Conditional Risk Assessment Considering Hull Girder Failure of Vessels With Collision-Induced Damage Amidships

2011 ◽  
Author(s):  
Huirong Jia ◽  
Torgeir Moan
Keyword(s):  
Risk Assessment ◽  
Failure Probability ◽  
Load Condition ◽  
Sea State ◽  
Hull Girder ◽  
Collision Event ◽  
Conditional Risk ◽  
Double Hull ◽  
The Given ◽  
Oil Tanker

This paper deals with conditional risk assessment considering hull girder failure of damaged vessels. Only damages amidships are investigated. Conditional risk in this paper is defined as the probability of a given damage multiplied by the probability of hull girder failure conditioned upon the given damage. Taking a double hull oil tanker at full load condition as an example, the 3-hour’s failure probabilities conditioned upon damage properties are estimated. The statistical database for collision event in the HARDER project is adopted to assess the probability of sea state and damage. The sensitivity of 3-hour’s failure probability to the sea state and damage properties is investigated. Furthermore, the conditional risk is also assessed.

Rapid Assessment of Hull Girder Collapse for Corroded Double Hull Oil Tanker After Collision

2016 ◽  
Author(s):  
Sung Hwan Noh ◽  
Jung Kwan Seo ◽  
Jeom Kee Paik ◽  
Samy A. M. Youssef
Keyword(s):  
Finite Element ◽  
Structural Damage ◽  
Rapid Assessment ◽  
Probabilistic Approach ◽  
Hull Girder ◽  
The Alps ◽  
Oil Tankers ◽  
Double Hull ◽  
Oil Tanker ◽  
Probability Density Function Pdf

Corroded tankers might be subjected to a very serious structural damage if involved in collision accidents. For understanding or preventing the collision accidents, various studies are being proposed by researchers to improve the analysis method. In this paper, four types of double hull oil tankers (Panamax, Aframax, Suezmax and VLCC) are used. Probabilistic approach is used to create ship-ship collision scenarios for each target structure and the ultimate longitudinal hull girder strength of the hypothetical oil tanker’s hull cross-section. The ALPS/HULL is used to simulate and is intelligent supersize finite element method (ISFEM) software. A relevant probability density function (PDF) is introduced using the results from finite element simulations of the ship-ship collisions, which is commonly used to predict residual strength.

The Effect of Sloshing in Tanks on the Hull Girder Bending Moments and Structural Reliability of Damaged Vessels

2012 ◽  
Vol 56 (01) ◽  
pp. 48-62
Author(s):  
Huirong Jia ◽  
Torgeir Moan
Keyword(s):  
Failure Probability ◽  
Structural Reliability ◽  
Bending Moments ◽  
Multimodal Approach ◽  
Coupled Motion ◽  
Rectangular Shape ◽  
Hull Girder ◽  
Set Up ◽  
Oil Tanker ◽  
Damaged Vessel

The structural reliability analysis of damaged vessels has commonly been conducted by neglecting the effect of sloshing. In this paper, the coupled motion of the damaged vessel and sloshing is set up based on the assumption that the damaged tanks are of rectangular shape. The sloshing effects in tanks are modeled by a linear multimodal approach. Then the effect of sloshing in tanks on the hull girder bending moments and the failure probability are studied for an oil tanker in various damage conditions. It is concluded that in certain tank resonance conditions, sloshing effects cannot be neglected. In such cases sloshing damping plays an important role on the sloshing effects.

scholarly journals Structural Reliability Assessment of an Oil Tanker Accidentally Grounded in the Adriatic Sea

2017 ◽  
Author(s):  
Maro Ćorak ◽  
Joško Parunov ◽  
C. Guedes Soares
Keyword(s):  
Structural Reliability ◽  
Adriatic Sea ◽  
Bending Moment ◽  
Sea State ◽  
Hull Girder ◽  
Increased Risk ◽  
Mc Simulation ◽  
Safety Indices ◽  
Oil Tanker ◽  
Rock Size

