The lightning damage resistance of Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) panels was characterized experimentally. Two unprotected PRSEUS panels were subjected to standard impulse current waveforms (consistent with actual lightning strikes) with 50, 125, and 200 kA nominal peak currents at a variety of panel locations. Lightning-induced damage to the PRSEUS panels was a strong function of (1) the peak current, (2) the lightning attachment location (mid-bay, stringer, frame, etc.) that involved different through-thickness Vectran™ stitching, and (3) the presence of a surface finish paint. The sizes of the damaged regions increased as the peak current increased, since greater peak current leads to more Joule heating. The lightning-damaged PRSEUS panels exhibited unique damage features due to the presence of through-thickness Vectran™ stitches and warp-knitted fabrics. Through-thickness Vectran™ stitches constrained the development and spread of intense local damage in the vicinity of the lightning attachment point. The polyester warp-knit threads used to stitch the warp-knitted laminates together appeared to influence the development of widespread small-scale fiber damage in the region surrounding the strike. Consequently, the Vectran™ structural stitches, as well as the polyester knit threads holding the tows together, have a significant beneficial effect on both the size of the impingement region and the subsequent damage propagation within the laminate. In addition, damage to the painted panel was greater for each current level than for the sanded (unpainted) panel.
- Lightning strike tests
- Stitched laminated composites