Determination of fracture mechanics

Components may already show cracks or similar defects during the manufacturing process. Using static tests on deeply cracked specimens to determine fracture toughness, manufacturers and users can prevent material failure through controlled crack growth, monitoring and - if necessary - maintenance/repair.

The test system in the example consists of one or two Inspekt 100 kN universal testing machines, each with a temperature chamber with a temperature range from -70°C to +350°C and a HT strain transducer. It enables the fracture mechanics to be tested in accordance with standards.

The procedures for determining fracture mechanics are laid down in the following three standards:

• ASTM E 399: Standard test method for linear-elastic planar fracture toughness KIC of metallic materials
• ASTM E1820: Standard fracture toughness test method
• ISO12135: Metallic materials - Uniform test method for the determination of quasi-static fracture toughness