CN207215010U - A kind of device for measuring flexible beam transverse vibrational displacement and strain stress relation - Google Patents

Abstract

The utility model discloses a device for measuring the relationship between lateral vibration displacement and strain of a flexible beam, which comprises a flexible cantilever beam, one end of the flexible cantilever beam is fixed by a base, and the other end is a free end. Multiple resistance strain gauges are installed on the opposite side, and multiple laser displacement sensors for measuring the vibration and lateral displacement at the geometric center point of the resistance strain gauge are installed directly in front of the other side of the flexible cantilever beam. It also includes a computer, a power amplifier, a motion control card, The vibration exciter and the dynamic strain gauge adopt the device of the utility model to obtain the relationship diagram of strain distribution and displacement distribution of low-order modal vibration.

Description

A device for measuring the relationship between lateral vibration displacement and strain of flexible beam

technical field

The utility model relates to the technical field of vibration analysis of flexible structures, in particular to a device for measuring the relationship between lateral vibration displacement and strain of a flexible beam.

Background technique

The vibration modal analysis and vibration control methods and devices of flexible cantilever beams are relatively mature. The existing technology is basically based on the strain measurement of the vibration of the flexible cantilever beam for analysis and feedback control; or based on the acceleration sensor installed on the cantilever beam to measure vibration and feedback control; or based on the laser displacement sensor to measure the lateral vibration displacement of the flexible beam Perform vibration analysis and feedback control.

The prior art seldom analyzes and researches the distribution of the relationship between lateral vibration displacement and strain of flexible cantilever beams in low-order mode vibrations. Because the relationship between lateral vibration and strain of flexible beams includes not only the distribution of small-amplitude linear vibrations, but also the distribution of lateral displacement and strain when large-amplitude nonlinear vibrations are excited. The utility model proposes a flexible cantilever beam experimental device with distributed and pasted multi-piece resistance strain gauge sensors and distributed installation of multiple laser displacement sensors, and uses the method of modal excitation vibration analysis to study the low-frequency vibration modes of each order in the large value and small value. The relationship between lateral displacement and strain distribution during amplitude vibration provides a device and method for vibration analysis of flexible beams.

Utility model content

In order to overcome the shortcomings and deficiencies of the prior art, the utility model provides a device for measuring the relationship between lateral vibration displacement and strain of a flexible beam.

The utility model adopts the following technical solutions:

A device for measuring the relationship between lateral vibration displacement and strain of a flexible beam, comprising a flexible cantilever beam, one end of the flexible cantilever beam is fixed by a base, and the other end is a free end, and a multi-chip resistor is installed on the front or back of the flexible cantilever beam For strain gauges, multiple laser displacement sensors are installed directly in front of the other side of the flexible cantilever beam for measuring the vibration lateral displacement at the geometric center point of the resistance strain gauge;

It also includes computer, power amplifier, motion control card, vibrator and dynamic strain gauge. The signal output by the computer to generate the low-order vibration of the flexible cantilever beam is output to the motion control card. After passing through the power amplifier, the vibrator is driven to excite the flexible cantilever beam. The vibration information of the flexible cantilever beam detected by the sheet resistance strain gauge is output to the motion control card through the dynamic strain gauge, and then input to the computer. Multiple laser displacement sensors detect the lateral vibration displacement information of the corresponding point of the flexible cantilever beam, and then input to the computer through the motion control card. middle.

There is a one-to-one correspondence between the resistance strain gauge and the laser displacement sensor, and the measurement point of the laser displacement sensor is the geometric center point where the resistance strain gauge is pasted.

The plurality of resistance strain gauges and the plurality of laser displacement sensors are arranged in a straight line.

A method for measuring the relationship between lateral vibration displacement and strain of a flexible beam, comprising the steps of:

The first step is to identify the low-order vibration modal frequencies of the flexible cantilever beam, including the first order, second order and third order;

In the second step, the computer outputs the low-order excitation vibration signal of the corresponding flexible cantilever beam and outputs it to the motion control card. After D/A conversion, it is output to the power amplifier and drives the vibrator to excite the vibration of the low-order mode of the flexible cantilever beam;

In the third step, the vibration strain information detected by the resistance strain gauge is output to the motion control card through the dynamic strain gauge, and then enters the computer for A/D conversion. At the same time, the lateral vibration displacement information of the corresponding point of the flexible cantilever beam detected by the multi-laser displacement sensor The control card enters the computer after A/D conversion;

The fourth step is to analyze the distribution relationship between strain and lateral displacement based on the measured data, including the distribution relationship between small-amplitude linear vibration and large-amplitude nonlinear vibration, and give the strain distribution and displacement of low-order modal vibration of the flexible cantilever beam system Distribution diagram.

The beneficial effects of the utility model:

(1) Distributed and pasted multi-piece resistance strain gauges are small in size, light in weight, and use less glue, which basically does not affect the vibration characteristics of the flexible beam; the lateral displacement measured by the laser displacement sensor is a non-contact measurement and will not affect the flexible beam. influence on the vibration characteristics;

(2) By adjusting the amplitude of the exciter drive signal and the set frequency, the device can excite modal vibrations of different amplitudes of the flexible cantilever beam, including small-amplitude linear vibrations and large-amplitude nonlinear vibrations. By measuring Strain and lateral displacement, the distribution relationship of lateral displacement and strain of linear vibration and nonlinear vibration can be obtained;

(3) By setting the excitation signal frequency of the vibrator to be consistent with the vibration mode frequency of the flexible cantilever, the vibration of the corresponding mode can be excited, so the device can be used to analyze the lateral vibration of the low-frequency multi-mode vibration of the flexible cantilever Vibration displacement and strain relationship.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Detailed ways

The utility model will be described in further detail below in conjunction with the embodiments and accompanying drawings, but the implementation of the utility model is not limited thereto.

