Study on the Wave Loads and Strength Assessment Method on Semi-Submersible Platform

2009 ◽  
Author(s):  
Hui Li ◽  
Huilong Ren ◽  
Tao Wei ◽  
Guoqing Feng
Keyword(s):  
Fatigue Strength ◽  
Assessment Method ◽  
Wave Method ◽  
Wave Loads ◽  
Strength Assessment ◽  
Buckling Strength ◽  
Comprehensive Comparison ◽  
Comparison Of The Results ◽  
Classification Society

In this paper, the wave loads of a semi-submersible platform is calculated by the deterministic design wave method and the stochastic design wave method based on the rules established by ABS and DNV classification society respectively. Then, the yielding strength, buckling strength and fatigue strength of important members are assessed according to these different rules. Through the comprehensive comparison of the results of wave loads and strength assessment, the differences between these rules are summarized. Then some significant suggestions are given.

Assessment of Free Spanning Pipeline Strength

2013 ◽  
Vol 310 ◽  
pp. 194-197
Author(s):  
Hong Jun Zhu ◽  
Xing Qi ◽  
Yong Chuang Yang ◽  
Ming Yang Wang ◽  
Xiao Xu Liu ◽  
...  
Keyword(s):  
Yield Strength ◽  
Fatigue Failure ◽  
Assessment Method ◽  
Submarine Pipeline ◽  
Strength Assessment ◽  
Buckling Strength ◽  
Safety Design ◽  
Pipeline Failures

Submarine pipeline failures usually occur at free span part, and free spanning pipeline is easily induced vibration by vortex, which accelerates the fatigue failure of pipe. Therefore, it is necessary to assess the strength of free spanning pipeline at regular intervals. In this paper, considering the effects of VIV, resonance assessment and yield strength assessment as well as buckling strength assessment are enumerated. And an illustration is calculated to verify the reliability of assessment method. This research may provide a guide for safety design, installation and maintenance of submarine pipeline.

The Fatigue Strength Assessment for Hull Structure of Steel Fishing Vessel

2012 ◽  
Vol 189 ◽  
pp. 334-339
Author(s):  
Gao Sheng Yang ◽  
Yong He Xie
Keyword(s):  
Fatigue Strength ◽  
Fishing Vessel ◽  
Strength Assessment ◽  
Computing Platform ◽  
Hull Structure ◽  
Fatigue Strength Assessment ◽  
Classification Society

According to the norms “the fatigue strength assessment for hull structures in 2007” issued by China Classification Society, the combined computing platform established is composed of mature hydrodynamic software SESAM from Det NorskeVeritas(DNV)and MSC.PATRAN/NASTRAN, the fatigue strength assessment for hull structure of a steel fishing vessel is studied.

Fatigue Yield of Ship Structures

2009 ◽  
Author(s):  
Kalman Zˇiha ◽  
Branko Blagojevic´
Keyword(s):  
Fatigue Strength ◽  
Fatigue Damage ◽  
Fatigue Analysis ◽  
Assessment Method ◽  
Rule Based ◽  
Strength Assessment ◽  
Variable Amplitude ◽  
Damage Progression ◽  
Double Hull ◽  
Fatigue Endurance

The paper on the first place summarizes the fatigue yield approach as a cause-effect interaction between fatigue damage progression and fatigue endurance. Secondly it investigates the fatigue strength worsening on experimental S-N data and the load variability effects in shipbuilding. Next it applies the Classification Society’s rule-based procedure for fatigue analysis of ship’s structure that uses a simplified fatigue strength assessment method. The example elaborates fatigue yield effect on the seagoing operation of a double hull 47400 tdw tanker. At the end the paper recommends the procedure for assessment of ship lifetime shortening due to the fatigue yielding under constant and variable amplitude block loadings.

Fatigue Strength Assessment Analysis of Large Container Ship

2014 ◽  
Vol 602-605 ◽  
pp. 385-389 ◽  
Author(s):  
Feng Lei Han ◽  
Chun Hui Wang ◽  
An Kang Hu ◽  
Ya Chong Liu
Keyword(s):  
Fatigue Strength ◽  
Hot Spot ◽  
Direct Calculation ◽  
Linear Wave ◽  
Container Ship ◽  
Wave Loads ◽  
Wave Load ◽  
Strength Assessment ◽  
Fatigue Strength Assessment ◽  
Large Container

Fatigue assessments of container ship structures can be processed using various direct calculation approaches or various approaches of classification societies [1,2]. In this investigation, the fatigue strength assessment to the key positions of a 9200TEU container ship has been performed ,subjected to the rules of BV about fatigue strength specification of large container ships, based on design wave method and Miner fatigue cumulative damage theory analysis method. Wave loads have been computed using linear wave load calculation method based on three-dimensional potential flow theory. And the fatigue strength assessment of the typical hot spot structures has also been conducted based on a series of critical single design wave.

scholarly journals Assessment of Lacrimal Duct Patency in Patients Undergoing Endoscopic Medial Maxillectomy

