ALso, out of curiosity, what is the material that the brake discs are made of?
All the teams currently use carbon fibre composite brake discs.
I believe the failure wasn't caused by the brakes themselves. It somehow resembles Virgin's front wing problem, which they encountered back in winter testing.
I think that after Buemi had pressed the brake pedal, the load on the front wheels was at its peak, as the weight "shifted" to the front. STR engineers might have underestimated the forces that are present in such conditions, and therefore their suspension wasn't durable enough to withstand them. Just a wild guess but hey, we'll never be sure