Modal measurement device and modal measurement method for cylindrical structure

Abstract

The invention relates to the technical field of modal measurement, and provides modal measurement equipment and a modal measurement method for a cylindrical structural body, and the equipment comprises a non-contact excitation unit which outputs vibration excitation energy towards the cylindrical structural body; the non-contact vibration measuring unit is used for detecting the vibrating cylindrical structural body to obtain a vibration response signal; the motion unit forms relative motion between the vibration measurement unit and the cylindrical structure so as to correspond to a measurement position; and the signal processing unit obtains vibration data of the corresponding measurement position according to the vibration response signal, and obtains modal information of the corresponding measurement position based on the vibration data. By combining the technology of non-contact excitation and vibration measurement on the cylindrical structure, various problems of a contact sensor are avoided, and the measurement accuracy and reliability are improved; and in addition, high-precision modal measurement can be realized in combination with high-precision automatic control.

Description

Technical Field

[0001] The present disclosure relates to the field of modal measurement technology, and in particular to a modal measurement device and a modal measurement method for a cylindrical structure. Background Art

[0002] Cylindrical structures such as tanks, pipes and cylindrical shells are widely used in industry and engineering, especially in petrochemical, aerospace, nuclear power and construction industries. These structures are usually in a complex stress environment and are easily affected by external loads, internal pressure and vibration, which may cause fatigue, damage and even failure of the structure. Therefore, accurate understanding of the modal characteristics of cylindrical structures is crucial for predicting and preventing structural failures.

[0003] Traditional modal analysis methods mostly rely on contact sensors and manual operations. Although these methods can obtain the modal parameters of the structure to a certain extent, they have significant limitations. First, the installation and layout of contact sensors are complicated, especially when measuring large or complex geometric structures, which may affect the accuracy of the measurement results. Secondly, traditional methods often require manual point-by-point movement of sensors and excitation sources for measurement, which is inefficient and prone to errors. In addition, contact excitation methods, such as the use of vibrating hammers or mechanical exciters, may interfere with the structure being measured, affect its natural vibration state, and cause distortion of the measurement results. Summary of the invention

[0004] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a modal measurement device and a modal measurement method for a cylindrical structure, so as to automatically control and non-contactly excite vibrations of the cylindrical structure and perform vibration detection to achieve modal measurement, thereby solving the problems in the related art.

[0005] A first aspect of the present disclosure provides a modal measurement device for a cylindrical structure, comprising: a non-contact excitation unit, used to output vibration excitation energy for exciting the cylindrical structure to vibrate; a non-contact vibration measuring unit, used to output a detection signal to the vibrating cylindrical structure and receive an echo signal corresponding to a vibration response of a measurement position on the cylindrical structure to be measured, and obtain vibration data of the measurement position according to the echo signal; a motion unit, used to drive the relative movement between the vibration measuring unit and the cylindrical structure so that the non-contact vibration measuring unit reaches a position corresponding to the measurement position on the cylindrical structure; and a signal processing unit, coupled to the non-contact vibration measuring unit, used to obtain modal information according to the vibration data of each measurement position.

[0006] In an embodiment of the first aspect, an execution control unit is used to control the execution actions of the excitation unit, the vibration measuring unit and the motion unit based on the set execution parameters, so as to automatically complete the traversal detection of each measurement position and obtain corresponding modal information in the signal processing unit.

[0007] In an embodiment of the first aspect, the moving unit carries the cylindrical structure and is capable of rotating around an axis of the cylindrical structure and reciprocating along the axis.

[0008] In an embodiment of the first aspect, a vibration isolator is provided between the motion unit and the loaded cylindrical structure and / or between a support supporting the motion unit and the motion unit.

[0009] In an embodiment of the first aspect, the excitation unit includes a sound-excited vibration device; the sound-excited vibration device includes a speaker and an acoustic signal generator coupled to the speaker.

[0010] In an embodiment of the first aspect, the excitation unit includes: a power amplifier connected between the transducer outputter and the signal generator.

[0011] In an embodiment of the first aspect, the excitation frequency of the vibration excitation energy varies within a preset frequency range covering the natural frequencies of different modes of the cylindrical structure, so that the natural frequencies of different modes of the cylindrical structure are identified by a vibration measuring unit and vibration data based on different natural frequencies are obtained.

[0012] In an embodiment of the first aspect, the vibration measuring unit is mounted on the moving unit so as to be driven by the moving unit to move around the axis of the cylindrical structure and to reciprocate along the axis.

[0013] In an embodiment of the first aspect, the moving unit moves in a preset step to determine that the vibration measuring unit corresponds to each of the measurement positions.

[0014] In an embodiment of the first aspect, the excitation unit includes an acoustically excited vibration device or an electromagnetic vibration excitation device; and / or the vibration measuring unit includes an optical vibration measuring device.

[0015] In an embodiment of the first aspect, the vibration measuring unit includes at least one of the following detection light sources: a point light source, a line light source, and a surface light source.

[0016] In an embodiment of the first aspect, at least one of the excitation unit and the vibration measuring unit is disposed in the cylindrical structure.

[0017] In an embodiment of the first aspect, a cross-section of the cylindrical structure includes one of the following: circular, elliptical, square, trapezoidal, and triangular.

[0018] In an embodiment of the first aspect, the modal information includes first N-order modal spectra, where N≥1.

[0019] A second aspect of the present disclosure provides a modal measurement method for a cylindrical structure, which is applied to the modal measurement equipment described in any one of the first aspects, and the method comprises: acquiring the set execution parameters; based on the execution parameters, causing the excitation unit to output vibration excitation energy for exciting the cylindrical structure to vibrate; based on the execution parameters, driving the relative movement between the vibration measuring unit and the cylindrical structure so that the non-contact vibration measuring unit traverses and detects each measurement position and obtains a corresponding vibration response signal; obtaining vibration data of each corresponding measurement position according to the vibration response signal; and obtaining modal information of each corresponding measurement position based on the vibration data.

[0020] As described above, the present disclosure relates to the field of modal measurement technology, and provides a modal measurement device and a modal measurement method for a cylindrical structure. The device includes a non-contact excitation unit that outputs vibration excitation energy toward the cylindrical structure; a non-contact vibration measurement unit that detects the vibrating cylindrical structure to obtain a vibration response signal; a motion unit that forms a relative motion between the vibration measurement unit and the cylindrical structure to correspond to the measurement position; a signal processing unit that obtains vibration data of the corresponding measurement position according to the vibration response signal, and obtains modal information of the corresponding measurement position based on the vibration data. By combining the non-contact excitation and vibration measurement technology of the cylindrical structure, various problems of contact sensors are avoided, and the measurement accuracy and reliability are improved; in addition, high-precision automatic control can be combined to achieve high-precision modal measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram showing the structure of a modal measurement device for a cylindrical structure in one embodiment of the present disclosure.

[0022] Figure 2 A schematic structural diagram of the excitation unit described in one embodiment of the present disclosure is shown.

[0023] Figure 3 A schematic diagram of the structure of an acoustically excited vibration device in one embodiment of the present disclosure is shown.

[0024] Figure 4 A schematic diagram showing the structure of an electromagnetic excitation vibration device in one embodiment of the present disclosure.

[0025] Figure 5 A schematic diagram showing the structural layout of a modal measurement device in a second embodiment of the present disclosure is shown.

[0026] Figure 6 A schematic diagram showing the structural layout of a modal measurement device in the third embodiment of the present disclosure is shown.

[0027] Figure 7 A schematic diagram showing the structural layout of a modal measurement device in a fourth embodiment of the present disclosure is shown.

[0028] Figure 8 A schematic diagram showing the structural layout of a modal measurement device in the fifth embodiment of the present disclosure is shown.

[0029] Fig. 9 A schematic diagram showing the structural layout of a modal measurement device in a sixth embodiment of the present disclosure is shown.

[0030] Fig.10 A schematic diagram of the structural layout of a modal measurement device in the seventh embodiment of the present disclosure is shown.

[0031] Fig.11 A schematic structural diagram of a modal measurement device in a specific embodiment of the present disclosure is shown.

[0032] Fig.12 exhibit Fig.11 Schematic diagram of the structure of the middle cylinder structure.

[0033] Fig.13 exhibit Fig.11 Schematic diagram of the structure of the two-axis rotating indexing plate.

