Fatigue advisor- Materials

[napoleonm]

According with the help, fatigue advisor can deal only with low alloy steels (4340 -4130 -8620), unallowyed steels(1008 - 1045), Aluminiun and titanium.


What happen with stainless steels (316- 316L -304 ? or other materials as Hastelloy (nickel based material).


(TPI-135398 is not clear with the definition of materials available).


is itpossible or not to perform an analysis using SS?


is it possible to create a other material database?..what is the format to use?





Regards.

 

[mechg]

Dear Napoleon,Fatigue Advisor is a cut-down version of FE-Fatigue from nCode. It uses the strain-life approach to fatigue life estimation and so requires 4 parameters to characterise a material. There is a config option < http-equiv="Content-" content="text/; charset=utf-8">< name="ProgId" content="Word.">< name="Generator" content="Microsoft Word 11">< name="Originator" content="Microsoft Word 11">

SIM_FATIGUE_EXTERNAL_MATDATA, which you can use to point to additional fatigue life data. Take a look at the simulation help or call PTC tech support for more information on the format required.Regards,Rod GilesP.S. Are you coming to the Mechanica User Group meeting in Birmingham on the 9th July? Go to www.promechuser.org.uk to sign up.

 

[napoleonm]

Rod.


Thanks fot your replay, I had an answer from ptc support about the topic for creating new material...for those who are interested here a copy:


Additional Information
<DIV =indent10>


Description
-----------------
How to specify external fatigue material properties in Pro/MECHANICA?

Alternate Technique
-----------------

See resolution below

Resolution
-----------------

It is possible to define external fatigue material properties in
Pro/Mechanica by following exactly the steps below.

1/Create a file with the extension .mat, which contains the fatigue
properties. (the most likely problems are with the format of the
material file)
the format is shown below (these are the properties for copper)

uts=50
young_modulus=1.14e5
ys=206
me=0.33
mp=0.5
sf_prime=573
b=-0.143
ef_prime=0.492
c=-0.537
n_prime=0.27
k_prime=719
rc=2.00e8
see=0
sep=0
sec=0

-Only see,sep,sec can be zero (file must contain Poisson's ration me and mp)
-Number format must de general or scientific notation format (e.g. 2e8 not 2E+08)
-No comment lines can exist in the material file
-Ensure that fatigue properties parameters in the external file are in
the correct order. (follow the format shown above)
-The material filename must be the same name as the material defined in
the Pro/Mechanica material library.( see file with .mat extension)
(not case sensitive)
-If using external file, you need to at least review the fatigue
properties and assign arbitrary values. Be sure to run the error
checking.

2/Config.mech options

Fatigue config.mech options are used by the engine (not the UI), they
must be saved to a file (not in session)
-Set the config.mech option FATIGUE_USER_DIRECTORY to the directory
where the external fatigue material properties has been saved.
-Set the option FATIGUE_EXTERNAL_MATDATA to ON

After Wildfire1 release these config.mech options have been changed to become config.pro options sim_fatigue_user_directory and sim_fatigue_external_matdata (setting yes/no) respectively.



3/ Check in the summary file to see if external material will be used. if
external material is not found, properties will be taken from the UI.


Abbreviations used the in the external file:

Uts = Ultimate Tensile Strength
young_modulus = Young?s modulus of elasticity (E)
ys = yield strength
me = Elastic Poisson?s ratio
mp = Plastic Poisson?s ratio
sf_prime = Fatigue strength coefficient (sf`)
b = Fatigue Strength Exponent
ef_prime = Fatigue Ductility Coefficient (ef`)
c = Fatigue Ductility Coefficient
n_prime = Cyclic strain hardening exponent (n`)
k_prime = Cyclic strength coefficient (k`)
rc = Endurance limit in reversals
see = Standard error in measured data for Basquin Line
sep = Standard error in measured data for Coffin-Manson line
sec = Standard error in measured data for cyclic stress-strain curve</PRE>


Now, I am trying to look for the Stainless steels coefficients (material widely used but not cover by the faigue advisor data base!!!!..), and being honest it quite hard to find them.


even if F-advisor is a cut-down of nCode FE-fatigue (http://www.ncode.com/Product.aspx?Product_ID=90)


it is quite good to evaluate if fatigue can be a issue or not in your model.


Does any body want to share that information?.


Can you help me with that Rod?.</DIV>

 

[mechg]

Napoleon,

I use data from 'Mechanical Behavior of Materials' by N.E. Dowling. The chapter on strain-based approach to fatigue is very comprehensive. However, the material data on page 720 (3rd ed.) doesn't include any stainless steels. The range of slopes of the elastic region (b-parameter) is between 0.07 and 0.14 and the plastic region slope (c-parameter) is between 0.5 and 0.8.

The references for materials are BOLLER & SEEGER 'Materials Data for Cyclic Loading', which is 5 volumes and sounds expensive and LAMPMAN 'ASM Handbook, Vol 19 Fatigue & Fracture'

Regards,

Rod

 

[Fatiguester]

Hi to everybody,

I'm a german student working on Fatigue Advisor with WF5. Tried to add some external material data, but it didn't work.
I've changed the options in config.pro sim_fatigue_user_directory and sim_fatigue_external_matdata.
Created a *.mat file with the same name my mechanica material has.
WF5 creates *.mtl files insted of *.mat files. So I renamed my material data from my library to *.mat. Even created a *.mtl file but no result.
Shouldn't I see the changes inside the material properties? Where can I do error checking?

Thanks a lot!
Stephan