Buoyancy impact testing machine

Abstract

A buoyancy impact testing machine belongs to the technical field of impact tests. The buoyancy impact testing machine comprises a pool, a bearing table, a bearing table guide, a bearing table buffer, a large-mass foundation, a hydraulic station, a vibration isolator, a pressing oil cylinder, a limiting spring, an impact hammer guide rod, an impact hammer capable of moving along the impact hammer guide rod, and a brake release oil cylinder. The large-mass foundation is arranged on the water pool through the vibration isolator, the bearing table is supported through the bearing table guide and the bearing table buffer and is arranged on the large-mass foundation, the impact hammer guide rod is arranged at the bottom of the large-mass foundation, and the oil cylinder can push the impact hammer to be immersed in the water pool through a piston rod of the oil cylinder. A brake release oil cylinder is arranged at the contact position of the impact hammer and the impact hammer guide rod, and the upper end of the bearing table guide rod is sleeved with a limiting spring. According to the buoyancy impact testing machine, the impact force of the impact hammer can be conveniently adjusted by adjusting the immersion depth or inflation pressure of the impact hammer. As the impact hammer impacts the freely placed test bench by using buoyancy, the impact vibration generated has small influence on the surrounding environment.

Description

Technical Field

[0001] The present invention relates to the technical field of impact testing, in particular to a buoyancy impact testing machine. Background Art

[0002] During combat, naval vessels are inevitably subject to explosive shocks from weapons such as torpedoes, mines, and missiles. While the ship's structure may remain intact under these conditions, its equipment may lose functionality. This equipment is a weak link in a ship's shock resistance. To ensure its shock resistance, it must undergo shock resistance assessments before installation.

[0003] Impact testing machine is the main assessment tool for the impact resistance of ship equipment. It has multiple main power sources, namely: elastic energy storage, gravity energy storage, compressed air energy storage, etc. The adjustment of impact force of previous impact testing machines requires complex mechanical structures, and the cost is high; the impact force of traditional impact machines has a greater impact on the foundation and nearby buildings, and the impact vibration generated will be transmitted to ground buildings, causing damage or noise impact on the nearby building environment; previous impact testing machines cannot achieve positive and negative dual-wave impacts, and usually need to replace and adjust part of the structure of the testing machine, which is highly complex and cannot be repeated. It is difficult to meet the structural requirements of ultra-large dual-wave impact testing machines. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a buoyancy impact testing machine, aiming to solve the problems in the prior art that the impact testing equipment has a complex structure, limited impact load, a large impact on buildings, and cannot realize positive and negative dual-wave impact experiments.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A buoyancy impact testing machine includes a water pool, a bearing platform, a bearing platform guide, a bearing platform buffer, a large-mass foundation, a hydraulic station, a vibration isolator, a downward pressure cylinder, a limit spring, an impact hammer guide rod, an impact hammer, and a brake release cylinder; The large mass foundation is arranged on the water pool through a vibration isolator, the bearing platform guide and the bearing platform buffer are arranged at the upper end of the large mass foundation, the bearing platform is supported by the bearing platform guide and the bearing platform buffer, the impact hammer guide rod and the oil cylinder are arranged at the bottom of the large mass foundation, and the downward pressure oil cylinder can push the impact hammer into the water pool through a piston rod arranged inside; A brake release oil cylinder is provided at the contact point between the impact hammer and the impact hammer guide rod, a limit spring is provided on the upper end of the impact hammer guide, and a hydraulic station is arranged on the upper end of the water pool; the impact hammer is placed in the water pool and can move along the impact hammer guide rod.

[0006] Furthermore, the impact hammer is impact hammer 1, the lower part of the impact hammer is a hollow sealed cylinder, and the impact hammer 1 is mounted on the impact hammer guide rod through multiple guide sleeves. A brake release cylinder is provided at the contact point between the guide sleeve and the impact hammer guide rod.

[0007] Furthermore, several auxiliary floats are arranged on one side of the impact hammer, and flange plates are provided on the upper and lower parts of the impact hammer. Upper and lower openings are provided on the flange plates, which are aligned with each other, and the auxiliary floats are looped in the upper and lower openings with gaps; the auxiliary floats have limit rings, and the diameter of the limit rings is larger than the diameter of the lower openings.

