Joints, whether mechanical, adhesive, or hybrid, are critical to the performance of a composite structures because they transfer high loads even as they create significant stress concentrations. Structural failures usually originate at joints.
Bolted joints are an important area of interest because of their widespread use for ease of assembly/disassembly; and their application to thick composite sections is a major focus of this thrust area. Design and optimization of joints requires creative thinking, complex numerical analyses, and extensive experimental validations. Fully 3-dimensional static and dynamic finite element analyses are coupled with novel experimental methods for validation.
Fiber optic strain gages embedded during manufacturing provide through-the-thickness strain analysis. Digital speckle pattern interferometry is also used for surface and interior strain field measurements. Long-term objectives include the exploration of hybrid mechanical/adhesive joining of composites and the design of a novel hybrid system for structural and panel connections.