Consideration of Collision and Contact Damage Risks in FPSO Structural Designs

In this study, the risk of collision and grounding accidents on bulk carrier and general cargo ships was investigated. A comprehensive risk analysis consisting of past accident reports, fault tree analysis (FTA) and Cut sets importance measure (CS-I) methods was carried out. The failures effective in the occurrence of collision and grounding accidents were determined by examining past accident reports. In the study, the probability for each failure was derived by using real accident data. Using FTA, various potential accident occurrence combinations/scenarios, also known as minimal cut sets (MCSs), for both accident types were obtained. In addition, prioritization was conducted for the MCSs of both types of accidents using CS-I sensitivity analyses. The faults that increase the risk of collision accidents the most were found to be interpretation failure of the Convention on the International Regulations for Preventing Collisions (COLREG) and lack of situational awareness. In addition, the top failures that lead to groundings were determined to be lack of communication in bridge resource management (BRM), fatigue/sleeplessness and inappropriate voyage plan. Recommendations are made for eliminating potential risk factors, preventing the recurrence of such accidents and establishing safer maritime transport.

Closed-form expressions to estimate the collision energy and damage extent for ship collision analysis have been developed and finalized in Zhang et al. (2019a). This analysis procedure has also been adopted in the Guidance Notes for Collision Assessment for the Location of Low-Flashpoint Fuel Tanks (Lloyd’s Register 2016) and for collision risk assessments of LNG carriers. To develop the analytical procedure detailed and comprehensive validations with experiments and finite element simulations were carried out to gain confidence for applications. It was concluded that the analytical method gives consistently good agreement with experiments and simulations. This paper presents the representative case studies used for the validation of the analytical methods: one laboratory experiment, one experiment on sea, two collision accidents and one application example.

With the development of society, international trade is playing an important role. Maritime transport has become the main mode of transport in international trade with its advantages of low transport price, large transport volume and low environmental pollution. However, the rapid development of maritime transport is accompanied by the risk of maritime accidents. Studies show that ship collision accident has always been the main type of maritime accidents, and ship collision caused by human factors accounts for more than 90% of the total accidents. It has become a key issue in the research field of ship navigation safety to analyze the causes of ship collision and explore the mechanism of human factors. By analyzing the ship collision accident reports, this paper summarizing the main human factors of ship collision, and through analyzing the causal chain of ship collision accident to determine the Bayesian network structure. Finally, this paper using the accident reports into the model to illustrate the effectiveness of the Bayesian network model; meanwhile, by analyzing the cause of the Bayesian network model, this paper gets most likely cause chain that cause collision accident happens, so as to providing safety management countermeasures for the crew, ship company and ship safety management department.

The article analyzes and assesses the risk of accidents at a water treatment facility — a chlorine storage warehouse. A "typical chlorine storage warehouse" with the characteristics most common at water treatment facilities is considered. The authors present the distribution of hazardous substances in the chlorine warehouse by the elements of the facility. The main causes of the accident at the facility are considered, all the causes are divided into two groups: occupational and non-occupational. The factors contributing to the occurrence of negative events have been identified. The types of possible accidents in the chlorine warehouse are considered. A brief description of the scenarios of the most likely accidents is presented. The most probable zones of action of damaging factors depending on weather conditions are revealed. The sizes of contaminated zones (area and depth) with lethal toxodose and with threshold toxodose for different scenarios of the most probable accidents under different weather conditions are determined. Data on the size of the probable zones of action of damaging factors for the considered accident scenarios, determined according to the calculation model presented in the "Methodology for assessing the consequences of chemical accidents" (the "Toxi" methodology). Possible accidents are dangerous both for the working shift and the maintenance staff of the chlorine warehouse, and for the technical staff personnel of third-party enterprises and organizations, as well as for the public. Information about possible health damage from accidents is provided. The analysis and assessment of the risk of accidents based on data on the indicators of the risk of harm to employees and other individuals were carried out. Data on the composition of affected workers and other individuals in the chlorine warehouse for different accident scenarios and different weather conditions are presented

