[MAP Logo]

Materials Algorithms Project
Program Library



Program MAP_NEURAL_MA-STEELS

  1. Provenance of code.
  2. Purpose of code.
  3. Specification.
  4. Description of subroutine's operation.
  5. References.
  6. Parameter descriptions.
  7. Error indicators.
  8. Accuracy estimate.
  9. Any additional information.
  10. Example of code
  11. Auxiliary subroutines required.
  12. Keywords.
  13. Download source code.
  14. Links.

Provenance of Source Code

A.Y. Badmos and H.K.D.H. Bhadeshia,
Phase Transformations Group,
Department of Materials Science and Metallurgy,
University of Cambridge,
Cambridge, U.K.

Top | Next

Purpose

To predict the yield strength, ultimate tensile strength and elongation of the mechanically alloyed oxide dispersion strengthened (MA-ODS) ferritic stainless steels as a non-linear function of the important processing and service variables.

Top | Next | Prev

Specification

Language:FORTRAN
Product form:Source code

      DOUBLE PRECISION AW(14),YSRES(26),UTSRES(26),ELRES(26)
      DOUBLE PRECISION AVER,SIGYS,SIGUTS,SIGEL
      INTEGER ID

      DOUBLE PRECISION X(12),AMIN(13),AMAX(13),AW(14)
      DOUBLE PRECISION W1Y1(14,12),W2Y1(14),THETA1Y1(14)
      DOUBLE PRECISION W1Y2(10,12),W2Y2(10),THETA1Y2(10)
      DOUBLE PRECISION W1Y3(11,12),W2Y3(11),THETA1Y3(11)
      DOUBLE PRECISION W1Y4(16,12),W2Y4(16),THETA1Y4(16)
      DOUBLE PRECISION W1Y5(6,12),W2Y5(6),THETA1Y5(6)
      DOUBLE PRECISION SIGMA,RES(26)

      DOUBLE PRECISION W1U1(16,12),W2U1(16),THETA1U1(16)
      DOUBLE PRECISION W1U2(15,12),W2U2(15),THETA1U2(15)
      DOUBLE PRECISION W1U3(15,12),W2U3(15),THETA1U3(15)

      DOUBLE PRECISION X(14),AMINEL(15),AMAXEL(15),AW(14)
      DOUBLE PRECISION W1E1(14,14),W2E1(14),THETA1E1(14)
      DOUBLE PRECISION W1E2(14,14),W2E2(14),THETA1E2(14)
      DOUBLE PRECISION W1E3(11,14),W2E3(11),THETA1E3(11)
      DOUBLE PRECISION W1E4(13,14),W2E4(13),THETA1E4(13)
      DOUBLE PRECISION W1E5(8,14),W2E5(8),THETA1E5(8)
      DOUBLE PRECISION W1E6(7,14),W2E6(7),THETA1E6(7)

Top | Next | Prev

Description

MAP_MA-STEELS_NEURAL uses the parameters obtained from a neural network training process to predict the yield strength, ultimate tensile strength and percent elongation of the MA-ODS ferritic steels.

Tensile properties data from published literature were analysed using a neural network technique within a Bayesian framework (Ref. 1-2). The analysis, though empirical, can after appropriate training and with the use of committee of models, produce results which are metallurgically reasonable.

The predictions are made with committees which are composed of 5 models for yield strength, 3 models for ultimate tensile strength and 6 models for elongation. These are as a function of the following variables within the stated ranges:

Parameter Maximum Minimum
Chromium, wt.% 0.1300D+02 0.2000D+02
Aluminium, wt.% 0.0000D+00 0.4500D+01
Titanium, wt.% 0.5000D+00 0.3500D+01
Molybdenum, wt.% 0.0000D+00 0.1500D+01
Yttria, wt.% 0.0000D+00 0.5000D+00
Annealing temp., C 0.2000D+02 0.1330D+04
Annealing time, sec. 0.0000D+00 0.1200D+03
Ageing temp., C 0.2000D+02 0.8000D+03
Ageing time, sec. 0.0000D+00 0.2888D+04
Cold-work, % 0.0000D+00 0.7000D+02
Test temp., C 0.0000D+00 0.1250D+04
Strain rate, 1/s. 0.3330D-07 0.3330D-01

In addition to the parameters above, yield strength and ultimate tensile strength are also included as variables in the predictions of elongation.

