A bellows impact fatigue test device and test method

Abstract

The present invention discloses a bellows impact fatigue life test device, which includes a base. There are two groups of support plates arranged on the base. There are two groups of driving units arranged outside the two groups of support plates. A test piece unit is fixed in the middle of the two groups of support plates. The driving unit and the test piece unit are cooperated through a thrust rod unit. The driving unit includes a plate, a power source and a push plate. A guiding shaft is arranged on the substrate. The push plate is in sliding fit with the guiding shaft. A plurality of spring sleeves are arranged on the inner side of the push plate. The test piece unit includes two groups of bellows. A pressure tapping joint and a plug are respectively arranged on the flanges on both sides. By utilizing the inherent elastic modulus characteristics of the spring, the present invention effectively controls the moving distance of the pusher, so that impact tests with different accelerations can be realized as required, with a wide application range, effectively simulating the impact conditions that may occur in the actual working environment and having good experimental effects.

Description

Technical Field

[0001] The present invention belongs to the technical field of bellows testing devices, and particularly relates to a bellows impact fatigue testing device and a testing method. Background Art

[0002] A bellows is a circular thin-walled shell with waveforms, which is used as a displacement compensator, vibration isolation, sealing, and flexible connection device in pipeline and equipment systems, and is widely used in industries such as petrochemical, electric power, water conservancy projects, and military. In actual applications, the pipeline system is often subjected to an instantaneous shock wave. After being impacted, the pipeline deforms too much and is damaged, resulting in the loss of function of the system. As an important component for displacement compensation and buffering of the pipeline, the performance index of the bellows under impact loads is crucial. Impact resistance belongs to the physical properties of steel, which refers to the ability of a specimen to resist the action of impact loads. Currently, the popular life assessment of bellows in the market usually adopts a low-speed static assessment method or a small-amplitude vibration impact, and cannot achieve the test conditions of large displacement and high acceleration. Summary of the Invention

[0003] The purpose of the present invention is to provide a bellows impact fatigue life test device, which can apply an impact force to the bellows under simulated high-speed and high-acceleration conditions, so as to accurately test the compensation performance and life of the bellows.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions: A bellows impact fatigue life test device, characterized in that: it includes a base, two groups of support plates are arranged on the base, two groups of driving units are arranged outside the two groups of support plates, a test piece unit is fixed in the middle of the two groups of support plates, and the driving unit and the test piece unit are cooperated through a thrust rod unit; the driving unit includes a substrate fixed on the base, a power source is fixed outside the substrate, the output end of the power source is connected to a push plate, a guide shaft is arranged inward on the substrate, the push plate is slidably connected with the guide shaft through a linear bearing, multiple groups of spring sleeves are arranged inside the push plate, and springs are arranged inside the spring sleeves; the thrust rod unit includes a thrust rod slidably connected to the support plate, a connecting plate is arranged at the end of the thrust rod, and a secondary spring sleeve cooperating with the spring is arranged outside the connecting plate; a braking device cooperating with the thrust rod is also arranged on the support plate; the test piece unit includes two groups of bellows, the two groups of bellows are respectively welded to the flanges on both sides and the middle flange, and a pressure tapping joint and a plug are respectively arranged on the flanges on both sides.

[0005] Further: The support seat is slidably connected with the base through a linear slide rail, the linear slide rail is fixed on the base, and a locking device cooperating with the slide rail is also arranged on the support seat.

[0006] Further: A buffer cooperating with the push plate is arranged outside the support plate.

[0007] The present invention also discloses a test method for the impact fatigue life of a corrugated pipe. Using the device as described above, it is characterized in that it includes the following steps:

[0008] S1. Weld two corrugated pipe specimens of the same model to two flanges and an intermediate flange respectively to form a test specimen unit to be tested. Fix the flanges of the test specimen unit to two support plates respectively, and connect and fix the intermediate flange of the test specimen unit to the thrust rod in the thrust rod unit;

[0009] S2. Adjust the position of the support plate according to the total length after the specimens are connected, so that the test specimen to be tested is in the initial state, and lock the braking device;

[0010] S3. Adjust the positions of the support plate and the buffer on the support plate according to the displacement requirements of the corrugated pipe to be tested;

[0011] S4. Connect the pressure tapping joint of the corrugated pipe to an external pressure source, input a medium with a certain load, and reach the set test pressure value;

[0012] S5. Turn on the power supply to make the braking device in the braking state, drive the left power source, push the push plate to move and compress the spring unit to store energy;

[0013] S6. Control the braking device to open, instantaneously release the spring energy, push the thrust rod unit to do an accelerated motion, and apply an impact force to the corrugated pipe;

[0014] S7. Drive the power source to return to its original position. After the intermediate flange is stationary, the braking device brakes to complete one impact;

[0015] S8. Alternately drive the power sources on both sides, repeat steps S6 - S7 until the specified number of times or until damage occurs to complete the test.

