Materials Algorithms Project
Program Library

Program MAP_IRRADIATED_AUSTENITIC_STEEL_YS

Provenance of code.
Purpose of code.
Specification.
Description of subroutine's operation.
References.
Parameter descriptions.
Error indicators.
Accuracy estimate.
Any additional information.
Example of code
Auxiliary subroutines required.
Keywords.
Download source code.
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Provenance of Source Code

S. Martin, T. Jacobs, Y. Zhang, J. Chen and R. Kemp
Phase Transformations Group,
Department of Materials Science and Metallurgy,
University of Cambridge,
Cambridge, U.K.

The neural network program was produced by:

David MacKay,
Cavendish Laboratory,
University of Cambridge,
Madingley Road,
Cambridge, CB3 0HE, U.K.

Added to MAP: March 2004

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Purpose

Estimation of yield stress of irradiated austenitic stainless steels under tensile testing as a function of irradiation conditions (overall damage (dpa), He production, irradiation temperature) and tensile test temperature.

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Specification

Language:	FORTRAN / C
Product form:	Source code / Executable files
Operating System:	Solaris 5.5.1; Macintosh OSX; Linux

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Description

MAP_IRRADIATED_AUSTENITIC_STEEL_YS contains a suite of programs which enable the user to estimate the yield stress of a tensile specimen of irradiated stainless steel as a function of irradiation and test conditions. It makes use of a neural network program called generate44, which was developed by David MacKay and is part of the bigback5 program. The network was trained using a database of experimental results [1, 5]. This suite of programs calculates the results of the model to produce a prediction and error estimate, as described by MacKay [page 387 of reference 3]. The source code for the neural network program can be downloaded from David MacKay's website; the executable files only are available from MAP. Also provided are FORTRAN programs (as source code) for normalising the input data, averaging the results from the neural network program and unnormalising the final output file, along with other files necessary for running the program.

Programs are available which run on Solaris 5.5.1, Linux, and Macintosh OSX. A set of program and data files are provided for the model, which calculate the yield stress (MPa). The files are included in a directory called SS_IRR_YS. This directory contains the following files and subdirectories:

README: A text file containing step-by-step instructions for running the program, including a list of input variables.
MINMAX: A text file containing the minimum and maximum limits of each input and output variable. This file is used to normalise and unnormalise the input and output data.
run_data.dat: An input text file containing the input variables used for predictions.
model.gen: This is a shell script containing the command steps required to run the module. It can be executed by typing ./model.gen at the command prompt in a terminal. This shell file compiles and runs all the programs necessary for normalising the input data, executing the network and unnormalising the output data.
spec.t1: A dynamic file, created by spec.ex, which contains information about the module and the number of data items being supplied. It is read by the program generate44.
norm_test.in: This is a text file which contains the normalised input variables. It is generated by the program normtest.for in subdirectory s.
generate44/generate55: This is the executable file for the neural network program. It reads the normalised input data file, norm_test.in, and uses the weight files in subdirectory c. The results are written to the temporary output file _out.
_ot, _out, _res, _sen: These files are created by generate44 and should be deleted automatically.
final_result: Contains the final un-normalised results for the predicted YS, along with a calculation of the modelling uncertainty.
SUBDIRECTORY s
spec.c: The source code for program spec.ex.
normtest.for: Program to normalise the data in test.dat and produce the normalised input file norm_test.in. It makes use of information read in from no_of_rows.dat and committee.dat.
gencom.for: This program uses the information in committee.dat and combines the predictions from individual models (in cases where there is more than one model), in subdirectory outprdt, to obtain an averaged value (committee prediction). The output (in normalised form) is written to com.dat.
treatout.for: Program to un-normalise the committee results in com.dat and write the output predictions to unnorm_com.
committee.dat: A text file containing the number of models to be used to form the committee result and the number of input variables. It is read by gencom.for, normtest.for and treatout.for.
extradata.for: Program to calculate dependent inputs (total He concentration, for example). Reads from run_data.dat and writes to test.dat.
unln.for: Program to calculate actual YS from the model outputs. These outputs are then written to final_result
no_of_lines.c: Program to count the number of input data.
SUBDIRECTORY c
_w_*f: The weights files for the different models.
_*.lu: Files containing information for calculating the size of the error bars for the different models.
_c_*: Files containing information about the perceived significance value [2] for each model.
_R_*: Files containing values for the noise, test error and log predictive error [2] for each model.
SUBDIRECTORY d
outran.x: A normalised output file which was created when developing the model. It is accessed by generate44 via spec.t1.
SUBDIRECTORY outprdt
out1, out2 etc.: The normalised output files for each model.
com.dat: The normalised output file containing the committee results. It is generated by gencom.for.

Detailed instructions on the use of the program are given in the README file. Further information about this suite of programs can be obtained from reference 4.

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References

ITER Materials Database, ITER Document No. S 74 MA 2.
H. K. D. H. Bhadeshia, Neural Networks in Materials Science, ISIJ International 39 (1999) No. 10, 966 - 979.
D.J.C. MacKay, Mathematical Modelling of Weld Phenomena 3 (1997), eds. H. Cerjak & H.K.D.H. Bhadeshia, Inst. of Materials, London, pp 359.
D.J.C MacKay's website at https://wol.ra.phy.cam.ac.uk/mackay/README.html#Source_code
Martin, Jacobs, Zhang and Chen, Modelling Austenitic Stainless Steels for Fusion Reactors, MPhil dissertation (2003)

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Parameters

Input parameters

The input variables for the model are listed in the README file in the corresponding directory. The maximum and minimum training values for each variable are given in the file MINMAX.

Output parameters

These program gives the yield stress in MPa. The corresponding output file is called final_result. The format of the output file is:

Prediction     Negative uncertainty      Positive uncertainty
   (MPa)                (MPa)                    (MPa)

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Error Indicators

None.

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Accuracy

As this model was trained on a very limited dataset, no allowance is made for elemental composition variations or different heat treatments of the steels. It should therefore be used for general predictions of material behaviour rather than specific predictions of the behaviour of a particular steel. See 5 for more details.

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