2021 ◽  
Vol 10 (2) ◽  
pp. 245
Author(s):  
Andrzej Sieśkiewicz ◽  
Tomasz Łysoń ◽  
Marek Rogowski ◽  
Marek Bielecki ◽  
Ewa Gindzienska-Sieskiewicz ◽  
...  
Keyword(s):  
Assessment Method ◽  
Test Results ◽  
Functional Disorders ◽  
Lacrimal Duct ◽  
Assessment Tests ◽  
Number Of Patients ◽  
Study Results ◽  
Assessment Techniques ◽  
Medial Maxillectomy ◽  
Comparison Of The Results

Purpose: The risk of epiphora after medial maxillectomy with lacrimal duct transection is difficult to assess. The data available in the literature are inconclusive due to various operating techniques used by the authors of medical publications, different additional procedures aimed at improving tear drainage after maxillectomy, and a variety of lacrimal duct patency assessment techniques. The aim of our work was to assess the anatomical and functional patency of lacrimal ducts after medial maxillectomy without performing additional procedures to improve tear drainage as well as comparison of the results obtained with different assessment tests. Materials and methods: 21 patients who underwent medial maxillectomy in the years 2016–2019 were assessed for discomfort and epiphora based on patients’ own reports and basic clinical examination, lacrimal duct rinse test, the Munk score, and a modified endoscopic Jones I test. Results: Gradually increasing the sensitivity of the assessment method resulted in an increase in the number of patients with potential tear drainage disorders, starting from 0% in the rinsing test, 4.8% self-reported tearing complaints, 14.3% Munk score, and 19% modified endoscopic Jones I test. Conclusions: The study results revealed that a small fraction of patients tend to report epiphora as a consequence of medial maxillectomy themselves. Subtle functional disorders, which are not particularly bothersome to patients, are more common. More sensitive lacrimal duct patency tests reveal more cases of tear drainage disorders. The results of studies assessing the incidence of epiphora after medial maxillectomy appear to depend on the type of test used.

Structural Safety Assessment of a 1100 TEU Container Ship, Based on a Enhanced Long Term Fatigue Analysis

2014 ◽  
Vol 1036 ◽  
pp. 935-940
Author(s):  
Leonard Domnisoru ◽  
Ionica Rubanenco ◽  
Mihaela Amoraritei
Keyword(s):  
Safety Assessment ◽  
Safety Evaluation ◽  
Irregular Waves ◽  
Structural Safety ◽  
Random Wave ◽  
Wave Loads ◽  
Strength Assessment ◽  
Integrated Method ◽  
Hydroelastic Response

This paper is focused on an enhanced integrated method for structural safety assessment of maritime ships under extreme random wave loads. In this study is considered an 1100 TEU container test ship, with speed range 0 to 18 knots. The most comprehensive criteria for ships structural safety evaluation over the whole exploitation life is based on the long term ship structures analysis, that includes: stress hot-spots evaluation by 3D/1D-FEM hull models, computation of short term ship dynamic response induced by irregular waves, long term fatigue structure assessment. The analysis is enhanced by taking into account the ships speed influence on hydroelastic response. The study includes a comparative analysis on two scenarios for the correlation between the ships speed and waves intensity. The standard constant ship speed scenario and CENTEC scenario, with total speed loss at extreme waves condition, are considered. Instead of 20 years ship exploitation life estimated by classification societies rules from the long term structural safety criteria, the enhanced method has predicted more restrictive values of 14.4-15.7 years. The numerical analyses are based on own software and user subroutines. The study made possible to have a more realistic approach of ships structural strength assessment, for elastic and faster ships as container carriers, in compare to the standard one based only on naval rules, delivering a method with higher confidence in the designed structural safety.

Buckling and Ultimate Strength Assessment of FPSO Structures

2005 ◽  
Author(s):  
Haihong Sun ◽  
Xiaozhi Wang
Keyword(s):  
Ultimate Strength ◽  
Oil And Gas ◽  
Element Analysis ◽  
Strength Criteria ◽  
Strength Assessment ◽  
Stiffened Panels ◽  
Oil And Gas Fields ◽  
Extensive Test ◽  
Offshore Oil And Gas ◽  
Classification Society

Floating production, storage and offloading systems (FPSOs) have been widely used for the development of offshore oil and gas fields because of their attractive features. They are mostly ship- shaped, either converted from existing tankers or purposely built, and the hull structural scantling design for tankers may be applicable to FPSOs. However, FPSOs have their unique characteristics. FPSOs are sited at specific locations with a dynamic loading that is quite different from those arising from unrestricted service conditions. The structures are to be assessed to satisfy the requirements of all in-service and pre-service loading conditions. The fundamental aspects in the structural assessment of FPSOs are the buckling and ultimate strength behaviors of the plate panels, stiffened panels and hull girders. The focus of this paper is to address the buckling and ultimate strength criteria for FPSO structures. Various aspects of the criteria have been widely investigated, and the results of the design formulae proposed in this paper have been compared to a very extensive test database and numerical results from nonlinear finite element analysis and other available methods. The procedures presented in this paper are based on the outcomes of a series of classification society projects in the development of buckling and ultimate strength criteria and referred to the corresponding classification society publications.

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