Prepare your samples accordingly. We currently use pin-on-three-ball or ball-on-three-ball design.
We strongly suggest following demension for specimens based on the apparatus we have in our lab. Disk diameter: 10, 13, or 17 mm, Support diameter: 8, 11, or 15 mm, thickness: 1/10-1/12 of the specimen diameter. We normally do not test square plate, but it seems possible.
Specimen should be flat.
Edge failure should be miminized. Extra edge beveling or edge finish in not necessary, but poor edge finish is not a good practise.
Biaxial flexual strength test fixture side viewBiaxial flexual strength test fixture side viewSpecimen is loaded for biaxial flexual strength testBiaxial flexual strength test equation.
Equipment Preparation:
Check the power switch of instron and printer.
Check the status of computer, log in as administrator.
Check the load cell cable is connected and in the proper load range as you need.
Prepare fixture for your specimens.
Testing:
Run BlueHill 3 from computer.
Load your testing method and choose testing filename, save to your own folder. Each group pf specimens can be included in one data file.
Align the load pusher concentric to the central hole of the fixture. Secure the fixture.
Meaure the thickness of the specimen. It is very critical to get accuracy better than 0.002mm for thin specimens. Input specimen information in Bluhill 3.
Mount your specimens in the biaxial flexual strength test fixture. Load pusher should be concentric to specimen within 0.5% error. Inset 0.05 mm polyethelene sheet between specimen and pusher.
IMPORTANT! Set the extension reset before the test of one group. Set the frame safety sensors for upper and lower limit.
Install proper protection shield around the fixture and wear safety googoles for yourself.
Click "start" to test.
Collect finished specimens fragments and save for further fractograph analysis. Do not match fracture surfaces togather, which will smear off important microstructures.
Fracture initiated from the edge is not meeting the requirements and must be investigated.
Save the results after testing one group specimens. Do not mix different groups of specimens in one data file.
Print important results when necessary.
Related Standard References:
ISO 6872 Flexural Strength Dentistry Ceramic.
ASTM F394 Test Method for Biaxial Flexure Strength (Modulus of Rupture) of Ceramic Substrates (Withdrawn 2001 without replacement).
ASTM C1499-05 Standard Test Method for Monotonic Equibiaxial Flexural Strength of Advanced Ceramics at Ambient Temperature.