[0008] Furthermore, a limiting rope is provided at the bottom of the auxiliary buoy, the upper end of the limiting rope is tied to the bottom of the auxiliary buoy, and the lower end is fixed to the bottom of the pool.

[0009] Furthermore, the impact hammer is a second impact hammer, an air pump is provided at the upper end of the water pool, the second impact hammer is mounted on the impact hammer guide rod, the lower part of the hammer head of the second impact hammer is a cylinder with one end open, a fixed piston is provided in the cylinder, and a closed chamber is formed between the cylinder and the fixed piston; An air inlet D is provided on the side wall of the second impact hammer, and the air pump is connected to the closed cavity inside the second impact hammer through the air inlet D. A universal push rod is provided between the fixed piston and the bottom of the water pool.

[0010] Furthermore, both ends of the universal push rod are connected to the fixed piston and the bottom of the pool by using ball hinge joints.

[0011] Furthermore, the impact hammer is impact hammer three, and the impact hammer three is mounted on the impact hammer guide rod, and the lower part of the impact hammer three is a cylindrical inner cavity with one end open; An inverted U-shaped jet piston is provided in the cylindrical inner cavity of the impact hammer three, and a closed cavity is formed between the cylindrical inner cavity and the inverted U-shaped jet piston. An air inlet hole D is opened on the side wall of the closed cavity, and the air pump is connected to the inside of the closed cavity through the air inlet hole D; a push rod is also provided in the water pool directly below the jet piston.

[0012] Furthermore, a locking portion is provided between the impact hammer three and the inverted U-shaped jet piston, which enables the two to slide relative to each other at a predetermined position.

[0013] Furthermore, the locking portion includes a pin shaft provided on the third outer wall of the impact hammer, the pin shaft is hinged with a pawl, the third outer wall of the impact hammer is provided with a notch at a position corresponding to the pawl, and a spring is provided between the third outer wall of the impact hammer and one end of the pawl; A hollow ring is provided on the outer wall of the lower middle portion of the jet piston, and the other end of the pawl can pass through the notch and extend into the interior of the hollow impact hammer 3, supporting the jet piston through the upper edge of the hollow ring; A stopper is provided in the water pool and is located outside the impact hammer three. When the impact hammer three and the inverted U-shaped jet piston move upward together, the stopper can press down one end of the pawl with a spring, and the other end of the pawl swings out of the hollow ring around the pin shaft.

[0014] Furthermore, the spring is a pre-compressed spring.

[0015] The technical solution adopted by the present invention has the following beneficial effects: (1) Compared with the traditional vertical impact tester, the buoyancy impact tester has a simpler structure and lower cost. The impact force can be easily adjusted by adjusting the water immersion depth or inflation pressure of the impact hammer. (2) It is easy to realize positive and negative dual-wave impact, the test repeatability is good, and it meets the structural requirements of ultra-large dual-wave impact testing machines; (3) The impact force of traditional impact machines has a greater impact on the foundation and nearby buildings. The impact tester of the present invention uses the buoyancy of water to impact the freely placed test bench upwards. Therefore, the impact vibration generated will not be transmitted to the ground buildings, and the impact on the surrounding environment is very small and basically negligible; (4) The device adopts a modular bundled buoy structure design, which can flexibly configure the number and arrangement of auxiliary buoys according to actual test requirements to achieve precise adjustment and optimization of impact force.