[0034] Fig.14 A schematic flow chart showing a modal measurement method performed based on a modal measurement device in an embodiment of the present disclosure.

[0035] Fig.15 As shown, a specific embodiment of the present disclosure is shown based on Fig.11 Schematic diagram of the modal measurement method performed by the modal measurement equipment.

[0036] Fig.16 A schematic diagram showing the structure of a computer device in an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0037] The following is an explanation of the embodiments of the present disclosure by specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the information disclosed by the present disclosure. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in the present disclosure can also be modified or changed in various ways according to different viewpoints and application modules without departing from the spirit of the present disclosure. It should be noted that the embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0038] The following is a detailed description of the embodiments of the present disclosure with reference to the accompanying drawings so that those skilled in the art can easily implement the present disclosure. The present disclosure can be embodied in many different forms and is not limited to the embodiments described herein.

[0039] In the representations of the present disclosure, the reference terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" and the like mean that the specific features, structures, materials or characteristics represented in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. Moreover, the specific features, structures, materials or characteristics represented may be combined in any one or a group of embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples represented in the present disclosure and the features of different embodiments or examples, unless they are mutually contradictory.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the representation of the present disclosure, "a group" means two or more, unless otherwise clearly and specifically defined.

[0041] In order to clearly describe the present disclosure, components not related to the description are omitted, and the same reference numerals are given to the same or similar components throughout the specification.

[0042] Throughout the specification, when a device is said to be "connected" to another device, this includes not only the case of "direct connection" but also the case of "indirect connection" by placing other elements therebetween. In addition, when a device is said to "include" a certain component, unless otherwise stated, it does not exclude other components, but means that other components may be included.

[0043] Although the terms first, second, etc. are used to represent various elements in this article in some examples, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, the first interface and the second interface, etc. are represented. Moreover, as used in this article, the singular forms "one", "one" and "the" are intended to also include plural forms, unless there is an opposite indication in the context. It should be further understood that the terms "comprising" and "including" indicate that there are the described features, steps, operations, elements, modules, projects, kinds, and / or groups, but do not exclude the existence, occurrence or addition of one or a group of other features, steps, operations, elements, modules, projects, kinds, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Therefore, "A, B or C" or "A, B and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B and C". Only when the combination of elements, functions, steps or operations is inherently mutually exclusive in some way, will there be an exception to this definition.

[0044] The technical terms used herein are only used to refer to specific embodiments and are not intended to limit the present disclosure. The singular form used herein also includes the plural form unless the sentence clearly indicates the contrary meaning. The meaning of "including" used in the specification is to specify specific characteristics, regions, integers, steps, operations, elements and / or components, and does not exclude the existence or addition of other characteristics, regions, integers, steps, operations, elements and / or components.

[0045] Although not defined differently, all terms, including technical and scientific terms used herein, have the same meaning as those generally understood by those skilled in the art to which the present disclosure belongs. Terms defined in commonly used dictionaries are additionally interpreted as having meanings consistent with relevant technical literature and the message of the present disclosure, and shall not be overly interpreted as ideal or very formal meanings unless defined.

[0046] Cylindrical structural components are widely used in industrial and engineering fields, such as petrochemical, aerospace, nuclear power, and construction. The measurement of the modal characteristics of cylindrical structures is crucial for predicting and preventing structural failures.

[0047] However, the current measurement method relies on contact sensors and manual operation. Although the modal parameters of the structure can be obtained to a certain extent, there are many problems. The installation and layout of contact sensors are complicated, especially when measuring large or complex geometric structures, which may affect the accuracy of the measurement results. Secondly, traditional methods often require manual movement of sensors or excitation sources point by point for measurement, which is inefficient and prone to errors. In addition, contact excitation methods, such as using a vibrating hammer or a mechanical exciter, may interfere with the structure being measured, affect its natural vibration state, and cause distortion of the measurement results.

[0048] In a related technical solution, a cylindrical structure is suspended on a bracket, a right-angle prism at a 45-degree angle is installed on the center line of the cylindrical structure inside the cylindrical structure, and fixed on one end of a rotational motion control system. The rotational motion control system is installed at the end of a linear motion control system. The linear motion control system is fixed on the bracket and parallel to the axis of the cylindrical structure. The laser head of the laser vibrometer is installed on the bracket, opposite to the inclined surface of the right-angle prism at a 45-degree angle. The laser vibrometer is connected to the data acquisition system, and the exciter is connected to the cylindrical structure through an elastic push rod. However, in this solution, since the contact connection of the elastic push rod is used to transmit vibration, the cylindrical structure is prone to unexpected vibration during the operation of the mechanical system, resulting in interference between mechanical components, vibration noise, mechanical failure and other irreparable losses. This modal testing method has the problems of requiring the attachment of sensors, increasing additional mass, and limited measurement results.

[0049] In another related technical solution, a system for wind turbine tower modal recognition is provided, including a high-definition camera, a vibration data acquisition device and a data analysis system, wherein the data analysis system includes a wind turbine impeller speed recognition module, a cabin yaw position recognition module and a wind turbine vibration response acquisition module, and the wind turbine impeller speed recognition module includes a video processing module, a conversion module and a calculation module. However, the three-dimensional digital image correlation method of this solution has problems in terms of large amount of calculation, long calculation time, and error proliferation caused by discontinuous deformation in the region of interest.

[0050] In another related technical solution, a large number of sensors are installed on the wind turbine tower and modal parameters are calculated through deep learning methods. However, there are problems such as the change of modal parameters is difficult to indicate the specific damage area and degree, and it is necessary to refer to the modal parameters in a healthy state.

[0051] In view of the problems in the related art, the present invention discloses a modal measurement device for a cylindrical structure, which excites and measures vibration in a non-contact manner, and the device can also automatically control the measurement process according to the set execution parameters, thereby effectively solving the structural complexity problem of the related art that requires the arrangement of contact vibration machinery (such as a vibrating hammer) and / or contact sensors to measure vibration, as well as the low efficiency problem of requiring manual operation and adjustment.

[0052] like Figure 1 As shown, a schematic diagram of the structure of a modal measurement device for a cylindrical structure in one embodiment of the present disclosure is shown.

[0053] It should be noted that the modal measurement device 100 can be applied to modal measurements of various shapes of cylindrical structures 200. For example, the cylindrical structure 200 can be a commonly used cylinder, that is, the cross section can be circular (specifically, a circular ring shape because the cylinder is hollow). However, the cylindrical structure 200 can also be a column with a cross section of an elliptical, square, trapezoidal, triangular, etc., and is not limited to a cylindrical body.

[0054] exist Figure 1 , a simplified structure of a modal measurement device 100 in an embodiment is shown. The modal measurement device 100 includes: a non-contact excitation unit 110, a non-contact vibration measurement unit 120, a motion unit 130, a signal processing unit 140 and an execution control unit 150.

[0055] The non-contact excitation unit 110 is used to output vibration excitation energy to the cylindrical structure 200 for exciting the cylindrical structure 200 to vibrate.

[0056] like Figure 2 As shown, a schematic diagram of the structure of the excitation unit 110 described in an embodiment of the present disclosure is shown.

[0057] The excitation unit 110 includes: a transducer output 111 and a signal generator 112. The signal generator 112 is used to generate an alternating signal. The transducer output 111 is coupled to the signal generator 112, and based on the alternating electrical signal output by the signal generator 112, it is converted into vibration excitation energy for output. As an example, the excitation unit 110 can be implemented as an acoustic excitation vibration device or an electromagnetic excitation vibration device. The signal generator 112 may include an oscillation circuit, which can output a high-frequency alternating electrical signal (such as an AC voltage / current signal). The transducer output 111 may include, for example, an acoustic transducer or an electromagnetic transducer, so as to generate a vibration excitation energy in the form of sound or magnetism according to the alternating electrical signal, which can act on the cylindrical structure 200 to excite the vibration of the cylindrical structure 200. It can be understood that when the excitation unit 110 uses an acoustic signal (such as sound wave / ultrasound wave) to excite the cylindrical structure 200 (for example Figure 1 ) when the cylindrical structure 200 is vibrated, the cylindrical structure 200 can be made of solid material. When the excitation unit 110 uses magnetic force to drive the cylindrical structure 200 to vibrate, the cylindrical structure 200 can be made of a metal material that can be driven by the magnetic force.

