Material mechanical properties testing device and method

Abstract

The present invention belongs to the technical field of intersection of scouring test and mechanical test, and specifically relates to a testing device and method for the mechanical properties of materials in pipeline dynamic water systems. The device can perform mechanical property tests on rod-shaped or shaped materials of limited specifications, introduce a flowing medium into a closed, corrosion-resistant metal pipeline, place a sample on a test pipe section, and mechanically load the sample with threaded fixed connection through a movable platform with a sensor, thereby realizing mechanical property tests of materials in dynamic water systems with different flow rates. The flow rate of the medium can be infinitely changed by adjustment to meet different test requirements, and the pipeline size can be changed according to actual requirements, and other parts can also be adjusted according to the size and specifications of the sample. The device has a simple structure, is easy to use, and has a large space for improvement and optimization. By replacing the fixture, mechanical property tests of samples of other specifications can be realized. By installing in series, mechanical tests of multiple groups of samples in the same flow rate system can be carried out simultaneously.

Description

Technical field:

[0001] The present invention belongs to the cross-technical field of scour test and mechanical test, and specifically relates to a test device and method for studying the mechanical properties of materials in a pipeline water dynamic system, which can obtain the mechanical properties of a sample in a flowing medium. Background technology:

[0002] Dynamic water scour tests can study the properties of materials in flowing media. These tests include both tests in actual natural water environments and in laboratory settings. They can investigate the effects of different media and flow rates on various material parameters, such as the effect of flowing seawater on metal corrosion. Scour test parameters in actual natural water environments are generally uncontrollable, making it difficult to study material regularities. In contrast, scour tests in laboratory settings allow for easy control of test parameters, allowing for the study of material performance differences under varying scour test parameters. Laboratory scour test equipment generally falls into two categories: rotating drum scour and pipeline dynamic water scour.

[0003] Mechanical properties tests can study how different materials behave under different types of mechanical loads, such as typical tension, compression, fatigue, and constant load tests. To meet practical needs, mechanical properties tests are also conducted in liquid media to study the mechanical properties of materials in different media, such as mechanical properties tests of materials in high-pressure seawater and in normal-pressure liquid media.

[0004] With the continuous advancement of technology, the types of mechanical properties tests and dynamic water erosion tests are becoming more and more diverse, the test accuracy and test stability are constantly improving, and there are also many solutions for the mechanical properties test of materials in the medium. For example, Chinese Patent No. 202010681228.7 discloses a multifunctional mechanical testing device, which includes a base, a hydraulic actuator, an adapter, a lower plate, a support device, an upper plate and a top plate arranged in sequence from bottom to top, wherein a guide rod is vertically fixed between the base and the top plate, and the lower plate and the upper plate are both sleeved on the guide rod, and the guide rod has multiple members; a damper is also provided between the upper plate and the lower plate, and the multifunctional mechanical testing device also includes a locking assembly capable of locking the upper plate and the lower plate to the guide rod; a first sensor is provided on the piston rod of the hydraulic actuator, a second sensor is provided between the lower plate and the upper plate, and a third sensor is provided between the upper plate and the top plate; the upper plate is flexibly or rigidly connected to the lower plate through the support device; the piston rod of the hydraulic actuator is flexibly connected to the lower plate through the adapter or rigidly connected to the damper through the adapter; Chinese Patent No. 201811223403.7 discloses a cylindrical scour test device, which includes a base, the middle part of the upper end of the base A barrel body is provided, a bottom cover is provided at the lower end of the barrel body, a rotating water body is filled in the barrel body, a transparent top cover is provided at the upper end of the barrel body, a cylinder is provided at the middle of the lower end of the bottom cover, the cylinder is provided in the base, and the upper and lower sides of the outer wall of the cylinder are sleeved with centripetal ball bearings, the outer side of the centripetal ball bearing is fixedly connected to the base, a thrust bearing is provided at the top end of the base, the thrust bearing is sleeved on the upper part of the outer side of the cylinder, and the outer side of the thrust bearing is sleeved with a gear ring, a cover is provided in the barrel body, and the cover includes An outer shielding cover is provided with a bottom column in the middle of the lower end of the outer shielding cover, a soil sample support plate is provided inside the outer shielding cover, a soil sample is provided on the outer side of the upper end of the soil sample support plate, an inner shielding cover is provided at the upper end of the outer shielding cover, static water is filled between the soil sample support plate and the outer shielding cover and the inner shielding cover, a suspension rod is provided in the middle of the upper end of the soil sample support plate, a tension-torsion sensor is provided at the upper end of the suspension rod, a connecting rod is provided at the upper end of the tension-torsion sensor, a servo actuator is installed on the connecting rod, and a lifting gantry crossbeam is provided at the upper end of the connecting rod. However, the above-mentioned patented products and the test devices in the prior art can basically only perform mechanical property tests on materials in static water media, and cannot meet the needs of actual scientific research and production processes for studying the mechanical properties of materials in dynamic water media, such as tensile tests of carbon steel in flowing seawater, mechanical property tests of titanium alloy specimens in flowing seawater, etc. Therefore, it is very necessary to develop and design a test device and method that can study the mechanical properties of materials in dynamic water media. Summary of the invention:

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and to develop a material mechanical properties testing device and method to test and study the mechanical properties of materials in a dynamic water environment.

[0006] In order to achieve the above-mentioned purpose, the main structure of the material mechanical properties testing device involved in the present invention includes a mechanical testing unit and a dynamic water pipeline unit connected thereto; the main structure of the mechanical testing unit includes a support frame, a fixed base, a support platform, a support shaft, a transmission platform, a limit adjustment motor, a test motor, a mechanical sensor, a connecting port, a pin, a connecting rod, a test pipe section, a slot, an upper connecting sleeve, an elastic membrane, a lower connecting sleeve, a clamp and a bracket; the main structure of the dynamic water pipeline unit includes a water tank, a drain outlet, a valve, a water outlet pipeline, a diversion pipeline, a return pipeline, a flow meter, a water pump and a solenoid valve.

[0007] The support frame disclosed by the present invention is used to support the mechanical test unit and keep it stable, and the support platform and the mechanical test unit are fixed to each other by a rib structure; the support platform provides a fixed lower fulcrum for the mechanical test; the transmission platform is equipped with a displacement sensor for collecting displacement information and providing a fulcrum platform for the test motor to apply a load; the limit adjustment motor can drive the transmission platform to move up and down along the support shaft when it is running, and the sample is replaced when it moves upward; when the test motor is running, it can provide a mechanical load for the sample of the mechanical test, and realize the mechanical load transmission of the sample through the mechanical sensor, the connecting port, the connecting rod, the slot and the upper connecting sleeve in sequence; the mechanical sensor is used to collect load data and transmit the load of the test motor; the pin can make the loading and unloading of the sample more convenient; the connecting rod is threadedly connected to the slot; the two sides of the test pipe section are flange structures, and a through hole is opened on the top To allow the connecting rod to extend into, the through hole is closed by an elastic membrane, and the central area inside is the mechanical testing area; a retractable fixing claw is provided inside the slot, and buttons are provided on both sides. When the button is pressed, the retractable fixing claw is retracted to facilitate the installation and removal of the upper connecting sleeve; the upper connecting sleeve and the lower connecting sleeve are both threaded connecting sleeves; the elastic membrane is a circular high-toughness elastic membrane, and the outer edge is fixed to the test pipe section by screws to seal it; the clamp is a U-shaped clamp, which cooperates with the bracket to keep the test pipe section stable; the water tank is used to hold liquid media, including natural seawater and tap water; the drain outlet is used to empty the liquid medium in the water tank; the valve is a manual valve, which controls the opening and closing state of the drain outlet; the flow meter is used to detect the flow information of the liquid medium and feed it back to the central control system; the water pump provides power for the circulation of the liquid medium; the solenoid valve is an adjustable opening and closing valve, which can adjust the flow of the diversion pipeline.