Example

As shown in Fig. 1, a kind of device for measuring the transverse vibration displacement and strain relation of flexible beam comprises flexible cantilever beam 1, and one end of described flexible cantilever beam is fixed with base, and the other end vibrates freely is free end, and described flexible cantilever beam Install multiple resistance strain gauges 2 on the front or back of the beam, and install multiple laser displacement sensors 3 for measuring the vibration lateral displacement at the geometric center point of the resistance strain gauges on the other side pasted with the resistance strain gauges. According to the measured strain signal and The lateral displacement signal is used to analyze the relationship between lateral vibration displacement and strain distribution of flexible beams.

In this embodiment, five laser displacement sensors 3 are installed in front of the other side of the flexible cantilever beam. The spacing is equal and arranged in a line. One side of the flexible cantilever beam 1 is pasted with five resistance strain gauges. The resistance strain gauges and the laser displacement sensors are one by one. Correspondence. Adjust and install the laser displacement sensor to ensure its measurement distance and measurement point, which is used to measure the vibration lateral displacement at the geometric center point where the strain gauge is pasted.

It also includes a computer 8, a power amplifier 5, a motion control card 7, an exciter 4 and a dynamic strain gauge 6. The computer outputs a signal that causes the low-order vibration of the cantilever beam to be output to the motion control card. Flexible cantilever beam, multi-piece resistance strain gauges detect the vibration information of the flexible cantilever beam through the dynamic strain gauge output to the motion control card and then input to the computer, multiple laser displacement sensors detect the lateral vibration displacement information of the corresponding point of the flexible cantilever beam, and then through the motion The control card is input into the computer.

The computer 8 outputs the low-order (such as the first order, second order, third order, etc.) excitation vibration signal of the flexible cantilever beam and outputs it to the motion control card 7, and outputs it to the power amplifier 5 after the D/A conversion of the motion control card The rear drive vibrator 4 excites the vibration of the low-order mode of the flexible cantilever beam 1, and the vibration and strain information detected by the multi-piece resistance strain gauge 2 passes through the dynamic strain gauge 6 and is output to the motion control card 7 for A/D conversion. The computer 8, at the same time, the lateral vibration displacement information of the corresponding point of the flexible beam detected by the multi-laser displacement sensor 3 enters the computer 8 after the A/D conversion is performed by the motion control card 7; the distribution relationship between the strain and the lateral displacement is analyzed according to the measured data, including small The distribution relationship between the linear vibration of the amplitude and the nonlinear vibration of the large value; the strain distribution and displacement distribution diagram of the low-order modal vibration of the flexible cantilever beam system is given to provide reference for vibration and analysis.

A method for measuring the relationship between lateral vibration displacement and strain of a flexible beam, comprising the steps of:

The first step is to first identify the low-order vibration modal frequencies of the flexible cantilever beam, such as the first-order, second-order, and third-order vibration modal frequencies;

In the second step, the computer outputs the signal corresponding to the excitation vibration frequency of the low order (such as the first order, the second order, the third order, etc.) of the cantilever beam and outputs it to the motion control card. After D/A conversion, it is output to the power amplifier to drive the excitation. The vibrator excites the vibration of the low-order mode of the flexible cantilever beam;

The third step is to output the vibration strain information detected by multi-piece resistance strain gauges to the motion control card for A/D conversion and then enter the computer through the dynamic strain gauge. At the same time, the multi-laser displacement sensor detects the lateral vibration displacement information of the corresponding point of the flexible beam Enter the computer after A/D conversion;

The fourth step is to analyze the distribution relationship between strain and lateral displacement based on the measured data, including the distribution relationship between small-amplitude linear vibration and large-amplitude nonlinear vibration; the strain distribution and displacement of the low-order modal vibration of the flexible cantilever beam system are given Distribution diagram.

The above-mentioned embodiment is a preferred implementation mode of the present utility model, but the implementation mode of the present utility model is not limited by the described embodiment, and any other changes, modifications, modifications, Substitution, combination, and simplification should all be equivalent replacement methods, and are all included in the protection scope of the present utility model.

Claims (3)

1. A device for measuring the lateral vibration displacement and strain relationship of a flexible beam, characterized in that it comprises a flexible cantilever beam, one end of the flexible cantilever beam is fixed by a base, and the other end is a free end, the front of the flexible cantilever beam Or install multiple resistance strain gauges on the opposite side, and install multiple laser displacement sensors for measuring the vibration lateral displacement at the geometric center point of the resistance strain gauge directly in front of the other side of the flexible cantilever beam; It also includes computer, power amplifier, motion control card, vibrator and dynamic strain gauge. The signal output by the computer to generate the low-order vibration of the flexible cantilever beam is output to the motion control card. After passing through the power amplifier, the vibrator is driven to excite the flexible cantilever beam. The vibration information of the flexible cantilever beam detected by the sheet resistance strain gauge is output to the motion control card through the dynamic strain gauge, and then input to the computer. Multiple laser displacement sensors detect the lateral vibration displacement information of the corresponding point of the flexible cantilever beam, and then input to the computer through the motion control card. middle. 2 . The device according to claim 1 , wherein the resistance strain gauge is in one-to-one correspondence with the laser displacement sensor, and the measurement point of the laser displacement sensor is the geometric center point where the resistance strain gauge is pasted. 3. The device according to claim 1, characterized in that the multiple resistance strain gauges and the multiple laser displacement sensors are arranged in a straight line.