Testing device and method for providing friction nonlinearity for rotating shaft structure

Abstract

The invention discloses a test device and method for providing friction nonlinearity for a rotating shaft structure, and belongs to the field of nonlinear dynamics research. The device is composed of two separated spring pieces, one end of the device is fixed to a fixing base through a bolt, and the device is fixed to the ground through a grounding plate to form clamped constraint. A spring is clamped between the two spring pieces at the other end, and a bolt penetrates through the two spring pieces and the spring in the middle through the through holes and is fastened on the other side through a nut. The device is fixed on the two sides of the rotating shaft, and the radial pressure applied to the rotating shaft by the spring piece can be changed by adjusting the fastening tightness of the nut, so that the friction force in the torsion direction is increased. The friction coefficient of the contact rotating shaft can be changed by sticking materials with different roughness on the inner surface of the annular part of the friction spring piece, so that the friction force is changed.

Description

Technical Field

[0001] The invention relates to a test device and a method for providing friction nonlinearity for a rotating shaft structure, and belongs to the field of nonlinear dynamics research. Background Art

[0002] Nonlinear dynamics is a discipline that studies the dynamic behavior of systems with nonlinear characteristics in time evolution. Compared with linear dynamics, nonlinear dynamic systems exhibit more complex and diverse behaviors, including but not limited to periodicity, quasi-periodicity, chaos, and bifurcation. Due to the complex behavior of nonlinear systems, vibration control strategies may need to be specially designed to adapt to the nonlinear characteristics of the system. Existing research programs for nonlinear systems focus on the study of gap nonlinearity in the system. For the friction nonlinearity of each structure in the system, especially for the rotating shaft, it is difficult to apply friction nonlinearity and there is no good solution. Summary of the invention

[0003] The purpose of the present invention is to provide a simple and convenient device for providing friction nonlinearity for nonlinear tests of structures with rotating shafts, in view of the difficulties faced in existing tests. When conducting nonlinear tests, the friction nonlinearity between the spring sheet and the rotating shaft can be changed by changing the degree of tightening of the bolts or by pasting different materials on the inner surface.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] A test device for providing friction nonlinearity for a rotating shaft structure, the device comprises a grounding plate and a rotating shaft, the device comprises a first spring sheet and a second spring sheet, the straight section of the first spring sheet and the straight section of the second spring sheet are fixed to a fixing frame by bolts, the annular section of the first spring sheet and the annular section of the second spring sheet are arranged on the outside of the rotating shaft, a spring is arranged between the tangent section of the first spring sheet bolt and the straight section of the second spring sheet bolt, and the two are connected by a spring bolt; by adjusting the tightness of the spring bolt, the radial pressure applied by the first spring sheet and the second spring sheet to the rotating shaft is changed, and the friction force in the torsional direction is changed;

[0006] The center angle of the first spring leaf annular segment is 90 degrees, and the first spring leaf bolt tangent segment is tangent to the first spring leaf annular segment; the center angle of the second spring leaf annular segment is 180 degrees;

[0007] An inner patch is arranged in the first spring sheet annular segment and / or the second spring sheet annular segment to change the roughness of the inner patch, thereby changing the friction coefficient and friction force in contact with the rotating shaft.

[0008] A working method of a test device for providing friction nonlinearity for a rotating shaft structure comprises the following steps:

[0009] S1. The first spring sheet annular segment and the second spring sheet annular segment are wound around the shaft;

[0010] S2. The first straight section of the spring sheet and the second straight section of the spring sheet are fixedly supported and restrained, and the two are fixed to the fixing frame by bolts;

[0011] S3. A spring is provided between the first spring sheet bolt tangent segment and the second spring sheet bolt segment, and then a spring bolt is passed through the first spring sheet and the second spring sheet and fastened;

[0012] S4. When conducting relevant nonlinear tests, the friction force between the friction spring sheet and the rotating shaft, i.e. the friction nonlinearity, is changed by adjusting the tightness of the spring bolt;

[0013] And / or by changing the roughness of the contact surface between the inner patch and the rotating shaft, the friction coefficient of the contact rotating shaft is changed, thereby changing the friction force between the first spring sheet, the second spring sheet and the rotating shaft, that is, the friction nonlinearity.

