337

1 INTRODUCTION

KM. Sabuk Nusantara is a ship built to fulfill the

government of Indonesia's program on TOL LAUT

through the ministry of Transportation. Like other

sister ships, the Sabuk Nusantara ship, is also a

development of previous designs [1]. This ship is

pioneer ships to carry out inter-island shipping in

Indonesian sea. The vibrations that occur on the ship

have a side effect that has a large enough effect on the

resistance of the ship construction [2]. In planning a

construction of the internal part of the ship, see from

the design ability and the capacity of the stress

modulus it can accept [3, 4]. A construction that is

constantly subjected to vibrations is at great risk of

structural failure because the vibration itself is

destructive [5].

The greatest vibration occurs in the engine room,

but all other parts of the ship also experience

vibrations because it is propagating. Even though

there are methods to reduce these vibrations such as

engine beds, they can only reduce the damaging

effects and cannot completely eliminate the vibrations

themselves [6]. The propeller design planning can also

affect the vibrations that occur due to the less effective

pitch planning immersed in a draft of ship [7, 8]. From

the phenomenon that occurs, corrective steps can be

taken to reduce vibrations that occur in the engine

room of the ship. Ship vibration measurement process

KM. Sabuk Nusantara 71 is carried out in several

parts, and for a while it shows a fairly large indication

of local vibrations in the engine room section of the

ship, see figure 1.

Measurement of Maximum Vibration After the Addition of the

orger Construction to Evaluate the Side Deck Girder

onstruction Planning in the Ship Engine Room

. Sugeng, B. Utomo, S.D. Said, A.K. Yusim, A. Windyandari, S.F. Khristyson, L.

Afrizal,

.B. Jatmiko & Z.Z. Sanjiwo

Diponegoro University

, Semarang, Central Java, Indonesia

ABSTRACT: The greatest vibration occurs in the engine room, but all other parts of the ship also experience

vibrations because it is propagating. Even though there are methods to reduce these vibrations such as engine

beds, they can only reduce the damaging effects and cannot completely eliminate the vibrations themselves. The

method used in this research is to compare the measurement of good vibrations in the conditions before the

addition of construction and after the addition of construction for later comparison with numerical calculation

data. The purpose of this study is to obtain the maximum vibration value in the conditions after the addition of

the gorger construction before the addition of the side deck girder construction as a means of evaluating the

side deck girder construction planning in the ship engine room ship 2000 DWT. The result consideration of

adding construction becomes one or the alternative in providing reinforcement so that it can reduce the

vibration that occurs. From analyze results after addition of a sized T profile FB 180 x 8 mm FP 75 x 10 mm,

which ranges from 28 - 29 m/s

for the x-axis vibration value, while for vibrations on the y-axis the maximum is

10-11 m/s

, and on the maximum z-axis. at 20-21 m/s

, this analyze vibration is based on the time between 0 - 15

seconds or per 15 second interval, able to reduce percentage of vibration in the ship engine room area is 34.91%.

http://www.transnav.eu

the

International Journal

on Marine Navigation

and Safety of Sea Transportation

Volume 16

Number 2

June 2022

DOI: 10.12716/1001.16.0

2.16

338

Figure 1. Ship vibration measurement

Previous research has shown the path integration

method is used to address a stochastic response of

excited marine risers parametrically and externally

with correlated noise [9 – 11]. On the basis of the

nonlinear vibration equation, a vibration suppressor,

first-order vibration modes are studied and their

regulatory equations are formulated [12]. In the

research with the title “Probabilistic analysis on

parametric random vibration of a marine riser excited

by correlated Gaussian white noises”, Zhu et al. [13]

explain the results of the different time interval

approaches are compared with the results of the

Monte-Carlo model (MCS) simulation to show

adequate time intervals. After that, the path

integration method file with the Gauss - Legendre

scheme is used to obtain a solution for stationary

displacement and velocity vibrations. The path

integration solution (PIS) is compared to the

equivalent linearization method (EQL) and MCS [13].

