We report a new core-shell microcapsule system for the visual detection of mechanical damage. The core material, 1,3,5,7-cyclooctatetraene, is a conjugated cyclic olefin and a precursor to intensely colored polyacetylene. A combination of poly(urea-formaldehyde) and polyurethane is required to effectively encapsulate the volatile core material. Increasing the outer shell wall thickness and incl...

The diagnostic algorithm introduced by Wayland et al. to test for degrees of visible determinism in complex dynamical behavior is applied to precise estimation of noise level for the gear-noise sound emanated from automobile automatic transmissions. It is shown that the method successfully captures such a small difference in acoustical characteristics indicating micro mechanical flaws on the ge...

Fully integrated monitoring systems have shown promise in improving confidence in composite materials while reducing lifecycle costs. A distributed optical fibre sensor is embedded in a fibre reinforced composite laminate, to give three sensing regions at different levels through-the-thickness of the plate. This study follows the resin infusion process during fabrication of the composite, monit...

OF THE THESIS Damage Detection in Dynamic Systems with Nonlinearities by William Bruce Dunbar Master of Science in Engineering Sciences (Applied Mechanics) University of California, San Diego, 1999 Professor John B. Kosmatka, Chair In general, damage detection can be described by the process of monitoring a physical dynamic (moving) system accompanied by con rmation and assessment of any degrad...

The emerging electro-mechanical impedance technology has high potential for in-situ health monitoring and NDE of structural systems and complex machinery. At first, the fundamental principles of the electro-mechanical impedance method are briefly reviewed and ways for practical implementation are highlighted. The equations of piezo-electric material response are given, and the coupled electro-m...

In order to investigate the stress characteristics of ballastless track under high latitude, and multi-source multi-field extreme temperature conditions. Based on finite element theory elastic foundation beam–plate principle, a model considering limit convex abutment, gel resin, interlayer bonding is established. The mechanical slab–CAM layer state, mortar separation, freeze–thaw degradation fo...