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Abstract
This paper describes the application of a simplified collision model to optimize crashworthiness in a tanker structural design. The objective of this optimization is to minimize mean collision damage penetration over a probabilistic sample of 10000 collision scenarios. The simplified collision model (SIMCOL) is used in a Monte Carlo simulation to predict mean probabilistic damage penetration. All designs must meet minimum regulatory and class requirements, but structural crashworthiness is not currently regulated. Additional crashworthiness, beyond that resulting from other requirements, is an option for the owner/operator that may be driven by their desire to reduce liability in a collision. Selection of a particular design depends on the decision-maker's preference for cost and crashworthiness. By performing a series of optimizations, varying the structural weight constraint, this becomes a probabilistic multi-objective (penetration and weight) optimization. The product of this optimization is a non-dominated (ND) frontier that specifies mean damage penetration as a function of structural weight. The non-dominated frontier is an excellent tool for selecting a preferred level of crashworthiness. It provides a picture of the optimum cost/crashworthiness trade-off. Trends in structural parameters over the non-dominated frontier also provide excellent guidance on where to place added weight for optimum crashworthiness.
Ship collisions and grounding continue to occur regardless of continuous efforts to prevent such accidents. Given the recent Brazilian government investments in a new ship fleet, and taking into account the increasing demand for safety at sea and protection of the environment, the consideration of ship collisions is of crucial importance. The purpose of this paper is to present a review of studies about ship collision. This review is focused in researches on the structural aspects involved in a ship collision event, particularly studies about theoretical, experimental and numerical analyses of singular and complex naval structures. Some articles about an energy approach, kinematic systems and probabilistic analysis of the global collision event are also mentioned.
The results summarized in this paper represent the work of SNAME Ad Hoc Panel #6 convened under the SNAME Technical and Research Program. This is a summary and overview paper. Topics discussed will be addressed individually and in more detail in later publications. The 2nd International Conference on Collision and Grounding of Ships, to be held in Copenhagen, July 1-3, 2001, will also present and discuss many of the results of this panel and other related research. The paper discusses four primary areas of panel work: collision and grounding models, data, accident scenarios and design applications. A probabilistic framework for assessing the crashworthiness of ships is presented. Results obtained from various grounding and collision models are compared to validating cases and to each other. Data necessary for proper model validation and probabilistic accident scenario development are identified. Deformable striking-ship bow models and their application are described. Potential design applications and alternatives for improving crashworthiness are discussed.
ABSTRACT This paper describes a method for developing probability density functions (pdfs) describing struck ship damage,in ship col- lisions. Struck and striking ship speed, collision angle, striking ship type and striking ship displacement are treated as inde- pendent random,variables in this problem. Other striking ship characteristics are treated as dependent variables derived from the independent variables based on relationshipsdeveloped,from,worldwide,ship data. A simplified collision model (SIM- COL) is used in a Monte Carlo simulation to predict probabilistic damage,extents. SIMCOL applies the scenario variables directly in a time-stepping simultaneous solution of internal (structural) deformation,and external (ship) dynamics. Results are presented for collisions with four notional tankers designs. 1.,INTRODUCTION The serious consequences,of ship collisions necessitate the development,of regulations and requirements for the subdivision and structuraldesign of ships to minimize damage, reduce environmental pollution, and improve safety. The Society of Na- val Architects and Marine Engineers (SNAME) Ad Hoc Panel #6was,established to study the effect of structuraldesign on the extent of damage in ship collisionand grounding. SNAME and the Ship Structure Committee (SSC) sponsor the research under this panel that is presented in this paper. The International Maritime Organization (IMO) is responsible for regulating the design of oil tankers and other ships to provide for ship safety and environmental,protection. Their ongoing transition toprobabilistic performance-based standards requires the ability to predict the probabilistic environmental performance,and safety of specific ship designs. This is a diffi-