Qiu Chang-hua

Key technology of ship product data exchange based on STEP

In this paper, in order to implement the share and exchange of the ship product data, a new kind of global function model is established. By researching on the development and trend of the application of ship STEP (standard for the exchange of product model data) standards, the AIM (application interpreted model) of AP216 is developed and improved as an example, aiming at the characteristics and practical engineering of ship industry in our country. The data exchange interfaces are formed based on STEP in the CAD/CAM for the ship by all function modules and shared databases under the global function model. The share and exchange of all information and data are solved in the design, manufacture and all life-cycle of ship products among different computer application systems. The research work makes foundation for the ship industry informatization.

Application of neural network method to process planning in ship pipe machining

Based on artificial neural network for process planning decision in ship pipe manufacturing, a novel method is established by analyzing process characteristics of the ship pipe machining. The process knowledge of pipe machining is shifted from the expression of the external rules to the description of the internal net weight value in order for the net inferring engine to decide the process route of pipe machining rapidly and rightly. Simulation shows that the method can resolve problems of process decision, and overcome the drawbacks of “matching difficulty” and “combination explosion” in traditional intelligent CAPP based on symbol reasoning.

Optimization Research of Mooring Base of the Ship-Based Helicopter

The problems about the calculation of mooring tension and the layout optimization of mooring base are studied. On the basis of considering the elastic deformation of mooring cables, the compression deformation of tyre is calculated. The relational expressions among the tyre compression deformation, the energy of deformation and external loads are derived. After the coordinate transformation relation between the helicopter and ship is determined, and the displacement calculation model of helicopter is presented, the final mooring tension of the ship-based helicopter is solved according to the advanced energy method. The mooring point coordinate is searched and solved in standard and nonstandard parking positions by the first-order optimization method. Some added constraint conditions are taken into account for optimization. Through the comparison of the relative changing ratio of the position coordinates before and after optimization, the layout scheme that makes the forces of the helicopter body and mooring equipments more reasonable is established.

Simulation Calculation of Mooring Tension of the Ship-Based Helicopter

The helicopter on the ship deck must be moored due to the impact of winds and waves. The forces of the ship-based helicopter are analyzed comprehensively and the expression of inertial acceleration from the movement of ship is derived. The mooring cable is a nonlinear flexible body and is handled by the finite element method instead of the equivalent modulus of elasticity modifier formula. The parameterized FEM model is established with the language APDL. After defining the constraint conditions and applying external loads, the mooring tension is calculated by considering some main factors, such as the warp of parking position, speed of wind and change of sea conditions. Compared with the theoretical and actual value, the result of the mooring tension is verified reliable. The new calculation method and reference are supplied to improve the calculation of the mooring tension.

Calculation of Mooring Tension of the Ship-Based Helicopter Based on FEM

The forces of the ship-based helicopter are analyzed comprehensively in the winds and waves. The parameterized FEM model about the ship-based helicopter body, the mooring cable and the mooring base is established with the language APDL. The parameterized FEM model is used to calculate the tension of the mooring cables for different sea conditions. The mooring cable will present strong nonlinearity under the action of external force. So the cable structure is disposed by the finite element method. The warp of parking position and change of sea conditions are taken into account for calculation. After defining the constraint conditions and applying external loads, the mooring tension is obtained. Compared with the theoretical and actual value, the result of the mooring tension is verified reliable. The new calculation method is supplied to improve the force state of the mooring facility.

Multi-objective shop scheduling scheme well-chosen decision making based on A-E method

Multi-objective shop scheduling optimization approach often presents the scheduling decision makers a set of Pareto solutions, which is hard to select the most satisfactory one from them. Therefore, a new method was put forward to select the best solution from the Pareto solutions. Firstly, a new weight-confirming method which contained subjective factors and objective factors was obtained by combining analytic hierarchy process and entropy theory (A-E). Then, the distance between ideal scheme and spare schemes was illuminated by Euclid norm as a standard to select the best scheme. Finally, the result testifies that using A-E method can make a right decision quickly which can help the decision-maker get the most satisfied solution from the set of Pareto solutions.