[0008] When the material mechanical properties testing device of the present invention is used:

[0009] The water inlet and outlet of the test pipe section are flange-connected to the outlet and return pipes respectively, and insulating washers are installed at the connections for sealing; the limit adjustment motor, test motor, mechanical sensor, flow meter, water pump and solenoid valve are connected to the central control system through data cables for signal transmission and signal feedback, thereby achieving the established functions;

[0010] Connect the upper and lower ends of the specimen to the upper and lower connecting sleeves respectively, connect the slot to the upper connecting sleeve, insert the elastic membrane between the connecting rod and the slot, and fix and seal the elastic membrane to the test pipe section with washers and screws. Control the limit adjustment motor through the central control system to move the transmission platform to the set position, connect the mechanical sensor to the connecting rod, and insert the pin;

[0011] Close the valves and water pumps, and add the test medium, such as seawater or distilled water, to the water tank. The central control system controls the operation of the water pump, and adjusts the flow rate of the medium through the water pump and solenoid valve. After the flow rate of the medium stabilizes, the built-in programmable control program in the central control system is used to set mechanical test parameters. For example, mechanical property tests under an intermittent flushing system and mechanical property tests of materials under periodic flow rate changes are performed. Specific mechanical properties include load bearing tests, fatigue tests, and tensile tests. The central control system processes the test data to obtain data graphs and related mechanical property parameters, such as yield strength, tensile strength, and elongation.

[0012] During the test, the mechanical testing unit is used to perform mechanical tests on the specimens, collect relevant parameters (such as mechanical values ​​and displacement values) during the test, and upload them to the central control system. At the same time, the command signal of the central control system is fed back to realize the corresponding functions; the dynamic water pipeline unit is used to realize dynamic medium flushing of the specimens, adjust and record the flow rate, and upload relevant parameter information to the central control system. At the same time, the command signal of the central control system is fed back to realize the corresponding functions; the central control system controls the mechanical testing unit and the dynamic water pipeline unit through built-in programmable control programs and software, so that they can coordinate to realize various tests. At the same time, the parameter information of the mechanical testing unit and the dynamic water pipeline unit is collected and processed and exported through the software; among them, when the dynamic water pipeline unit is in operation, due to the pressure of the medium in the pipe, an upward force will be generated on the card slot and the elastic membrane. In order to prevent this force from affecting the test, the mechanical parameters of different flow rates and different media are preset in the central control system before the test to eliminate the influence. Therefore, during the test, there is no need to consider the influence of the pressure generated by the medium on the mechanical testing unit.

[0013] The specimens involved in the present invention include threaded rod-shaped specimens, sheet-shaped specimens, and CT specimens; the main structure of the central control system includes a shell for accommodating and protecting the integrated control system, a display screen for displaying test information and data processing operations, an external device window for expanding system functions, and a host cabinet door that protects internal host components and related modules and can be opened in the event of a fault to provide a window for system maintenance.

[0014] Compared with the prior art, the present invention can perform mechanical property tests on rod-shaped or shaped materials of limited specifications, introduce a flowing medium into a closed, corrosion-resistant metal pipeline, place the sample in a test pipe section, and mechanically load the sample with threaded fixed connection through a movable platform with a sensor, thereby realizing mechanical property tests of materials in dynamic water systems with different flow rates, and through adjustment, the flow rate of the medium can be infinitely changed to meet different test needs, and the pipeline size can be changed according to actual requirements, and other parts can also be adjusted according to the size and specifications of the sample; it has a simple structure, is easy to use, and has a large space for improvement and optimization. By replacing the fixture, it can realize mechanical property tests of samples of other specifications, and through series installation, it can simultaneously carry out mechanical tests of multiple groups of samples in the same flow rate system. Description of the drawings:

[0015] Figure 1 It is a schematic diagram of the main structural principle of the present invention.

[0016] Figure 2 This is a schematic diagram of the main structural principle of the mechanical testing unit involved in the present invention.

[0017] Figure 3 This is a schematic diagram of the local structural principle of the mechanical testing unit involved in the present invention.