In his Swiss cheese model, Reason states that no one can foresee all possible accident scenarios. If holes can be visualized and the relationship between holes and latent conditions can become clear, then it is possible to control the occurrence of holes. The objective of this research is to determine the relationship between latent conditions and the characteristics of holes. In this study, 84 serious marine accidents, divided into six types, were analyzed. Furthermore, the safety management system (SMS) in organizations and risk management at local workplaces were considered as defensive layers, and 10 latent conditions were defined by modifying the software–hardware–environment–liveware (SHEL) model. The following results were found. Holes in the SMS defensive layer tend to arise during the early stages of the plan–do–check–act (PDCA) cycle, except for cases involving sinking. Holes in the defensive layer of risk management tend to arise during the early stages of the risk management process in cases involving collisions, occupational casualties, fire, or explosion. The most frequent latent condition was an inadequate condition of operators, but was not necessarily the same for different types of accidents. These findings indicate that the locations of and reasons for the opening of holes can be determined. By applying a method for closing holes in combination with the findings of this study, accidents can be systematically prevented.

Risk assessment of fatal accidents due to work at heights activities using fault tree analysis: Case study in Malaysia

Risk-based maintenance of ethylene oxide production facilities

The growing threats posed by wildfires in Southern Europe are calling for the development of comprehensive and sound management and risk assessment strategies. In this work, we present the application of wildfire simulation modeling based on the minimum travel time (MTT) algorithm to assess fine-scale (100-m resolution) wildfire hazard, transmission, and exposure to communities in the Italy-France Maritime cooperation area (Sardinia, Corsica, Tuscany, Liguria and Provence-Alpes-Côte d’Azur), which cover about 72,000 km2 of land. We simulated thousands of wildfires considering the current landscape and characterized and measured fine-scale wildfire risk factors and profiles by taking into account historical fire regimes, fuels, winds and fuel moisture conditions associated with the occurrence of the largest wildfires (>100 ha) that affected the study area in the last 20 years. Individual fires were simulated at 100-m resolution, consistent with the input files. Modeled annual burn probability and ignition probability revealed that Sardinia was the Region most affected by wildfires. The wildfire simulation outputs were then combined with main land uses and building footprint locations to characterize wildfire transmission and exposure to communities, and were summarized for main vegetation types and Regions. This study presents a cross-boundary and standardized approach based on wildfire spread modeling to analyze and quantify wildfire risk profiles in Southern Europe. The stochastic wildfire modeling systems we implemented used harmonized sets of data for a vast, fire-prone Mediterranean area, where previous similar studies were conducted at coarser resolutions and covered lower extent of lands. The approach presented in this work can be used as a reference pillar for the development and implementation of a common wildfire risk monitoring, management, and governance plan in the study area. The methods and findings of this study can be replicated in neighboring Mediterranean and other regions threatened by wildfires.

Study on the DLOFC and PLOFC accidents of the 200 MWe pebble-bed modular high temperature gas-cooled reactor with TINTE and SPECTRA codes

Due to increased variety of actions caused by signal changes, rear-end accidents is the most common accident type at signalized intersections. The accident of rear-end collision is closely related with the driving behavior, this including the use of wireless telephone is one among the key factors. This paper utilized the logit model of stop/go decision during yellow interval to estimate rear-end collision probability on the basis of driving simulator data. Monte - Carlo simulation is used to find out how wireless phone use, age, and gender influences the rear-end collision potential. The results show that: 1) Probability of stop decision for outgoing call is the highest. 2)For middle age people, the probability of stop decision is the lowest, showing that the middle-aged people have more aggressive driving behavior than the other two age groups. 3) Probability of stop decision of female people is lower on the whole.

The investigation and reconstruction are fundamental to enable designers to improve the subway vehicle’s crashworthiness. In this paper, a crashworthiness study of a subway vehicle collision accident in Beijing was conducted. Based on field investigation, the full-scale detail finite-element model, has established to calculate the dynamic behaviour of the vehicle in the accident. Then, the numerical simulation assists with the field investigation to identifying the structural weakness, which leading the injury of the occupant. Finally, an enhancement design for the structural weak point was considered to improve the vehicle crashworthiness in the same accident scenario.

