Fracture and Fatigue

creep-failure
Creep Fracture – leading failure

Fracture refers to the separation of a material or component into two or more pieces due to loading (stress).

When a component fractures without warning, subsequent damage to the system may occur.  For example, a single turbine blade fractures and travels through several stages of the engine causing additional damage.  When materials fracture they leave behind evidence of the cause.  The fracture of a material is the reason behind many Failure Analysis investigations.  The type of fracture says a great deal about its operating environment. Below are examples of fracture types we have worked on:

  • Overload fracture – excessive stress which may have brittle and ductile components
  • Brittle fracture –little or no deformation prior to breaking
  • Fatigue fracture – cyclic loading leading to crack initiation and propagation
  • Creep fracture – high temperature growth and cracking
  • Corrosion fatigue – fatigue exacerbated by environmental attack
  • Embrittlement – hydrogen or liquid metal causing premature fracture

Often a fracture leads to the failure of a critical component or an entire system.  Because different materials (metals, polymers, ceramics, etc.) have varying properties, the study of fracture requires a thorough understanding of crystal structures, dislocation theory and fractography.  If you have a fractured component or are uncertain if your current material is adequate we can help.  We will modify or select new materials as appropriate or provide an impartial analysis of  your current design to locate any potential areas of weakness.