[0016] (5) The auxiliary buoy is made of lightweight non-metallic composite materials, which significantly reduces the overall weight while ensuring the structural volume, thus meeting the high buoyancy requirements and effectively controlling the mass of the impact hammer; (6) Relying on high-pressure piston jet to assist in increasing the impact velocity, a greater impact force can be obtained under the same volume; (7) Compared with traditional hydraulic or mechanical impact testing machines, the present invention uses buoyancy as the power source, which is more energy-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the front view of the basic structure of the buoyancy impact machine of the present invention in the state of preparing for impact; Figure 2 This is a left side schematic diagram of the basic structure of the buoyancy impact machine of the present invention in the state of preparing for impact; Figure 3 It is a left side schematic diagram of the basic structure of the buoyancy impact machine of the present invention at the moment of impact; Figure 4 This is a schematic front view of the fixed piston-assisted structure of the buoyancy impact machine of the present invention in a state ready for impact; Figure 5 It is a left side schematic diagram of the fixed piston power-assisted structure of the buoyancy impact machine of the present invention at the moment of impact; Figure 6This is a schematic front view of the fixed piston-assisted structure of the buoyancy impact machine of the present invention in a state ready for impact; Figure 7 It is a left side schematic diagram of the piston jet-assisted structure of the buoyancy impact machine of the present invention in the middle of impact; Figure 8 It is a left side schematic diagram of the instantaneous impact state of the piston jet-assisted structure of the buoyancy impact machine of the present invention; Figure 9 The impact hammer of the basic structure of the buoyancy impact machine of the present invention is pressed to the depth below the water surface. x Calculation principle diagram; Figure 10 This is a diagram of the water surface position at the moment of impact of the basic structure of the buoyancy impact machine of the present invention.

[0018] Figure 6 、 Figure 7 、 Figure 8 middle, L 0< L 1< L 2 Description of reference numerals: 1—Water pool; 2—Carrying platform; 3—Carrying platform guide; 4—Carrying platform buffer; 5—Mass foundation; 6—Hydraulic station; 7—Isolator; 8—Down-pressure cylinder; 81—Piston rod; 9—Limiting spring; 10—Impact hammer guide rod; 11—Impact hammer 1; 12—Brake release cylinder; 13—Brake release piston; 14—Auxiliary float; 141—Limiting ring; 15—Upper opening; 16—Lower opening; 17—Limiting rope; 18—Air pump; 19—Impact hammer 2; 20—Fixed piston; 21—Universal push rod; 22—Impact hammer 3; 221—Notch; 222—Pin shaft; 223—Pawl; 224—Compression spring; 23—Jet piston; 231—Hollow ring; 24—Block; 25—Push rod; A—Upper oil inlet and return port; B—Lower oil inlet and return port; C—Brake release cylinder oil inlet and return port; D—Air inlet hole. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] The present invention is based on the principles of conservation of momentum and energy. Through the implementation of the present invention, during the test, the supporting platform 2 is supported on the large mass base 5 by the supporting platform guide 3 and is pulled by the supporting platform buffer 4 with an initial velocity of zero. According to the masses of the supporting platform 2 and the impact hammer, the instantaneous impact velocity of the impact hammer when it strikes the supporting platform from bottom to top is determined according to different impact requirements. According to different embodiments, different sinking depths of the impact hammer (i.e., the buoy) are determined to complete the bottom-up impact test requirements of the impact hammer.

[0021] A buoyancy impact testing machine includes three schemes: implementation cases 1, 2, and 3.

[0022] Implementation Case 1 is the basic type, which is a pure buoyancy impact type and is the main implementation structure of this patent. Figure 1 、 Figure 2 、 Figure 3 The main structure includes a water pool 1, a load-bearing platform 2, a load-bearing platform guide 3, a load-bearing platform buffer 4, a large-mass foundation 5, a hydraulic station 6, a vibration isolator 7, a downward pressure cylinder 8, a limit spring 9, an impact hammer guide rod 10, an impact hammer 11, a brake release cylinder 12, and a brake release piston 13. It also includes an auxiliary buoy 14, a limit ring 141, an upper auxiliary buoy sleeve 15, a lower auxiliary buoy sleeve 16, and a limit rope 17. Except for the load-bearing platform 2, the load-bearing platform guide rod 3, the load-bearing platform buffer 4, and the hydraulic station 6, most of the components are placed in the water pool 1.

