Modal test excitation system for light flexible structure

Abstract

The invention belongs to the technical field of excitation tests, and particularly relates to a modal test excitation system for a light flexible structure. Comprising the steps that one end of the flexible test piece is fixed, and an excitation point is arranged on the flexible test piece; the magnet is mounted at an excitation point of the flexible test piece; the dynamic signal acquisition analyzer is provided with a signal output channel and a signal input channel; the power amplifier is connected with a signal output channel of the dynamic signal acquisition analyzer; the excitation coil is connected with the power amplifier through a wire, and a metal plate is installed on the end face, close to the excitation point of the flexible test piece, of the excitation coil. The force sensor is arranged between the metal plate and an excitation point of the flexible test piece, and the force sensor is connected with a signal input channel of the dynamic signal acquisition analyzer. According to the invention, the non-contact excitation of the test piece is realized by replacing the push-pull force of the excitation rod with the magnetic force, and additional rigidity and additional mass are not generated.

Description

Technical Field

[0001] The present application belongs to the technical field of vibration test, and in particular relates to a modal test vibration excitation system for lightweight flexible structures. Background Art

[0002] With the development of materials science, more and more lightweight structures have emerged. These lightweight structures are widely used in many fields such as aviation and automobiles.

[0003] In view of the small mass and small stiffness of such structures, the hammer method is usually used for testing in order to study their structural dynamic characteristics. However, when such structures have mechanisms that may cause nonlinear problems in the structure, modal tests need to study the impact of changes in the exciting force on its structural dynamic characteristics, which usually requires excitation by an exciter. The conventional exciter method is to connect the excitation rod to the test piece and then excite it. This method has large additional stiffness and mass, and the test results have large deviations.

[0004] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned defects of the prior art. Summary of the invention

[0005] The purpose of the present application is to provide a modal test excitation system for a lightweight flexible structure to solve at least one problem existing in the prior art.

[0006] The technical solution of this application is:

[0007] A modal test excitation system for a lightweight flexible structure, comprising:

[0008] A flexible test piece, one end of which is fixed and an excitation point is provided on the flexible test piece;

[0009] A magnet, the magnet being mounted at an excitation point of the flexible test piece;

[0010] A dynamic signal acquisition and analysis instrument, wherein the dynamic signal acquisition and analysis instrument has a signal output channel and a signal input channel;

[0011] A power amplifier connected to a signal output channel of the dynamic signal acquisition and analysis instrument;

[0012] An excitation coil, the excitation coil is connected to the power amplifier through a wire, and a metal plate is installed on the end surface of the excitation coil close to the excitation point of the flexible test piece;

[0013] A force sensor is provided between the metal plate and the excitation point of the flexible test piece, and the force sensor is connected to a signal input channel of the dynamic signal acquisition and analysis instrument.

[0014] In at least one embodiment of the present application, the magnet is in the shape of a coin.

[0015] In at least one embodiment of the present application, the magnet is fixedly connected to the flexible test piece by an adhesive.

[0016] In at least one embodiment of the present application, the dynamic signal acquisition and analyzer outputs a sinusoidal AC signal.

[0017] In at least one embodiment of the present application, the magnitude of the exciting force applied to the flexible test piece is controlled by changing the amplitude of the sinusoidal AC signal.

[0018] In at least one embodiment of the present application, the excitation coil is fixedly mounted on a base.

[0019] The invention has at least the following beneficial technical effects:

[0020] The modal test excitation system for lightweight flexible structures of the present application realizes non-contact excitation of the test piece by replacing the push-pull force of the excitation rod with magnetic force. Since there is no direct contact between the excitation system and the test piece during the excitation process, no additional stiffness and additional mass are generated. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of a modal test excitation system for a lightweight flexible structure according to an embodiment of the present application.

[0022] in:

[0023] 1-flexible test piece; 2-magnet; 3-dynamic signal acquisition and analysis instrument; 4-power amplifier; 5-excitation coil; 6-force sensor; 7-base. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the embodiment of this application will be described in more detail below in conjunction with the drawings in the embodiment of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be construed as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0025] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present application.

[0026] The following is combined with Figure 1 This application is described in further detail.

[0027] The present application provides a modal test excitation system for a lightweight flexible structure, comprising: a flexible test piece 1, a magnet 2, a dynamic signal acquisition analyzer 3, a power amplifier 4, an excitation coil 5 and a force sensor 6.