To run the program MAP_MA-STEELS_NEURAL the following files are required, and should not be altered:

Y1WT, Y2WT, Y3WT, Y4WT, Y5WT
Contain neural network information for yield strength.
U1WT, U2WT, U3WT
Contain neural network information for ultimate tensile strength.
E1WT, E2WT, E3WT, E4WT, E5WT, E6WT
Contain neural network information for elongation.

The raw data used in the training of the neural network is contained in the file `neural-dataset'

Top | Next | Prev

References

  1. A.Y. Badmos and H.K.D.H. Bhadeshia, Neural Network Models for the Tensile Properties of the Mechanically Alloyed ODS Iron-Alloys, accepted for publication in Materials Science and Technology.
  2. A.Y. Badmos, Ph.D. Thesis, University of Cambridge, UK, 1998.

Top | Next | Prev

Parameters

Input parameters

AW - real array of dimension 14
AW contains the input data from the file ALLINPUT, which includes the variables known to be important in influencing the mechanical properties of the alloys.
 
X - real array of dimensions 12 (yield & UTS) and 14 (elongation)
Contains normalized input variables.
 
W1Y1 - real array of dimension (14,12)
W1Y1 contains weights read in from the file Y1WT, which are coefficients for the first member of the committee model used in the prediction of yield strength.
 
W2Y1 - real array of dimension 14
W2Y1 contains weights read in from the file Y1WT, which are coefficients for the first member of the committee model used in the prediction of yield strength.
 
THETA1Y1 - real array of dimension 14
THETA1Y1 contains the biases associated with W1Y1, and is read in from the file Y1WT.
 
THETA2Y1 - real
THETA2Y1 is the bias associated with W2Y1, and is read in from the file Y1WT.
 
W1Y2 - real array of dimension (10,12)
W1Y2 contains weights read in from the file Y2WT, which are coefficients for the second member of the committee model used in the prediction of yield strength.
 
W2Y2 - real array of dimension 10
W2Y2 contains weights read in from the file Y2WT, which are coefficients for the second member of the committee model used in the prediction of yield strength.
 
THETA1Y2 - real array of dimension 10
THETA1Y2 contains the biases associated with W1Y2, and is read in from the file Y2WT.
 
THETA2Y2 - real
THETA2Y2 is the bias associated with W2Y2, and is read in from the file Y2WT.
 
W1Y3 - real array of dimension (11,12)
W1Y3 contains weights read in from the file Y3WT, which are coefficients for the third member of the committee model used in the prediction of yield strength.
 
W2Y3 - real array of dimension 11
W2Y3 contains weights read in from the file Y3WT, which are coefficients for the third member of the committee model used in the prediction of yield strength.
 
THETA1Y3 - real array of dimension 11
THETA1Y3 contains the biases associated with W1Y3, and is read in from the file Y3WT.
 
THETA2Y3 - real
THETA2Y4 is the bias associated with W2Y4, and is read in from the filE Y4WT.
 
W1Y4 - real array of dimension (16,12)
W1Y4 contains weights read in from the file Y4WT, which are coefficients for the fourth member of the committee model used in the prediction of yield strength.
 
W2Y4 - real array of dimension 16
W2Y4 contains weights read in from the file Y4WT, which are coefficients for the fourth member of the committee model used in the prediction of yield strength.
 
THETA1Y4 - real array of dimension 16
THETA1Y4 contains the biases associated with W1Y6, and is read in from the file Y4WT.
 
THETA2Y4 - real
THETA2Y4 is the bias associated with W2Y4, and is read in from the file Y4WT.
 
W1Y5 - real array of dimension (6,12)
W1Y5 contains weights read in from the file Y5WT, which are coefficients for the fifth member of the committee model used in the prediction of yield strength.
 
W2Y5 - real array of dimension 6
W2Y5 contains weights read in from the file Y5WT, which are coefficients for the fifth member of the committee model used in the prediction of yield strength.
 
THETA1Y5 - real array of dimension 6
THETA1Y5 contains the biases associated with W1Y5, and is read in from the file Y5WT.
 
