| Description |
xi, 84 leaves : illustrations ; 29 cm |
| Summary |
"Cascaded inertial vibration isolation systems are examined in this report. Systems employing one, two or three masses in series on isolators are investigated. The objective is to determine if the cascaded systems have appreciable advantages over the classical single mass system. The equations of motion for these systems are derived by applying Newton's second law of motion. The homogeneous and steady state sinusoidal excitation solutions have been established. Transmissibility of forces and moments to the foundation has been obtained for several cases of force excitation. Comparisons of the cases investigated are based upon the principal mode frequencies, mode shapes, center of mass displacements and transmissibilities. The ratio of the maximum forcing function to the total weight of the system has in all cases been held at a level of one to four. The spring coefficients have been chosen such that each sub-system, i.e., one mass and its direct supporting springs, have a natural frequency of approximately one cps. The amplitudes of the top mass, in general, increase with the natural frequency bandwidths. Cases which do not follow this trend are those where some isolators connect the top mass directly to the foundation and cases having a lighter mass at the top. Transmissibilities are the lowest for the three mass system and the highest for the conventional one mass system"--Abstract, leaf ii. |
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