[0016] Furthermore, data is collected throughout the process by a computer to monitor the test state of the specimen and the pressure condition inside the corrugated pipe in real time, and to judge the state of the test specimen to be tested.

[0017] The advantages of the present invention are as follows: The present invention utilizes the inherent elastic modulus characteristics of the spring to effectively control the moving distance of the pusher, so that impact tests with different accelerations can be realized according to needs, and the application range is wide. During the dynamic simulation test process of this structure, a high-speed and high-acceleration environment is provided, with a maximum speed of up to 3 m / s and a maximum acceleration of up to 17 g, effectively simulating the impact situations that may occur in the actual working environment, and the experimental effect is good. The test specimens of the present invention are installed using a slide rail type mounting rack to compensate for the machining errors of the specimens, so that the application range of the test specimens to be tested is wide. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 is a schematic cross-sectional view of the present invention;

[0020] Figure 3 is a schematic structural view of the left drive unit;

[0021] Figure 4 is a schematic structural view of the thrust rod unit;

[0022] Figure 5 is a schematic structural view of the test piece unit.

[0023] In the figure: 1 - base; 2 - drive unit; 3 - support plate; 4 - linear slide rail; 5 - thrust rod unit; 6 - locking device; 9 - braking device; 10 - test piece unit; 11 - linear bearing; 12 - buffer;

[0024] 2.1 - power source; 2.2 - substrate; 2.3 - guide shaft; 2.4 - linear bearing; 2.5 - spring sleeve; 2.6 - spring; 2.7 - push plate;

[0025] 5.1 - auxiliary spring sleeve; 5.2 - connecting plate; 5.3 - thrust rod;

[0026] 10.1 - pressure connection; 10.2 - flange 1; 10.3 - bellows; 10.4 - intermediate flange; 10.6 - plug. Detailed implementation manners

[0027] Such as Figures 1-5The present invention shows a bellows impact fatigue life test device, which includes a base 1, two groups of support plates 2 are arranged on the base, two groups of drive units 2 are arranged on the outside of the two groups of support plates (on the side away from the bellows), a test piece (i.e., bellows) unit is fixed in the middle of the two groups of support plates, and the drive unit and the test piece unit 10 are matched through a thrust rod unit 5; the drive unit 2 includes a base plate 2.2 fixed on the base, a power source 2.1 is fixed on the outside of the base plate, and the power source can be a cylinder, a hydraulic cylinder or an electric telescopic cylinder, etc., the output end of the power source is connected to a push plate 2.7, a guide shaft 2.3 is arranged inwardly on the base plate, and the push plate is slidably matched with the guide shaft through a linear bearing 2.4, and a plurality of spring sleeves 2.5 are arranged on the inside of the push plate, and a spring 2.6 is arranged in the spring sleeve. ; The thrust rod unit 5 includes two thrust rods 5.3 slidingly connected to the support plate, and a connecting plate 5.2 is fixed at the end of the thrust rod. A secondary spring sleeve 5.1 cooperating with the spring is provided on the outside of the connecting plate. The spring sleeve and the secondary spring sleeve can be plugged together, and a spring is installed inside. In order to prevent it from falling out, one end or both ends of the spring are fixed to the sleeve body; a braking device 9 cooperating with the thrust rod is also provided on the support plate. The braking device can be in the form of an electric brake, etc. When started, the thrust rod is locked so that it is relatively fixed to the support seat; the test piece unit 10 includes two groups of bellows 10.3, which are respectively welded to the flanges 10.2 on both sides and the middle flange 10.4. A pressure joint 10.1 and a wire plug 10.6 are respectively provided on the flanges on both sides, and the wire plug hole can be used for exhaust.

[0028] Preferably: the support seat is slidably connected with the base through a linear slide rail 4, and the linear slide rail is fixed on the base. A locking device 6 that cooperates with the slide rail is also provided on the support seat. The locking device can be a mechanical lock, etc., which is used to lock the support seat after determining the position.

[0029] Preferably, a buffer 12 is provided on the outside of the support plate to cooperate with the push plate. The buffer can be a rubber pad or a spring, etc., to prevent damage to the equipment during impact and play a role in position limiting protection.

[0030] The present invention also discloses a bellows impact fatigue life test method, which uses the above-mentioned device and includes the following steps:

[0031] S1. Weld two bellows specimens of the same model to two flanges and an intermediate flange to form a test piece unit. Fix the flanges of the test piece unit to two support plates. Connect and fix the intermediate flange of the test piece unit to the thrust rod of the thrust rod unit.

