Fatigue and Durability

Basic Methods for Fatigue analysis

Our Finite Element (FE) Fatigue analysis can produce results from which fatigue lives can be calculated. Several methods may be used, according to the problem considered:

• E-N analysis (Crack Initiation Method)
  • Relates nominal nominal or or local elastic stress local elastic stress to to total life total life
• S-N analysis (Total Life Method)
  • Relates local strain local strain to to crack initiation life crack initiation life
• LEFM (Crack Propagation Method)
  • Relates stress intensity stress intensity to to crack propagation rate crack propagation rate

Multiaxial Assessment and Analysis

Some structures experience multiaxial loadings in critical locations. A simple uniaxial approach is sometimes used and is fine for many cases, but where the loading is multiaxial, especially when it is non-proportional, something more sophisticated is required. The following analysis can be performed:

• Multiaxial E-N analysis
• Multiaxial Safety Factor analysis
  • Dang Van Criterion Criterion
  • McDiamird

Further Advanced Fatigue Analyses

• Spot Weld and Seam Weld analysis
• Multi-curve S-N analysis
• Temperature corrected fatigue analysis
• Vibration fatigue analysis
• Bastenaire S-N analysis

Purposes and Advantages of Fatigue Analysis

• To reduce development time and costs
• Allow components to be optimized for performance, weight, cost and fatigue life
• Avoid costly recall and aftersales alterations
• Avoid needless testing and analysis of non-critical components
• “Flag” potential problem areas early in the design cycle