CN103115572B - A kind of measurement apparatus coupling faying face fine motion displacement and measuring method thereof - Google Patents

Abstract

The invention discloses a measuring device and a detection method for the micro-motion displacement of a joint joint surface, and belongs to the technical field of unique joint detection. The measuring device for the micro-motion displacement of the coupling joint surface of the present invention includes a laser, the laser is connected with several branches through optical fibers, each branch is connected with a circulator through an optical fiber, and the circulators are respectively connected with laser detectors through an optical fiber. A device and a measuring head, wherein the measuring head is placed on the part on one side of the connecting surface in the measuring hole, and a reflective head is provided on the part on the other side of the connecting surface in the measuring hole, and the measuring head and the reflecting head are matched with each other . The measuring device and method for measuring the micro-movement of the joint surface of the present invention can directly detect the relative displacement of the joint surface, avoid the interference factors caused by state monitoring with other indirect physical quantities, and have high measurement accuracy and adaptability to the environment Strong, able to work in harsh environments such as high pressure, high temperature, and corrosion.

Description

A measuring device and measuring method for fretting displacement of joint joint surface

technical field

The invention relates to a measuring device and a measuring method for measuring the micro-vibration displacement of a connecting joint surface by utilizing the self-reflection interference principle of the fiber end face of a laser, and is suitable for monitoring the connecting state of the connecting link in an engineering structure.

Background technique

Links exist widely in various engineering structures. Long-term work in a complex vibration environment often leads to changes in the connection state, which may lead to failure of the connection or even a major accident if left unchecked. Therefore, it is of great significance for the healthy operation of engineering structures and the prevention of joint failure to directly measure the relative micro-amplitude vibration response signal of the joint joint surface in the vibration environment, and carry out effective analysis and processing.

The relative displacement of the bonding surface in the normal connection state is extremely small, only a few nanometers (the displacement can increase to a few microns when approaching the failure state). The general displacement measurement method is difficult to measure it dynamically, not to mention that the joint surface is still in a closed state, which increases the difficulty of direct measurement. In the current connection state monitoring, common vibration measurement methods are generally used to measure the vibration signal near the connection link, and the method of indirectly obtaining connection state information is used to monitor the connection state. Such measurements are inevitably influenced by other factors in the structure that are not related to the state of the joints.

Contents of the invention

The purpose of the present invention is to solve the problems mentioned above, to provide a measuring device and method for measuring the micro-vibration displacement of the joint joint surface by using the self-reflection interference principle of the optical fiber end face of the laser, and to realize the joint joint surface under complex vibration environment. The direct and accurate measurement of micro-amplitude vibration displacement is suitable for real-time monitoring of important connection links in engineering structures, and prevents malignant accidents caused by connection failures; the measurement device and its measurement method have high measurement accuracy and strong adaptability to the environment. It can work in harsh environments such as high pressure, high temperature, corrosion, etc., especially in the measurement of small dynamic displacements, it also has the advantages of wide dynamic range and sensitive response, and is very suitable for dynamic monitoring of the contact state of joint joints.

The technical scheme that the present invention adopts is as follows:

The measuring device for the micro-motion displacement of the coupling joint surface of the present invention includes a laser, the laser is connected with several branches through optical fibers, each branch is connected with a circulator through an optical fiber, and the circulators are respectively connected with laser detectors through an optical fiber. A device and a measuring head, wherein the measuring head is placed on the part on one side of the connecting surface in the measuring hole, and a reflective head is provided on the part on the other side of the connecting surface in the measuring hole, and the measuring head and the reflecting head are matched with each other .