[0018] Figure 4 This is a schematic diagram of the main structural principle of the dynamic water pipeline unit involved in the present invention.

[0019] Figure 5 This is an enlarged view of the local structure of the mechanical testing unit involved in the present invention.

[0020] Figure 6 It is a schematic diagram of the connection relationship between the connecting rod, the clamping slot and the elastic membrane according to the present invention.

[0021] Figure 7 This is a schematic diagram of the connection relationship between the card slot, the upper connecting sleeve and the sample involved in the present invention. Specific implementation methods:

[0022] The present invention will be further described below with reference to the accompanying drawings and specific implementation methods.

[0023] Example 1:

[0024] The main structure of the material mechanical property testing device involved in this embodiment includes a mechanical testing unit A and a water-dynamic pipeline unit B connected thereto; the main structure of the mechanical testing unit A includes a supporting frame 1, a fixed base 2, a supporting platform 3, a supporting shaft 4, a transmission platform 5, a limit adjustment motor 6, a test motor 7, a mechanical sensor 8, a connecting port 9, a latch 10, a connecting rod 11, a test pipe section 12, a slot 13, an upper connecting sleeve 14, an elastic membrane 15, a lower connecting sleeve 16, a clamp 17 and a bracket 18; the supporting frame 1 is composed of a horizontal part and a vertical part, a fixed base 2 is provided on the horizontal part, a supporting platform 3 is provided on the vertical part, two supporting shafts 4 arranged in parallel on the fixed base 2 pass through the supporting platform 3 and the transmission platform 5 in sequence, limit adjustment motors 6 are provided on both sides of the interior of the transmission platform 5, and a test motor 7 is provided in the middle, the test motor 7 is connected to the upper end of the mechanical sensor 8, and a connecting port 9 is provided at the lower end of the mechanical sensor 8. The connecting port 9 is connected to the connecting rod 11 through a latch 10, and the connecting rod 11 passes through the test pipe section 12 and then passes through The card slot 13 is connected to the upper connecting sleeve 14, an elastic membrane 15 is provided between the connecting rod 11 and the test pipe section 12, a lower connecting sleeve 16 is provided at the bottom of the test pipe section 12, and the test pipe section 12 is fixed on the support platform 3 by a clamp 17 and a bracket 18; the main structure of the dynamic water pipeline unit B includes a water tank 20, a drain port 21, a valve 22, a water outlet pipe 23, a diversion pipe 24, a return pipe 25, a flow meter 26, a water pump 27 and a solenoid valve 28; a drain port 21 is provided on one side of the water tank 20, and a drain port 22 is provided on the other side of the water tank 20. A valve 22 is provided at 1, an outlet pipe 23 is provided at a lower point on the other side of the water tank 20, a diversion pipe 24 and a return pipe 25 are provided at a higher point, the diversion pipe 24 extends out for a section and then merges into the return pipe 25, the outlet pipe 23 is connected to the water inlet of the test pipe section 12, and the return pipe 25 is connected to the water outlet of the test pipe section 12, and flow meters 26 are provided on the outlet pipe 23, the diversion pipe 24 and the return pipe 25. A water pump 27 is also provided on the outlet pipe 23, and a solenoid valve 28 is also provided on the diversion pipe 24.

[0025] The material mechanical properties testing device involved in this embodiment cooperates with the central control system C to perform a fatigue test in flowing seawater. The process is as follows:

[0026] Duplex stainless steel was processed into a rod-shaped specimen 19 according to the set requirements. The diameter of the thinnest part of specimen 19 was 1 mm. Seawater was poured into a water tank 20 with a flow rate of 2 m / s. Based on the diameter of specimen 19, the maximum tensile force was set to 235 N, the minimum tensile force was set to 78 N, the transformation cycle was 10 s, and the total test time was set to 1 month. The mechanical load was transformed in the form of a sine wave. The maximum cross-sectional pressure of specimen 19 was 300 MPa and the minimum was 100 MPa. After 20 days of testing, specimen 19 broke. The fracture mechanism was studied through fracture analysis of the test parameters and fracture surface of specimen 19.