[0023] The large mass foundation 5 is set on the water pool 1 through the vibration isolator 7, and the bearing platform guide 3 and the bearing platform buffer 4 are set at the upper end of the large mass foundation 5. The bearing platform guide 3 has two components, one is a guide sleeve fixed above the large mass foundation 5, and the other is a guide rod fixed to the bottom of the bearing platform 2. The bearing platform 2 can move up and down along the guide sleeve through the guide rod, and the bearing platform 2 is also supported by the bearing platform guide 3. A bearing platform buffer 4 is also provided on the large mass foundation 5. The lower part of the bearing platform buffer 4 is universally hinged above the large mass foundation 5, and the upper part is universally hinged below the bearing platform 2. The impact hammer guide rod 10 and the downward pressure cylinder 8 are arranged at the bottom of the large mass foundation 5. The upper oil inlet and return port A and the lower oil inlet and return port B at the upper and lower ends of the downward pressure cylinder 8 are both connected to the hydraulic station 6. When in use, the downward pressure cylinder 8 can push the piston rod 81 arranged inside downward through the upper oil inlet and return port A. The piston rod 81 pushes the impact hammer to be immersed in the water pool 1, and can press the impact hammer down to a predetermined water depth position. After the impact hammer is adjusted, the downward pressure cylinder 8 can push the piston rod 81 upward and retracted through the lower oil inlet and return port B. By adjusting the downward pressure depth of the impact hammer, the buoyancy of the impact hammer is adjusted, and then the impact force of the impact hammer is adjusted, thereby achieving adjustable impact force.

[0024] In the present invention, the vibration isolator 7 adopts the spring vibration isolator commonly used in the prior art to reduce the impact of the impact hammer on nearby buildings, and at the same time provide a buffer between the water pool 1 and the large mass foundation 5. In addition, the vibration isolator can also adopt the vibration isolator of the commonly used model in the prior art. As long as it can achieve the purpose of the present invention, technical personnel in this field can choose according to actual needs.

[0025] A brake release cylinder 12 is also provided at the contact point between the guide sleeve 111 and the impact hammer guide rod 10. The hydraulic station 6 is arranged at the upper end of the water pool 1. The impact hammer is placed in the water pool 1 and can move along the impact hammer guide rod 10. A brake release piston 13 is assembled inside the brake release cylinder 12. The oil filling hole C of the cylinder behind the brake release piston 13 is connected to the oil pipe of the hydraulic station 6. The brake release piston 13 and the brake release cylinder 12 constitute a brake release device for the impact hammer. When no high-pressure oil enters the rear of the brake release piston 13, the brake device is in a relaxed state. When high-pressure oil enters, The brake release piston 13 presses the impact hammer guide rod 10. At this time, the brake release device puts the impact hammer 11 in a braking state. When in use, after the impact hammer is pressed down to a predetermined water depth, the release of high-pressure oil can be controlled by the hydraulic station 6, so that the brake release piston 13 presses the impact hammer guide rod 10 and locks the impact hammer, which can prevent the impact hammer from moving due to the retraction of the piston rod 81. When the hydraulic station 6 stops releasing the high-pressure oil, the brake release piston 13 releases the lock on the impact hammer guide rod 10, so that the impact hammer generates an upward impact force under the action of buoyancy, completing the impact test.

[0026] A limit spring 9 is provided on the upper end of the impact hammer guide 10. Since the impact hammer needs to be used repeatedly, the impact hammer guide sleeve 111 directly impacts the large-mass foundation 5 multiple times, which will inevitably cause hard damage. Therefore, a limit spring 9 is provided on the upper end of the impact hammer guide 10 to buffer the impact force between the impact hammer guide sleeve 111 and the large-mass foundation 5, limit excessive impact, and better protect the structure from damage.

[0027] During use, the mass of the impact hammer is relatively large. In order to generate sufficiently large buoyancy without increasing the mass of the impact hammer, the impact hammer adopts an impact hammer 11. The lower part of the impact hammer 11 adopts a hollow closed cylindrical structure. The impact hammer 11 is mounted on the impact hammer guide rod 10 through multiple guide sleeves 111.

[0028] like Figure 2 As shown, a plurality of pairs of upper openings 15 and lower openings 16 are correspondingly provided on the upper and lower flanges of the outer contour of the hollow impact hammer 11. Each pair of upper openings 15 and lower openings 16 is fitted with an auxiliary float 14, which is used to assist in providing buoyancy. A limiting ring 141 is provided at the bottom of the auxiliary float 14. The outer diameter of the limiting ring 141 is larger than the aperture of the lower opening 16. When the buoyancy floats the auxiliary float 14, the limiting ring 141 limits the auxiliary float 14 to both sides of the impact hammer. When the impact hammer 11 is pressed down by the piston rod 81, the impact hammer 11 also presses the auxiliary float 14 down through the limiting ring 141. When the impact hammer 11 floats up, the auxiliary float 14 is also pushed upward by the buoyancy.

