Methods for hull structure strength analysis and ships service life evaluation, under extreme hydroelastic wave loads, for a large oil-tanker

2011 ◽  
pp. 459-471
Author(s):  
L Domnisoru ◽  
A Chirica
Keyword(s):  
Service Life ◽  
Strength Analysis ◽  
Wave Loads ◽  
Life Evaluation ◽  
Hull Structure ◽  
Structure Strength ◽  
Oil Tanker

Numerical Methods for Hull Structure Strength Analysis and Ships Service Life Evaluation, for a LPG Carrier

2008 ◽  
Author(s):  
Leonard Domnisoru ◽  
Dumitru Dragomir ◽  
Alexandru Ioan
Keyword(s):  
Service Life ◽  
Dynamic Response ◽  
Ship Hull ◽  
Design Stage ◽  
Head Wave ◽  
Strength Analysis ◽  
Response Analysis ◽  
Wave Loads ◽  
Life Evaluation ◽  
Hull Structure

In this paper the authors focus on the ship hull structure strengths and fatigue analyses, in order to estimate the ship service life period at the initial design stage. The topic of the paper is divided in three-interlinked parts. The first part includes the method for the hull strength analysis, based on 3D/1D-FEM models, under equivalent quasi-static head wave loads. The second part presents the method for the ship hull dynamic response analysis, based on non-linear hydroelasticity theory with second order wave spectrum. The last part includes the fatigue analysis method for the initial ship hull structure, based on the long-term prediction ship dynamic response, the cumulative damage ratio and the design S-N material curves. The numerical analyses are carried out for a LPG carrier with independent cargo-tanks type A. Two significant load cases are considered: full and ballast. The numerical results outline the extreme wave loads and the ships initial service life evaluation.

Structure Strength Analysis for Universal Coupling of Medium Thickness Plate Mill Based on FEM

2013 ◽  
Vol 321-324 ◽  
pp. 1794-1798
Author(s):  
Li Kun Guan ◽  
Wei Dong Liu ◽  
Ning Ning Wang
Keyword(s):  
Optimization Design ◽  
Maximum Load ◽  
Coupling Model ◽  
Strength Analysis ◽  
Plate Mill ◽  
Medium Thickness ◽  
Element Analysis ◽  
Fork Head ◽  
Structure Strength ◽  
Universal Coupling

In this paper,in view of the fork head often broken of the main drive system of a medium thickness plate mill,finite element analysis software ANSYS is used to establish universal coupling model and analyse static strength of the universal coupling, woning maximum stress value of the fork head and cross shaft at maximum load and analysing fracture reason of the fork,which could provide a theoretical basis for the cross shaft universal coupling strength analysis and structural optimization design.

Hull Deformation Effect on Membrane-Type LNG Containment Systems

2016 ◽  
Author(s):  
Bo Wang ◽  
Yung-Sup Shin ◽  
Eric Norris
Keyword(s):  
Structural Integrity ◽  
Water Pressure ◽  
Local Deformation ◽  
Fatigue Tests ◽  
Wave Loads ◽  
Insulation System ◽  
Structural Fatigue ◽  
Hull Structure ◽  
Membrane Type ◽  
Global Deformation

The objective of this study is to investigate the relationship between the maximum allowable hull deformation, which includes global elongation and local deflection, and the capacity of the CCS in membrane-type LNG vessels. The LNG CCS mainly consists of the primary barrier (e.g. a corrugated membrane for GTT MK III system and an invar membrane for GTT NO 96 system) and the insulation panel which is attached to the inner hull through mastics or couplers. The excessive hull elongation due to dynamic wave loads may cause fatigue damage of the primary barrier. Thus, the maximum allowable hull elongation (global deformation) can be determined based on the fatigue strength of the primary barrier. On the other hand, the excessive hull deflection due to cargo or ballast water pressure may cause failure of the insulation panel and the mastic. Therefore, the maximum allowable hull deflection (local deformation) in the hull design can be determined based on the strength of the insulation panel and the mastic. In the present paper, the determination of fatigue life vs. strain curves of materials has been summarized for the primary barrier. Fatigue curves based on either structural fatigue tests or standard specimen tests can be applied in fatigue assessment of a primary barrier. As an example, the finite element (FE) analysis has been conducted on the MK III CCS with the hull structure under pressure loads. Two different load cases including full load and ballast load conditions have been considered to evaluate the structural integrity of the insulation system in numerical simulations. FE results show that the mechanical behavior of the insulation system and the mastic under the maximum allowable hull deflection has been examined based on the yielding strength of each individual component. Finally, the complete procedure to determine the maximum allowable hull elongation and the maximum allowable hull deflection has been developed for meeting the requirements of containment system design for membrane-type LNG carriers.