[0027] Example 2:

[0028] The material mechanical properties testing device involved in this embodiment cooperates with the central control system C to perform a tensile test in periodically flowing distilled water. The process is as follows:

[0029] TC4 titanium alloy was processed into a rod-shaped sample 19 according to the set requirements. The diameter of the thinnest part of the sample 19 was 1.5 mm. Distilled water was poured into the water tank 20. The distilled water flow rate was set to 1 m / s. After each flushing for 10 minutes, it was left for 20 minutes. The displacement speed was set to 1×10 -5 m / s, the loading force is tensile force, and the test end condition is until it breaks; after the test, the mechanical test data of sample 19 in intermittent flowing distilled water are obtained, the fracture surface of sample 19 is analyzed, and the fracture type is studied.

Claims

1. A material mechanical properties testing device, characterized in that: The main structure includes a mechanical test unit and a water dynamic pipeline unit connected thereto; the main structure of the mechanical test unit includes a support frame, a fixed base, a support platform, a support shaft, a transmission platform, a limit adjustment motor, a test motor, a mechanical sensor, a connection port, a latch, a connecting rod, a test pipe section, a slot, an upper connecting sleeve, an elastic membrane, a lower connecting sleeve, a clamp and a bracket; the main structure of the water dynamic pipeline unit includes a water tank, a drain port, a valve, a water outlet pipeline, a diversion pipeline, a return pipeline, a flow meter, a water pump and a solenoid valve; Among them, the support frame consists of a horizontal part and a vertical part, a fixed base is provided on the horizontal part, and a support platform is provided on the vertical part, two support shafts arranged in parallel on the fixed base pass through the support platform and the transmission platform in sequence, and limit adjustment motors are provided on both sides of the interior of the transmission platform, and a test motor is provided in the middle, the test motor is connected to the upper end of the mechanical sensor, and a connecting port is provided at the lower end of the mechanical sensor, which is connected to the connecting rod through a pin, and the connecting rod passes through the test pipe section and is connected to the upper connecting sleeve through a slot, an elastic membrane is provided between the connecting rod and the test pipe section, and a lower connecting sleeve is provided at the bottom of the test pipe section, and the test pipe section is fixed on the support platform by a clamp and a bracket; A drain outlet is provided on one side of the water tank, and a valve is provided at the drain outlet. An outlet pipe is provided at a lower point on the other side of the water tank, and a diversion pipe and a return pipe are provided at a higher point. The diversion pipe extends out for a section and then merges into the return pipe. The outlet pipe is connected to the water inlet of the test pipe section, and the return pipe is connected to the water outlet of the test pipe section. Flow meters are provided on the outlet pipe, diversion pipe and return pipe. A water pump is also provided on the outlet pipe, and an electromagnetic valve is also provided on the diversion pipe.

2. The material mechanical properties testing device according to claim 1, characterized in that: The support frame is used to support the mechanical test unit and keep it stable, and the support platform and the mechanical test unit are fixed to each other through the rib structure; the support platform provides a fixed lower fulcrum for the mechanical test; the transmission platform has a built-in displacement sensor for collecting displacement information and providing a fulcrum platform for the test motor to apply load; when the limit adjustment motor is running, it can drive the transmission platform to move up and down along the support shaft, and when it moves upward, the sample is replaced; when the test motor is running, it can provide a mechanical load for the specimen of the mechanical test, and realize the mechanical load transmission of the specimen through the mechanical sensor, connecting port, connecting rod, slot and upper connecting sleeve in sequence; the mechanical sensor is used to collect load data and transmit the load of the test motor; the pin can make the loading and unloading of the specimen more convenient; the connecting rod is threadedly connected to the slot; the two sides of the test pipe section are flange structures, and a through hole is opened on the top for connection The connecting rod is extended into the through hole and closed by an elastic membrane, and the central area inside is the mechanical test area; a retractable fixing claw is provided inside the slot, and buttons are provided on both sides. When the button is pressed, the retractable fixing claw is retracted to facilitate the installation and removal of the upper connecting sleeve; the upper connecting sleeve and the lower connecting sleeve are both threaded connecting sleeves; the elastic membrane is a circular high-toughness elastic membrane, and the outer edge is fixed to the test pipe section by screws to seal it; the clamp is a U-shaped clamp, which cooperates with the bracket to keep the test pipe section stable; the water tank is used to hold liquid media, including natural seawater and tap water; the drain outlet is used to empty the liquid medium in the water tank; the valve is a manual valve, which controls the opening and closing status of the drain outlet; the flow meter is used to detect the flow information of the liquid medium and feed it back to the central control system; the water pump provides power for the circulation of the liquid medium; the solenoid valve is an adjustable opening and closing valve, which can adjust the flow of the diversion pipeline.

