×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

allowable stress in tension for Vton A

allowable stress in tension for Vton A

allowable stress in tension for Vton A

(OP)
I would like to know the allowable stress in tension for Viton A rubber expressed either as Pounds per square inch or elongation %.
Thanks
Saitools

RE: allowable stress in tension for Vton A

Allowable stress?  Isn't allowable stress determined by the designer. Shouldn't that be maximum or yield stress?  What temperature?

RE: allowable stress in tension for Vton A

You should contact Dupont-Dow for specifics, but what I found was 1600 psi stress and 165% elongation.  I assume these are ambient numbers.

RE: allowable stress in tension for Vton A

(OP)
The designer can design the component only on the basis of the allowable stress for the material.The working stress will be much lower than the yield/max stress .I want to know the safety factor on yield/ Ultimate tensile stress.
All temperatures are ambient.
Thanks
Rajan

RE: allowable stress in tension for Vton A

Had to pull out my statics and strengths of materials book.  What I found was
Allowable stress is the yield stress divided by factor of safety (for materials with elongation greater than 5%), with factors of safety range between 1.5 and 4.0.

When I worked on NASA contracts the factor of safety was dictated prior to any design (normally 1.5).  I was told by an aircraft engineer their factor of safety for design was 1.25.  

If you have test capabilities you may want to run some samples.

RE: allowable stress in tension for Vton A

(OP)
My understanding is rubber does not have an yield point/it is not reported in standard specs.Can we safely use 1/3 of UTS which is a guaranteed value as Minimum UTS by all rubber manufacturers?
Please advice
Thanks a million
Best regards
Rajan

RE: allowable stress in tension for Vton A

You're right.  I've always reported max. stress (ultimate stress) whenever I've tested elastomer samples.  The curve (stress/strain or displacement) is linear.  1/3 of the ultimate would probably be a safe bet. I would rather design on the side of safe operation.  

RE: allowable stress in tension for Vton A

One other thing, if you have the capability to test the rubber it would be advisable to test a few samples and use the test data to determine ultimate stress.  I'm not from Missouri, but I prefer to use test data over vendor's stated values.

RE: allowable stress in tension for Vton A

(OP)
BLN,
You have been most helpful!
Million thanks.
Best regards,
Rajan

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources