%).
Detection chance of expected (50%) crack size.

Large crack size estimate (84% exceedance).

Growth rate of large crack size (84%).
Detection chance of large crack (84%) estimate.

Very largest crack size (97.5% exceedance).

Growth rate of very largest crack (97.5%).
Detection chance of very largest crack (97.5%).

Chance of having run to rupture.

Distinguished crack size.

Probability of exceeding distinguished size.
Growth rate at the distinguished size.
Chance of detecting crack of distinguished size.

Auxiliary Starter:
Program software is not verified.