3. The material mechanical properties testing device according to claim 1 or 2, characterized in that: When using: Connect the test pipe section to the outlet pipe and the return pipe; connect the limit adjustment motor, test motor, mechanical sensor, flow meter, water pump and solenoid valve to the central control system respectively; Connect the specimen to the upper and lower connecting sleeves, connect the slot to the upper connecting sleeve, insert the elastic membrane between the connecting rod and the slot, fix and seal the elastic membrane to the test pipe section, control the limit adjustment motor to move the transmission platform to the set position through the central control system, connect the mechanical sensor to the connecting rod, and insert the pin; Close the valve and water pump and add medium into the water tank. Control the water pump operation through the central control system and adjust the flow rate of the medium. After the flow rate of the medium stabilizes, set the mechanical test parameters through the central control system and process the test data to obtain data graphs and related mechanical performance parameters.

4. The material mechanical properties testing device according to claim 3, characterized in that: When using, the specific steps are: The water inlet and outlet of the test pipe section are flange-connected to the outlet and return pipes respectively, and insulating washers are installed at the connections for sealing; the limit adjustment motor, test motor, mechanical sensor, flow meter, water pump and solenoid valve are connected to the central control system through data cables for signal transmission and signal feedback, thereby achieving the established functions; Connect the upper and lower ends of the specimen to the upper and lower connecting sleeves respectively, connect the slot to the upper connecting sleeve, insert the elastic membrane between the connecting rod and the slot, and fix and seal the elastic membrane to the test pipe section with washers and screws. Control the limit adjustment motor through the central control system to move the transmission platform to the set position, connect the mechanical sensor to the connecting rod, and insert the pin; Close the valves and water pumps, and add seawater required for the test into the water tank. Control the water pump operation through the central control system, and adjust the flow rate of the medium through the water pump and solenoid valve. After the flow rate of the medium stabilizes, set the mechanical test parameters through the built-in programmable control program in the central control system, and process the test data to obtain data graphs and related mechanical performance parameters.

5. The material mechanical properties testing device according to claim 4, characterized in that: During the test, the mechanical testing unit is used for mechanical testing of the specimen, collects relevant parameters during the test, and uploads them to the central control system, while also feeding back the command signal of the central control system; the dynamic water pipeline unit is used to achieve dynamic medium flushing of the specimen, adjust and record the flow rate, and upload relevant parameter information to the central control system, while also feeding back the command signal of the central control system; the central control system controls the mechanical testing unit and the dynamic water pipeline unit through built-in programmable control programs and software, so that they can collaboratively implement various tests, and at the same time, collect parameter information of the mechanical testing unit and the dynamic water pipeline unit, and process and export it through software.

6. The material mechanical properties testing device according to claim 4, characterized in that: The specimens include threaded rod specimens, sheet specimens, and CT specimens.

7. The material mechanical properties testing device according to claim 4, characterized in that: The main structure of the central control system includes a shell for accommodating and protecting the integrated control system, a display screen for displaying test information and data processing operations, an external device window for expanding system functions, and a host cabinet door that protects internal host components and related modules and can be opened in the event of a fault to provide a window for system maintenance.

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