Compared with the prior art, the laser in the present invention is mainly used to generate the monochromatic laser required for measurement; several splitters are mainly used to equally divide the laser emitted by the laser into several incident lasers, which can monitor multiple channels at the same time. Each incident laser is connected to the circulator through an optical fiber, and the circulator mainly prevents the laser from propagating backwards and avoids interfering with the laser work; after each incident laser leaves the circulator, it is connected to the measuring head through the optical fiber, and the measuring head is placed in the Connect the parts on the side of the joint surface in the hole, so that a part of the incident laser light is reflected by the end face of the measuring head, forming the first reflected laser light; the measuring head and the reflective head are paired with each other, so that the other part of the incident laser light is emitted out of the optical fiber, and the irradiated reflected light On the head, the reflective head enters the optical fiber again to form a second reflected laser. The reflective head is set on the part on the other side of the connecting surface in the measurement hole. When the connecting surface of the connecting link vibrates relatively, a slight displacement occurs , the phase difference between the second reflected laser and the first reflected laser will change with the vibration displacement. The two reflected lasers leave the special measuring head, pass through the original optical fiber to the circulator, and then detect it through the laser connected to the circulator. Convert the interference signal into an electrical signal, filter and amplify it, and output it for further collection, analysis and display. The measuring device for measuring the micro-vibration displacement of the joint joint surface of the present invention uses the self-reflection interference principle of the optical fiber end face of the laser to realize the direct and accurate measurement of the micro-amplitude vibration displacement of the joint joint surface in a complex vibration environment, and is suitable for important joint links in engineering structures Real-time monitoring to prevent vicious accidents caused by connection failure; the measuring device has high measurement accuracy and strong adaptability to the environment, and can work in harsh environments such as high pressure, high temperature, corrosion, etc., especially in the measurement of small dynamic displacements It also has the advantages of wide dynamic range and sensitive response, and is very suitable for dynamic monitoring of the contact state of joint joints. The invention directly detects the relative displacement of the bonding surface, avoiding the interference factors caused by other indirect physical quantities for state monitoring.

In the device for measuring the micro-motion displacement of the coupling surface of the present invention, the measuring head includes a measuring head housing that can be fixed in the detection hole, and a metal optical fiber ferrule and a self-focusing lens are arranged in the measuring head housing. The focusing lens is located at the front end of the measuring head, and the center of the metal optical fiber ferrule is pierced with a pigtail.

Compared with the prior art, the measuring head in the present invention is bonded by three parts: the measuring head housing, the self-focusing lens and the metal optical fiber ferrule, and the measuring head housing plays the role of fixing the self-focusing lens and the metal optical fiber ferrule Function; the self-focusing lens can turn the incident light from the optical fiber into a parallel light with a larger beam, and irradiate the reflective surface of the reflective head. At the same time, it can receive the reflected light from the reflective surface and couple it into the optical fiber, which plays a role Enhance the effect of signal strength.

In the measuring device for the micro-motion displacement of the connecting surface of the present invention, the reflective head is limited in the measuring hole by a fine-tuning screw, and the fine-tuning screw is connected to the inner wall of the measuring hole, and the reflective head is made of stainless steel, wherein the reflective head The reflective surface roughness is less than 0.4 microns.

Compared with the prior art, in the reflective head of the present invention, the fine-tuning screw is limited in the measuring hole, and the metal reflective head is made of stainless steel, and the roughness of the reflective surface is Ra<0.4 micron, which ensures the measurement accuracy, and is connected by a thread to the The function of the fine-tuning screw is to fine-tune the position of the reflective head through the pre-tightening force, so as to ensure that the displacement measurement is in the measurement range with good linearity.

The method for measuring the fretting displacement of the coupling surface of the present invention comprises the following steps:

Step 1. The laser emits laser light, and the splitters connected by optical fibers are divided into several paths of incident laser light;

Step 2. Each incident laser light is transmitted to each circulator through the optical fiber;

Step 3. Each incident laser light is transmitted from the circulator to the measuring head through the optical fiber, and the measuring head is fixed on the part on the side of the joint surface in the measuring hole through threads, and a part of the incident laser light is reflected by the self-focusing lens of the measuring head to form the first The laser is reflected by the path and returns to the circulator through the optical fiber;

Step 4. The other part of the incident laser light exits the optical fiber, and is reflected on the reflective surface of the reflective head through the self-focusing lens. The reflective head is fixed on the part on the other side of the connecting surface in the measurement hole by the fine-tuning screw. The reflected The laser light enters the optical fiber through the self-focusing lens again to form the second reflected laser, and returns to the circulator through the optical fiber;

Step 5. The first reflected laser light and the second reflected laser light are respectively transmitted to the circulator, and then transmitted to the laser detector through the optical fiber. The laser detector converts the laser interference signal into an electrical signal, and outputs it after filtering.

