The invention is a composite system useful for indicating and preventing fatigue on essentially any metallic structure.
Detection of failures and/or potential failures in fatigue-critical connections in structures is problematic. It is also important to have an effective method for preventing the propagation of existing fatigue cracks in various structures once they are detected. An invention that has a system and method that can provide fatigue enhancement and at the same time provide visual indication of the fatigue state of the connection would significantly enhance the safety of the system. The composite system developed by the researchers at the University of Kansas works as a surface treatment for existing structural elements. The system reduces stress levels at structural details so that the adverse effects of structural fatigue are substantially reduced. Additionally, the composite system provides a method of fatigue level indication at the given structural detail.
New and existing bridge structures, metal structures
The composite system is bonded to the prepared surfaces of structural members by a structural adhesive or is applied by spray application. As the structural member is exposed to fatigue loading, the system accepts a portion of the load. Because many details are particularly fatigued in bending, the added local structural thickness substantially improves stiffness, even though the material stiffness of the system may be considerably lower than the underlying material. If fatigue level is reached, the composite material will crack through and essentially unzip the surface of the structure, exposing an indicator. The indicator then alerts the engineers to the exact location and fatigue levels being encountered at a specific structural detail.
This invention significantly enhances the safety of new and existing metal structures. It improves the fatigue resistance of the overall structure. It acts as an indicator of fatigue, failure, and damage levels.
This invention combines the benefits of a structural doubler and a fatigue fuse. The combination is much more useful in fatigue reduction techniques as well as indication methods. The indication methods include the capability of gross coloration and form factor changes depending on the level of fatigue, failure, or damage.
Detection and prevention of fatigue on any metallic structures