Automated Attribute Inheritance Method For Ship Finite Element Based On NX Platform

The finite elements need to be given attributes when finite element modeling.That’s because finite element attributes serve as key input parameters for finite element calculation.However,the attribute inheritance process is usually done manually,which has the disadvantages of high work complexity,high operation repetition,high execution error rate and long process time.The attribute inheritance process has become the bottleneck of the whole finite element modeling.Combined with the project of “COMPASS 3D” of China Classification Society,The paper describes the ship’s finite element attribute inheritance process based on the NX platform,carefully analyzes the relationship between multiple model structures in CAD/CAE integration modeling,explains the far-reaching effects of model conversion operation,and indicates the problems in the process of attribute inheritance.In order to solve the problems of the existing attribute inheritance methods,such as redundant data,ill-considered cases and low efficiency,a ship finite element attribute automatic inheritance method based on NX is proposed.The method fully exploits the characteristics of CAD / CAE integrated system and deeply digs the information provided in the model;and quickly reduces the target by using geometric topological relations obtained by the octree partitioning algorithm;selects feature points to simplify the process of geometric matching;uses bounding boxes to eliminate irrelevant elements and reduce computations;calculates the exact distance to regulate the geometric matching results;defines processing rules to solve the exceptional cases caused by model idealization;extracts geometries from existing model files as a property source to prevent data redundancy.Finally,the finite element attribute automatic inheritance system that based on the proposed method is implemented on the NX platform.The materials & profiles library is placed outside the NX software to solve the inconvenience of using materials & profiles data and handle the problem of volume expansion of the model;the proposed method is used to achieve the automation of the finite element attribute inheritance process;the attribute color atlas is utilized to check the attribute inheritance results.By using the system to carry out the attribute inheritance process of the actual ship model and through the comparison with the traditional manual attribute inheritance method,the feasibility and practicality of the system is verified.