frakturmekaniske

Frakturmekaniske, commonly known in English as fracture mechanics, is a field in materials science and mechanical engineering that analyzes the initiation and propagation of cracks in materials and the conditions under which those cracks lead to failure. The central aim is to predict when a structure will fail due to crack growth and to guide designs that prevent such failures.

Core concepts include the Griffith criterion, which links crack growth to energy balance, and the development of linear elastic fracture mechanics (LEFM). LEFM uses the stress intensity factor (K) and fracture toughness (K_IC) to characterize crack behavior in brittle and moderately ductile materials. For materials with significant plastic deformation, elastic-plastic fracture mechanics (EPFM) extends the analysis to account for plastic zones at the crack tip. The energy release rate (G) is another fundamental measure, related to how quickly fracture energy is consumed as a crack propagates. In fatigue fracture mechanics, crack growth under cyclic loading is often described by Paris-like relations, linking da/dN to ΔK.

Methods in fracture mechanics combine experiments and modeling. Experimental tests such as compact tension (CT) and single-edge notch bending (SENB) specimens quantify fracture toughness and crack growth resistance. Numerical approaches include finite element analysis and cohesive zone models to simulate crack initiation and progression.

Applications span aerospace, automotive, civil infrastructure, and energy sectors, where reliability and safety depend on understanding and mitigating fracture under static, dynamic, and environmental loading. Challenges include handling mixed-mode and large-plasticity fractures, environmental effects, and complex materials such as composites. The field continues to evolve with multi-physics and probabilistic approaches to assess fracture risk and service life.