He designed an innovative "triple-stage isolation" engine-mounting system that significantly quieted the vehicle, allowing the submarine to pass sound restrictions.
Figure 11 shows the influence of frequency ratio and damping ratio on the vibration transmission in the two-stage isolation case.
Results show that a two-stage isolation could reduce the excitation transmission and make the vibration of carbody and equipment acceptable.
Open image in new window Fig. 11 The acceleration transmissibility of two-stage isolation with different frequency ratios between two stages (a) and different secondary damping ratios (b). Figure 11a gives the acceleration transmissibility in different frequency ratio cases, where ωn_s represents the second suspension frequency, while the ωn_p represents the primary suspension frequency [19].
To analyze the effects of dynamic unbalance excitation from equipment on carbody vibration, a 20 g rotating unbalance in 0.1 100 Hz frequency range is applied on the equipment in a single-stage isolation system using a sweep frequency excitation method, and the acceleration of carbody center and equipment are analyzed.
To establish a two-stage isolation protocol, based on the time required for BMSCs to adhere to the culture flask, the cells were plated at low density to obtain colony-forming units-fibroblast (CFU-F) [ 8].
In an effort to develop a method to produce large numbers of cells with the characteristics stated above, we have undertaken studies to stratify human BMSCs obtained through a two-stage isolation protocol based on the time required for the cells to adhere to the culture flask surface.
And the dynamic unbalance and impact turbulence excitation from equipment were taken into account in a single-stage and two-stage vibration isolation system, respectively.
In this work, in order to reduce the vibration transmission, we modeled the carbody as an Euler Bernoulli beam to consider the flexible vibration of the carbody itself; the attached equipment under the chassis contains various exciting vibration sources, in a single-stage and two-stage vibration isolation system, respectively.
Each stage provides isolation in all directions of translation and rotation.