[0032] S2, adjust the position of the support plate according to the total length of the test piece after connection, so that the test piece is in the initial state, and lock the brake device;

[0033] S3. Adjust the positions of the support plate and the buffers on the support plate according to the displacement requirements of the bellows under test;

[0034] S4. Connect the pressure tapping joint of the bellows to an external pressure source, input a medium with a certain load, and reach the set test pressure value;

[0035] S5. Switch on the power supply to make the braking device in the braking state, drive the left power source, push the push plate to move and compress the spring unit to store energy;

[0036] S6. Control the braking device to open, instantaneously release the spring energy, push the thrust rod unit to do an accelerated movement, and apply an impact force to the bellows;

[0037] S7. Drive the power source to return to its original position, and after the middle flange is stationary, the braking device brakes to complete one impact;

[0038] S8. Alternately drive the power sources on both sides, repeat steps S6 - S7 until the specified number of times or damage occurs to complete the test.

[0039] Preferably: The data is collected by a computer throughout the process, the test state of the specimen and the pressure condition inside the bellows are monitored in real time, and the state of the specimen under test is judged.

[0040] The following further describes the structure of the present invention in conjunction with the attached Figures 1 to 5 figures.

[0041] Embodiment 1

[0042] A bellows impact fatigue life test device includes a base. At both ends of the base, a set of power units are symmetrically arranged. At the middle position, two sets of parallel linear slide rails are bolted to the base. The support plate for connecting and fixing the specimen (i.e., the bellows) is connected to the slider on the slide rail by bolts and can move freely in the horizontal direction and adjust the middle distance at will to adapt to specimens of different specifications. A mechanical lock is arranged between the support plate and the slide rail and is fixed on the support plate to lock and fix the position at will. A linear bearing, a buffer and a braking device are configured on the support plate. The buffer is fixed on the support plate by bonding or clamping. The braking device is an electric brake. A pair of thrust rods pass through the support plate, the linear bearing and the electric brake on the support plate and are connected to each other by a connecting push plate at both ends to form a whole, and are in contact with the driving units on both sides at both ends. The power source cylinder is bolted to the left side of the base plate, and the cylinder extension rod is connected to the push plate on the right side of the base plate. The spring sleeve and the linear bearing are respectively bolted to the right side surface of the push plate. The spring unit is placed in the spring sleeve, and the linear shaft cooperates with the guide shaft installed on the base plate. Then, driven by the push and pull of the cylinder extension rod, the push plate and the spring unit do a directional horizontal movement and move to the right to compress the spring group. The specimen to be tested is composed of two bellows specimens of the same model and the bellows specimens are connected in series and welded together through an intermediate flange. Flanges are welded at both ends. Connection holes are opened on the flanges. A pressure injection joint is installed on one side and a plug is installed on the other side to form a specimen unit. During the impact movement of the bellows, since the internal volume remains unchanged, the test pressure is kept constant. The two ends of the specimen to be tested are connected to the support plate, and the intermediate flange is connected and fixed to the thrust rod. During the extension of the cylinder, the electric brake is in a locked state, the spring is compressed to store energy, and the release of the brake is controlled by the electrical control system. The energy is instantaneously released to push the push rod to do an accelerated movement and drive the intermediate flange of the bellows to do an instantaneous accelerated movement. By adjusting the buffer fixed on the support plate, the displacement control of the bellows to be tested is realized.

[0043] As Figure 5 shown, the specimen unit 10 to be tested is composed of two bellows specimens of the same model connected in series and welded together through an intermediate flange 10.4. Flanges 10.2 are welded at both ends. Connection holes are opened on the flanges 10.2. A pressure injection joint 10.1 is installed on one side and a plug 10.6 is installed on the other side to form a specimen unit to be tested. During the impact movement of the bellows, since the lengths of the two bellows remain unchanged, approximately equal to the distance between the two support plates, the diameters remain unchanged, and the two pipe cavities are connected, therefore, regardless of whether the position of the intermediate flange changes or not, the internal volumes of the two pipes remain unchanged, so the test pressure is constant.

[0044] As Figure 3As shown, the cylinder 2.1 in the left drive unit 2 is bolted to the left side of the base plate 2.2. The cylinder's extended rod is connected to the push plate 2.7 on the right side of the base plate. A spring housing 2.5 and a linear bearing 2.4 are bolted to the right side of the push plate 2.7. The spring unit 2.6 is placed within the spring housing 2.5. The linear shaft 2.4 engages the guide shaft 2.3 mounted on the base plate. Driven by the extended rod of the cylinder 2.1, the push plate 2.7 and the spring unit perform directional horizontal motion. The right drive unit 8 is identical in composition to the left drive unit 2.