[0029] A limiting rope 17 is fixedly provided at the lower part of each auxiliary buoy 14 , and the other end of the limiting rope 17 is fixed to the bottom of the pool 1 . Before the test, the limiting rope 17 is in a relaxed state.

[0030] like Figure 3 As shown, before the impact hammer 11 hits the supporting platform 2, the limit rope 17 is tightened and the auxiliary float 14 is pulled down to break away from the impact, so that the impact force will not be transmitted to the auxiliary float 14, avoiding damage to the auxiliary float 14 due to participation in the impact.

[0031] The auxiliary float 14 can be made of non-metallic materials to meet the requirements of small mass and large buoyancy.

[0032] Implementation Case 2 is a fixed piston power-assisted type, refer to Figure 4 、 Figure 5 This type includes most of the basic structure of Implementation Example 1, with the difference that the impact hammer is a second impact hammer 19, an air pump 18 is provided at the upper end of the water tank 1, the second impact hammer 19 is mounted on the impact hammer guide rod 10, and the lower part of the hammer head of the second impact hammer 19 is a cylinder with one end open, a fixed piston 20 is provided in the cylinder, and a closed chamber is formed between the cylinder and the fixed piston 20; An air inlet D is provided on the side wall of the impact hammer 2 19, and the air pump 18 is connected to the closed chamber inside the impact hammer 2 19 through the air inlet D. A universal push rod 21 is provided between the fixed piston 20 and the bottom of the pool 1. A ball hinge is provided at the lower part of the fixed piston 20, which is universally connected to the universal push rod 21. A ball hinge is provided at the lower end of the universal push rod 21 and is connected to the bottom of the pool. Therefore, the fixed piston 20 is supported by the universal push rod 21. Relatively speaking, the impact hammer 2 19 can move up and down along the fixed piston 20. An air pump 18 is also provided above the pool 1. When working, high-pressure gas is filled into the upper part of the fixed piston 20 through the air inlet D. P 0. The impact hammer 21 has basically no buoyancy effect, and the universal push rod 21 is provided with a ball hinge to prevent the fixed piston 20 from being stuck due to different axes.

[0033] An auxiliary buoy 14 and a limiting rope 17 are also provided, and their structure and function are the same as those in implementation case 1.

[0034] Implementation case 3 is a piston jet-assisted type, such as Figure 6 、 Figure 7 、 Figure 8 As shown, the main body is still the basic structure of the implementation case 1, and the impact hammer is the impact hammer 3 22. The structure of the impact hammer 3 22 is as follows: Figure 6 As shown, the impact hammer 3 22 is mounted on the impact hammer guide rod 10, and the lower portion of the impact hammer 3 22 is a cylindrical inner cavity with one end open; An inverted U-shaped jet piston 23 is provided in the cylindrical inner cavity of the impact hammer 3 22, and a closed cavity is formed between the cylindrical inner cavity and the inverted U-shaped jet piston 23. An air inlet D is opened on the side wall of the closed cavity, and the air pump 18 is connected to the inside of the closed cavity through the air inlet D; a push rod 25 is also provided in the water pool directly below the jet piston 23.

[0035] A locking portion is provided between the impact hammer 3 22 and the inverted U-shaped jet piston 23 to enable the two to slide relative to each other at a predetermined position. The locking portion is composed of the following structure.

[0036] like Figure 6 As shown, the locking portion includes a pin 222 provided on the outer wall of the third impact hammer 22, the pin 222 is hinged with a pawl 223, a notch 221 is provided on the outer wall of the third impact hammer 22 corresponding to the pawl 223, and a spring 224 is provided between the outer wall of the third impact hammer 22 and one end of the pawl 223; The outer wall of the lower middle portion of the jet piston 23 is provided with a hollow ring 231. The other end of the pawl 223 can pass through the notch 221 and extend into the interior of the hollow impact hammer 22, supporting the jet piston 23 through the upper edge of the hollow ring 231. A stopper 24 is provided in the water pool 1 and is located outside the impact hammer 3 22. When the impact hammer 3 22 and the inverted U-shaped jet piston 23 move upward together, the stopper 24 can press down one end of the pawl 223 with a spring 224, and the other end of the pawl 223 swings out of the hollow ring 231 around the pin 222. Figure 8 shown.

