相控阵超声PAUT实战指南：叶片翼梁帽检测、缺陷分类与验收标准

Why Spar Caps Demand Volumetric UT

Spar caps are the thickest laminate sections in a blade, up to 80 mm of unidirectional glass or carbon fibre. Defects that are invisible at the surface, internal wrinkles, resin-starved layers, kissing bonds at ply drops, become critical under the 10⁸ fatigue cycles a blade sees in its lifetime.

Visual inspection and tap testing cannot detect these. Thermography sees near-surface anomalies but cannot resolve through-thickness defects in thick carbon laminates. Only volumetric ultrasonic inspection gives full-depth coverage.

The PAUT Advantage

A phased array probe with 64 elements can steer and focus the ultrasonic beam electronically, generating a sector scan that covers 40-70° through the spar cap laminate in one pass. This eliminates the mechanical raster scanning that makes conventional UT so slow.

At 500 mm/s, a linear PAUT array covers the full width of a 600 mm spar cap in a single longitudinal pass. The same coverage with a single-element probe would require 20 parallel passes and take 5 times longer.

Dual-Modality: PAUT + TOFD

PAUT excels at detecting planar defects parallel to the laminate, delamination and dry laminate. Time-of-Flight Diffraction (TOFD) is complementary: it detects volumetric defects like porosity clusters and resin-starved zones regardless of orientation.

Running both modalities simultaneously on a 256-channel acquisition system gives you both detection mechanisms in one scan pass. The C-scan map overlays PAUT amplitude data with TOFD depth data, producing a complete picture of spar cap integrity.

IEC 61400-5 Acceptance Criteria (Simplified)

IEC 61400-5 Annex G defines the following maximum allowable indications in spar cap laminates:

Automated PAUT enforces these criteria objectively, the software flags every indication that exceeds the threshold, removing operator judgement from the accept/reject decision.

Inline Integration

At a blade plant producing one shell per mould per day, the inspection window is measured in minutes, not hours. The MIS-100 gantry integrates PAUT scanning into the moulding station workflow:

1. Post-infusion: PAUT scan of the spar cap within 30 minutes of infusion completion
2. Pre-bonding: TOFD scan of bond-line preparation surfaces
3. Post-assembly: Full-volume scan of the completed shell before painting

Results from all three stations feed into a single digital record per blade serial number, traceable from lay-up to field service.