[0058] In some embodiments, the frequency of the oscillation excitation signal generated by the signal generator 112 can vary within a preset frequency range to form an oscillation excitation signal that can sweep within a certain frequency range. The frequency of the corresponding oscillation excitation energy also changes accordingly, thereby exciting the cylindrical structure 200 to vibrate within the response frequency range to cover each natural frequency and obtain vibration data at each natural frequency.

[0059] In different scenarios, since the cylindrical structure 200 may have different sizes and materials, if the vibration excitation signal is generated based only on the oscillation excitation signal generated by the signal generator 112, its energy may not necessarily be able to excite the cylindrical structure 200 to achieve the required amplitude of vibration to obtain an obvious vibration response. Therefore, in an optional embodiment, a power amplifier 113 can also be coupled between the transducer output 111 and the signal generator 112 to amplify the electrical energy provided by the oscillation excitation signal, thereby increasing the vibration excitation energy output by the transducer output 111. It is understandable that the amplification factor of the power amplifier 113 can be set according to the vibration amplitude of the cylindrical structure 200 to be achieved to meet the actual scene requirements.

[0060] like Figure 3 As shown, a schematic diagram of the structure of the acoustically excited vibration device in one embodiment of the present disclosure is shown.

[0061] The acoustic excitation vibration device 110a transmits vibration excitation energy by emitting a vibration excitation signal (which may be an acoustic signal or an ultrasonic signal depending on the frequency). Specifically, the acoustic excitation vibration device 110a transmits a vibration excitation signal to the cylindrical structure 200 to transmit the vibration excitation energy to the cylindrical structure 200 to excite the cylindrical structure 200 to vibrate accordingly.

[0062] The acoustically excited vibration device 110a includes: an acoustic signal generator 112a and a speaker 111a coupled thereto. Optionally, an acoustic power amplifier 113a may be coupled between the acoustic signal generator 112a and the speaker 111a. As an example, the acoustic signal generator 112a may include an oscillation circuit for being applied with electrical energy to output an oscillation excitation signal of a certain frequency. The speaker 111a is an electroacoustic transducer component, which, under the action of the oscillation excitation signal, causes the transducer to vibrate to output a vibration excitation signal through principles such as electromagnetic, piezoelectric or electrostatic effects. If the acoustically excited vibration device 110a outputs sound waves, the speaker 111a may be implemented as a speaker, and the transducer may be implemented as a paper cone or a diaphragm. If the acoustically excited vibration device 110a outputs ultrasonic waves, the transducer may be implemented as a piezoelectric ceramic.

[0063] like Figure 4 As shown, a schematic diagram of the structure of an electromagnetic excitation vibration device in one embodiment of the present disclosure is shown.

[0064] The electromagnetic excitation vibration device 110b may include an electric signal generator 112b and an electromagnetic conversion component 111b coupled thereto. Optionally, an electric power amplifier 113b may be coupled between the electric signal generator 112b and the electromagnetic conversion component 111b. As an example, the electric signal generator 112b may include an oscillation circuit for outputting an oscillation excitation signal; the electric power amplifier 113b may amplify the oscillation excitation signal and output a current signal. The electromagnetic conversion component 111b may include one or more electromagnetic elements (such as a coil with or without an iron core), and the electromagnetic conversion component 111b passes the current signal, and the changing magnetic field forms a magnetic force that changes the direction of vibration of the cylindrical structure 200.

[0065] Back to Figure 1, the non-contact vibration measuring unit 120 is used to output a detection signal to the vibrating cylindrical structure 200 and receive an echo signal corresponding to the vibration response of the measuring position on the cylindrical structure 200, and obtain the vibration data of the measuring position according to the echo signal. In some embodiments, the vibration measuring unit 120 may include an optical vibration measuring device, which is used to emit an optical signal to the measuring position on the cylindrical structure and receive the optical signal of the reflected echo, thereby forming a vibration response signal output. Optionally, the optical vibration measuring device can be implemented as a laser vibrometer 120a, etc. Further optionally, the vibration measuring unit 120 includes at least one of the following detection light sources: a point light source, a line light source, a surface light source, etc., such as a point laser vibrometer 120a, a line laser vibrometer 120a or a surface laser vibrometer 120a. Based on the size of the measuring position on the cylindrical structure 200 that needs to be detected each time, a laser vibrometer 120a suitable for the light source type can be selected.

[0066] In some embodiments, the excitation frequency of the vibration excitation energy varies within a preset frequency range covering the natural frequencies of different modes of the cylindrical structure 200, i.e., frequency sweeping. For example, when the excitation unit 110 is implemented as an acoustic excitation vibration device 110a, the acoustic signal generator 112a outputs an acoustic excitation signal that sweeps within a preset frequency range that may cover different natural frequencies of the cylindrical structure 200. As an example, the acoustic excitation signal may be a linear or logarithmic frequency modulation signal, expressed as:

[0067]

[0068] Where: f start is the starting frequency of the sweep, f end is the end frequency of the sweep, and T is the duration of the sweep.

[0069] The swept frequency acoustic excitation signal is amplified by the acoustic power amplifier 113a and then transmitted to the speaker 111a as an excitation source. The speaker 111a converts the electrical signal into an acoustic signal and applies a swept frequency excitation to the cylindrical structure 200 to excite vibrations at different frequencies. The intensity and frequency of the excitation are controlled by the signal generator 112 and the power amplifier 113 to ensure that the intensity of the excitation signal is sufficient to allow the cylindrical structure 200 to produce the desired obvious vibration response.

[0070] The vibration measuring unit 120 identifies the natural frequencies of different modes of the cylindrical structure 200 based on the vibration response, and obtains vibration data based on different natural frequencies. As an example, during the frequency sweep excitation process, the vibration measuring unit 120 records the vibration response of the cylindrical structure 200 at different frequencies. By analyzing the change in the vibration amplitude, the natural frequency of the structure can be identified. Among them, the natural frequency generally corresponds to the position with the largest vibration amplitude, that is, the peak value, so the corresponding natural frequency can be identified based on the detection of the amplitude peak value, that is:

[0071]

[0072] Where: X(f) is the amplitude of the vibration response, f n is the natural frequency. The cylindrical structure 200 may have multiple natural frequencies, corresponding to different modes.

[0073] Further optionally, based on different natural frequencies, the corresponding vibration data can be calculated using the principle of Doppler frequency shift (i.e., the frequency of sound waves increases when the sound source moves toward the observer, and decreases when the sound source moves away from the observer). As an example, the vibration data based on different natural frequencies collected for each measurement position may include at least one of the following: displacement , i.e. the instantaneous displacement of the measuring position; speed , which is the time rate of change of displacement; acceleration , which is the acceleration of the vibration response.

[0074] In an optional embodiment, the sampling frequency of the vibration measuring unit 120 needs to be high enough, usually much higher than the excitation frequency. For example, the sampling frequency is a preset multiple (such as 100 times) of the excitation frequency to ensure accurate capture of the vibration response. As a result, the vibration measuring unit 120 can collect and store vibration data at each measurement position covering the excitation frequency, that is, store the displacement, velocity and acceleration data of each measurement position at different frequencies for subsequent modal analysis.

