CN212871602U - Test system for identifying rotational inertia of body structure of railway vehicle - Google Patents

Abstract

The utility model provides a test system for discerning rail vehicle body structure inertia, including rigid support body (2), force sensor, elastic support body (4), acceleration sensor (5), power hammer (6) to and data acquisition device (7). The rigid support body is provided with at least four supporting points for erecting a rail vehicle body, the force sensor and the elastic support body are used for being placed on the supporting points of the rigid support body, the acceleration sensor is used for being fixed on the rail vehicle body, the force hammer is used for hammering the rail vehicle body, and the force sensor, the force hammer and the acceleration sensor are all electrically connected with the data acquisition device. The utility model provides a test system does not have high expectations to the space place, is favorable to reducing investment cost, and what adopt this test system to implement is the quality line method, can portably accurate discernment rail vehicle body structure inertia.

Description

Test system for identifying rotational inertia of body structure of railway vehicle

Technical Field

The utility model relates to an experimental modal analysis technical field especially relates to a test system for discerning rail vehicle body structure inertia.

Background

The inertia parameters of the structure of the railway vehicle body are basic parameters for optimization analysis and calculation of the railway vehicle, and because the vehicle body is a symmetrical structure with large length-width ratio, weight and volume, 6 parameters of the inertia parameter tensor have a difference of several orders of magnitude, which brings great difficulty to the identification of the inertia parameters.

When a three-line pendulum, torsional vibration method and excitation method which are commonly adopted in other industries are applied to the test of the rotational inertia of the body structure of the railway vehicle, the following two defects mainly exist: 1) a special test bed is required to be designed to enable the vehicle body structure to realize the motion with six degrees of freedom in space, and the investment cost of the test bed is very huge; 2) based on the characteristics of large length-width ratio, large weight and large volume of the rail vehicle body, a very large test space needs to be provided, so that the investment cost of the field is also very large.

In summary, how to provide a test system which has low requirements for a space field and can simply, conveniently and accurately identify the rotational inertia of the body structure of the rail vehicle becomes a technical problem to be solved by those skilled in the art.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model provides a test system for discerning rail vehicle body structure inertia, this test system require not high to the space place, consequently can effectively reduce investment cost, and what adopt this test system to implement is the quality line method, can portably accurately discern rail vehicle body structure inertia.

In order to achieve the above object, the utility model provides a following technical scheme:

a test system for identifying rotational inertia of a rail vehicle body structure, comprising:

a rigid support having at least four support points for overhead rail vehicle body;

at least four force sensors for placement on support points of the rigid support;

at least four elastic supports for placement on support points of the rigid support;

the acceleration sensor is used for being fixed on the rail vehicle body;

a force hammer for hammering the rail vehicle body;

and the force sensor, the force hammer and the acceleration sensor are electrically connected with the data acquisition device.

Optionally, in the above test system, the rigid support includes four columns, the four columns are distributed at four corners of the rectangle, and top ends of the columns are the supporting points.

Optionally, in the above test system, the elastic support is a rubber spring.

Optionally, in the above test system, the data acquisition device is a notebook computer with data acquisition software installed therein.

Optionally, in the above test system, the hammer head of the force hammer is a rubber hammer head or a nylon hammer head.

Optionally, in the above test system, the force sensor is a strain tube type force sensor or a diaphragm type force sensor.

Optionally, in the above test system, the acceleration sensor is a piezoelectric acceleration sensor, a capacitive acceleration sensor, or a servo acceleration sensor.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 and fig. 2 are schematic views of a use state of a testing system provided by an embodiment of the present invention;

FIG. 3 is a test coordinate system established for a rail vehicle body;

FIG. 4 is a graphical representation of an acceleration frequency response function of a rail vehicle body.

Labeled as:

1. a rail vehicle body; 2. a rigid support; 3. a force sensor; 4. an elastic support; 5. an acceleration sensor; 6. a force hammer; 7. a data acquisition device.

Detailed Description

For the sake of understanding, the present invention will be further described with reference to the accompanying drawings.

Referring to fig. 1 and fig. 2, the embodiment of the present invention provides a testing system including: the test system comprises a rigid support body 2, a force sensor 3, an elastic support body 4, an acceleration sensor 5, a force hammer 6 and a data acquisition device 7, and is used for identifying the rotational inertia of the body structure of the railway vehicle. The rigid support body 2 has at least four supporting points for the overhead rail vehicle body 1, the force sensors 3 and the elastic support bodies 4 are used for being placed on the supporting points of the rigid support body 2, therefore, the number of the force sensors 3 and the number of the elastic support bodies 4 are at least four, the acceleration sensors 5 are used for being fixed on the rail vehicle body 1, the force hammers 6 are used for hammering the rail vehicle body 1, and the force sensors 3, the force hammers 6 and the acceleration sensors 5 are all electrically connected with the data acquisition device 7.

The utility model discloses a test system is based on the inertia of quality line method discernment rail vehicle automobile body 1, introduces test process below.

Establishing a test coordinate system for a rail vehicle body 1

As shown in FIG. 3, the origin of the global test coordinate system is 0, the center of gravity of the rail vehicle body 1 is c, and the coordinates are (x)_c,y_c,z_c) (ii) a The mode test excitation point is f, and each coordinate is recorded as (x)_f,y_f,z_f) (ii) a The modal test response point is u, and each coordinate is recorded as (x)_u,y_u,z_u). It should be noted that the origin of the global test coordinate system is selected according to the structural characteristics of the shape of the rail vehicle body 1.