[0037] A pre-compressed spring 224 is provided below the pawl 223 and supported at the lower portion of the pawl 223 , so that the pawl 223 can swing around the pin 222 so that the upper end thereof is inserted into the notch 221 .

[0038] The three implementation cases are implemented according to the following processes.

[0039] Implementation Case 1: Implementation Case 1 The basic model is pure buoyancy impact type, refer to Figure 1 、 Figure 2 、 Figure 3 The pool 1 is filled with water to an appropriate depth. The device under test is mounted on the support platform 2, which is supported by the support platform guide 3. The corrugator is set, the required impact force is calculated, and the depth of the hammer below the water surface is predetermined. The hydraulic station 6 is activated, and hydraulic oil is injected into the upper chamber of the cylinder 8 through the hydraulic station 6. The pressurizing piston rod 81 extends, pushing the hammer downward to the predetermined depth. The hydraulic station injects hydraulic oil into the brake release cylinder 12 through the brake release cylinder inlet and return port C. The brake release piston 13 presses the hammer guide rod 10, and the hammer is braked to the predetermined position. At this time, the auxiliary buoy 14 is also brought to the corresponding position, and the limit rope 17 is in a relaxed state. Hydraulic oil is injected into the lower chamber of the cylinder 8, and the pressurizing piston rod 81 returns to the high position, and preparation is complete. The brake release cylinder 12 is drained, and the hammer 11 accelerates upward under the combined action of its own buoyancy and the auxiliary buoyancy of the auxiliary buoy 14 to complete the impact. Before the top of the impact hammer 11 and the bottom of the bearing platform 2 are about to impact, the limit rope 17 is straightened to pull the auxiliary buoy 14 out of the impact.

[0040] After the impact, the impact hammer 11 returns immediately, and the brake release cylinder 12 immediately supplies oil to brake the impact hammer 11 to prevent a secondary impact.

[0041] At the moment of collision, the edge of the impact hammer 11 also hits the limit spring 9, compressing the limit spring 9 to avoid the impact of excessive stroke.

[0042] In particular, the water level x The design is such that after the hammer breaks out of the water, the water level drops, reducing the buoyancy. The water level is such that the buoyancy is equal to the gravity of platform 2 at the moment of impact. This approach allows the hammer to be subjected to a constant upward force before impact, accelerating it upward. However, just as impact is about to occur, the force is zero. Upon reaching the designed speed and colliding with platform 2, the hammer can instantly return and be braked, preventing a secondary impact. This reduces the braking force required and facilitates brake control.

[0043] Taking implementation case 1 as an example, in order to make the impact hammer reach the required impact speed, according to Figure 9 Derivation of the depth to which the impact hammer 11 is pressed below the water surface x .

[0044] like Figure 9 As shown, x It is the depth of the predetermined impact hammer under the water surface, assuming that the impact hammer 11 and the auxiliary buoy 14 are cylindrical structures. S is the cross-sectional area, h is the height, m 2 is the total mass; ρ is the density of water; C d is the drag coefficient; g is the acceleration due to gravity; m 1 is the total mass of the carrier platform 2 and the device under test; h 1 is the height between the impact bottom of the bearing platform and the water surface; v 12 is the speed after the collision between the platform 2 and the device under test, h 1 is the height of the supporting platform 2 and the device under test from the pool plane.

[0045] Set another Y Axially, at the water surface y= 0 ，m The speed of 2 is v 20 , time is t 20 , before colliding with workbench 3, m The speed of 2 is v 21 , after the collision,m The speed of 2 is v 22 , m The speed of 1 is v 12 , the collision process satisfies the conservation of momentum and energy.

[0046] The upward impact movement of the impact hammer is divided into the following three stages: The first stage: the impact hammer 11 is completely immersed in the water surface, and the height of the hammer head 41 from the water surface is x , m 2Affected by gravity ,buoyancy and water resistance , the differential equation of motion is: (1) Right now set up , , the solution is (2) The second stage: the process from the impact hammer 11 starting to surface to the collision with the workbench 3.