On the other side in the research with the title

“Study on prediction methods and characteristics of

ship underwater radiated noise within full

frequency,” Zhang et al. [14] explain the results that

the calculation model has met the accuracy

requirements. To calculate the resulting vibrations

caused by the vibration of ships underwater at

medium and low frequencies, the finite element

method and the boundary element method (FE-BEM),

the finite element and the infinite element method

(FE-IFEM), and the finite element and the matching

layer automatic (FE-AML) is applied and shows the

respective results according to its characteristics. This

matter demonstrated that FE-BEM is the preferred

method for calculating ship underwater vibrations

and radiation in both modeling scales and

computational efficiency [14]. Calculation of hull

vibrations and underwater radiation noise at a high

enough frequency can be done to obtain noise and

vibration predictions [15]. Local vibrations can be

detected based on the directivity of the emitted waves

and affect the vibration distance [16 – 18].

Meanwhile in research with the title “Vibration

analysis of super-yachts: Validation of the Holden

Method and estimation of the structural damping,”

Alesandro explain the shape of the ocean waves

resulting from the hull being hit by the propeller spin,

is one of the most significant sources of vibrations

affecting the comfort of passenger ships.

Consequently, the evaluation of the propeller-

generated system via reliable numerical means during

the early stages of ship design is essential [6]. A

research result also shows that the predicted

magnitude of the propeller-induced dynamic

excitation is too high. In addition, the generated

propeller induced force and excitation of diesel

engine vibrations are applied to Finite Element

modeling to perform a series of forced vibration

analyzes and estimate the global structural damping

coefficient of the ship [19]. A study is also needed to

highlight the need to develop a new empirical

methodology, an analog measurement system for

application to modern ships [20].

Nevertheless, in each of these studies the

application is carried out on passenger ships,

considering that this passenger ship has a level of

comfort that must be considered. The concept of

vibration measurement is only centered on the

simulation and not correlated with field

measurements. So that it can make an opportunity for

this research to have a correlation where both the

calculation of vibrations that occur either before or

after the addition of a construction is carried out.

What is more of concern is that in this section the

measurement is rotated in the engine room, so that it

affects the performance of the ship's propulsion more.

The method used in this research is to compare the

measurement of good vibrations in the conditions

before the addition of construction and after the

addition of construction. For later comparison with

numerical calculation data. The purpose of this study

is to obtain the maximum vibration value in the

conditions after the addition of the gorger

construction before the addition of the side deck

girder construction as a means of evaluating the side

deck girder construction planning in the ship engine

room ship 2000 DWT.

2 MATERIALS AND METHODS

In this study, the ship used was KM. Sabuk Nusantara

71 with the main sizes, as can be seen in table 1.

Table 1. Main Size of the Ship

_______________________________________________

Description Score Unit

_______________________________________________

LOA (Length of Over All) 68.5 Meter

LBP (Length between Perpendicular) 63.00 Meter

B (Bearth) 14.00 Meter

H (Hight) 6.20 Meter

T (Draught) 3.50 Meter

DWT 2000 Ton

_______________________________________________

From the ship construction, the engine room

section was previously seen from the need for

additional construction. The engine room design can

be seen in Figure 2.

This Figure 2, shows a very complex engine room

construction design, the reinforcement system uses a

solid floor where the web used is a type of web frame

or T profile. The method used is the calculation

according to the numerical approach assisted by

computational software. The approximation to the

339

calculation of the formula vibration, itself is outlined

in the equation:

sinmx kx F t

−

(1)

where mx is the approximation to get mass (kg) and

multiplied by the displacement distance. For kx is the

constant of the type of vibration that occurs

multiplied by the addition of the length of the object's

position. and F is the force (N) and w is the weight of

the object (ton) sin wt is the position of the vibration

that is formed. From equation number 1 then if it is

described further, an approach can be written as in the

following equation

sin cos

xA tB t

ωω

=++

−

(2)

where ωn = k / m and the coefficients A1, B1 depend

on the velocity and displacement of mass when t = 0.

After the calculation values are obtained, they are

grouped to be analyzed and compared. From

equationNumber 2 the comparison uses a combined

graph to determine the maximum value of vibration

after and before the addition of the side girder

construction.

