Vibration test systems, equipment, and components as follows: a. Electrodynamic vibration test systems, having all of the following characteristics: 1. Employing feedback or closed loop control techniques and incorporating a digital control unit; 2. Capable of vibrating at 10 g RMS or more between 20 and 2000 Hz; and 3. Capable of imparting forces of 50 kN or greater measured ´bare table´; b. Digital control units, combined with "software" specially designed for vibration testing, with a real-time bandwidth greater than 5 kHz and being designed for a system specified in Item 1.B.6.a.; c. Vibration thrusters (shaker units), with or without associated amplifiers, capable of imparting a force of 50 kN or greater measured ´bare table´, which are usable for the systems specified in Item 1.B.6.a.; d. Test piece support structures and electronic units designed to combine multiple shaker units into a complete shaker system capable of providing an effective combined force of 50 kN or greater, measured ´bare table´, which are usable for the systems specified in Item 1.B.6.a.