Compared with the prior art, the present invention measures the fretting displacement of the coupling surface based on laser fiber interference, which has high measurement accuracy, strong adaptability to the environment, and can work in harsh environments such as high pressure, high temperature, corrosion, etc., especially In the measurement of small dynamic displacement, it also has the advantages of wide dynamic range and sensitive response, which is very suitable for the dynamic monitoring of the contact state of the joint joint surface; it can realize the direct and accurate measurement of the slight vibration displacement of the joint joint surface under complex vibration environment, and is suitable for engineering structures The real-time monitoring of the important connection link in the center can prevent the malignant accident caused by the failure of the connection. In addition to directly measuring the relative displacement of the joint surface, it also has the advantages of high detection sensitivity and large dynamic range.

In summary, owing to adopting above-mentioned technical scheme, the beneficial effect of the present invention is:

1. The measuring device for the fretting displacement of the connecting surface of the present invention has simple structure, easy operation, convenient use, low cost, convenient construction and production, high measurement accuracy and high reliability;

2. The device for measuring the fretting displacement of the coupling surface of the present invention directly detects the relative displacement of the coupling surface, avoiding the interference factors caused by using other indirect physical quantities for state monitoring.

3. The method for measuring the fretting displacement of the connecting surface of the present invention has high measurement accuracy, strong adaptability to the environment, and can work in harsh environments such as high pressure, high temperature, corrosion, etc., especially in the measurement of small dynamic displacements. With the advantages of wide range and sensitive response, it is very suitable for the dynamic monitoring of the contact state of the joint joint surface.

Description of drawings

The invention will be illustrated by way of example with reference to the accompanying drawings, in which:

Fig. 1 is the structural representation of measuring device of the present invention;

Fig. 2 is a schematic diagram of the structure of the present invention when measuring the coupling surface.

Marks in the figure: 1-Laser, 2-Branch, 3-Circulator, 4-Measuring head, 5-Reflective head, 6-Laser detector, 7-Joint surface, 8-Fine adjusting screw, 9-Reflective head reflection Surface, 4-1-Measuring head housing, 4-2-Metal fiber optic ferrule, 4-3-Self-focusing lens, 4-4-Exit pigtail.

detailed description

All features disclosed in this specification, or steps in all methods or processes disclosed, may be combined in any manner, except for mutually exclusive features and/or steps.

Any feature disclosed in this specification (including any appended claims, abstract and drawings), unless expressly stated otherwise, may be replaced by alternative features which are equivalent or serve a similar purpose. That is, unless expressly stated otherwise, each feature is one example only of a series of equivalent or similar features.

As shown in Fig. 1 and Fig. 2, the measuring device for the micro-motion displacement of the connection joint surface of the present invention includes a laser 1, and the laser 1 is connected with several branch devices 2 through an optical fiber, and each branch device 2 is connected to a circulator through an optical fiber. 3 connection, the circulator 3 is respectively connected with a laser detector 6 and a measuring head 4 through an optical fiber, wherein the measuring head 4 is placed on the part on the side of the connecting surface 7 in the measuring hole, wherein the measuring head 4 includes a fixed The measuring head housing 4-1 in the detection hole is provided with a metal optical fiber ferrule 4-2 and a self-focusing lens 4-3, and the self-focusing lens 4-3 is located in the measuring head At the front end of 4, the center of the metal optical fiber ferrule 4-2 is pierced with a pigtail 4-4, and the measuring head housing 4-1 plays a role in fixing the self-focusing lens 4-3 and the metal optical fiber ferrule 4-2 The effect of self-focusing lens 4-3 can change the incident light that comes from optical fiber into the parallel light of larger light beam, and shine on the reflective surface 9 of reflective head 5, simultaneously, can receive the reflected light of reflective surface 5, and will It is coupled into the optical fiber and plays a role in enhancing the signal strength. A reflective head 5 is provided on the part on the other side of the coupling surface 7 in the measuring hole, wherein the reflective head 5 is limited in the measuring hole by a fine-tuning screw 8, and the fine-tuning screw 8 is connected to the inner wall of the measuring hole, so The reflective head 5 is made of stainless steel, wherein the roughness of the reflective surface 9 of the reflective head 5 is less than 0.4 microns, and the function of the fine-tuning screw 8 is to fine-tune the position of the reflective head 5 through the pre-tightening force to ensure that the measurement of the displacement is in good linearity measurement range.