The aim of the paper is to present a methodology for the assessment of the structural reliability of an oil tanker damaged in a hypothetical grounding accident in the Adriatic Sea. The grounding accident affects the ultimate hull girder capacity in the damaged region, the still water bending moment (SWBM) distribution along the vessel as well as the vertical wave bending moments (VWBM). The extent of the damage on the ship’s hull after a grounding accident depends on several parameters such as ship‘s speed, rock size, penetration depth, longitudinal and transversal location of stranding along the hull. These parameters are in the present study assumed as random variables, described by probability density functions. Based on defined statistical properties, random realizations of grounding parameters are simulated by Monte Carlo (MC) simulation. For each such random grounding scenario, the damage size is calculated by the surrogate model based on numerical grounding simulations. Residual ultimate strength and SWBM distribution are determined based on the size and location of the damage. VWBM is calculated for average sea state in the area with increased risk of grounding accident in the Adriatic Sea. Structural reliability analysis is employed to determine the safety index with respect to the ultimate hull girder failure for salvage period of 12 hours. As each grounding scenario results in different hull-girder reliability, histogram of safety indices is obtained representing new measures for the performance assessment of the damaged ship.

scholarly journals Definitions and Concepts for Quantitative Rockfall Hazard and Risk Analysis

Geosciences ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 158
Author(s):  
Didier Hantz ◽  
Jordi Corominas ◽  
Giovanni B. Crosta ◽  
Michel Jaboyedoff
Keyword(s):  
Risk Assessment ◽  
At Risk ◽  
Failure Probability ◽  
Rockfall Hazard ◽  
Process Failure ◽  
Failure Propagation ◽  
Element At Risk ◽  
Hazard And Risk ◽  
Hazard And Risk Assessment ◽  
Definition Of

There is an increasing need for quantitative rockfall hazard and risk assessment that requires a precise definition of the terms and concepts used for this particular type of landslide. This paper suggests using terms that appear to be the most logic and explicit as possible and describes methods to derive some of the main hazards and risk descriptors. The terms and concepts presented concern the rockfall process (failure, propagation, fragmentation, modelling) and the hazard and risk descriptors, distinguishing the cases of localized and diffuse hazards. For a localized hazard, the failure probability of the considered rock compartment in a given period of time has to be assessed, and the probability for a given element at risk to be impacted with a given energy must be derived combining the failure probability, the reach probability, and the exposure of the element. For a diffuse hazard that is characterized by a failure frequency, the number of rockfalls reaching the element at risk per unit of time and with a given energy (passage frequency) can be derived. This frequency is relevant for risk assessment when the element at risk can be damaged several times. If it is not replaced, the probability that it is impacted by at least one rockfall is more relevant.

Hull girder fatigue strength of corroding oil tanker

2010 ◽  
pp. 149-154
Author(s):  
J Parunov ◽  
K _iha ◽  
P Mage ◽  
P Juri_i_
Keyword(s):  
Fatigue Strength ◽  
Hull Girder ◽  
Oil Tanker

Hull-Girder Reliability of a Chemical Tanker

2009 ◽  
Vol 46 (04) ◽  
pp. 192-199
Author(s):  
Jôsko Parunov ◽  
Maro Corak ◽  
C. Guedes Soares
Keyword(s):  
International Association ◽  
Progressive Collapse ◽  
Bending Moment ◽  
Single Step ◽  
Hull Girder ◽  
Structural Rules ◽  
Term Operation ◽  
Reliability Method ◽  
Reliability Bound ◽  
Oil Tanker