THETA2Y5 - real
THETA2Y5 is the bias associated with W2Y5, and is read in from the file Y5WT.
 
W1U1 - real array of dimension (16,12)
W1U1 contains weights read in from the file U1WT, which are coefficients for the first member of the committee model used in the prediction of ultimate tensile strength.
 
W2U1 - real array of dimension 16
W2U1 contains weights read in from the file U1WT, which are coefficients for the first member of the committee model used in the prediction of ultimate tensile strength.
 
THETA1U1 - real array of dimension 16
THETA1U1 contains the biases associated with W1U1, and is read in from the file U1WT.
 
THETA2U1 - real
THETA2U1 is the bias associated with W2U1, and is read in from the file U1WT.
 
W1U2 - real array of dimension (15,12)
W1U1 contains weights read in from the file U2WT, which are coefficients for the second member of the committee model used in the prediction of ultimate tensile strength.
 
W2U2 - real array of dimension 15
W2U2 contains weights read in from the file U2WT, which are coefficients for the second member of the committee model used in the prediction of ultimate tensile strength.
 
THETA1U2 - real array of dimension 15
THETA1U2 contains the biases associated with W1U2, and is read in from the file U2WT.
 
THETA2U2 - real
THETA2U2 is the bias associated with W2U2, and is read in from the file U2WT.
 
W1U3 - real array of dimension (15,12)
W1U3 contains weights read in from the file U3WT, which are coefficients for the third member of the committee model used in the prediction of the ultimate tensile strength.
 
W2U3 - real array of dimension 15
W2U3 contains weights read in from the file U3WT, which are coefficients for the third member of the committee model used in the prediction of the ultimate tensile strength.
 
THETA1U1 - real array of dimension 15
THETA1U3 contains the biases associated with W1U3, and is read in from the file U3WT.
 
THETA2U3 - real
THETA2U3 is the bias associated with W2U3, and is read in from the file U3WT.
 
W1E1 - real array of dimension (14,14)
W1E1 contains weights read in from the file E1WT, which are coefficients for the first member of the committee model used in the prediction of elongation.
 
W2E1 - real array of dimension 14
W2E1 contains weights read in from the file E1WT, which are coefficients for the first member of the committee model used in the prediction of elongation.
 
THETA1E1 - real array of dimension 14
THETA1E1 contains the biases associated with W1E1, and is read in from the file E1WT.
 
THETA2E1 - real
THETA2E1 is the bias associated with W2E1, and is read in from the file E1WT.
 
W1E2 - real array of dimension (14,14)
W1E2 contains weights read in from the file E2WT, which are coefficients for the second member of the committee model used in the prediction of elongation.
 
W2E2 - real array of dimension 14
W2E1 contains weights read in from the file E2WT, which are coefficients for the second member of the committee model used in the prediction of elongation.
 
THETA1E2 - real array of dimension 14
THETA1E2 contains the biases associated with W1E2, and is read in from the file E2WT.
 
THETA2E2 - real
THETA2E2 is the bias associated with W2E2, and is read in from the file E2WT.
 
W1E3 - real array of dimension (11,14)
W1E3 contains weights read in from the file E3WT, which are coefficients for the third member of the committee model used in the prediction of elongation.
 
W2E3 - real array of dimension 11
W2E3 contains weights read in from the file E3WT, which are coefficients for the third member of the committee model used in the prediction of elongation.
 
THETA1E3 - real array of dimension 11
THETA1E3 contains the biases associated with W1E3, and is read in from the file E3WT.
 
THETA2E3 - real
THETA2E3 is the bias associated with W2E3, and is read in from the file E3WT.
 
W1E4 - real array of dimension (13,14)
W1E4 contains weights read in from the file E4WT, which are coefficients for the fourth member of the committee model used in the prediction of elongation.
 
W2E4 - real array of dimension 13
W2E4 contains weights read in from the file E4WT, which are coefficients for the fourth member of the committee model used in the prediction of elongation.
 
THETA1E4 - real array of dimension 13
THETA1E4 contains the biases associated with W1E4, and is read in from the file E4WT.
 
THETA2E4 - real
THETA2E4 is the bias associated with W2E4, and is read in from the file E4WT.
 