[0047] (3) Right now set up , , the solution is (4) In the formula The third stage: the impact hammer 11 collides with the workbench 3, and the collision process satisfies the conservation of momentum and kinetic energy.

[0048] (5) (6) The solution is (7) Substituting equations (2) and (7) into equation (4), we get In the formula h 1 According to the patent feature - the impact hammer at the moment of impact is equal to the principle of buoyancy and gravity, such as Figure 10 As shown, assume that the distance between the upper surface of the impact hammer and the water surface at the moment of impact is h 2, then we have ( h ﹣h 2) sρ = m 2 Right now Assume that the water surface area is S 1, then Implementation Case 2: Implementation Case 2 is a fixed piston power-assisted type, refer to Figure 4 、 Figure 5 The buoyancy of this type of impact hammer 19 is very small and can be basically ignored. Its upward impact force comes from two aspects. One is the buoyancy provided by the auxiliary float 14, and the other is the upward pressure on the impact hammer 19 by the high-pressure gas filled in the closed cavity formed by the hollow cavity of the impact hammer 19 and the fixed piston 20.

[0049] During the test, calculate the impact hammer 219's pressing depth and fill pressure according to the required impact speed. P 0. The rest of the implementation process is the same as that of Implementation Case 1.

[0050] Features: Since the closed cavity formed by the hollow cavity of the impact hammer 2 19 and the fixed piston 20 contains compressed air, the compression distance is not large. Therefore, Implementation Case 2 is suitable for short-distance impact applications of the impact hammer 2 19, that is, the distance between the top of the impact hammer 2 19 and the bottom of the support platform 2 should be relatively close. If the auxiliary float 14 is relatively large in volume and provides the main impact force, or the air pump and pipeline provide compressed air at a fast speed, it is also suitable for general distances.

[0051] Implementation Case 3: Implementation case 3 is a piston jet-assisted type, such as Figure 6 、 Figure 7 、 Figure 8 As shown, it is expanded on the basis of Implementation Case 1. On the one hand, the main impact process is the same as Implementation Case 1. The impact force is provided by the closed cavity composed of the impact hammer 3 22 and the jet piston 23 and the buoyancy of the auxiliary float 14.

[0052] The difference is that on the other hand, the closed cavity formed by the impact hammer 22 and the jet piston 23 is filled with high pressure gas. P 0, that is, in addition to having buoyancy, the impact hammer 3 22 also serves as a high-pressure cylinder. During the test, the high-pressure air pushes the jet piston 23 to move downward at a high speed, spraying the water below it downward. The reaction force of the water reacts on the impact hammer 3 22 through the jet piston 23 and the gas to provide an upward thrust.

[0053] The formation of the closed cavity is carried out in this way, if Figure 8 In the initial state, the hydraulic station 6 injects high pressure oil into the upper chamber of the pressurized oil cylinder 8 (same as Figure 1), pushes the pressurizing piston rod 81 downward, the pressurizing piston rod 81 pushes the impact hammer 3 22 downward, the impact hammer 3 22 pushes the jet piston 23 downward together, when the jet piston 23 contacts the push rod 25, the jet piston 23 is stopped by the push rod 25, the impact hammer 3 22 continues to move downward and slides over the block 24, when the pawl 223 on the outer circle of the impact hammer 3 22 slides over the hollow ring 231 of the jet piston 23, the compression spring 224 makes the pawl 223 swing around the pin 222, so that the upper end of the pawl 223 extends into the hollow ring 231 and supports the upper edge of the hollow ring 231. When the pressurizing piston rod 81 stops pressing down, the brake release cylinder 12 is released through the port C The brake release piston 13 is pressed against the surface of the impact hammer guide rod 10 to achieve braking. High pressure gas is injected into the closed chamber formed by the impact hammer 3 22 and the jet piston 23. P 0, at this time the impact hammer 3 22 is in the state of preparing for impact, and the distance between the bottom of the impact hammer 3 22 and the bottom of the pool 1 is L 0, such as Figure 6 shown.

