This research was initiated with the goal of developing a significantly stronger
aircraft transparency design that would reduce transparency failures from bird
strikes. The objective of this research is to demonstrate the fact that
incorporating high-strength tempered glass into cockpit window constructions for
commercial aircraft can produce enhanced safety protection from bird strikes and
weight savings. Thermal glass tempering technology was developed that advances
the state of the art for high-strength tempered glass, producing 28 to 36%
higher tempered strength.
As part of this research, glass probability of failure prediction methodology was
introduced for determining the performance of transparencies from simulated bird
impact loading. Data used in the failure calculation include the total
performance strength of highly tempered glass derived from the basic strength of
the glass, the temper level, the time duration of the load, and the area under
load.
A high-strength transparency construction developed using advanced technology
tempered glass could produce significant weight saving estimated at 28% for a
typical Boeing 737 jetliner window, or about 11.5 kg for the four windows of the
Boeing 737 flight deck.
The conclusions from the principals developed in this research for an advanced
transparency construction including a 0.378-in. thick high-strength core ply
could reduce the probability of failure from bird strike loading from 4,503 to
953 parts-per-million (PPM). A 0.500-in. thick high-strength standard thickness
core ply could reduce the probability of failure from bird strike loading from
4,503 to 1.7 PPM.
