| Abstract Scope |
We have seen an increase in thermoplastic technology applications over the past 30 years. Also, applications with increasing structural significance, and thermoplastic assemblies rather than isolated press formed parts, using novel joining methods like welding.
Why thermoplastics? Lower manufacturing costs, lower weight and better durability, better performance at environmental conditions:
– Ease of manufacture (for example press forming)
– Better properties (lower moisture uptake, better through the thickness strength)
– Replacing traditional thermoset sandwich structures with discretely stiffened / monolithic
– Automation in the manufacturing process, short cycle times, high rate capable
– Saving energy cost (out-of-autoclave) using dedicated consolidation tools and recycling
For a new material and structurally significant application, it takes 10 – 12 years to complete all qualifications and develop the full suite of M&P specifications, analysis methods, and analysis – test correlations at every level of the certification test pyramid.
Ideally, one should also gather in-service experience with less significant applications first, or obtain experimental (‘flying demonstrator’) experience. Generally however, OEM’s only allow some 5 – 7 years between supplier selection / PDR and TC / EIS. It is difficult to develop the lower levels of the pyramid in time for upcoming applications, to develop new concepts, understanding, and develop a complete certification test pyramid. Process control in the production processes is key. And damage threats are real, impact events, lightning strike and severe hail strike examples will be covered. |