[0075] The motion unit 130 is used to drive the relative movement between the vibration measuring unit 120 and the cylindrical structure, so that the non-contact vibration measuring unit 120 reaches a position corresponding to the measurement position on the cylindrical structure 200. In some embodiments, for example Figure 1 As shown, the cylindrical structure 200 can be loaded on the motion unit 130 so that it can be driven by the motion unit 130 to move relative to the vibration measuring unit 120. The motion unit 130 carries the cylindrical structure 200 and can rotate around the axis of the cylindrical structure 200 and reciprocate along the axis. As an example, the motion unit 130 may include a bearing surface for carrying the cylindrical structure 200, the bearing surface is, for example, a horizontal surface, the cylindrical structure 200 is vertically arranged on the bearing surface, and the motion unit 130 can rotate around the axis Z of the cylindrical structure 200 (for example, Figure 1 The horizontal rotation shown by the arrow A in the middle), or the movement along the axis direction (for example Figure 1The lifting and lowering shown by the arrow B in the figure). Thus, through the above two relative movements, the vibration measuring unit 120 can correspond to measure most or all areas of the surface of the cylindrical structure 200, thereby completing the vibration measurement of each selected measurement position. In some embodiments, the measurement position is determined based on the movement mode of the motion unit 130 and the detection frequency of the vibration measuring unit 120. For example, the motion unit 130 drives the cylindrical structure 200 to rotate horizontally according to a preset step, such as rotating a° / second, then there is a measurement position corresponding to the vibration measuring unit 120 at every a° interval on the circumference of a horizontal height of the cylindrical structure 200 to be detected, and as the cylindrical structure 200 rotates horizontally for one circle, the measurement positions of the cylindrical structure 200 at 360° / a° intervals on the axial direction of the horizontal height are determined, which can be called a group of measurement positions. Similarly, when the motion unit 130 drives the cylindrical structure 200 to rise and fall, multiple groups of the measurement positions will be determined. If the vibration measuring unit 120 is implemented as a point laser vibrometer 120a, each detection point in the form of a dot matrix in the circumferential direction and the axial direction of the cylindrical structure 200 can be detected. Figure 1 In an embodiment, the motion unit 130 may be implemented as a two-axis rotating indexing plate 120a that can rotate and rise and fall.

[0076] In some embodiments, the cylindrical structure 200 can be fixed on the motion unit 130 by a tool, and the tool can fix the cylindrical structure 200 by means such as clamping, clamping, screw locking, etc. In order to prevent the vibration of the cylindrical structure 200 from being transmitted to the motion unit 130 and affecting the stability of the movement, optionally, a vibration isolation member can be provided between the motion unit 130 and the loaded cylindrical structure 200. Optionally, the motion unit 130 can be supported by a support, for example, it is provided on a test bench 180, and a vibration isolation member can be provided between the motion unit 130 and the support to isolate the vibration of the cylindrical structure 200 from reaching the support through the motion unit 130, so as to cause damage to other equipment (such as electronic devices, etc.) loaded on the surface of the support. As an example, the vibration isolation member can be implemented as a component with buffering capacity such as a foam board, a cushion, etc., to ensure the stability of the structure during the measurement process.

[0077] In some embodiments, before the vibration measuring unit 120 performs measurement, the number and distribution of measurement positions on the surface of the cylindrical structure 200 can be determined. For single-point measurement, the measurement position is the measurement point. The distribution of the measurement positions can cover the key positions of the cylindrical structure 200 to ensure that the measured data can fully reflect the vibration characteristics of the cylindrical structure 200. As an example, the measurement positions can be evenly distributed along the circumferential and axial directions of the cylindrical structure 200 to capture the global vibration mode.

[0078] In an optional example, the spacing of the measurement points can be set to 1 / 10 to 1 / 20 of the structural characteristic length of the cylindrical structure 200 to ensure sufficient spatial resolution. The structural characteristic length generally refers to the geometric characteristic length of an object or structure, reflecting some important characteristics of the object.

[0079] In addition, during the measurement process, the motion unit 130 can accurately drive the vibration measuring unit 120 to rotate, ensuring that the vibration measuring unit 120 can scan the surface of the cylindrical structure 200 position by position. When the motion unit 130 is implemented as a two-axis rotating indexing disk 120a, the two axes respectively control the angles of the structure in two mutually perpendicular dimensions (i.e., the circumferential direction and axial direction of the cylindrical structure 200). Taking the cylindrical structure 200 as an example, the circumferential direction is the horizontal direction and the axial direction is the height direction. The two-axis rotating indexing disk 120a rotates 5° or 10° horizontal angles each time until the entire circumference at a height is covered. And, the two-axis rotating indexing disk 120a gradually moves the measuring point in the height direction, and the step is, for example, 1cm~1.5cm, etc., to ensure that the entire surface of the cylindrical structure 200 is measured, so that the vibration measuring unit 120 can complete non-contact vibration measurement.

[0080] The signal processing unit 140 is coupled to the non-contact vibration measuring unit 120, and is used to obtain modal information according to the vibration data of each measuring position. In some embodiments, the signal processing unit 140 may include a signal demodulation device 141, which is used to demodulate the modulated signal formed by the modulated vibration data output by the vibration measuring unit 120 to obtain vibration data. The signal processing unit 140 analyzes the modal information according to the vibration data.

[0081] Mode is the inherent vibration characteristic of the structural system, and modal analysis obtains the vibration characteristics of the structure by analyzing the parameters such as the frequency, vibration mode and damping ratio of the structure. An example is given to illustrate the processing process. Based on the vibration data, Fourier transform is used to convert the time domain data into frequency domain data to obtain the frequency response function:

[0082] Where: X(f) is the vibration response amplitude at the measurement position, and F(f) is the oscillation excitation signal applied to the transducer output or the vibration excitation signal output by the transducer output. Through the frequency response function, the natural frequency f is extracted n , damping ratio ζn, mode shape ϕn.

[0083] Further optionally, the cylindrical structure 200 may be subjected to modal modeling based on, for example, the finite element method (FEM). The first N-order modes (for example, the 5th order) of the cylindrical structure 200 are generated by fitting the measured vibration response. The modal equation is exemplarily expressed as follows:

[0084]

[0085] Where: K is the stiffness matrix of the structure, M is the mass matrix, w is the angular frequency, w=2π*f n , is the mode shape vector.

[0086] Thus, the modal information can be obtained, and the modal information can include the first N-order modal spectra, where N≥ 1. The modal spectra can intuitively reflect the deformation modes of the cylindrical structure 200 at different frequencies, which is helpful for analyzing its dynamic performance.

[0087] In modal analysis, the first to sixth order modes of six degrees of freedom correspond to each other, and the order represents the vibration characteristics of the structure at different natural frequencies. Each of the six order modes has different meanings and application values. The first order mode represents the most basic vibration form of the structure, with the lowest frequency and the greatest contribution to the structural response. The vibration mode of the first order mode usually reflects the overall stiffness and mass distribution characteristics of the structure, which can be used to determine whether the stiffness and mass distribution are reasonable, and whether there is a problem of insufficient local stiffness, providing a basis for structural design and optimization. The frequency of the second order mode is higher than that of the first order mode, and its vibration mode is usually significantly different from that of the first order mode, reflecting the vibration characteristics of the structure in different directions or different parts. The second order mode helps to further evaluate the dynamic performance and stability of the structure, especially the response under multi-directional or complex loads. The third order mode, the frequency continues to increase, the vibration mode is more complex, and may involve the vibration of the local area of ​​the structure, which is important for understanding the local stability and dynamic response of the structure, and helps to discover potential vibration problems in the local area. ‌The frequency of the fourth-order mode continues to increase, and its vibration mode may present a more complex vibration mode, reflecting the dynamic characteristics of the structure in more local areas, which may include torsional or bending vibrations of the structure, which helps to discover higher-frequency vibration problems that may exist in the structure and provide guidance for structural optimization design. ‌The frequency of the fifth-order mode continues to increase, and its vibration mode may present a more complex vibration mode, reflecting the higher-frequency dynamic characteristics of the structure in certain local areas, which can provide a more comprehensive understanding of the dynamic performance of the structure and provide protection for the safe operation of the structure under complex working conditions. The sixth-order mode has the highest frequency, and its vibration mode may present a more complex vibration mode, reflecting the dynamic characteristics of the structure in more local areas, which helps to discover the highest-frequency vibration problems that may exist in the structure and provides an important reference for the ultimate design and optimization of the structure.

[0088] Further illustratively, the N can be set according to actual analysis requirements, for example, N=5, which means that the modal information includes the first 5 modal spectra, which can more comprehensively reflect the vibration characteristics of the cylindrical structure 200.

[0089] In some embodiments, the process of the signal processing unit 140 obtaining the modal information according to the vibration data of each measurement position can be illustrated as follows.

[0090] Convert the time domain signal to the frequency domain through Fourier transform:

[0091]

[0092] Where: X(f) is the amplitude in the frequency domain, is the measured vibration displacement, and Fourier transform helps to identify the vibration response of the structure at various frequencies.

[0093] According to the spectrum of the vibration signal obtained by Fourier transform, the frequency response function is calculated. The frequency response function H (f) is used to describe the dynamic response characteristics of the structure under different excitation frequencies. The formula is:

[0094]

[0095] Where: X(f) is the vibration data of the measurement position, and F(f) is the excitation signal applied to the speaker 111a. By calculating the frequency response function of each measurement position, the vibration characteristics of the structure can be understood, and the natural frequency of the cylindrical structure 200 and its corresponding vibration mode can be identified.

