How to do the Fatigue Analysis of Diesel Engine Piston???

Altair Forum User
Altair Forum User
Altair Employee
edited October 2020 in Community Q&A

Want to do fatigue analysis of diesel engine piston as the part of master's thesis.

 

 

Initially I have tried out a 2D fatigue analysis problem of a mild steel strip and got the results.

 

Then tried to do the fatigue analysis of piston using the same material and same method.

I got good VMS and displacement values for the static sub-case and the pictures are attached.

 

 

post-4480-0-17893600-1374573108_thumb.jp

 

 

But for the fatigue sub-case didnt give the necessary results.

 

 

post-4480-0-19233200-1374573128_thumb.jp

and

post-4480-0-14131000-1374573214_thumb.jp

 

I have followed the same method of 2D problem,PSOLID element is used for the analysis of piston.

(higher order tetrahedron element-10noded element)

Hope the wrong result is caused due to the lack of adjustments in converting a

2D problem to a 3D problem,like the changes needed for defining CARDS etc.

 

Varying pressure with respect to crank angle,for 100 cycles is applied for this fatigue analysis of Piston.

Please Help...

 

Ayyappadas

 

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited July 2013

    Someone plz reply... 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited July 2013

    Hi,

     

    it is a complex subject and not easy to give a answer.

     

    As i can see, you got damage at the right location (where the high stresses are located).

    Normaly damage has to be smaller then 1 for fatique strength. The values on your legend are very high.

     

    I can't see the problem, but i guess it is a problem of input parameters (especially for fatique).

     

    Sry, Regards

    Mario

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited July 2013

    Sir,

     

    I have further modified the problem and obtained results as shown below.

    Analysis is done for a  Single Cycle of pressure variation and values of life obtained are very low...

    <?xml version="1.0" encoding="UTF-8"?>post-4480-0-06444500-1375182648_thumb.jp

     

    damage

    <?xml version="1.0" encoding="UTF-8"?>post-4480-0-24386200-1375182634_thumb.jp

     

    Fatigue parameter CARD used also shown

    <?xml version="1.0" encoding="UTF-8"?>post-4480-0-66616200-1375183063_thumb.jp

     

    I have uploaded the complete analysis to Google Drive,and am happy to share the problem

    by giving you the IDs...

     

    ayyappadas73@gmail.com

    This is my mail ID, I can send the ID and password of Google drive to your mail.

     

    Please Help...

     

  • tinh
    tinh Altair Community Member
    edited September 2014
    Altair Forum User said:

    Hi,

     

    it is a complex subject and not easy to give a answer.

     

    As i can see, you got damage at the right location (where the high stresses are located).

    Normaly damage has to be smaller then 1 for fatique strength. The values on your legend are very high.

     

    I can't see the problem, but i guess it is a problem of input parameters (especially for fatique).

     

    Sry, Regards

    Mario

     

    Hi Mario

    Could you plz explain what 'damage (s)' means? what is it calculated from? what is '(s)'?    I cannot find in help

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