<div class="htmlview paragraph">This paper describes an experimental and epidemiological investigation of the potential application of a specific rollover occupant protection system, consisting of a rollover protective structure and occupant restraint (collectively referred to hereafter as ROPS), to all-terrain vehicles (ATVs). The ROPS investigated in this paper was proposed by Dahle [<span class="xref">1987</span>] as a means to improve the safety of ATV operation. Crash tests were performed with an unhelmeted instrumented dummy on 4-wheel ATVs equipped with the prototype Dahle ROPS (hereafter referred to as D-ROPS); the test results established that the D-ROPS design exhibited the potential for serious injury or death in lateral rollover, rearward pitchover, collision, and oblique frontal impact accident scenarios. Review of ATV-associated 1986 fatality reports from the U.S. Consumer Product Safety Commission (CPSC) indicated that, in a majority of cases, it would have been unlikely that adding D-ROPS to the ATVs would have prevented serious injury. Examination of ATV-associated injury reports from the CPSC's 1985 ATV Injury Survey suggested that many accidents that resulted in only minor injuries without a D-ROPS probably would have produced <i>more serious</i> outcomes if the vehicles had been equipped with D-ROPS. Consistent with our other studies, which indicate that ROPS limit ATV rider activity and adversely affect vehicle performance characteristics, handling, mobility, and utility, the results of this investigation indicate that ROPS in general, and the D-ROPS in particular, are inappropriate for ATVs.</div>

Purpose The modular integrated construction (MiC) method is promoted in Hong Kong to address the engineering limitations of prefabrication for high-rise buildings. However, MiC projects have encountered unprecedented challenges and risks, especially cost intensity. Studies have presented single-point risk assessment frameworks, which cannot capture and retain the distributions and profiles of various risks influencing the costs of MiC projects. Previous studies have also overlooked the significance of tail risks and failed to develop resource allocation schemes to manage cost risks in MiC projects. As such, this study aims to simulate and develop a probabilistic resource allocation scheme for cost risk management in MiC projects. Design/methodology/approach A questionnaire survey of 117 industry practitioners was conducted to assess the probability of occurrence and severity of impact of cost risks associated with MiC projects in Hong Kong. The data were analyzed using a Monte Carlo simulation and novel metrics. Findings The simulation revealed 26 significant cost risks in MiC projects in Hong Kong. It further revealed nine significant cost risks at 95% and 97.5% risk tolerance (RT) levels within the high-risk exposure zone and 82.5% and 85% RT levels within the medium-risk exposure zones of the risk matrix. Originality/value This study developed a probabilistic cost risk assessment and prioritization scheme that captures uncertainties associated with MiC project while considering the significance of tail risks to inform optimal resource allocation.

This paper reviews the latest research and analyses related to the risk assessment of ship-FPSO collision. The focus is placed on: existing criteria, FPSO collision accident, design scenarios for FPSO collision, mechanics of collision incidents, consequences and acceptance criteria. The research achievements of ships’ collision and grounding since 1990s are introduced. Issues specific to ship-FPSO collisions that deserve further development are addressed. The content of this paper is mainly drawn from the ISSC 2006 Specialist Committee V.1 on Collision and Grounding.

The Internet of Things has already demonstrated clear benefits when applied in many areas. In connected and autonomous vehicles (CAV), IoT data can help the autonomous systems make better decisions for safer and more secure transportation. For example, different IoT data sources can extend CAV's risk awareness, while the incoming data can update these risks in real-time for faster reactions that may mitigate possible damages. However, the current state of the art CAV research has not addressed this matter well enough. This paper proposes a profile-driven approach to manage IoT data in the context of CAV systems through a dynamic risk management framework. Unlike the current inflexible risk assessment strategies, the framework encourages more flexible investigation of risks through different risk profiles, each representing risk knowledge through a set of risk input considerations, assessment methods and optimal reaction strategies. As the risks change frequently with time and location, there will be no single profile that can cover all the risks that CAVs face on the road. The uses of different risk profiles, therefore can help interested parties to better understand the risks and adapt to various situations appropriately. Our framework includes the effective management of IoT data sources to enable the run-time risk assessment. We also describe a case study of using the proposed framework to manage the risks for the POD being developed in the Innovate UK-funded CAPRI project.
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