[0096] Furthermore, based on the frequency response functions of all points, the modal parameters of the structure are extracted, including the natural frequency f n : The natural frequency is identified by the peak value of the frequency response function, indicating the resonance of the structure at the natural frequency; Damping ratio ζn: The damping ratio is calculated by the width of the frequency response curve; Modal vibration shape φn: The vibration shape is extracted by the difference in vibration amplitude and phase at different measurement points.

[0097] As mentioned before, the natural frequency can be determined from the peak amplitude:

[0098]

[0099] And, the mode shapes can be obtained by solving the modal equations:

[0100]

[0101] Where: K is the stiffness matrix of the structure, M is the mass matrix, w is the angular frequency, w=2π*f n , is the mode shape vector.

[0102] The execution control unit 150 is used to control the execution actions of the excitation unit 110, the vibration measuring unit 120 and the motion unit 130 based on the set execution parameters, so as to automatically complete the traversal detection of each measurement position and obtain the corresponding modal information in the signal processing unit 140. In some embodiments, the execution control unit 150 may include a host computer (which may be implemented as a server, a desktop computer, a laptop computer, a smart phone, or a tablet computer, etc.). The execution control unit 150 may provide an input interface, such as a human-computer interaction interface (such as a graphical user interface or other input device, etc.), for the user to set the execution parameters. As an example, the execution parameters include at least one of the parameters such as the number of test positions, the excitation frequency and the time period. For example, the execution control unit 150 sets the excitation frequency for the excitation unit 110, and the excitation frequency can be swept within a preset frequency range. The execution control unit 150 sets the number of test positions for the vibration measuring unit 120, and the vibration measuring unit 120 performs the number of movements along the circumferential and / or axial directions of the cylindrical structure 200 according to the number of test positions. For example, if the circumferential step is 5°, 360° / 5°=72 measurement positions can be obtained in one circle. If the number of test positions set is 216, the number of axial movements is 216 / 72=3 times. The time period may include, for example, the motion cycle time of the motion unit 130, the duration period of the frequency sweep, etc.

[0103] In some embodiments, after obtaining the modal information, the signal processing device 142 can also verify the generated modal spectrum to ensure the accuracy and consistency of the measurement and modeling results. For example, by comparing the first 5 order modal spectra, the structural characteristics and modal response of the test cylindrical structure 200 can be evaluated. For example, the dynamic behavior and structural health of the cylindrical structure are evaluated. Specifically, after the modal analysis is completed, the evaluation results are evaluated to see whether they meet the design requirements of the structure. If the natural frequency of the mode is too low or the vibration amplitude of the structure is too large, it may indicate that there is a problem with the design of the structure, and further optimization of the design or structural reinforcement is required.

[0104] exist Figure 1 In the embodiment, the cylindrical structure 200 is vertically arranged on the motion unit 130 so as to be horizontally rotated and lifted by the motion unit 130. The excitation unit 110 and the vibration measuring unit 120 are arranged outside the cylindrical structure 200 to respectively excite vibration and detect vibration of the cylindrical structure 200 from opposite sides of the cylindrical structure 200. Thus, the vibration measuring unit 120 can be arranged as the above is only an exemplary structural layout, which can be changed in other embodiments and is not limited thereto.

[0105] like Figure 5, which shows a schematic diagram of the structural layout of the modal measurement device 100 in the second embodiment of the present disclosure.

[0106] exist Figure 5 In the embodiment, the cylindrical structure 200 can be placed horizontally, and its axis direction is in the horizontal direction. The motion unit 130 can be erected to connect with one end of the cylindrical structure 200, so as to drive the cylindrical structure 200 to rotate around the horizontal axis and to extend and retract along the horizontal axis. The excitation unit 110 and the vibration measuring unit 120 can be located on both sides of the cylindrical structure 200, for example Figure 5 It should be noted that the present embodiment is mainly for describing the structural layout relationship between the cylindrical structure 200, the excitation unit 110, the vibration measuring unit 120, and the motion unit 130, while the working principles of the signal processing unit 140 and the execution control unit 150 are similar to those of the previous embodiments, have been described and are not related to the structural position, so they are not repeated and shown in this embodiment.

[0107] like Figure 6 , which shows a schematic diagram of the structural layout of the modal measurement device 100 in the third embodiment of the present disclosure.

[0108] Figure 6 The diagram is shown as a top view. Figure 6 In the embodiment, the cylindrical structure 200 is illustratively placed upright (it can also be placed horizontally), the excitation unit 110 and the vibration measuring unit 120 are not arranged relative to each other, and the angle between the vertical lines from the positions of the excitation unit 110 and the vibration measuring unit 120 to the axis of the cylindrical structure 200 can be changed, for example, the angle between the two vertical lines is a right angle or an acute angle.

[0109] By setting the relative positions of the excitation unit 110 and the vibration measuring unit 120 to suit different scene environments, the applicability can be wider.

[0110] In some embodiments, at least one of the excitation unit 110 and the vibration measuring unit 120 may also be arranged in the cylindrical structure 200 .

[0111] like Figure 7 , which shows a schematic diagram of the structural layout of the modal measurement device 100 in the fourth embodiment of the present disclosure.

[0112] Figure 7It is shown as a top view schematic diagram, the cylindrical structure 200 is exemplarily placed vertically (it can also be placed horizontally), the excitation unit 110 can be arranged inside the cylindrical structure 200, and the vibration measuring unit 120 can be arranged outside the cylindrical structure 200. Since the excitation unit 110 is used to excite the vibration of the cylindrical structure 200, the relative position of the excitation unit 110 and the cylindrical structure 200 is not strictly set, so the excitation unit 110 is arranged inside the cylindrical structure 200. In the case of saving space, the distance between the excitation unit 110 and the inner surface of the cylindrical structure 200 is closer, and the vibration excitation energy may be more concentrated on the cylindrical structure 200 instead of falling outside the cylindrical structure 200, so that the excitation effect of exciting the vibration of the cylindrical structure 200 from the inner surface may be better than the excitation effect of exciting the vibration of the cylindrical structure 200 on the outer surface of the cylindrical structure 200.

[0113] It should be particularly noted that the excitation unit 120 can be set at various positions outside the cylindrical structure 200, as indicated by the dotted lines in the figure, such as opposite to, opposite to, and to the side of the excitation unit 120.

[0114] like Figure 8 , which shows a schematic diagram of the structural layout of the modal measurement device 100 in the fifth embodiment of the present disclosure.

[0115] Figure 8 It is shown as a top view schematic diagram, the cylindrical structure 200 is exemplarily placed vertically (it can also be placed horizontally), the vibration measuring unit 120 can be arranged inside the cylindrical structure 200, and the excitation unit 110 can be arranged outside the cylindrical structure 200. Then, the vibration measuring unit 120 is closer to the inner surface of the cylindrical structure 200, and the detection effect of detecting the vibration of the cylindrical structure 200 from the inner surface may be better than the effect of detecting the vibration of the cylindrical structure 200 on the outer surface of the cylindrical structure 200. In addition, the vibration measurement of the inner surface of the cylindrical structure 200 can also be combined with the optical detection method used to find the defects of the inner surface of the cylindrical structure 200, that is, the defects of the cylindrical structure 200 can be detected at the same time, making the detection content richer.

[0116] like Fig. 9 As shown, a schematic diagram of the structural layout of the modal measurement device 100 in the sixth embodiment of the present disclosure is shown.

[0117] Fig. 9 As shown in a top view, the cylindrical structure 200 is exemplarily placed vertically (it can also be placed horizontally), and the vibration measuring unit 120 and the excitation unit 110 are both arranged in the cylindrical structure 200. Therefore, the structure in this embodiment can save as much space as possible outside the cylindrical structure 200. It is also possible to obtain better excitation and vibration measuring effects.

[0118] In the above-mentioned embodiment, it has been described that the moving unit 130 can drive the loaded cylindrical structure 200 to rotate and extend around the axis to move relative to the vibration measuring unit 120, so that each measurement position can be measured by the vibration measuring unit 120. It can be understood that in other embodiments, the cylindrical structure 200 may not move, and the moving unit 130 may also carry the vibration measuring unit 120 to move relative to the cylindrical structure 200.

