4. Structural Health Monitoring of Composite Tubes

Chapter 4 develops a genetic fuzzy system for structural health monitoring of thin-walled composite tubes. Such tubes are used for power transmission poles and in other important structures. The vibration analysis of the composite tube is conducted using the finite element method. A long pole proposed for power transmission is used for the numerical simulations. Matrix crack damage in the composite material is modeled using a theory based on effective elastic modulus applicable to cross-ply laminates. Composite materials are susceptible to many types of damage, but matrix crack is typically the first damage which occurs in these materials. Furthermore, matrix crack saturation marks the onset of other more serious damages such as delamination and fiber breakage. The genetic fuzzy system is developed to detect the location and size of matrix cracks in the composite pole. The genetic fuzzy system is developed by maximizing the success rate for damage detection under noisy conditions and is tested with noisy data. The misclassification behavior of the fuzzy system is analyzed, and it is found that the genetic fuzzy system works very well for the health monitoring problem.