Journal of Marine Science and Engineering

Research

18 pages, 3215 KiB

Open AccessArticle

Vibration Isolation Performance of a Constrained Damping Base for a High-Pressure Plunger Pump

by Zepeng Zheng, Shuqing Wang, Xiancang Song and Xichen Wang

J. Mar. Sci. Eng. 2024, 12(5), 738; https://doi.org/10.3390/jmse12050738 - 28 Apr 2024

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Based on the effect of damped shear deformation on energy dissipation, a new constrained damping base for a polymer injection platform deck is proposed to reduce the excessive vibrations caused when multiple plunger pumps are jointly operated. A model for analyzing the vibration [...] Read more.

Based on the effect of damped shear deformation on energy dissipation, a new constrained damping base for a polymer injection platform deck is proposed to reduce the excessive vibrations caused when multiple plunger pumps are jointly operated. A model for analyzing the vibration response of an I-beam-constrained damping base for a polymer injection platform with multiple plunger pumps was established using Abaqus 6.14 software and compared with rigid base and traditional rubber vibration isolators in terms of its vibration isolation performance. Furthermore, the effects of the damping material’s loss factor, the thickness of the damping layer, and the number of expansion layers on the vibration isolation characteristics of the constrained damping base were explored. This study shows that, with an increase in the damping material’s loss factor, the thickness of the damping layer and the number of extended layers, the vibration isolation performance of the constrained damping base is gradually enhanced. When the damping material’s loss factor is 1.0, the thickness of the damping layer is 20 mm, and the number of extended layers is 3, the constrained damping base’s vibration damping effect is optimized, and its vibration isolation rate becomes as high as 46.63%, which can significantly reduce the vibration response of the polymer injection platform. Full article

(This article belongs to the Special Issue Anti-explosion, Anti-impact and Vibration Isolation Advanced Protection Design in Naval Architecture and Ocean Engineering)

19 pages, 10318 KiB

Open AccessArticle

Study on the Deformation Mode and Energy Absorption Characteristics of Protective Honeycomb Sandwich Structures Based on the Combined Design of Lotus Root Nodes and Leaf Stem Veins

by Wei Chen, Chunyang Chen, Yiheng Zhang, Pu Li, Mengzhen Li and Xiaobin Li

J. Mar. Sci. Eng. 2024, 12(4), 652; https://doi.org/10.3390/jmse12040652 - 14 Apr 2024

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Abstract

Sandwich structures are often used as protective structures on ships. To further improve the energy-absorbing characteristics of traditional honeycomb sandwich structures, an energy-absorbing mechanism is proposed based on the gradient folding deformation of lotus root nodes and a leafy stem vein homogenizing load [...] Read more.

Sandwich structures are often used as protective structures on ships. To further improve the energy-absorbing characteristics of traditional honeycomb sandwich structures, an energy-absorbing mechanism is proposed based on the gradient folding deformation of lotus root nodes and a leafy stem vein homogenizing load mechanism. A honeycomb sandwich structure is then designed that combines lotus root nodes and leafy stem veins. Four types of peak-nest structures, traditional cellular structure (TCS), lotus root honeycomb structure (LRHS), leaf vein honeycomb structure (LVHS), and lotus root vein combined honeycomb structure (LRVHS), were prepared using 3D printing technology. The deformation modes and energy absorption characteristics of the four honeycomb structures under quasistatic action were investigated using a combination of experimental and simulation methods. It was found that the coupling design improved the energy absorption in the structural platform region of the LRHS by 51.4% compared to that of the TCS due to its mechanical mechanism of helical twisting and deformation. The leaf vein design was found to enhance the peak stress of the structure, resulting in a 4.84% increase in the peak stress of the LVHS compared to that of the TCS. The effects of the number, thickness, and position of the leaf vein plates on the honeycomb structure were further explored. The greatest structural SEA effect of 1.28 J/g was observed when the number of leaf vein plates was four. The highest SEA of 1.36 J/g was achieved with a leaf vein plate thickness of 0.6 mm, representing a 7.3% improvement compared to that of the 0.2 mm thickness. These findings may provide valuable insights into the design of lightweight honeycomb sandwich structures with high specific energy absorption. Full article