[0028] Specifically, Figure 1 As shown, one end of the flexible test piece 1 is fixed, and an excitation point is set on the flexible test piece 1; the magnet 2 is installed at the excitation point of the flexible test piece 1; the dynamic signal acquisition analyzer 3 has a signal output channel and a signal input channel; the power amplifier 4 is connected to the signal output channel of the dynamic signal acquisition analyzer 3; the excitation coil 5 is connected to the power amplifier 4 through a wire, and a metal plate is installed on the end face of the excitation coil 5 close to the excitation point of the flexible test piece 1; the force sensor 6 adopts a non-contact magnetic sensor, the force sensor 6 is set between the metal plate and the excitation point of the flexible test piece 1, and the force sensor 6 is connected to the signal input channel of the dynamic signal acquisition analyzer 3.

[0029] In a preferred embodiment of the present application, the magnet 2 is in the shape of a coin, and the magnet 2 is fixedly connected to the flexible test piece 1 by an adhesive.

[0030] In a preferred embodiment of the present application, the dynamic signal acquisition and analysis instrument 3 outputs a sinusoidal AC signal, and the magnitude of the exciting force applied to the flexible test piece 1 is controlled by changing the amplitude of the sinusoidal AC signal.

[0031] In a preferred embodiment of the present application, the excitation coil 5 is fixedly mounted on a base 7 corresponding to the position of the excitation point, so that the excitation coil 5 is positioned relative to the excitation point of the flexible test piece 1, so that there is an appropriate distance between the end surface of the excitation coil 5 on which the metal plate is provided and the magnet 2 on the excitation point of the flexible test piece 1.

[0032] The modal test excitation system for lightweight flexible structures of the present application utilizes the principle of electromagnetic induction. When the excitation coil 5 passes current, a magnetic field is generated, and the magnetic field generates a magnetic force that interacts with the magnet 2 fixed on the flexible test piece 1. During the test, the excitation coil 5 is adjusted to a position with an appropriate distance from the magnet 2. According to the test requirements, a sinusoidal AC signal is output through the dynamic signal acquisition analyzer 3. After the sinusoidal AC signal passes through the power amplifier 4, a sinusoidal alternating current is generated in the excitation coil 5, and then the excitation coil 5 generates an alternating magnetic field. After the magnet 2 on the flexible test piece 1 is subjected to the magnetic force of the magnetic field, it drives the flexible test piece 1 to perform alternating motion of the same frequency, thereby achieving the effect of performing modal test excitation by replacing the excitation rod with magnetic force. When the amplitude of the sinusoidal AC signal output by the dynamic signal acquisition analyzer 3 is changed, the magnetic force between the magnet 2 and the excitation coil 5 also changes. Therefore, the magnitude of the exciting force applied to the flexible test piece 1 can be adjusted by changing the magnitude of the input amplitude of the sinusoidal AC signal.

[0033] The modal test excitation system for lightweight flexible structures of the present application replaces the excitation rod of the exciter with magnetic force, thereby avoiding the additional stiffness and additional mass brought by the exciter, thereby achieving the test purpose of studying the relationship between the modal frequency and the exciting force of the flexible structure. It has a good effect when conducting modal tests on flexible structures, and can also be used when it is difficult to connect the test piece to the exciter. Therefore, it has a better application space in some scenes where conditions are not suitable for direct excitation by the exciter.

[0034] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A modal test excitation system for lightweight flexible structures, characterized in that: include: A flexible test piece (1), one end of which is fixed, and an excitation point is provided on the flexible test piece (1); A magnet (2), the magnet (2) being mounted at an excitation point of the flexible test piece (1); A dynamic signal acquisition and analysis instrument (3), wherein the dynamic signal acquisition and analysis instrument (3) has a signal output channel and a signal input channel; A power amplifier (4), the power amplifier (4) being connected to a signal output channel of the dynamic signal acquisition and analysis instrument (3); an excitation coil (5), the excitation coil (5) being connected to the power amplifier (4) via a wire, and a metal plate being installed on an end surface of the excitation coil (5) close to an excitation point of the flexible test piece (1); A force sensor (6), wherein the force sensor (6) is arranged between the metal plate and the excitation point of the flexible test piece (1), and the force sensor (6) is connected to a signal input channel of the dynamic signal acquisition and analysis instrument (3).

2. The modal test excitation system for lightweight flexible structures according to claim 1, characterized in that: The magnet (2) is in the shape of a coin.

3. The modal test excitation system for lightweight flexible structures according to claim 1, characterized in that: The magnet (2) is fixedly connected to the flexible test piece (1) via an adhesive.

4. The modal test excitation system for lightweight flexible structures according to claim 1, characterized in that: The dynamic signal acquisition and analysis instrument (3) outputs a sinusoidal AC signal.

5. The modal test excitation system for lightweight flexible structures according to claim 4, characterized in that: The magnitude of the exciting force applied to the flexible test piece (1) is controlled by changing the amplitude of the sinusoidal alternating current signal.

6. The modal test excitation system for lightweight flexible structures according to claim 1, characterized in that: The excitation coil (5) is fixedly mounted on a base (7).

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