The measuring head 4 and the reflective head 5 are paired with each other.

The method for measuring the fretting displacement of the coupling surface of the present invention comprises the following steps:

Step 1. The laser 1 emits monochromatic laser light, and the splitter 2 connected by the optical fiber is divided into several incident laser lines, which are used for multi-channel measuring devices to monitor multiple connection links at the same time;

Step 2. Each incident laser light is transmitted to each circulator 3 through the optical fiber, that is, enters the circulator 3 that can prevent the reverse propagation of the laser through the single-mode optical fiber. The function of the circulator 3 is to prevent the reverse propagation of the laser light and avoid interfering with the laser.

Step 3, each incident laser light is transmitted from the circulator 3 to the measuring head 4 through the optical fiber, and the measuring head 4 is fixed on the part on the side of the joint surface 7 in the measuring hole through threads, and a part of the incident laser light is self-focused by the measuring head 4 The reflection of the lens 4-3 forms the first reflection laser, and returns to the circulator 3 through the optical fiber;

Step 4. The other part of the incident laser light is emitted from the optical fiber, irradiated by the self-focusing lens 4-3 on the reflective surface 9 of the reflective head 5 to be reflected, wherein the reflective head 5 is fixed on the other side of the joint surface 7 in the measurement hole by the fine-tuning screw 8 On the part on the side, the reflected laser light enters the optical fiber through the self-focusing lens 4-3 again to form the second reflected laser light, and returns to the circulator 3 through the optical fiber; The phase difference of the reflected laser along the way will change with the vibration displacement, which reflects the micro-movement displacement of the joint joint surface, making the detection accuracy high.

Step 5. The first reflected laser light and the second reflected laser light are transmitted to the circulator 3 respectively, and then transmitted to the laser detector 6 through the optical fiber. The laser detector 6 converts the laser interference signal into an electrical signal, and outputs it after filtering .

The present invention carries out experiment data to typical flange plate screw connection:

1. The steel flange is directly Φ200mm, the thickness of the flange is 6mm, the connecting bolts of grade 10.9 are 8??M6, the rated pre-tightening torque is 10Nm, and the quality of the flange body is 5.5Kg;

2. The vibration environment is: simple harmonic excitation vibration frequency 500Hz, effective value of vibration acceleration 5g;

3. When the pre-tightening torque is greater than 5Nm, the present invention cannot detect the vibration of the joint surface; when the pre-tightening torque is between 1-5Nm, the amplitude of the relative displacement of the joint joint surface 7 increases linearly with the reduction of the pre-tightening torque to 0.15 microns, less than 4Nm, the relative displacement of the joint surface 7 increases sharply, and the signal is extremely irregular.

The measuring device and method for measuring the micro-vibration displacement of the joint joint surface of the present invention utilizes the self-reflection interference principle of the optical fiber end face of the laser to realize the direct and accurate measurement of the micro-amplitude vibration displacement of the joint joint surface in a complex vibration environment, and is suitable for engineering structures The real-time monitoring of the important connection link in the medium and the prevention of serious accidents caused by the failure of the connection; the measuring device and its measuring method have high measurement accuracy and strong adaptability to the environment, and can work in harsh environments such as high pressure, high temperature and corrosion. Especially in the measurement of small dynamic displacement, it also has the advantages of wide dynamic range and sensitive response, and is very suitable for dynamic monitoring of the contact state of the joint joint surface.