[0119] like Fig.10 As shown, a schematic diagram of the structural layout of the modal measurement device 100 in the seventh embodiment of the present disclosure is shown.

[0120] Fig.10 It is shown as a top view. In this embodiment, the cylindrical structure 200 is exemplarily placed upright (it can also be placed horizontally). The motion unit 130 can rotate circumferentially around the cylindrical structure 200, and can reciprocate along the axis Z direction of the cylindrical structure 200. The solution in this embodiment can be applied to measurement scenarios with a large volume of the cylindrical structure 200. In this scenario, it is difficult to rotate or lift the cylindrical structure 200, or there are high requirements for the load-bearing movement capacity of the motion unit 130. Therefore, this problem can be avoided by allowing the motion unit 130 to carry the vibration measurement unit 120 for movement. In addition, in this embodiment, the vibration measuring unit 120 can be located outside the cylindrical structure 200 (or inside). In order to avoid position interference or mutual signal shielding between the vibration measuring unit 120 and the excitation unit 110 during movement, it is preferred that the excitation unit 110 and the vibration measuring unit 120 are located at different positions inside / outside the cylindrical structure 200. For example, when the vibration measuring unit 120 is outside the cylindrical structure 200, the excitation unit 110 is located inside the cylindrical structure 200, or the positions of the two are interchanged. Alternatively, when both are outside or inside the cylindrical structure 200, they need to be staggered in spatial position, for example, when the cylindrical structure 200 is erected, the radial position of the excitation unit 110 and the vibration measuring unit 120 in the radial direction of the cylindrical structure 200 is located on a ring of different diameter lengths around the cylindrical structure 200, or on an axial position, and at the moment of excitation or acquisition, the excitation unit 110 and the vibration measuring unit 120 also avoid positions where signals are blocked from each other. This can be achieved by setting the relative position of the excitation unit 110 and the vibration measuring unit 120, and setting execution parameters to determine the timing of excitation and acquisition.

[0121] exist Fig.10In an embodiment, the motion unit can be implemented as a moving mechanism that moves circumferentially and lifts along the cylindrical structure 200, such as a sliding member that moves along an annular slide rail / slide groove arranged around the cylindrical structure 200, and the sliding member can be loaded with a lifting mechanism, and the vibration measuring unit 120 is arranged in the lifting mechanism so that it can be lifted and lowered and driven by the sliding member.

[0122] In some embodiments, the excitation unit 110 may also move to adjust the position of the cylindrical structure 200 that is excited to generate vibration.

[0123] It should be particularly noted that, in the above embodiments, the movement of the excitation unit 110 and the vibration measuring unit 120 refers to that their signal receiving / transmitting parts can move. For example, when the vibration measuring unit 120 is an optical vibration measuring device, the optical transceiver component (such as including a single optical transmitter and an optical receiver or an array thereof) can be driven by the motion unit 130. When the excitation unit 110 is an acoustically excited vibration device 110a, the speaker 111a can move, etc., but it does not mean that their circuit parts also need to be carried and moved.

[0124] Some principle embodiments are provided above, and a number of specific embodiments may be provided below to illustrate the actual implementation of the modal measurement device 100 of the present disclosure.

[0125] like Fig.11 As shown, a schematic diagram of the structure of a modal measurement device in a specific embodiment of the present disclosure is shown.

[0126] In this embodiment, the modal measurement device 100 can be exemplarily arranged on a test bench 180. Preferably, the test bench 180 can be a vibration isolation platform. It can be suitable for arranging a small cylindrical structure 200 on the test bench 180 to perform high-precision modal analysis. It is also suitable for high-precision modal analysis of a cylindrical structure 200 with a complex structure.

[0127] It should be noted that the present embodiment is only an example solution. In other scenarios, if the cylindrical structure 200 is larger in volume, the specific implementation of the modal measurement device 100 may be changed and is not limited to the implementation of being loaded on the test bench 180 .

[0128] In this embodiment, the cylindrical structure 200 can be implemented as follows Fig.12 The cylindrical body shown in the figure also marks each measuring position on the cylindrical structure 200 as a measuring point. The motion unit is implemented as follows Fig.13The two-axis rotating indexing plate 130a in the embodiment. The excitation unit is implemented as a sound-excited vibration device 110a, and the vibration measuring unit is implemented as a laser vibrometer 120a. Specifically, the sound-excited vibration device 110a includes an acoustic signal generator 112a, a power amplifier 113, and a speaker 111a. As an example, the speaker 111a is fixedly mounted on the test bench 180 by the first fixing fixture 150, and is arranged toward the outer surface of the cylindrical structure 200. The laser vibrometer 120a includes an optical probe 121a (i.e., an optical transceiver component), which is fixedly mounted on the test bench 180 by the second fixing fixture 160, and is arranged toward the outer surface of the cylindrical structure 200.

[0129] The signal processing unit is implemented to include a coupled signal demodulation device 141 and a signal processing device 142. As an example, the signal processing device 142 can be implemented as a host computer, such as a desktop computer with a display for displaying a human-computer interaction interface. Optionally, in this embodiment, the signal processing device 142 can be implemented in the same host computer as the execution control unit.

[0130] When measuring, the loudspeaker 111a is provided with an oscillation excitation signal by the acoustic signal generator 112a, and the power amplifier 113 amplifies the oscillation excitation signal to a suitable energy level to ensure that the vibration response can be stably obtained at different excitation frequencies. Among them, the acoustic signal generator 112a generates a swept frequency oscillation excitation signal, which is amplified by the power amplifier 113 to form a vibration excitation signal in the loudspeaker 111a and output to the cylindrical structure 200 to excite vibration. During the frequency sweeping process of the acoustic excitation vibration device 110a, based on the control of the set frequency sweeping range and cycle, an oscillation excitation signal with a frequency change is continuously sent to the cylindrical structure 200, so that each natural frequency of the cylindrical structure 200 within the frequency sweeping range can be identified. This frequency sweeping excitation method not only overcomes the limitations of the traditional contact excitation method, but also ensures the stability of the excitation through the power amplifier, thereby improving the accuracy of modal measurement.

[0131] In an optional embodiment, the cylindrical structure 200 can be fixed on the two-axis rotating indexing plate 120a by the third fixing fixture 170, and the bottom is equipped with a vibration isolator (such as a foam board) to isolate vibration and ensure the stability of the structure during the measurement process. The two-axis rotating indexing plate 120a accurately controls the horizontal and vertical rotation angles of the cylindrical structure 200, and the laser vibrometer 120a is responsible for measuring the vibration response of the surface of the cylindrical structure 200 point by point and obtaining vibration data. Among them, by using the laser vibrometer 120a, the measurement can be completed in a non-contact manner, and the vibration data of each measurement point at different angles can be accurately captured, including displacement, velocity and acceleration. The process of the acoustic excitation vibration device 110a, the laser vibrometer 120a and the two-axis rotating indexing plate 120a cooperating with each other to complete the measurement of vibration data of each measurement point can be completed by automatically coordinating the actions in time sequence according to the execution parameters sent by the host computer. For example, when the acoustic excitation vibration device 110a is started, the two-axis rotating indexing plate 120a starts to move a corresponding number of times according to the movement frequency and the number of measurement points set. Each time it moves a step, the laser vibrometer 120a measures the vibration data of a measurement point corresponding to the current position. And so on, until the measurement of all measurement points is completed.

[0132] After the measurement is completed, the signal demodulation device 141 demodulates the vibration data collected in real time and transmits it to the signal processing device 142 for further analysis. The signal processing device 142 performs modal analysis on the measured data as in the previous example, and extracts vibration characteristic information such as natural frequency, damping ratio and modal vibration type of each measurement point. Through the comprehensive analysis of the vibration characteristic information of multiple measurement points, the first N-order (such as the 5th order) modal spectrum of the cylindrical structure 200 can be generated, which can be used to show the vibration characteristics of the structure of the cylindrical structure 200 under different modes. Therefore, by automatically controlling the measurement of vibration data of each measurement point and subsequently automatically performing signal processing of modal analysis to obtain modal information, not only the efficiency of modal analysis is improved, but also high-precision modal analysis is achieved through non-contact measurement and automatic control, providing reliable technical support for the dynamic performance evaluation of complex industrial structures.

