Nevertheless composite airplanes have been around for more than 60 years now and there is quite a bit of experience with them. The flexing a high performance glider plane wing can withstand is impressive, in gusts you can see waveforms travelling through the wing and torsion during highspeed flight is quite severe. Happens nearly every flight and correctly repaired wings and fuselages have no performance issues at all, which is quite something considering that the normal operating envelope is +5,3g/-2,6g.