ISO 18249:2015

Overview

ISO 18249:2015 - Non-destructive testing - Acoustic emission testing - Specific methodology and general evaluation criteria for testing of fibre-reinforced polymers (FRP) - defines how to apply acoustic emission testing (AT) to materials, components and structures made from fibre-reinforced polymers. The standard covers AT uses including materials characterization, proof testing and manufacturing quality control, retesting and in‑service testing, and continuous or periodic health monitoring. It provides a FRP‑specific methodology for instrumentation, sensor arrangements, source location and data presentation, plus general evaluation criteria and formats for reporting acoustic emission test results.

Key topics and requirements

• Scope & objectives: AT for FRP for damage detection, integrity assessment and identification of high‑damage zones.
• Acoustic emission sources: Typical FRP failure mechanisms covered - matrix cracking, fibre/matrix debonding, fibre pull‑out, fibre breakage, delamination and micro‑fracture.
• Instrumentation & monitoring: Guidance on sensors, coupling and mounting, sensor spacing and typical arrays, waveform storage, detection thresholds and equipment characterisation.
• Wave propagation: Consideration of anisotropy, attenuation, mode and dispersion in FRP materials and effect of temperature and geometry on AE signals.
• Test methodology: Procedures for specimen, component and structure testing - test preparation, load profiles, written test procedures, stop criteria and real‑time monitoring graphs.
• Evaluation criteria & data formats: General criteria for qualitative AE evaluation, procedures to establish criteria where absent, and standardised formats to simplify comparison across sites and organisations.
• Personnel & competence: Recommends qualified personnel (e.g. per ISO 9712) and competent test laboratories.
• Limitations: Notes that AE evaluation criteria alone may not always determine structural significance and may require complementary NDT methods or fracture mechanics assessment.

Practical applications

• Manufacturing quality control: Proof testing and acceptance of FRP pressure vessels, tanks, pipelines and composite components.
• In-service inspection & health monitoring: Periodic or continuous AE monitoring of safety‑critical FRP structures (e.g. CNG/H2 cylinders, aerospace and civil components).
• Materials R&D: Characterization of damage mechanisms and validation of sensor layouts and AE processing methods for new composite layups.
• Comparative testing: Standardised reporting allows benchmarking of AE results between test sites and suppliers.

Who should use this standard

• NDT engineers and technicians performing acoustic emission testing on composites
• Structural and materials engineers working with FRP in aerospace, automotive, civil and energy sectors
• QA/QC teams and test laboratories involved in FRP certification, proof testing or health monitoring programs

Related standards

• ISO 9712 (NDT personnel qualification), ISO 12716 (AE vocabulary), ISO/IEC 17025 (laboratory competence)
• EN 13477‑1/2 (AE equipment characterisation), EN 14584 / EN 15495 (AE examination during proof testing)

Keywords: ISO 18249:2015, acoustic emission testing, non‑destructive testing, fibre‑reinforced polymers, FRP health monitoring, AE sensors, evaluation criteria.