Compression-After-Impact Reference

A quick reference for CAI — test procedure, failure mechanism, strength retention and design significance.

Advanced Damage & Failure2 min read

referenceCAIcompression after impacttestmechanismstrength retention

Key Facts

CAI test:
  Phase 1: Impact (drop-weight, specified energy → BVID)
  Phase 2: Compression (stabilised fixture → failure)

Failure mechanism:
  Delamination → sublaminate buckling →
  delamination growth → fibre failure → collapse

CAI strength:
  σ_CAI = P_failure / (w × t)
  Retention = σ_CAI / σ_undamaged
  Typically 40-70% for carbon/epoxy with BVID

Design significance:
  Primary damage tolerance metric
  Governs laminate design for compression-critical structure
  Drives inspection intervals