(This article belongs to the Special Issue Anti-explosion, Anti-impact and Vibration Isolation Advanced Protection Design in Naval Architecture and Ocean Engineering)

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19 pages, 7372 KiB

Open AccessArticle

Experimental Study of the Load-Transfer Law and Shock Environment of a Pipe–Float System

by Miaoran Li, Jun Li, Wei Chen, Zhiyang Lei, Lijiang Zhou, Mengzhen Li, Chun Bao Li and Xiaobin Li

J. Mar. Sci. Eng. 2024, 12(4), 650; https://doi.org/10.3390/jmse12040650 - 12 Apr 2024

Viewed by 519

Abstract

To study the load-transfer law and shock environment of a pipe–float system, an experimental model was designed, manufactured, and installed on a floating shock platform. Two underwater explosion cases were studied, focusing on vertical and horizontal shock cases. The experimental results show that [...] Read more.

To study the load-transfer law and shock environment of a pipe–float system, an experimental model was designed, manufactured, and installed on a floating shock platform. Two underwater explosion cases were studied, focusing on vertical and horizontal shock cases. The experimental results show that the structure of the system on the floating raft significantly influences the load acceleration transfer and the composition of the vertical and horizontal components. Furthermore, the flexible connector can effectively block the response behavior of the two ends of the pipe, and the peak acceleration difference between the two pipe ends is 98.9%. The vertical and horizontal components of the shock-wave load affect the stress concentration locations on the pipe. The main frequency in the shock environment at the connection point between the floating raft and the upper equipment shifts toward middle and low frequencies under the influence of the upper equipment, and it will be closer to the natural frequency of the upper equipment. Full article

(This article belongs to the Special Issue Anti-explosion, Anti-impact and Vibration Isolation Advanced Protection Design in Naval Architecture and Ocean Engineering)

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20 pages, 5711 KiB

Open AccessArticle

Study on Assessment of Collision Probability between Ship and Bridge Based on Automatic Identify System Data

by Jin Pan, Yong Wang, Tao Wang and Mingcai Xu

J. Mar. Sci. Eng. 2024, 12(3), 452; https://doi.org/10.3390/jmse12030452 - 03 Mar 2024

Viewed by 990

Abstract

With the development of bridge crossings over rivers, the accident of the vessel–bridge collision is increasing as well. It is important to assess probability of bridges colliding with passing ships. Firstly, the AIS (Automatic identify system) data was collected and decoded to obtain [...] Read more.

With the development of bridge crossings over rivers, the accident of the vessel–bridge collision is increasing as well. It is important to assess probability of bridges colliding with passing ships. Firstly, the AIS (Automatic identify system) data was collected and decoded to obtain the dynamic information of the ships passing the bridge including the distributions of ships position, speed, and yaw angle, which are then compared with the value recommended by the AASHTO (American Association of State Highway and Transportation Officials) specification. The mainly influential parameters of ship–bridge collision obtained from AIS data are used to correct the variables in the risk assessment of AASHTO specification, which intends to improve the assessment accuracy by considering the actual information of passing vessels. The collision probability with and without considering the actual situations of passing ships are compared. It is found that the distribution and transit path of passing ships significantly influence the collision probability. To improve the risk assessment accuracy, it is suggested to use the actual distributions of passing ships from AIS data. Full article

(This article belongs to the Special Issue Anti-explosion, Anti-impact and Vibration Isolation Advanced Protection Design in Naval Architecture and Ocean Engineering)

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20 pages, 9851 KiB

Open AccessArticle

An Investigation of the Damage Mechanism of Multilayer Liquid-Containing Protective Structure under Combined Blast Wave and Fragment Loading

by Zeqing Fan, Xiaobin Li, Tao Huang and Wei Chen

J. Mar. Sci. Eng. 2023, 11(12), 2327; https://doi.org/10.3390/jmse11122327 - 08 Dec 2023

Cited by 1 | Viewed by 851

Abstract

A multilayer liquid-containing protective structure is composed of a liquid tank, ceramic, a honeycomb sandwich and homogeneous steel. This structure has superior resistance to combined blast wave and fragment loading. Due to the relatively complicated construction of the structure, the inner damage, energy [...] Read more.