[0014] The beneficial effects of the present invention are as follows: the scheme of the present invention is simple and convenient. When conducting an experiment, the device does not need to be disassembled, and the friction force can be increased by tightening the bolts and reduced by loosening the bolts. The two spring sheets can be easily disassembled and replaced, and the friction force can be changed by pasting materials of different roughness inside the annular part of the spring sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a three-dimensional schematic diagram of the test device.

[0016] Figure 2 is a top view of the test apparatus.

[0017] Figure 3 It is a schematic diagram of the working of the test device.

[0018] Figure 4 This is a comparison chart of the vibration acceleration of the rudder surface before and after the test device is used.

[0019] Figure 5 It is a comparison chart of the vibration amplitude of the rudder surface before and after the test device is used.

[0020] In the figure: 1, first spring sheet, 1a, first spring sheet straight section, 1b, first spring sheet annular section, 1c, first spring sheet bolt tangent section, 2, second spring sheet, 2a, second spring sheet straight section, 2b, second spring sheet annular section, 2c, second spring sheet bolt straight section, 3, spring, 4, grounding plate, 5, rotating shaft, 6, fixing frame, 7, spring bolt, 8, inner patch. DETAILED DESCRIPTION

[0021] The present invention is described below with reference to the accompanying drawings and specific embodiments:

[0022] Figures 1 to 3 A test device for providing friction nonlinearity for a rotating shaft structure is shown, the device includes a grounding plate 4 and a rotating shaft 5, the device includes a first spring sheet 1 and a second spring sheet 2, the first spring sheet straight segment 1a and the second spring sheet straight segment 2a are fixed to a fixing frame 6 by bolts, the first spring sheet annular segment 1b and the second spring sheet annular segment 2b are arranged on the outside of the rotating shaft 5, a spring is arranged between the first spring sheet bolt tangent segment 1c and the second spring sheet bolt straight segment 2c, and the two are connected by a spring bolt 7; by adjusting the tightness of the spring bolt 7, the radial pressure applied by the first spring sheet 1 and the second spring sheet 2 to the rotating shaft 5 is changed, and the friction force in the torsional direction is changed.

[0023] The center angle of the first spring sheet annular segment 1b is 90 degrees, and the first spring sheet bolt tangent segment 1c is tangent to the first spring sheet annular segment 1b; the center angle of the second spring sheet annular segment 2b is 180 degrees. An inner patch 8 is arranged in the first spring sheet annular segment 1b and / or the second spring sheet annular segment 2b to change the roughness of the inner patch 8, thereby changing the friction coefficient and friction force in contact with the rotating shaft.

[0024] A working method of a test device for providing friction nonlinearity for a rotating shaft structure comprises the following steps:

[0025] S1. The first spring ring segment 1b and the second spring ring segment 2b are wound around the shaft 5;

[0026] S2. The first straight spring segment 1a and the second straight spring segment 2b are fixedly supported and restrained, and the two are fixed to the fixing frame 6 by bolts;

[0027] S3. A spring 3 is provided between the first spring leaf bolt tangent segment 1c and the second spring leaf bolt segment 2c, and then a spring bolt 7 is passed through the first spring leaf 1 and the second spring leaf 2 and fastened;

[0028] S4. When conducting relevant nonlinear tests, by adjusting the tightness of the spring bolt 7, the friction force between the friction spring sheet and the shaft is changed, that is, the friction nonlinearity;

[0029] And / or by changing the roughness of the contact surface between the inner patch 8 and the rotating shaft, the friction coefficient of the contact rotating shaft is changed, thereby changing the friction force between the first spring sheet 1, the second spring sheet 2 and the rotating shaft 5, that is, the friction nonlinearity.