Study on the Design of SMA Mixture on Expressway

2014 ◽  
Vol 496-500 ◽  
pp. 2582-2585
Author(s):  
Jian Ping Xu ◽  
Fu Ming Liu
Keyword(s):  
Service Life ◽  
Laboratory Test ◽  
Material Properties ◽  
Road Traffic ◽  
Jiangxi Province ◽  
Skid Resistance ◽  
Maintenance Costs ◽  
Modified Asphalt ◽  
Superior Surface ◽  
Structure Strength

The rapid growth of road traffic brings some requirements on driving comfort and safety, which include good smoothness, skid resistance and reduced noise of the pavement. SMA has adequate structure strength to reduce rutting and provide superior surface function of skid resistance. Modified asphalt as mixture binder, has considerable durability to ensure the service life with less maintenance costs. Associated with laboratory test and trial section, some suggestion and requirements are brought forward in this paper for the material properties and mixture design of SMA on the FuZhou-JiAn expressway in Jiangxi Province.

Springing Responses Analysis and Segmented Model Testing on a 550,000 DWT Ore Carrier

2016 ◽  
Author(s):  
Hui Li ◽  
Di Wang ◽  
Cheng Ming Zhou ◽  
Kaihong Zhang ◽  
Huilong Ren
Keyword(s):  
Natural Frequency ◽  
Design Stage ◽  
Resonant Vibration ◽  
Bending Moments ◽  
Wave Loads ◽  
Regular Waves ◽  
Segmented Model ◽  
Ship Model ◽  
Hull Structure ◽  
Stiffness Distribution

For ultra large ore carriers, springing response should be analyzed in the design stage since springing is the steady-state resonant vibration and has an important effect on the fatigue strength of hull structure. The springing response of a 550,000 DWT ultra large ore carrier has been studied by using experimental and numerical methods. A flexible ship model composed of nine segments was used in the experiment. The model segments were connected by a backbone with varying section, which can satisfy the request of natural frequency and stiffness distribution. The experiments in regular waves were performed and the motions and wave loads of the ship were measured. The experimental results showed that springing could be excited when the wave encounter frequency coincides with half or one-third the flexural natural frequency of the ship. In this paper, the analysis of the hydroelastic responses of the ultra large ore carrier was also carried out using a 3-D hydroelastic method. Comparisons between experimental and numerical results showed that the 3-D hydroelastic method could predict the motions and the vertical bending moments quite well. Based on this numerical method, the fatigue damage was estimated and the contribution of springing was analyzed.

Analysis on Concrete Neutralization and Life Evaluation of Reinforced Concrete Chimney

2013 ◽  
Vol 671-674 ◽  
pp. 1672-1675
Author(s):  
Yan Hui Li ◽  
Yang Yang Zhang ◽  
Jing Cun Wei ◽  
Yun Feng Wu
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Concrete Structure ◽  
Concrete Cover ◽  
Initiation Time ◽  
Reinforcement Corrosion ◽  
Single Factor ◽  
Routine Examination ◽  
Life Evaluation ◽  
Reinforced Concrete Chimney

Through calculation and analysis on routine examination and neutralization of reinforced concrete chimney, the service life of concrete structure was evaluated only considering neutralization of concrete single factor. The results show that the neutralization of the reinforced concrete chimney was serious than that of other similar projects. The initiation time of reinforcement corrosion were 19.3a, cracking time of concrete cover were 27.35a.

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