High-speed train head shape parameterization method

Abstract

The invention discloses a high-speed train head shape parameterization method in the field of high-speed train head shape design. The method comprises the following steps of dividing a spatial three-dimensional surface forming a geometric shape of an existing high-speed train head into a plurality of areas according to a curvature, a trend and an extension tendency, and obtaining a plurality of molded lines used for dividing the spatial three-dimensional surface into the areas, wherein the molded lines are represented by line segments, arcs and Ferguson curves; acquiring high-speed train headtype control parameters generated according to design requirements, wherein the control parameters comprise size parameters and deformation parameters, constructing the line segments and the arcs by using the size parameters, connecting the line segments and the arcs through the Ferguson curves, and forming a cubic NURBS curve constrained by the size parameters as a control molded line, wherein the deformation parameters are used for modifying tension values of the tail ends of the Ferguson curves; and constructing middle process surfaces through the control molded line, and forming the high-speed train head through combination of the middle process surfaces.

Description

technical field [0001] The invention belongs to the field of high-speed train head shape design, and specifically discloses a high-speed train head shape parameterization method. Background technique [0002] Parametric design means that the shape of the product is compared and stereotyped, and a set of parameters are used to constrain the structural dimension sequence of its geometry, and the parameters are explicitly corresponding to the control dimensions of the design object. When different parameter sequence values ​​are assigned, it can drive the generation of new The target geometry for which the design result is a model that contains design information. Parameterization provides a means for product model variability, reusability, parallel design, etc., so that users can easily modify and rebuild existing models, and obtain various similar product models that are consistent with the original design intent, thereby greatly improving Design efficiency. [0003] Accord...

AI Technical Summary

Problems solved by technology

The advantage of this kind of parametric head shape design is that it can get a smooth control line, which can be modified by dragging, changing the number of control points, etc., and the shape of the line can change freely; the disadvantage is that it cannot establish an effective relationship with the size. If the number of points is small, complex shapes cannot be expressed, and when there are many control points, due to the local modification of the NURBS curve, dragging the control point shape line only changes locally, it is difficult to effectively control the whole, and the workload of shape modification is large

(2) A parametric design method without a basic shape. This method has no basic shape, and defines a geometric shape to control the shape line according to the size to create a new head shape

[0004] The current commonly used geometric shape parameterization methods have problems such as the need to fit the initial shape, the number of design variables is limited, and the generated geometric shape is not smooth.

Because the optimal shapes corresponding to different aerodynamic performance parameters are often contradictory (for example, the total resistance of the train is the smallest when the head car is ellipsoidal and the rear car is flat shuttle-shaped, while the flat and wide shape of the train intersection pressure wave is the smallest, and the ellipsoid is the largest), in During the development of high-speed trains, a variety of shapes with different geometric forms appeared, and the geometric shapes are generally more complex. As a result, the current parametric design of the shape of the train head is very limited in engineering applications, and it cannot fundamentally improve the design efficiency and design efficiency. quality

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