The present invention is not limited to the foregoing specific embodiments. The present invention extends to any new feature or any new combination disclosed in this specification, and any new method or process step or any new combination disclosed.

Claims (4)

1. the measurement apparatus coupling faying face fine motion displacement, it is characterised in that: it includes laser instrument (1), described laser instrument (1) some splitters (2), laser instrument (1) is had to send laser by optical fiber connection, through splitter (2) decile that optical fiber connects If for main line incident laser, each splitter (2) is connected with circulator (3) by optical fiber, and each road incident laser is respectively through light Fibre reaches each circulator (3), and described circulator (3) is connected to laser detector (6) by optical fiber and measures head (4), Wherein measure head (4) to be placed on the inline part connecing faying face (7) side of measured hole, at the inline faying face (7) that connects of measured hole The part of opposite side is provided with reflective head (5), each road incident laser from circulator (3) through optical fiber be transferred to measure head (4), one Point incident laser, by measuring the end face reflection of head (4), defines first via reflection laser, another part incident laser injection light Fibre, is irradiated on reflective head (5) and is reflected, and the laser after reflection is again introduced into optical fiber and forms the second tunnel reflection laser, described survey Amount head (4) is mutually paired with reflective head (5), and when the faying face Relative Vibration of connecting link, when producing fine motion displacement, the second tunnel is anti- The phase contrast penetrating laser and first via reflection laser can change along with vibration displacement, and two-way reflection laser leaves measurement head (4), Reach circulator (3) through optical fiber, then spread out of through the upper laser detector (6) connected of circulator (3).

2. the measurement apparatus coupling faying face fine motion displacement as claimed in claim 1, it is characterised in that: described measurement head (4) Including being securable to detect the measurement casing (4-1) in hole, in measuring casing (4-1), it is provided with metal optical fiber contact pin (4- 2) and GRIN Lens (4-3), described GRIN Lens (4-3) is positioned at the forward end measuring head (4), described metal optical fiber Contact pin (4-2) center is installed with extraction tail optical fiber (4-4).

3. the measurement apparatus coupling faying face fine motion displacement as claimed in claim 1 or 2, it is characterised in that: described reflective head (5) being trimmed off screw (8) to be limited in measured hole, described micrometer adjusting screw (8) is connected on the inwall of measured hole, described reflective head (5) using stainless steel material to make, reflective surface (9) roughness of the most reflective head (5) is less than 0.4 micron.

4. the measuring method of the measurement apparatus coupling faying face fine motion displacement described in a claim 3, it is characterised in that: it Comprise the following steps:

Step 1, laser instrument (1) send laser, through optical fiber connect splitter (2) if being divided into main line incident laser；

Step 2, each road incident laser reach each circulator (3) through optical fiber respectively；

Step 3, each road incident laser are transferred to measure head (4) through optical fiber from circulator (3), measure head (4) and are threadably secured On the inline part connecing faying face (7) side of measured hole, the GRIN Lens of the measured head of a portion incident laser (4) (4-3) reflect to form first via reflection laser, and return circulator (3) through optical fiber；

The incident laser output fiber of step 4, additionally part, is irradiated in the reflective surface of perflectometer (5) through GRIN Lens (4-3) (9) being reflected on, wherein perflectometer (5) is trimmed off screw (8) and is fixed on the inline part connecing faying face (7) opposite side of measured hole On, the laser after reflection again enters optical fiber through GRIN Lens (4-3) and forms the second tunnel reflection laser, and returns ring through optical fiber Shape device (3)；

Step 5, first via reflection laser and the second tunnel reflection laser reach circulator (3) respectively, and by the incoming laser of optical fiber Detector (6), laser detector (6) exports after laser interference signal is converted to the signal of telecommunication, and filtered process.