[0045] like Figure 4 As shown, the thrust rod unit 5 consists of two thrust rods 5.3, two connecting plates 5.2 and two sets of spring sleeves 5.1. The two thrust rods 5.3 are placed in parallel and connected together at both ends by bolts using connecting plates 5.2 to form an integrated part. The spring sleeve 5.1 assembly is bolted to the outer surfaces of the two connecting plates 5.2.

[0046] like Figures 1-2 As shown, a group of drive units 2 are symmetrically arranged at both ends of the base 1, and two groups of parallel linear slide rails 4 are provided in the middle position and fixed to the base 1 by bolts. The support plate 3 and the support plate 7 are connected to the sliders on the slide rails 4 by bolts, and can move freely in the horizontal direction and the middle distance can be adjusted at will to adapt to test pieces of different specifications; a mechanical lock 6 is provided between the support plate and the slide rail 4 and fixed on the support plate to realize arbitrary locking and fixing of the position; the linear bearing 11, the buffer 12 and the electric brake are installed on the support plate 3, and the buffer 12 is bonded or clamped to the support plate 3; the thrust rod unit 5 passes through the linear bearings 11 and the electric brake 9 on the support plate 3 and the support plate 7, and its two ends are in contact with the driving force units on both sides.

[0047] The advantages of the present invention are: the present invention utilizes the inherent elastic modulus characteristics of the spring to effectively control the movement distance of the pusher, thereby realizing impact tests of different accelerations as needed, and having a wide range of applications. During the dynamic simulation test, this structure provides a high-speed and high-acceleration environment, with a maximum speed of 3m / s and a maximum acceleration of 17g, effectively simulating the impact that may occur in the actual working environment, and achieving good experimental results. The present invention adopts a slide rail mounting frame for the specimen installation, which compensates for the machining errors of the specimen and makes the tested specimens have a wide range of applications.

Claims

1. A bellows impact fatigue life test device, characterized in that: It includes a base, on which two sets of support plates are provided. On the outside of the two sets of support plates, two sets of driving units are provided. In the middle of the two sets of support plates, a test piece unit is fixed. The driving unit and the test piece unit are cooperated through a thrust rod unit; The driving unit includes a substrate fixed on the base. On the outside of the substrate, a power source is fixed. The output end of the power source is connected to a push plate. On the substrate, a guide shaft is arranged inward. The push plate is slidably connected with the guide shaft through a linear bearing. On the inner side of the push plate, multiple spring sleeves are arranged, and springs are arranged in the spring sleeves; The thrust rod unit includes a thrust rod slidably connected to the support plate. At the end of the thrust rod, a connecting plate is provided. On the outside of the connecting plate, a secondary spring sleeve cooperated with the spring is provided; A braking device cooperated with the thrust rod is also provided on the support plate; The test piece unit includes two sets of bellows, which are respectively welded to the flanges on both sides and the middle flange. On the flanges on both sides, a pressure testing joint and a plug are respectively provided; A buffer cooperated with the push plate is provided on the outside of the support plate.

2. The bellows impact fatigue life test device according to claim 1, characterized in that: The support plate is slidably connected with the base through a linear slide rail. The linear slide rail is fixed on the base. A locking device cooperated with the slide rail is also provided on the support plate.

3. A test method for the impact fatigue life of a corrugated pipe, using the device as described in claim 1 or 2, characterized in that: It includes the following steps: S1. Weld two bellows test pieces of the same model to two flanges and one middle flange respectively to form a test piece unit. Fix the flanges of the test piece unit on the two support plates respectively, and connect and fix the middle flange of the test piece unit to the thrust rod in the thrust rod unit; S2. According to the total length after the test pieces are connected, adjust the position of the support plate to make the test piece in the initial state, and lock the braking device; S3. According to the displacement requirement of the bellows to be tested, adjust the positions of the support plate and the buffer on the support plate; S4. Connect the pressure testing joint of the bellows to an external pressure source, input a medium with a certain load, and reach the set test pressure value; S5. Turn on the power supply to make the braking device in the braking state. Drive the left power source to push the push plate to move and compress the spring unit to store energy; S6. Control the braking device to open, instantaneously release the spring energy, push the thrust rod unit to do an accelerated movement, and apply an impact force to the bellows; S7. Drive the power source to return to its position. After the middle flange is stationary, the braking device brakes to complete one impact; S8. Alternately drive the power sources on both sides, repeat steps S6 - S7 until the specified number of times or breakage occurs to complete the test.

4. The bellows impact fatigue life test method according to claim 3, wherein: Data is collected by a computer throughout the process to monitor the test state of the test piece and the pressure condition inside the bellows in real time, and judge the state of the test piece.

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