Figure 2. Engine Room Construction

3 RESULTS AND DISCUSSION

Based on the measurement results, it is reviewed into

several points that represent the vibrations that occur

on the ship while operating. The measurement results

can be seen in Figure 3.

Figure 3. Evaluation Result Vibration Test

From 32 measurement points location,

measurement results obtained both vertically and

horizontally, obtained plot data that shows the

highest value at location number 10, this shows that in

that area it is very necessary to provide reinforcement

to reduce the level of vibrations that occur and reduce

the occurrence of excessive vibrations. Then, the

addition of the T profile size as a damper medium to

reduce the vibration level is planned according to the

modulus calculation with the profile size as shown in

Figure 4.

Figure 4. Addition plan side deck girder construction in

engine room

The profile size used is FB 180 x 8 mm FP75 x 10

mm. From the side deck girder construction, the

vibration analyze are then carried out again after the

construction is installed. From the calculation results

according to the numerical approach, the results are as

shown in Figure 5.

Figure 5. Vibrations before adding a side deck girder

From figure 5, it can be seen that the waveform still

has a high enough peak value, which ranges from 48 -

49 m/s

for the x-axis vibration value, while for

vibrations on the y-axis the maximum is 8-9 m/s

, and

on the maximum z-axis. at 28-29 m/s

, this calculation

vibration is based on the time between 0 - 15 seconds

or per 15 second interval. Then it is compared with

the calculation after adding the side deck girder

construction, as shown in figure 5.

Figure 6. Vibrations after adding a side deck girder

340

From figure 6, it can be seen that the waveform still

has a high enough peak value, which ranges from 28 -

29 m/s

for the x-axis vibration value, while for

vibrations on the y-axis the maximum is 10-11 m/s

and on the maximum z-axis. at 20-21 m/s

, this

calculation vibration is based on the time between 0 -

15 seconds or per 15 second interval. From the

comparison results, the percentage of vibration

reduction on the x-axis was 40.28%, on the y-axis

33.33%, on the z-axis of 27.59%. So that the average

decrease in vibration due to the addition of side desk

girder construction in the ship engine room area is

34.91%. This shows the effect of vibration reduction

because the modulus of the profile that is planned is

suitable and is able to provide construction strength in

the ship engine area, so that it can be optimal in its

application.

4 CONCLUSION

The vibration of a structure makes the comfort level of

use and hunger deficient. Therefore, we need an

additional construction that can reduce the vibrations

that occur. The modulus of calculation of construction

planning construction succeeds in making vibrations

from the results shown at the beginning of the

measurement. The consideration of adding

construction becomes one or the alternative in

providing reinforcement so that it can reduce the

vibration that occurs.

Based on the results of vibration analyze, it was

found that the vibration value decreased after adding

the construction of the side deck girder to the engine

room. From calculation results, which ranges from 28

- 29 m/s

for the x-axis vibration value, while for

vibrations on the y-axis the maximum is 10-11 m/s

and on the maximum z-axis. at 20-21 m/s

, this

vibration sample is measured based on the time

between 0 - 15 seconds or per 15 second interval.

Evaluation results from the addition of a sized T

profile FB 180 x 8 mm FP 75 x 10 mm, able to reduce

percentage of vibration on the x-axis was 40.28%, on

the y-axis 33.33%, on the z-axis of 27.59%. So that the

average decrease in vibration due to the addition of

side deck girder construction in the ship engine room

area is 34.91%.

REFERENCES

[1] Tillig F., Ringsberg J. W., “Design, operation and

analysis of wind-assisted cargo ships,” Ocean

engineering, vol. 211, pp. 107603, 2020.

[2] Qian J., Chen L., “Random vibration of SDOF vibro-

impact oscillators with restitution factor related to

velocity under wide-band noise excitations,” Mechanical

Systems and Signal Processing, vol. 147, pp. 107082,

2021.

[3] Guo H. P., Zou Z. J., Wang F., Liu Y., “Numerical

investigation on the asymmetric propeller behavior of a

twin-screw ship during maneuvers by using RANS

method,” Ocean Engineering, vol. 200, pp. 107083, 2020.

