What NVH issues are common in driveshaft systems and how are they addressed?

Common driveshaft NVH issues include: Vibration from imbalance or runout (addressed by precision balancing and machining), Critical speed vibration (shaft resonance - addressed by tuning shaft length, diameter, or adding dampers), U-joint angle vibration (maintain equal angles, proper phasing), Torque fluctuation excitation (use constant velocity joints), and Boom from shaft resonance at specific speeds. Analysis involves modal testing, order tracking, and simulation. Solutions include tuned mass dampers, carbon fiber shafts, and two-piece designs with center bearing.