The complex load system of a bogie frame requires calibrating the load of each support. There are currently no effective methods for improving the anti-interference ability of support mount calibration in bogie frames with a complex structure. Therefore, in this study, a load decoupling calibration method was carried out for support mounts with complex shapes, and the maximum load response coefficient with a minimum influence from other loads was obtained.
In this paper, the typical calibration methods of structural components and the load characteristics of a bogie frame are analyzed and the basic requirements of the load calibration method for the bogie bracket are presented. Based on the characteristics of a bogie frame with curved-contour trapezoidal-cross-section supports and hangers, an independent load decoupling method for its bracket is presented. Based on the analysis of the least-squares surface and B-spline ruled surface fitting and interpolation methods, an intercity electric multiple units (EMU) bogie framework was analyzed as an example. The results calculated for the load distribution of a bogie frame with curved-contour trapezoidal-cross-section supporters and hangers using the B-spline ruled surface fitting with parabolic endpoint and free end conditions were consistent with actual test results. This method for the curved-contour trapezoidal-cross-section bracket bogie frame load decoupling could effectively identify the maximum response and calibrate the independent bracket load series. The results of the line tests also show that using the decoupling method for this type of support can maximize the removal of other load disturbances and improve the load calibration factor.
Compared with the conventional least-squares method for fitting test results, the straight B-spline surface can both fit the appearance of a complex support profile and obtain a more accurate load solution for the purpose of load decoupling.
This method can be used when the support structure is a face structure, which is the most commonly used structure in bogie frames today.
Research on accurate load calibration can provide robustly designed loads when designing individual bogies. The development of this method will help China Railway Corporation factories obtain bogie frame load spectra.
Based on the least square surface and B-spline ruled surface fitting interpolation method, according to the obtained boundary conditions and the finite element calculations, the detailed region with greater loudness of the identified load is identified and the decoupling calibration coefficients of the identified loads are obtained using the B-spline interpolation calculation method, which is carried out with the other loads being zero. In this way, an effective load calibration method is developed.