[0133] like Fig.14 As shown, a flow chart of a modal measurement method performed based on the modal measurement device in an embodiment of the present disclosure is shown.

[0134] exist Fig.14 The process specifically includes:

[0135] Step S1401: Obtain the set execution parameters.

[0136] Step S1402: Based on the execution parameters, the excitation unit is instructed to output vibration excitation energy for exciting the cylindrical structure to the cylindrical structure.

[0137] Step S1403: Based on the execution parameters, drive the relative movement between the vibration measuring unit and the cylindrical structure so that the non-contact vibration measuring unit traverses and detects each measuring position and obtains a corresponding vibration response signal.

[0138] Step S1404: Obtaining vibration data of each corresponding measurement position according to the vibration response signal.

[0139] Step S1405: Obtaining the modal information of each corresponding measurement position based on the vibration data.

[0140] It should be noted that the implementation and principle of each step in this embodiment can refer to the specific principles of the excitation unit 110, the vibration measurement unit 120, the motion unit 130, the signal processing unit 140, etc. in the previous embodiments, and will not be repeated here. Fig.14 The method can be implemented in the execution control unit 150 to control the excitation unit 110, the vibration measurement unit 120, the motion unit 130, the signal processing unit 140, etc. to complete the execution. When the execution control unit 150 and the signal processing unit 140 are an integrated host computer, it can be implemented in the host computer.

[0141] For example Fig.15 As shown, a specific embodiment of the present disclosure is shown based on Fig.11 Schematic diagram of the modal measurement method performed by the modal measurement device in the embodiment. The modal measurement method in this embodiment exemplarily includes the arrangement steps of each unit, and the arrangement steps can be completed manually or automatically by an automated machine. It should be particularly noted that the method in this embodiment is only an optional embodiment, and is not limited to this.

[0142] exist Fig.15 The modal measurement methods in include:

[0143] Step S1501 : fix the cylindrical barrel structure 200 on the two-axis rotating indexing plate 120 a , and place a vibration isolator at the bottom of the barrel structure 200 .

[0144] In this way, it is ensured that the vibration of the structure is not disturbed by external factors during the test.

[0145] Step S1502 : Install the speaker 111 a in front of the cylindrical structure 200 through the first fixing device 150 .

[0146] The vibration excitation signal output by the speaker 111a is controlled by the sweep frequency excitation signal provided by the signal generator 112. The signal generator 112 is connected to the speaker 111a via the power amplifier 113, so that the speaker 111a can output sound wave excitation at different frequencies to make the cylindrical structure 200 produce a stable vibration response.

[0147] Step S1503: Start the signal generator 112, gradually increase the frequency from the lower limit of the frequency range (such as 10 Hz~20 Hz) to the upper limit of the frequency range (such as 10 kHz), apply sweep frequency excitation; and let the laser vibrometer 120a synchronously monitor the vibration response of the cylindrical structure 200 to identify the natural frequency.

[0148] Among them, the first five natural frequencies can be determined through the frequency response function H(f) for subsequent modal analysis.

[0149] Step S1504: The horizontal axis and the vertical axis of the two-axis rotating indexing plate 120a are used to control the rotation angle movement of the cylindrical structure 200 on the two axes, ie, horizontal rotation and height lifting.

[0150] As an example, the horizontal axis controls the cylindrical structure 200 to rotate in 5° steps on the circumference, and the vertical axis controls the angle change along the height of the cylindrical structure 200, with each vertical step of 1 cm. Through this rotation method, the indexing plate can cover all key areas on the surface of the cylindrical structure 200. After each rotation, the laser vibrometer 120a automatically collects the vibration response of the new measurement point.

[0151] Step S1505: The laser vibrometer 120a measures the set measuring points along the surface of the cylindrical structure 200 point by point to obtain vibration data.

[0152] As an example, the vibration data for each measurement point includes the displacement ,speed and acceleration The rotation of the two-axis rotary indexing disk 120a enables the laser vibrometer 120a to accurately measure vibration responses at multiple angles and measurement points.

[0153] Step S1506 : the collected vibration data is demodulated by the signal demodulation device 141 and then transmitted to the signal processing device 142 .

[0154] Step S1507 : the signal processing device 142 performs modal modeling on the structure of the cylindrical structure 200 based on the finite element method (FEM).

[0155] Convert the time domain signal to the frequency domain through Fourier transform:

[0156]

[0157] According to the spectrum of the vibration signal obtained by Fourier transform, the frequency response function is calculated. The frequency response function H (f) is used to describe the dynamic response characteristics of the structure under different excitation frequencies. The formula is:

[0158]

[0159] Where: X(f) is the vibration data of the measurement position, and F(f) is the excitation signal applied to the speaker 111a. By calculating the frequency response function of each measurement position, the vibration characteristics of the structure can be understood, and the natural frequency of the cylindrical structure 200 and its corresponding vibration mode can be identified.

[0160] Furthermore, based on the frequency response functions of all points, the modal parameters of the structure are extracted, including the natural frequency f n : The natural frequency is identified by the peak value of the frequency response function, indicating the resonance of the structure at the natural frequency; Damping ratio ζn: The damping ratio is calculated by the width of the frequency response curve; Modal vibration shape φn: The vibration shape is extracted by the difference in vibration amplitude and phase at different measurement points.

[0161] As mentioned before, the natural frequency can be determined from the peak amplitude:

[0162]

[0163] And, the mode shapes can be obtained by solving the modal equations:

[0164]

[0165] Where: K is the stiffness matrix of the structure, M is the mass matrix, w is the angular frequency, w=2π*f n , is the mode shape vector.

[0166] Step S1508: The signal processing device 142 generates a modal spectrum of the test cylindrical structure 200 according to the modeling results and the first five natural frequencies, and displays the vibration shape and dynamic characteristics under each mode.

[0167] The modal spectrum intuitively reflects the deformation mode of the cylindrical structure at different frequencies, which is helpful for analyzing its dynamic performance.

[0168] Step S1509: Verify the generated modal spectrum to ensure the accuracy and consistency of the measurement and modeling results.

[0169] By comparing the first five modes, the structural characteristics and modal responses of the test cylindrical structure 200 are evaluated. These results can provide key data support for structural health monitoring and design optimization.

[0170] like Fig.16, which shows a schematic diagram of the structure of a computer device in one embodiment of the present disclosure.

[0171] The computer device 1600 includes a bus 1601, a processor 1602, and a memory 1603. The processor 1602 and the memory 1603 can communicate with each other through the bus 1601. The memory 1603 can store a computer program or instruction. The processor 1602 implements the functions of the signal processing unit or the execution control device in the previous embodiment by running the computer program or instruction in the memory 1603.

[0172] The bus 1601 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, although only one thick line is used in the figure, it does not mean that there is only one bus or one type of bus.

[0173] In some embodiments, the processor 1602 may be implemented as a central processing unit (CPU), a microcontroller unit (MCU), a system on chip (System On Chip), or a field programmable logic array (FPGA). The memory 1603 may include a volatile memory (Volatile Memory) for temporary storage of data when running a program, such as a random access memory (Random Access Memory, RAM).

[0174] The memory 1603 may also include a non-volatile memory (non-volatile memory) for data storage, such as a read-only memory (ROM), a flash memory, a hard disk drive (HDD), or a solid-state disk (SSD).

[0175] In some embodiments, the computer unit 1600 may further include a communicator 1604. The communicator 1604 is used to communicate with the outside. In a specific example, the communicator 1604 may include one or a group of wired and / or wireless communication circuit modules. For example, the communicator 1604 may include one or more of a wired network card, a USB module, a serial interface module, etc. The wireless communication protocols followed by the wireless communication module include: for example, near field communication (NFC) technology, infrared (IR) technology, global system for mobile communications (GSM), general packet radio service (GPRS), code division multiple access (CDMA), wideband code division multiple access (WCDMA), time division code division multiple access (TD-SCDMA), long term evolution (LTE), Bluetooth (BT), global navigation satellite system (GNSS), etc. One or more.

[0176] In an embodiment of the present disclosure, a computer-readable storage medium may be provided, storing a computer program or instructions, which, when executed, implements the functions of the control unit 1600 in any of the previous embodiments.