The aim of the paper is to calculate hull-girder reliability of chemical tanker according to the reliability model proposed by International Maritime Organization (IMO). The probability of hull-girder failure is calculated using a first-order reliability method for two operational profiles—one typical for oil tanker and the other one modified in order to reflect differences between oil tanker and chemical tanker. The evaluation of the wave-induced load effects that occur during long-term operation of the ship in the seaway is carried out in accordance with International Association of Classification Societies (IACS) recommended procedure. The stillwater loads are defined on the basis of a statistical analysis of loading conditions from the loading manual. The ultimate collapse bending moment of the midship cross section, which is used as the basis for the reliability formulation, is evaluated by progressive collapse analysis and by single-step procedure. The reliability analysis is performed for "as-built" ship and for "corroded" ship according to corrosion deduction thickness from new Common Structural Rules for double-hull oil tankers. It is shown that hull-girder failure probability of "as-built" chemical tanker is well above the upper reliability bound proposed by IMO, while the "corroded" ship is slightly unconservative since the reliability index is lower than IMO lower reliability bound.

The BP Oil Tanker Structural Monitoring System

1995 ◽  
Vol 32 (04) ◽  
pp. 277-296
Author(s):  
David J. Witmer ◽  
Jack W. Lewis
Keyword(s):  
Monitoring System ◽  
Structural Damage ◽  
Prolonged Exposure ◽  
North Pacific Ocean ◽  
The United States ◽  
Management Program ◽  
Structural Monitoring ◽  
Hull Girder ◽  
Response Data ◽  
Oil Tanker

BP Oil Company time-charters a fleet of American-flag tankers for the ocean transportation of crude oil and petroleum products to the East, West and Gulf Coasts of the United States. Commencing in 1991, ship response and structural monitoring instrumentation was installed on the four ships of the Atigun Pass-class. These crude carriers are operated in the Trans-Alaska Pipeline Service, or "TAPS" trade, sailing the waters of the North Pacific Ocean and Gulf of Alaska. The structural monitoring systems were designed to measure the effects of subjecting a ship to the typical loads and forces encountered while at sea: hogging, sagging, slamming, hydrostatic pressure, and hull girder springing. Additionally, BP was interested in developing a system that could provide shiphandling guidance to the master or watch officer so that the detrimental effects of prolonged exposure to such loads and forces could be effectively minimized. The paper describes in detail the physical arrangement of the BP Oil Tanker Structural Monitoring System (BPSMS), including the suite of sensors employed to measure ship responses and hull girder stresses. It explains how the response data collected by the sensors is analyzed by the onboard computer located on the ship's bridge and how ship response data are presented back to the deck officers via a family of display monitor screens. These displays provide the officers with a "tool" that can be used to effectively monitor the physical and structural response of their ship to waves, and to quantify, in terms of lowering the wave bending moment and reducing the risk of slamming, the result of an action or actions taken to minimize the risk of incurring structural damage. Onboard ship response and structural monitoring is now an integral part of BP's tanker fleet structural management program. The units have greatly increased the awareness of the ship's officers regarding their role in helping to control the amount of structural damage done to the ships. Data from the units have also helped management make more informed decisions regarding operational requirements placed on the ships.

Impact of Risk Assessment Models on Risk Factors

2018 ◽  
pp. 134-153
Author(s):  
K. Madhu Kishore Raghunath ◽  
S. L. Tulasi Devi ◽  
Chandra Sekhar Patro
Keyword(s):  
Risk Factors ◽  
Risk Assessment ◽  
Risk Management ◽  
Empirical Evidence ◽  
The Other ◽  
Risk Models ◽  
Public And Private ◽  
Risk Assessment Models ◽  
General Business ◽  
The Given

World is vicinity full of opportunities given the amount of economic and non-economic transactions taking place every moment. With ubiquitous opportunities all around, businesses can assume inherent risk everywhere in one or the other way. In this chapter, the authors have deliberated the general business scenario to prove the given inferences. The readers will come across why the risk management is gaining so much gravity and across risk strategy of top business players. The chapter will bring into light the various risk factors in business and study the various risk assessment models present to fortify the negativity of these risk factors. Simultaneously, the authors will draw empirical evidence on the effectiveness, qualitative and quantitative risk models have on risk factors in public and private business organisations.

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