A multilayer liquid-containing protective structure is composed of a liquid tank, ceramic, a honeycomb sandwich and homogeneous steel. This structure has superior resistance to combined blast wave and fragment loading. Due to the relatively complicated construction of the structure, the inner damage, energy absorption and the protection characteristics of the multilayer liquid-containing protective structure need to be further studied. In this paper, a multilayer liquid-containing structural model is constructed, the dynamic response process of multilayer liquid-containing structure under combined blast wave and fragment loading is analyzed, and the damage and energy absorption characteristics of each layer structure are investigated. In addition, the effects of the charge mass and fragment form on the structural failure modes and energy absorption characteristics are discussed. The results indicate that different modes of damage occur in each layer structure. The front plate of the liquid tank sustains the most damage and absorbs the most energy, and the honeycomb sandwich absorbs the second most energy. The damage area of the front plate and the degree of compression collapse of the honeycomb sandwich increase with increasing charge mass. When the charge mass is small, the damage mode of the multilayer liquid-containing structure is greatly affected by fragments, and the damage effect of the blast wave increases with increasing charge mass. For a constant charge mass, the degree of damage to the protective structure is minimally impacted by the fragment weight, and the degree of damage can be substantially reduced by reducing the number of fragments. Full article

(This article belongs to the Special Issue Anti-explosion, Anti-impact and Vibration Isolation Advanced Protection Design in Naval Architecture and Ocean Engineering)

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14 pages, 6946 KiB

Open AccessArticle

Research on the Shock Environment Characteristics of a Marine Diesel Engine Based on a Large Floating Shock Platform

by Yu Zhang, Jun Li, Chunhui Zhang, Wei Chen, Zhipeng Du and Xiaobin Li

J. Mar. Sci. Eng. 2023, 11(12), 2308; https://doi.org/10.3390/jmse11122308 - 06 Dec 2023

Viewed by 702

Abstract

To conduct a precise shock assessment of marine diesel engines, a 200 t floating shock platform was utilized to simulate realistic testing conditions. The testing generated the acceleration time curve and the shock response spectrum for the diesel engine. According to the applicable [...] Read more.

To conduct a precise shock assessment of marine diesel engines, a 200 t floating shock platform was utilized to simulate realistic testing conditions. The testing generated the acceleration time curve and the shock response spectrum for the diesel engine. According to the applicable standards, the spectral velocity was chosen as the evaluation index, and an evaluation of the longitudinal, transverse, and vertical shock environment of the diesel engine was conducted. The shock factor interpolation method was corrected using the confidence interval based on normal distribution, and the interpolated confidence interval of the shock factor was determined. The findings reveal that shock waves were identified as the primary external force, and it was found that the influence of bubble pulsation can be disregarded when assessing a floating shock platform. This paper proposes the use of normal-distribution-based shock factor confidence intervals, which can accurately predict multidirectional shock factors and offer improved shock safety compared to the traditional method of unidirectional shock factor interpolation. The results and methods obtained in this study can provide valuable guidance and assistance for predicting the shock environment of large shipboard machinery on significant floating shock platforms. Full article

(This article belongs to the Special Issue Anti-explosion, Anti-impact and Vibration Isolation Advanced Protection Design in Naval Architecture and Ocean Engineering)

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18 pages, 18708 KiB

Open AccessArticle

Study of Mechanical Properties of Three-Dimensional Framed Plate Protective Structures with Negative Poisson’s Ratio

by Weijun Lin, Mengzhen Li, Pu Li, Qianning Li and Wei Chen

J. Mar. Sci. Eng. 2023, 11(12), 2261; https://doi.org/10.3390/jmse11122261 - 29 Nov 2023

Viewed by 737

Abstract

In this paper, the negative Poisson’s ratio and rigidity of a protective structure are improved to allow the structure to exert a negative Poisson’s ratio effect in multiple directions and to enhance the structural load-carrying capacity. Therefore, a 3D framed plate honeycomb is [...] Read more.

