A Nondestructive Inspection Method to Determine Fatigue in Chemical Protective Suit and Shelter Materials

摘要: This study demonstrated the initial feasibility of using nondestructive inspection (NDI) penetrant-based methods for detecting fatigue cracks and similar breaches integrity in chemical protective clothing shelter materials. Such a technique could provide simple but direct means determining remaining life suits shelters. Chemical materials range from coated fabrics to highly engineered multi-layer, multi-film composites. Selected were tested off-the-shelf penetrant systems normally used inspecting metallic surfaces. Microscopy, biopenetration, permeation verify results NDI testing. The selected fatigued "Gelbo flex tester" simulate wear repeated flexing. Controlled diameter depth punctures also induce material defects. Fluorescent penetrants applied Teflon/Nomex or fiberglass/Teflon composite laminates formed large florescent halos around defects which had breached top layer Teflon. These easily observed show through translucent coating result wicking into fibrous center layer. detection success outer Teflon was virtually 100%. Halo indications typically 7 mm 0.12 puncture defect-representing an amplification factor over 50. When sample failed same level produced positive testing results. Penetrant correlated well with controlled half as deep thickness. Other types suit tested, including PVC butyl fabrics. While occurred some these materials, background coloring other caused interference technique.