[0030] Two spring sheets are put together around the rotating shaft, and the two are fixedly supported and constrained at the longer end; a spring is installed at the shorter end and fastened with a bolt; when conducting relevant nonlinear tests, the friction between the friction spring sheet and the rotating shaft, that is, the friction nonlinearity, is changed by adjusting the tightness of the bolt; when conducting relevant nonlinear tests, the friction coefficient of contacting the rotating shaft can be changed by pasting materials with different roughness on the inner surface of the annular part of the friction spring sheet, thereby changing the friction between the friction spring sheet and the rotating shaft, that is, the friction nonlinearity; the device includes two friction spring sheets that can be put together up and down. One end of the spring sheet can be fixedly supported. The other end of the spring sheet can clamp a spring of appropriate size. The spring sheet can be deformed by changing the tightness of the bolt, changing the radial pressure between it and the rotating shaft, thereby changing the friction. The annular part that passes around the rotating shaft can have materials with different roughness pasted on its inner surface to change the friction coefficient of contact with the rotating shaft, thereby changing the friction.

[0031] When conducting experiments, there is no need to disassemble the device. The friction force can be increased by tightening the bolts and reduced by loosening the bolts. The two spring leaves can be easily disassembled and replaced, and the friction force can be changed by sticking materials of different roughness inside the annular part of the spring leaf.

[0032] When the above technical solution is adopted, a wind tunnel test of a rudder surface system with a rotating shaft is performed using the present invention as an example, and the acceleration signal of the rudder surface system in the wind tunnel is collected. By comparing the results collected without a damping device and with a damping device, it can be clearly seen that the present invention has an inhibitory effect on the vibration amplitude and period of the rudder surface. By using frequency domain response analysis, the frequency spectrum of the two is obtained, and it can be seen that after the friction device is added, the vibration is greatly suppressed, which can prove the effectiveness of the present invention and the obvious effect.

Claims

1. A test device for providing friction nonlinearity for a rotating shaft structure, the device comprising a ground plate (4) and a rotating shaft (5), characterized in that: The device comprises a first spring sheet (1) and a second spring sheet (2); the first spring sheet straight section (1a) and the second spring sheet straight section (2a) are fixed to a fixing frame (6) by means of bolts; the first spring sheet annular section (1b) and the second spring sheet annular section (2b) are arranged outside a rotating shaft (5); a spring is arranged between the first spring sheet bolt tangent section (1c) and the second spring sheet bolt straight section (2c); the two are connected by means of a spring bolt (7); by adjusting the tightness of the spring bolt (7), the radial pressure applied by the first spring sheet (1) and the second spring sheet (2) to the rotating shaft (5) is changed, thereby changing the friction force in the torsional direction; The center angle of the first spring leaf annular segment (1b) is 90 degrees, and the first spring leaf bolt tangent segment (1c) is tangent to the first spring leaf annular segment (1b); the center angle of the second spring leaf annular segment (2b) is 180 degrees; An inner patch (8) is arranged in the first spring sheet annular segment (1b) and / or the second spring sheet annular segment (2b), and the roughness of the inner patch (8) is changed, thereby changing the friction coefficient and friction force in contact with the rotating shaft.

2. A working method of a test device for providing friction nonlinearity for a rotating shaft structure according to claim 1, characterized in that: The following steps are involved: S1. The first spring sheet annular segment (1b) and the second spring sheet annular segment (2b) are wound around the rotating shaft (5); S2. The first spring sheet straight section (1a) and the second spring sheet straight section (2b) are fixedly supported and restrained, and the two are fixed to the fixing frame (6) by bolts; S3. A spring (3) is provided between the first spring sheet bolt tangent segment (1c) and the second spring sheet bolt segment (2c), and a spring bolt (7) is passed through the first spring sheet (1) and the second spring sheet (2) and fastened; S4. When conducting the relevant nonlinear test, by adjusting the tightness of the spring bolt (7), the friction force between the friction spring sheet and the rotating shaft is changed, that is, the friction nonlinearity; And / or by changing the roughness of the contact surface between the inner patch (8) and the rotating shaft, the friction coefficient of the contact rotating shaft is changed, thereby changing the magnitude of the friction force between the first spring sheet (1), the second spring sheet (2) and the rotating shaft (5), that is, the magnitude of the friction nonlinearity.

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