Procedure of a Fracture Mechanical Evaluation using the Material HCT590X

For a reliable, strength-compliant and fracture-resistant design of components and technical structures and for the prevention of damage cases, both the criteria of strength calculation and fracture mechanics are essential. Thereby, the comparison of the effective load with strength parameters enables the prevention of strength failure. In contrast, fracture mechanical failure is caused by defects and cracks which initiate and/or propagate under the operational load. The present paper illustrates the general procedure of a fracture mechanical evaluation of fatigue cracks in order to evaluate practical damage cases. Fracture mechanical fundamentals which are essential for the calculation of the stress intensity factors K and the experimental determination of fracture mechanical material parameters (e.g. threshold Δ K against fatigue crack growth, crack growth rate curve) are explained in detail. The subsequent fracture mechanical evaluation on the basis of the local stress situation at the crack tip and the fracture mechanical material data is executed for different materials (e. g. HCT590X) and selected crack problems.