In this paper, the negative Poisson’s ratio and rigidity of a protective structure are improved to allow the structure to exert a negative Poisson’s ratio effect in multiple directions and to enhance the structural load-carrying capacity. Therefore, a 3D framed plate honeycomb is designed on the basis of a traditional 2D negative Poisson’s ratio honeycomb. The Poisson’s ratio and modulus of elasticity are derived, and the equivalent mechanics model (EMM) of a 3D framed plate protective structure is established by combining bending deformation, shear deformation, and compression deformation. To verify the validity of the equivalent mechanics model (EMM), a compression test and numerical simulation study are carried out by combining 3D printing technology and numerical simulation methods. In addition, the effects of structural parameters on the modulus of elasticity, negative Poisson’s ratio, and other mechanical properties are discussed. The results show that, under vertical loading, the equivalent Poisson’s ratio and the modulus of elasticity of the cell elements decrease with the increase in the ratios of the lengths of the cell element walls in the upper and lower planes to the length of the diagonal cell element in the concave direction. In addition, it is shown that the elastic modulus increases with increasing concave angle and thickness. Moreover, under lateral loading, the equivalent Poisson’s ratio of the cell elements increases with the ratios of the lengths of the upper and lower planar cell element walls to the length of the diagonal cell element walls, with the angle of concavity and with the thickness of the plate frame, while the modulus of elasticity of the cell elements exhibits the opposite trend and decreases with the thickness of the framed plate structure. Full article

(This article belongs to the Special Issue Anti-explosion, Anti-impact and Vibration Isolation Advanced Protection Design in Naval Architecture and Ocean Engineering)

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15 pages, 9875 KiB

Open AccessArticle

The Effect of the Layout of a Rigid Splitter Plate on the Flow-Induced Vibration of a Downstream Cylinder Subjected to Wake Flow

by Li Ruan, Dingyong Yu, Jian Bao and Jinxin Zhao

J. Mar. Sci. Eng. 2023, 11(11), 2138; https://doi.org/10.3390/jmse11112138 - 09 Nov 2023

Viewed by 812

Abstract

In this study, the effect of additional positions of rigid splitter plates on the response characteristics of tandem cylinders at a Reynolds number of 150 and a fixed distance ratio of 5.0 was numerically investigated via the computational fluid dynamics (CFD) method. Four [...] Read more.

In this study, the effect of additional positions of rigid splitter plates on the response characteristics of tandem cylinders at a Reynolds number of 150 and a fixed distance ratio of 5.0 was numerically investigated via the computational fluid dynamics (CFD) method. Four layouts for the cylinder–plate body, including a downstream cylinder (DC), a downstream cylinder–plate body with a wake side plate (DCP), a downstream plate–cylinder body with an incoming flow side plate (DPC), and a downstream plate–cylinder–plate body with a double-sided plate (DPCP), are considered. The results show that the splitter plate attached to the incoming flow side or the wake side can suppress the vibration of the downstream cylinder in a specific reduced velocity range (4.0 < U_r ≤ 10.0). Compared with the DC, the maximum response amplitude of the DPC and DCP in the lock-in region is reduced by 30.8% and 47.4%, and the lock-in bandwidth is also significantly narrower. The layer separation point of the upstream cylinder moves downstream upon adding splitter plates to both the incoming flow and wake sides, and the resulting splitter shear layer of the DPCP is completely parallel to the free flow, while the maximum response amplitude is reduced by 93.6%, which realizes the best effect of stream-induced vibration suppression. Full article

(This article belongs to the Special Issue Anti-explosion, Anti-impact and Vibration Isolation Advanced Protection Design in Naval Architecture and Ocean Engineering)

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