This video demonstrates how to perform a fracture toughness test to ASTM E399 on a ZwickRoell HA250 servo-hydraulic testing machine to determine the K1C value. About the test: The test consists of two main parts 1. Pre-cracking 2. Tensile test for fracture toughness First the the specimen dimensions are measured and entered in the software. Then the pre-cracking is performed until the target cracklength is reached. For measuring the cracklength an COD extensometer is attached on the machined blades of the specimen. After the pre-cracking the machine performst the tensile test. After the specimen is broken the user measures the real crack-length of the sample and enters these values in the software. The software then automatically checks all validity criteria and calculates the critical stress intensity k1C 00:07 – overview test setup 00:21 – setting up a crackgrowth test 01:12 – pre-cracking CT sample 01:23 – fracture toughness test 01:42 – Measuring crack length 01:57 – exporting data 02:05 – Advantages and features of HA250 #k1cdetermination #fracturetoughness #ASTME399