Plastic 3 Point Bend Flexural Test - ASTM D790

The ASTM D790 is the most common flexural test performed on plastic. Common measurements are flexural strength and flexural modulus. The test is performed on a Universal Testing Machine equipped with a 3 point bend fixture. Read more here: www.admet.com/testing-applica...
Testing the Flexural Properties of Plastics
Summary of Test
ASTM D790 is one of the most commonly used specifications in the plastics industry. This test measures the flexural strength and flexural modulus of reinforced and unreinforced plastics. These calculations relate to the stiffness of your material and allow you to choose materials that do not bend when supporting the loads you require for your application. The test uses a universal testing machine and a three point bend fixture to bend plastic test bars to acquire the data needed to make the calculations.
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Test Procedure
To run the test, begin by die cutting, sawing, or injection molding your samples to a shape specified in the ASTM specification.
Adjust the support span length that you find in the standard determined by your sample size
Place the test bar on the 3 point bend fixture and begin the test
End the test after bending to 5% strain or until the sample breaks
Equipment Required for ASTM D790
A Universal Testing Machine with the following specifications:
Servo-control to ensure constant rate of speed
Meets accuracy of testing machines specified in ASTM E4
ADMET Recommends: eXpert 2600 Dual Column Testing Machine, eXpert 7600 Single Column Testing Machine
Deflection measuring device
This can be the standard crosshead movement indicator or an auxiliary deflection measuring device such as a displacement transducer
ADMET Recommends: Deflectometers
Software or suitable electronics are required to operate the machine and to take the measurements
Basic systems will provide the raw data and stress-strain charts. Using these data, you can determine and calculate all of the analyses needed. Fully PC-based systems have the capability to calculate all of these automatically. ADMET offers both
ADMET Recommends: MTESTQuattro PC-based Controller
Three Point Bend Fixture
There are many different styles of bend fixtures available. Select one appropriate for the capacity and size of your samples
ADMET Recommends: 3 Point Bend Fixture
For more information on Bend Test Equipment, read our blog post here: www.admet.com/bend-testing-eq...

[@michaelnicholson9630]

Well done!

[@cloudssky951]

Hi thank you for the interesting video, may i ask what kind of dimension you used for the specimen?

[@afgzakria]

search for astm d790 pdf

[@fixitmekanik412]

How are you measuring strain without a strain gage? Using the position is inaccurate.

[@uwofracture]

Thank you.
What is the condition for end of the test? Is it based on rate of flexure load? If yes what sensitivity did you define for the test

[@sachinpatare5887]

Curious to know the same. There is no visible deformation and hence want to know when should we stop the test.

[@gregthelen3811]

@@sachinpatare5887 per ASTM the stop point is either breakage of the sample or 5% strain on the outer member.

[@temitope97]

Anyone here know the standards used for a sandwich panel with styrofoam core ?

[@sushpendrasingh3752]

VERY IMPORTENT

[@ted.bowted]

how do you know that the specimen has reached the 5% strain?

[@fredsingateh9701]

Aqilah Kamal there's an equation that the computer can calculate for strain you can find it in ASTM D790-17.

[@amruth2545]

Thanks my engeneering is done
End to deal with all this crap

[@sushpendrasingh3752]

BUT NOT CONFIRME TEST STAPE