An Approach to Calculation of Marine Machinery Flexible Seating
; Hrvatski registar brodova, Split
; Fakultet strojarstva i brodogradnje Sveučilišta u Zagrebu
; Fakultet elektrotehnike, strojarstva i brodogradnje Sveučilišta u Splitu
APA 6th Edition Vulić, N., Šestan, A. i Barle, J. (2008). JEDAN PRISTUP PRORAČUNU ELASTIČNOG TEMELJENJA BRODSKIH STROJEVA. NAŠE MORE, 55 (3-4), 127-136. Preuzeto s https://hrcak.srce.hr/29434
MLA 8th Edition Vulić, Nenad, et al. "JEDAN PRISTUP PRORAČUNU ELASTIČNOG TEMELJENJA BRODSKIH STROJEVA." NAŠE MORE, vol. 55, br. 3-4, 2008, str. 127-136. https://hrcak.srce.hr/29434. Citirano 20.04.2019.
Chicago 17th Edition Vulić, Nenad, Ante Šestan i Jani Barle. "JEDAN PRISTUP PRORAČUNU ELASTIČNOG TEMELJENJA BRODSKIH STROJEVA." NAŠE MORE 55, br. 3-4 (2008): 127-136. https://hrcak.srce.hr/29434
Harvard Vulić, N., Šestan, A., i Barle, J. (2008). 'JEDAN PRISTUP PRORAČUNU ELASTIČNOG TEMELJENJA BRODSKIH STROJEVA', NAŠE MORE, 55(3-4), str. 127-136. Preuzeto s: https://hrcak.srce.hr/29434 (Datum pristupa: 20.04.2019.)
Vancouver Vulić N, Šestan A, Barle J. JEDAN PRISTUP PRORAČUNU ELASTIČNOG TEMELJENJA BRODSKIH STROJEVA. NAŠE MORE [Internet]. 2008 [pristupljeno 20.04.2019.];55(3-4):127-136. Dostupno na: https://hrcak.srce.hr/29434
IEEE N. Vulić, A. Šestan i J. Barle, "JEDAN PRISTUP PRORAČUNU ELASTIČNOG TEMELJENJA BRODSKIH STROJEVA", NAŠE MORE, vol.55, br. 3-4, str. 127-136, 2008. [Online]. Dostupno na: https://hrcak.srce.hr/29434. [Citirano: 20.04.2019.]
Sažetak Marine propulsion and auxiliary machinery are seated on stiff seating (metal supports or resin chocks) or flexible seating (elastic supports with rubber parts). The basic purpose of flexible seating is to reduce detrimental influence of vibrations and direct transfer of noise to the ship structure. Consequentially, flexible seating is usually implemented in passenger ships.
The aim of this paper is to present a simplified procedure for calculation of flexible seating for marine machinery, in order to ease the work of designers of marine propulsion and auxiliary machinery. The simplified calculation basically contains of evaluation of static forces in the flexible supports, as well as the natural frequencies for the six degree-of-freedom system, from which critical rotational speeds can be determined. The calculation is presented in matrix form (similar to the conventional FEM calculations of linear elastic systems) with all the necessary details enabling a designer’s autonomous work. Generally, the methodology of calculation of system dynamic response to forced damped vibrations is also presented.
The contribution of the paper is in the calculation methodology presented in matrix form, as well as in the proposal to avoid evaluation of excitation forces. Under certain conditions it is enough to know only the frequency of the excitations, caused by internal combustion engine cylinders and propeller in operation, but not their magnitude or phase, as well as to compare that frequency in Campbell diagram with the calculated natural frequencies to make the decision about the necessity of more complex approach.
An example of calculation results for the flexibly mounted propulsion system of a series of newbuildings, built in a domestic shipyard, has been presented, together with the comparison with the measurement results from the literature on the first ship. It is concluded that the calculation of flexible seating should not be avoided in practice, what is a common situation. Contrary, by implementing the proposed simplified calculation procedure the necessary static and dynamic analyses should be performed. This is the way to avoid difficulties during the design phase early enough, which are not easy to deal with later on.