Composite Bonded Joints Analysis, Data, and Substantiation – Industry Directions and Technical Issues

Hoyt, D.M., Ward S.H.

FAA Composite Bonded Joints Workshop Seattle, WA , June 16-18, 2004.

D.M. Hoyt (NSE Composites) and Steve Ward (SW Composites) provided perspectives on composite bonded joint analysis, design data, and structural substantiation. The application of bonding in the structure of different product types was considered in developing their assessment of the current state of the art in this area. Many different analysis methods were summarized in their presentation ranging from simple uniaxial, in-plane loading assumptions to complex multiaxial loading, combined with out-of-plane considerations. Their presentation pointed out the need to establish design criteria and analysis methods, which address manufacturing defects and service damage and are consistent with the economic realities associated with the inspection and disposition of defects in the factory and field. This was the thrust in their discussion of analysis methods available to support the design of bonded structure with damage. Without such analysis capability, the industry is forced to rely on testing and conservative design practices. Several engineering methods currently appear practical for applications, but there is still considerable dependence on building block testing at sufficient scale to incorporate real design, loading, and damage complexities. Hoyt and Ward provided a number of recommendations on analysis development and test standardization needed to answer the difficult questions arising with expanded applications of bonded structure (e.g., defect allowances, structural redundancy, and repairable damage limits).