Description / Abstract: Introduction

Note: Nothing in this standard supercedes applicable laws and regulations.

Note: In the event of conflict between the English and domestic language, the English language shall take precedence.

Purpose. The purpose of this standard is to provide a guideline for performing pseudo-fatigue damage analysis for structural durability analysis as used in laboratory testing.

Applicability. This standard is based on the strain-life approach and is intended to be used on load or strain data for metallic components. It is not to be used with displacement or acceleration data. Plastic, composite, or elastomeric components may require use of the stress-life, fracture mechanics, strain energy or other approaches which are not covered in this document.

Remarks. This standard applies to the pseudo-fatigue damage analysis typically used to compare road data to laboratory data. Pseudo-Fatigue Damage is a damage value calculated using a time history (load, displacement, etc.) with non-strain engineering units to approximate the strain at a hypothetical notch on the test specimen. This standard is written such that it could be used for several software packages, but with an emphasis on MTS’ RPC Pro (see Appendix B). Issues considered by this document include rainflow cycle counting, material, linearity of the material model, which back-calculation factor (Kf or Sf) to back-calculate to, mean stress correction, polarity, assumed life, damage distribution and optimization. The type of input data (strain or load) affects some of the choices.

For special cases, deviation from this standard may be acceptable. The Computer Aided Test (CAT) Technology Manager should be consulted regarding the deviation.