W1E5 - real array of dimension (8,14)
W1E5 contains weights read in from the file E5WT, which are coefficients for the fifth member of the committee model used in the prediction of elongation.
 
W2E5 - real array of dimension 8
W2E5 contains weights read in from the file E5WT, which are coefficients for the fifth member of the committee model used in the prediction of elongation.
 
THETA1E5 - real array of dimension 8
THETA1E5 contains the biases associated with W1E5, and is read in from the file E5WT.
 
THETA2E5 - real
THETA2E5 is the bias associated with W2E5, and is read in from the file E5WT.
 
W1E6 - real array of dimension (7,14)
W1E6 contains weights read in from the file E6WT, which are coefficients for the sixth member of the committee model used in the prediction of elongation.
 
W2E6 - real array of dimension 7
W2E6 contains weights read in from the file E6WT, which are coefficients for the sixth member of the committee model used in the prediction of elongation.
 
THETA1E6 - real array of dimension 7
THETA1E6 contains the biases associated with W1E6, and is read in from the file E6WT.
 
THETA2E6 - real
THETA2E6 is the bias associated with W2E6, and is read in from the file E6WT.
 
AMIN - real array of dimension 12
AMIN contains the minimum value of the variables in the experimental dataset used to develop the models for the yield strength and the ultimate tensile strength.
 
AMAX - real array of dimension 12
AMAX contains the maximum value of the variables in the experimental dataset used to develop the models for the yield strength and the ultimate tensile strength.
 
AMINEL - real array of dimension 14
AMIN contains the minimum value of the variables in the experimental dataset used to develop the model for the elongation.
 
AMAXEL - real array of dimension 14
AMAX contains the maximum value of the variables in the experimental dataset used to develop the model for the elongation.

Output parameters

All output is to STDOUT and to a datafile, nominally called OUT.

Top | Next | Prev

Error Indicators

None.

Top | Next | Prev

Accuracy

The full calculation of the error bars as presented in [1-2] is not reproduced in this program. An average error of 20% of 95% error limits is assumed reasonable, though not in all cases.

Top | Next | Prev

Further Comments

None.

Top | Next | Prev

Example

1. Program text

       Complete program.

2. Program data

20.0D0 	  Cr 
4.50D0    Al 
0.50D0    Ti 
0.00D0    Mo 
0.50D0    Y  
1300.0D0  Annealing temperature
60.0D0    Annealing time
20.0D0    Ageing temperature
0.0D0     Ageing time
0.0D0     Cold-work
20.0D0    Test temperature
8.33D-5	  Strain rate

3. Program results

    *********************************************************************************


              **    Properties  of Mechanically Alloyed Iron **

                             Cambridge University 
                             Badmos and Bhadeshia         

             Identification Number   20       Program Version 5.2


           Chromium   20.000  wt.%          Aluminium    4.500  wt.%
           Titanium    0.500  wt.%          Molybdenum   0.000  wt.%
           Yttria      0.500  wt.%

           Recrystallisation Temperature     1300. C
           Recrystallisation Time              60. min
           Ageing Temperature                  20. C
           Ageing Time                          0. min
           Cold Work                            0. %
           Test Temperature                    20. C
           Strain rate                      0.00008 1/s





   Individual model Yield Strength (MPa):
     543.   619.   627.   566.   610.

   Individual model Ultimate Strength (MPa):
     647.   646.   683.

   Individual model elongations (%):
      10.     7.     8.     8.     6.     7.

                     Mean Yield Strength    =    593. +-   8.MPa
                     Mean Ultimate Strength =    658. +-   7.MPa
                     Mean Elongation        =      8. +-  13.%

 The error bars (95% confidence) do not include 
 the uncertainty in fitting the data to the function,
 simply the unexplained noise in the data.

 *********************************************************************************

Top | Next | Prev

Auxiliary Routines

None.

Top | Next | Prev

Keywords

neural network, MA-ODS iron-alloys, yield strength, ultimate tensile strength, elongation

Top | Next | Prev

Download

Download source code

Top | Prev


MAP originated from a joint project of the National Physical Laboratory and the University of Cambridge.

MAP Website administration / map@msm.cam.ac.uk

Top | Index | MAP Homepage Valid HTML 3.2!