The axial direction of the vehicle body is the positive direction of an X axis, the radial direction of the vehicle body is the positive direction of a Y axis, the upward direction vertical to the floor of the vehicle body is the positive direction of a Z axis, and the main moment of inertia of the vehicle body relative to an original point 0 is I_xx、I_yy、I_zzProduct of inertia I_xy、I_yz、I_xz(ii) a The moment of inertia of the vehicle body relative to the center of mass c is I₁₁、I₂₂、I₃₃Product of inertia I₁₂、I₂₃、I₁₃。

(II) weighing of the Rail vehicle bodywork 1

As shown in fig. 1, the force sensor 3 is placed on a support point of the rigid support body 2, and the entire weight of the rail vehicle body 1 is supported by the rigid support body 2. The test value of each force sensor 3 is F_iThe mass of the rail vehicle body 1 is:

(III) mode test by hammering method

As shown in fig. 2, after weighing is completed, the force sensor 3 is replaced with the elastic support 4, the acceleration sensor 5 is fixed to the modal test response point, the modal test excitation point is hammered with the force hammer 6, and the data acquisition device 7 acquires test data.

Fig. 3 shows the acceleration frequency response function curve obtained from the test data, and it can be seen from fig. 3 that under the supporting action of the elastic supporting body 4, an elastic mode exists in addition to a rigid mode. The frequency band close to the straight line between the elastic mode and the rigid mode is the frequency band of the mass line, and the function value of the frequency response in the frequency band is only related to the mass of the vehicle body and each inertia parameter in the mass matrix. The mass of the vehicle body and the inertial parameters are inherent properties of the vehicle body. The frequency band is not changed, so the frequency band is a fixed value straight line.

(IV) calculating the moment of inertia of the rail vehicle body 1

Selecting a mass line of an acceleration frequency response function, and outputting a mass matrix M and an acceleration response self-power function vector in the mass line segment

The relationship to the force hammer excitation response input from the power function vector f (ω) is as follows:

wherein the acceleration and angular acceleration vectors of the vehicle body motion are

The force and moment vector acting on the vehicle body is { f }_x f_y f_z t_x t_y t_z}^T。

At a certain excitation frequency, the above formula is converted to obtain an algebraic equation about the physical parameter:

and selecting a plurality of frequency points within the mass line range to establish an equation, and obtaining more than 9 linear equation sets according to the equation. And 9 physical parameters of the centroid coordinates and the rotational inertia matrix except the mass can be obtained by using a least square method.

Φ＝[x_c y_c z_c I_xx I_yy I_zz I_xy I_xz I_yz]^T

The moment of inertia I can be obtained according to the following coordinate conversion relation₁₁、I₂₂、I₃₃。

I₁₂＝I₂₁＝I_xy-m(x_c×y_c)

I₁₃＝I₃₁＝I_xz+m(z_c×x_c)

I₂₃＝I₃₂＝I_zy+m(z_c×y_c)

According to the above test process, the utility model provides a test system is not high to the space field requirement, consequently can effectively reduce investment cost, and what adopt this test system to implement is the quality line method, can portably accurate discernment rail vehicle body structure inertia.

In order to reduce the cost, the present embodiment designs four columns as the rigid supporting body 2, the four columns are distributed at four corners of the rectangle, and the top ends of the columns are supporting points. Correspondingly, four force sensors 3 and four elastic supports 4 are employed.

In a specific practical application, the force sensor 3 may be a strain tube type force sensor or a diaphragm type force sensor, the elastic support 4 may be a rubber spring, and the acceleration sensor 5 may be a piezoelectric acceleration sensor, a capacitive acceleration sensor or a servo acceleration sensor.

The data participating in the calculation in the acceleration frequency response function are frequency bands in a low frequency range, and therefore, the force hammer 6 is usually a softer hammer, for example, a rubber hammer or a nylon hammer. In order to be convenient to carry, the data acquisition device 7 is generally a notebook computer, and certainly, data acquisition software needs to be installed in the notebook computer.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (7)

1. A test system for identifying rotational inertia of a body structure of a rail vehicle, comprising:

a rigid support body (2), said rigid support body (2) having at least four support points for the overhead rail vehicle bodywork;

at least four force sensors (3), said force sensors (3) being intended to be placed on support points of said rigid support body (2);

at least four elastic supports (4), said elastic supports (4) being intended to be placed on support points of said rigid support (2);

the acceleration sensor (5), the said acceleration sensor (5) is used for fixing on the said rail vehicle car body;

a hammer (6) for hammering the rail vehicle body;

the force sensor (3), the force hammer (6) and the acceleration sensor (5) are all electrically connected with the data acquisition device (7).

2. Test system according to claim 1, characterized in that said rigid support (2) comprises four uprights distributed at the four corners of a rectangle, the top ends of which are said support points.

3. Testing system according to claim 1, characterized in that the elastic support (4) is a rubber spring.

4. Testing system according to claim 1, characterized in that the data acquisition device (7) is a laptop computer equipped with data acquisition software.

5. Test system according to any one of claims 1 to 4, characterized in that the hammer head of the force hammer (6) is a rubber hammer head or a nylon hammer head.

6. Test system according to claim 5, characterized in that the force sensor (3) is a strain tube force sensor or a diaphragm force sensor.

7. Test system according to claim 5, characterized in that the acceleration sensor (5) is a piezoelectric acceleration sensor, a capacitive acceleration sensor or a servo acceleration sensor.

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