[0177] That is, the method steps in the above embodiments are implemented as software or computer code that can be stored in a recording medium (such as a CD ROM, RAM, floppy disk, hard disk or magneto-optical disk), or are implemented as computer code originally stored in a remote recording medium or a non-temporary machine-readable medium downloaded via a network and to be stored in a local recording medium, so that the method represented herein can be stored in such software processing on a recording medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware (such as an ASIC or FPGA).

[0178] In the embodiments of the present disclosure, a computer program product may be provided, one or more computer programs or instructions, which, when executed, fully or partially execute the functions of the signal processing unit or execution control device in the embodiments of the present disclosure. The computer program product includes one or more computer programs or instructions.

[0179] The computer program or instructions may be stored in a readable storage medium or transmitted from one readable storage medium to another readable storage medium, for example, the computer program or instructions may be transmitted from one website, computer, server or data center to another website, computer, server or data center by wired or wireless means. The readable storage medium may be any available medium that can be accessed or a data storage device such as a server, data center, etc. that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, a hard disk, or a magnetic tape; it may also be an optical medium, such as a digital video disk; it may also be a semiconductor medium, such as a solid state drive. The computer readable storage medium may be a volatile or non-volatile storage medium, or may include both volatile and non-volatile types of storage media.

[0180] In summary, the present disclosure relates to the field of modal measurement technology, and provides a modal measurement device and a modal measurement method for a cylindrical structure. The device includes a non-contact excitation unit that outputs vibration excitation energy toward the cylindrical structure; a non-contact vibration measurement unit that detects the vibrating cylindrical structure to obtain a vibration response signal; a motion unit that forms a relative motion between the vibration measurement unit and the cylindrical structure to correspond to the measurement position; a signal processing unit that obtains vibration data of the corresponding measurement position according to the vibration response signal, and obtains modal information of the corresponding measurement position based on the vibration data. By combining the non-contact excitation and vibration measurement technology of the cylindrical structure, various problems of contact sensors are avoided, and the measurement accuracy and reliability are improved; in addition, high-precision automatic control can be combined to achieve high-precision modal measurement.

[0181] Through the equipment and method provided in the embodiments of the present disclosure, efficient and automated modal measurement of cylindrical structures can be achieved, which is particularly suitable for non-contact excitation and vibration measurement of complex structural parts, as well as modal analysis and health monitoring. This design not only overcomes the limitations of traditional contact measurement methods, but also ensures the stability and accuracy of measurement by introducing a rotating indexing plate and laser vibration measurement technology, providing a more reliable solution for modal analysis of complex structures.

[0182] Compared with the prior art, the solution in the embodiment of the present disclosure has the following significant beneficial effects:

[0183] 1. Based on non-contact vibration excitation and measurement technology, it avoids the problems of complex installation and interference with measurement accuracy brought by traditional contact sensors, and significantly improves the accuracy and reliability of modal analysis.

[0184] 2. Provide stable sweep frequency excitation through the excitation unit to ensure the stability of the vibration response of the cylindrical structure at different frequencies. The motion unit based on high-precision stepping motion can accurately control the change of the measurement position, so that the vibration measurement unit can automatically measure the vibration data at multiple angles, improving the efficiency and accuracy of modal measurement. In addition, by introducing a power amplifier in the excitation unit, it can be ensured that sufficient vibration excitation energy can be provided in a wide frequency range, and the stability of the vibration excitation signal can be guaranteed, thereby ensuring the consistency of the structural vibration response and the reliability of the data, effectively improving the accuracy of modal analysis.

[0185] 3. Through multi-position measurement and modal analysis algorithms, the natural frequency, damping ratio and modal vibration shape of the cylindrical structure in different modes are accurately captured. Through non-contact measurement and automatic rotation control, high-precision modal analysis of complex structures is achieved, which is suitable for modal detection and dynamic performance evaluation of complex shapes and structures.

[0186] 4. By processing the collected vibration data in real time, the modal spectrum and other key analysis data are quickly generated, which significantly improves the efficiency of modal analysis. The equipment provides strong technical support and data support for engineering applications and scientific research, and is suitable for efficient and automated modal detection tasks.

[0187] 5. Simple structure, easy operation, suitable for modal measurement in various complex structures and environments. Especially in the fields of aerospace, machinery manufacturing, civil engineering, etc., which require high-precision modal analysis, the health monitoring and performance evaluation of cylindrical structures have broad application prospects.

[0188] The above embodiments are merely illustrative of the principles and effects of the present disclosure, and are not intended to limit the present disclosure. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present disclosure. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the present disclosure shall still be covered by the protection scope of the present disclosure.

Claims

1. A modal measurement device for a cylindrical structure, characterized in that: include: A non-contact excitation unit, used for outputting vibration excitation energy for exciting the cylindrical structure to the cylindrical structure; A non-contact vibration measuring unit, used for outputting a detection signal to the vibrating cylindrical structure and receiving an echo signal corresponding to the vibration response of the measuring position on the cylindrical structure to be measured, and obtaining vibration data of the measuring position according to the echo signal; A motion unit, used to drive the relative movement between the vibration measuring unit and the cylindrical structure, so that the non-contact vibration measuring unit reaches a position corresponding to a measurement position on the cylindrical structure; The signal processing unit is coupled to the non-contact vibration measuring unit and is used to obtain modal information according to the vibration data of each measuring position.

2. The modal measurement device according to claim 1, characterized in that include: The execution control unit is used to control the execution actions of the excitation unit, the vibration measuring unit and the motion unit based on the set execution parameters, so as to automatically complete the traversal detection of each measurement position and obtain the corresponding modal information in the signal processing unit.

3. The modal measurement device according to claim 1, characterized in that The moving unit carries the cylindrical structure and can rotate around the axis of the cylindrical structure and reciprocate along the axis.

4. The modal measurement device according to claim 1, characterized in that A vibration isolator is provided between the motion unit and the loaded cylindrical structure and / or between a support supporting the motion unit and the motion unit.

5. The modal measurement device according to claim 1, characterized in that The excitation unit includes: an energy output device and a signal generator coupled to the energy output device.

6. The modal measurement device according to claim 5, characterized in that The excitation unit includes: a power amplifier connected between the transducer output device and the signal generator.

7. The modal measurement device according to claim 1, characterized in that The excitation frequency of the vibration excitation energy varies within a preset frequency range covering the natural frequencies of different modes of the cylindrical structure, so that the vibration measuring unit can identify the natural frequencies of different modes of the cylindrical structure and obtain vibration data based on different natural frequencies.

8. The modal measurement device according to claim 1, characterized in that The vibration measuring unit is mounted on the moving unit so as to be driven by the moving unit to move around the axis of the cylindrical structure and to reciprocate along the axis.

9. The modal measurement device according to claim 1, characterized in that: The moving unit moves in a preset step to determine that the vibration measuring unit corresponds to each of the measuring positions.

10. The modal measurement device according to claim 1, characterized in that The excitation unit includes an acoustically excited vibration device or an electromagnetic vibration excitation device; and / or, the vibration measuring unit includes an optical vibration measuring device.

11. The modal measurement device according to claim 1, characterized in that: The vibration measuring unit includes at least one of the following detection light sources: a point light source, a line light source, and a surface light source.

12. The modal measurement device according to claim 1, characterized in that At least one of the vibration excitation unit and the vibration measuring unit is disposed in the cylindrical structure.

13. The modal measurement device according to claim 1, characterized in that The cross-section of the cylindrical structure includes one of the following: circular, elliptical, square, trapezoidal, and triangular.

14. The modal measurement device according to claim 1, characterized in that The modal information includes the first N-order modal spectra, where N≥1.

15. A modal measurement method for a cylindrical structure, characterized in that: Applied to the modal measurement device according to any one of claims 1 to 14, the method comprising: Get the set execution parameters; Based on the execution parameters, the excitation unit is caused to output vibration excitation energy for exciting the cylindrical structure to the cylindrical structure; Based on the execution parameters, the relative movement between the vibration measuring unit and the cylindrical structure is driven so that the non-contact vibration measuring unit traversally detects each measurement position and obtains a corresponding vibration response signal; vibration data of each corresponding measurement position is obtained according to the vibration response signal; and modal information of each corresponding measurement position is obtained based on the vibration data.

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