×
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

Fracture Toughness Testing

Fracture Toughness Testing

Fracture Toughness Testing

(OP)
I am looking to undertake some fracture toughness testing of aluminium metal matrix composites (SiC particulate reinforcement). There are a number of test standards, ie. ASTM E399, ASTM E1820, BS 7448 etc.
Have anyone undertaken these tests and are able to advise on the pro and con of each test method and on the different specimen designs.

Thanks for your assistance.

RE: Fracture Toughness Testing

ASTM E1820 is more comprehensive testing than E399. E1820 provides data for the entire R-curve, while E399 provides the single value of KIc. What is your goal?

RE: Fracture Toughness Testing

(OP)
The intention is to compare the toughness between three different, but similar materials. I am reading through E1820 and E399 and I have to say I am getting lost!!

RE: Fracture Toughness Testing

(OP)
Further to my last reply. E399, contains recommended sizes to ensure plane-strain in the specimen, E1820, does not as it no longer covers plane-strain. If my requirement is just to compare the toughness of different materials (SiC particulate reinforced aluminium, with diffrent reinformace loading, which chagnes stiffness and strength), is it necessary to used plain-strain (and the large specimens specified, as a result of the ratio of yield strength over modulus)?

As only a comparsion is required, would simple charpy testing be a viable alternative?

RE: Fracture Toughness Testing

It depends on how brittle they will be.
If they will have very low impact toughness then maybe you could use unnotched bars, of go to a bending test like they do with ceramics (4 point bending).
You don't want to prep CVN bars and have them only absorb 5 lb-ft on impact.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Fracture Toughness Testing

(OP)
If we approach this from a different direction. The structures personnel in my company wishes to obtain some 'toughness' values for range of material. They will not be used for design purposes, but to provide some information on the relative 'robustness' or 'tolerance' of components made from different material to unexpected overloads and or damage.

If you had a clean sheet to start, what would be the recommended test to carry out, which would require reasonable amounts of material (some of the material I have will likely require 100mm3 samples to obtain plane-strain fracture toughness).

RE: Fracture Toughness Testing

One easy place to start is by pulling both smooth and notched tensile bars. It will give you and indication of notch sensitivity and damage tolerance.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Fracture Toughness Testing

If you want qualitative toughness, then a Charpy impact test (ASTM E23) is another test to consider. If you want quantitative toughness, then ASTM E1820.

RE: Fracture Toughness Testing

The place I worked at previously would conduct CTOD (crack tip opening displacement) tests to examine crack progression in materials.

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