[4] Ortolani F., Capone A., Dubbioso G., Pereira F. A.,

Maiocchi A., Di Felice F., “Propeller performance on a

model ship in straight and steady drift motions from

single blade loads and flow field measurements,” Ocean

Engineering, vol. 197, pp. 106881, 2020.

[5] Zheng H., Liu G. R., Tao J. S., Lam K. Y., “FEM/BEM

analysis of diesel piston-slap induced ship hull vibration

and underwater noise,” Applied Acoustics, vol. 62, no.

4, pp. 341-358, 2001.

[6] Zambon A., Moro L., Biot M., “Vibration analysis of

super-yachts: Validation of the Holden Method and

estimation of the structural damping,” Marine

Structures, vol. 75, pp. 102802, 2021.

[7] Chitrakar P., Baawain M. S., Sana A., Al-Mamun A.,

“Current status of marine pollution and mitigation

strategies in arid region: a detailed review,” Ocean

Science Journal, vol. 54, no. 3, pp. 317-348, 2019.

[8] Eskandarian M., Liu P., “A novel maneuverable

propeller for improving maneuverability and propulsive

performance of underwater vehicles,” Applied Ocean

Research, vol. 85, pp. 53-64, 2019.

[9] Baltzer J., Maurer N., Schaffeld T., Ruser A., Schnitzler J.

G., Siebert U., “Effect ranges of underwater noise from

anchor vibration operations in the Wadden Sea,” Journal

of Sea Research, vol. 162, pp. 101912, 2020.

[10] Guo J., Huang S., Nikolay T., Li M., “Vibration

damping of naval ships based on ship shock trials,”

Applied Acoustics, vol. 133, pp. 52-57, 2018.

[11] Li D. Q., Hallander J., Johansson T., “Predicting

underwater radiated noise of a full scale ship with

model testing and numerical methods,” Ocean

Engineering, vol. 161, pp. 121-135, 2018.

[12] Wang F., Lu Y., Lee H. P., Ma X., “Vibration and noise

attenuation performance of compounded periodic struts

for helicopter gearbox system,” Journal of Sound and

Vibration, vol. 458, pp. 407-425, 2019.

[13] Zhu H., Geng G., Yu Y., Xu L., “Probabilistic analysis

on parametric random vibration of a marine riser excited

by correlated Gaussian white noises,” International

Journal of Non-Linear Mechanics, vol. 126, pp. 103578,

2020.

[14] Zhang B., Xiang Y., He P., Zhang G. J., “Study on

prediction methods and characteristics of ship

underwater radiated noise within full frequency,”

Ocean Engineering, vol. 174, pp. 61-70, 2019.

[15] Li L., Gu X., Sun S., Wang W., Wan Z., Qian P., “Effects

of welding residual stresses on the vibration fatigue life

of a ship's shock absorption support,” Ocean

Engineering, vol. 170, pp. 237-245, 2018.

[16] Bai Y., Jin W. L, “Ship Vibrations and Noise Control”,

in Marine Structural Design, 2nd ed., Oxford:

Butterworth-Heinemann, pp. 259-273, 2015.

[17] Borelli D., Gaggero T., Rizzuto E., Schenone C.,

“Onboard ship noise: Acoustic comfort in cabins,”

Applied Acoustics, vol. 177, pp. 107912, 2021.

[18] Cinquemani S., Braghin F., “Decentralized active

vibration control in cruise ships funnels,” Ocean

Engineering, vol. 140, pp. 361-368, 2017.

[19] Soni T., Das A. S., Dutt J. K., “Active vibration control of

ship mounted flexible rotor-shaft-bearing system during

seakeeping,” Journal of Sound and Vibration, vol. 467,

pp. 115046, 2020.

[20] Liu H., Lian Z., Gong Z., Wang Y., Yu G., “Thermal

comfort, vibration, and noise in Chinese ship cabin

environment in winter time,” Building and

Environment, vol. 135, pp. 104-111, 2018.