Structural optimization evaluation index

Maximum collision force Fmax fender The deformation size S and the energy absorption capacity E of the ship or the fender absorption capacity E * are the direct reflection of the excellent fender structure design. Obviously, the smaller the Fmax, the better; Under the condition of ensuring Fmax, the smaller the better, which can not only protect the bridge, but also make the fenders not to be replaced once hit, so as to extend the service life of the fenders; The smaller the E, the better or the larger the E *, the better. However, there is coupling between them. Therefore, this paper uses the weight method to determine the comprehensive evaluation index OB of the structural optimization design of the anti-collision fender by comprehensively considering the three factors:

min[OB=W1 × Fmax+W2 × E+W3 × S]

Wherein, W1, W2 and W3 are weights, which are 0.7, 0.2 and 0.1 respectively in this paper.

Sensitivity analysis of design variables

1. Orthogonal test scheme

The energy dissipation capacity of the anti-collision fender is affected by the thickness of the fender plate, the diameter of the glass fiber core column and the position of the internal energy dissipation plate. The structural parameters obtained directly through theoretical calculation are very complex, and it is difficult to determine through numerical simulation, which affects the design efficiency. By selecting thickness parameters, glass fiber core column diameter parameters and energy dissipation plate position parameters through orthogonal tests, the number of tests can be effectively reduced and the design efficiency can be improved. In this paper, the thickness of fender plate and the diameter of glass fiber core column are set to be the same, both of which are expressed by thickness parameters. According to the calculation and actual production situation, the orthogonal test is determined as 2 factors and 3 levels

According to the number of test factors and the number of test levels, the orthogonal table is selected to draw up the test scheme, as shown in Table 3. OB is used as the evaluation index of orthogonal test.

2. Sensitivity analysis

Carry out finite element numerical simulation according to the orthogonal test scheme in Table 3, derive the calculated OB value from the results, and fill the mean range of the three levels in Table 3. It can be seen that the extreme difference value of thickness parameters is almost three times of the extreme difference value of position parameters, indicating that the sensitivity of thickness parameters to the performance of anti-collision fenders is much higher than that of position parameters.

Structural optimization design of anti-collision fender based on Isigh platform

Through the calculation and analysis results of the orthogonal test, it can be seen that the thickness parameters and position parameters have a certain impact on the anti-collision effect of the anti-collision fender. Better location parameters can be selected according to the principle of looking small in the orthogonal test results Φ 2000mm is the optimal parameter of the structure, and the thickness parameters are optimized again using the method of combining ANSYS/LS-DYNA and Isight integrated optimization platform.