The Structural Strength Evaluation Of Rotomoulded Ship Based-on Temperature Load

In recent years, with the characteristics of high speed, good stability, energy efficient and environmentally friendly, rotomoulded ship has become more and more popular, and its development has been highly regarded by all countries in the world.There are two reasons for this paper that the affect of temperature load about the strength problems of the rotomoulded ship:Firstly, there are not have a complete specification of strength calculation for rotomoulded ship in current, domestic and foreign researchers have calculated and analyzed the structural strength and thermal stress of various types of steel Ships, their research focus only on the process and manufacturing of this ship.scecondly, when the main engine is running, the ship structure will be a large temperature gradient with the surrounding media, which takes a significant additional temperature stress to the structure, while being under the wave pressure and propeller vibration or external force, and can produce large deformation and endanger the safety of the structure, so we need to evaluate the structural strength of rotomoulded ship. To ensure the safety and practicality of the hull in transit, so it is significant to analyze its structural strength.This paper takes a 11.4 meters rotomoulded ship as an example, considering the temperature load on the structure for analysis and verification. In order to analyze the component size of thermal stress in the structural strength, the load calculation is divided into three parts: Firstly, to calculate the design loads; scecondly, calculating the temperature loads; then calculate the actual loads(it is a combination of design load and temperature load). The calculation are as follows:Firstly, using the FEM to Build three-dimensional model of entire ship. Secondly, defining the property of heat transferred-model,applying on relevant boundary Conditions and analysis the process of transferring heat. Gain the temperature distribution of empty and fully loaded of the entire model, and set up the relevant temperature field. Again, definie the boundary conditions and material properties, impose constraints, determine the design loads(including propeller exciting force, wave pressure and fixed load), and calculate and analyze the structural strength under fully and empty load conditions. Then, re-define the material properties, and calculate the temperature load under fully load conditions(temperature field will be converted into the calculated temperature loads). Finally,calculate the structural strength under the actual load(including temperature load and design load) and check the results.Through the calculation and research, we can see that it’s feasible to use the finite element method to analyze and calculate the structural strength of rotomoulded ship in taking account of temperature load. Through this research work, we can get the distribution of temperature field, deformation and stress level of ship structure, and also draw some useful conclusions. The research work of this paper has certain reference value for the designing of this ship.