Secondary structures may have to endure severe vibration amplitudes under the influence of the primary structures on which they are mounted. A series of numerical case studies are presented in this thesis to investigate the effectiveness of a passive vibration controller which combines a conventional tuned absorber with an impact damper, to attenuate the excessive vibration amplitudes of light secondary structures. In addition, experimental measurements are reported for some selective cases and comparisons are made with numerical predictions. This suggested configuration seems to suit ideally as an add-on enhancer for existing conventional absorbers. Most of the Results are presented for random white noise excitation, and a few representative transient vibration cases are also studied. / Thesis / Master of Engineering (ME)