Structural Crashworthiness Study On Ocean Fishing Vessels

With the development of National Marine strategy towards deep sea, the ocean fishing vessels which used in Marine biological resource development get more and more attention. As the key equipment, ocean fishing vessels go to global area to get the fishery resources, including polar ice zone. In addition, in the south China sea, for the sake of state peace and development of the overall situation, China's ocean fishing boats also bear the safeguard national Marine rights and interests, often with peripheral country invasion of ship collision. Security issues become a ship design elements of deep sea fishing boats. The crashworthiness of ship is ship safety problems of a key, is also to ensure that our fishery will be an important part in the development of health and safety.In addition to satisfying the basic functions of ordinary ships, ships operating in polar regions should be able to withstand the loads of special circumstances such as low temperature, ice, ocean currents and so on. Among them, the ice load, including the iceberg, is an urgent problem to be solved. The collision of polar ice, including small ice and large iceberg, with the polar ship, and the structural damage caused by the hull structure, the structural safety is reduced. It has become a hotspot in the design, construction and operation of polar vessels.Ship collision is a huge impact phenomenon between ships and ships, between ships and fixtures in a short time, is a transient, strong non-linear dynamic response of the structure. In the case of ships, collision of ships may lead to structural damage, loss of property or leakage of goods, loss of property, pollution of the surrounding marine environment, and possible casualties. While the collision of the polar ship with the polar sea ice has its own characteristics. Therefore, the research on the collision characteristics of polar vessels in polar ice area is proposed, and the suggestion to improve the crashworthiness of polar vessels is proposed, which is of great significance to improve the overall performance of polar ships.In this study, the theoretical analysis and numerical calculation are carried out for the ship collision problem of large fishing vessels in polar waters. In present article, the main work was written as follows:1. Based on the analysis of the typical ship collision model, the crashworthiness analysis of the side structure of the fishing vessel is carried out, and the collision dynamics of the side structure of the typical fishing vessel is obtained. Based on the structural crashworthiness, the research on the limit impact velocity of the side structure of the fishing vessel was carried out. Finally, the ship crashworthiness optimization is studied with the objective of improving the crashworthiness of the vessel structure, and the improvement of the crashworthiness is put forward.2.The collision model of the fishing vessel is studied and the collision dynamics of the fishing vessel bow is obtained. In order to improve the bow crashworthiness of fishing vessels as the goal, the paper puts forward the improvement measures of strengthening the bow with composite material.3.Based on the polar ice-ship collision problem, the theory and numerical analysis of ice-fishing collision are carried out. The collision characteristics of ship structures under different ice loads are obtained. Finally, the suggestions for structural strengthening are put forward.By carrying out the research of this paper, the innovation in the following aspects:1. the crashworthiness evaluation model of ship structure with limit impact speed is proposed, and the corresponding crashworthiness optimization model is established.2. Taking the active impact as the target, the strengthening form of ship bow composite shell is put forward aiming at improving the crash strength of bow.3. The calculation model of polar ice load is established, and the structural strength optimization and evaluation criterion of fishing vessel ice load is put forward with the maximum permissible stress as the index.