How to Distinguish Failure Initiation from Damage Evolution
A procedure for correctly interpreting failure predictions — distinguishing when damage begins from how it progresses and when the structure collapses.
When to use this guide
Use this guide when interpreting composite failure predictions to avoid confusing initiation with final failure.
Key distinctions
- Failure initiation = damage mechanism begins (FI = 1.0) — NOT structural failure
- Damage evolution = stiffness degrades after initiation — the softening phase
- Structural collapse = structure can no longer carry load — the ultimate event
- Residual strength = load capacity with existing damage — for damage tolerance
- A failure index of 1.0 means damage initiates — the structure may have significant reserve