[0054] The brake release cylinder 12 drains oil, and the brake release piston 13 releases the brake. Under the buoyancy of the impact hammer 3 22 and the auxiliary float 14, the impact hammer 3 22 accelerates upward. When the top of the impact hammer 3 22 is about to hit the bottom of the support platform 2 (the bottom of the impact hammer 3 22 is at a distance of 1 / 4 from the bottom of the pool 1), the impact hammer 3 22 moves upward. L 1, such as Figure 7 As shown), the lower end of the pawl 223 hits the stopper 24, and its lower end is pressed down by it, and the upper end withdraws from the notch 221 and loses support for the jet piston 23. P 0, the jet piston 23 moves downward rapidly, pushing the water below to spray downward rapidly, and the impact hammer 3 22 completes the upward impact action under the combined action of its own buoyancy, the jet reaction force of the jet piston 23, and the buoyancy of the auxiliary float 14.

[0055] After the impact, the pawl 223 is still pressed by the block 24 and cannot rotate. Figure 8 , until the pressing oil cylinder 8 and the pressurizing piston rod 81 are started again, that is, the next test preparation is started.

[0056] Figure 6 To prepare for the release of the shock state, Figure 7 As the upward impact is in progress, Figure 8 is the instantaneous state of impact. In the figure, L 0< L 1< L 2.

Claims

1. A buoyancy impact testing machine, characterized in that: It includes a water pool (1), a bearing platform (2), a bearing platform guide (3), a bearing platform buffer (4), a large mass foundation (5), a hydraulic station (6), a vibration isolator (7), a downward pressure cylinder (8), a limit spring (9), an impact hammer guide rod (10), an impact hammer, and a brake release cylinder (12); The large mass foundation (5) is arranged on the water pool (1) through the vibration isolator (7), the bearing platform guide (3) and the bearing platform buffer (4) are arranged on the upper end of the large mass foundation (5), the bearing platform (2) is supported by the bearing platform guide (3) and the bearing platform buffer (4), the impact hammer guide rod (10) and the oil cylinder (8) are arranged at the bottom of the large mass foundation (5), and the downward pressure oil cylinder (8) can push the impact hammer to immerse in the water pool (1) through the piston rod (81) arranged inside; A brake release oil cylinder (12) is provided at the contact point between the impact hammer and the impact hammer guide rod (10), a limit spring (9) is provided on the upper end of the impact hammer guide (10), and a hydraulic station (6) is provided at the upper end of the water pool (1); the impact hammer is placed in the water pool (1), and the impact hammer can move along the impact hammer guide rod (10).

2. The buoyancy impact testing machine according to claim 1, characterized in that: The impact hammer is an impact hammer (11), the lower part of which is a hollow sealed cylinder. The impact hammer (11) is mounted on the impact hammer guide rod (10) through a plurality of guide sleeves (111), and a brake release oil cylinder (12) is provided at the contact point between the guide sleeve (111) and the impact hammer guide rod (10).

3. The buoyancy impact testing machine according to claim 2, characterized in that: Several auxiliary floats (14) are arranged on the side of the impact hammer (11). Flange plates are provided on the upper and lower parts of the impact hammer (11). An upper opening (15) and a lower opening (16) are provided on the flange plates. The upper and lower parts are aligned. The auxiliary floats (14) are looped in the upper opening (15) and the lower opening (16) with a gap. The auxiliary floats (14) are provided with a limiting ring (141), and the diameter of the limiting ring (141) is larger than the diameter of the lower opening (16).

4. The buoyancy impact testing machine according to claim 3, characterized in that: A limiting rope (17) is provided at the bottom of the auxiliary buoy (14), the upper end of the limiting rope (17) is tied to the bottom of the auxiliary buoy (14), and the lower end is fixed to the bottom of the pool (1).

5. The buoyancy impact testing machine according to claim 1, characterized in that: The impact hammer is impact hammer 2 (19), an air pump (18) is provided at the upper end of the water pool (1), impact hammer 2 (19) is mounted on the impact hammer guide rod (10), the lower part of the hammer head of impact hammer 2 (19) is a cylinder with an open end, a fixed piston (20) is provided in the cylinder, and a closed cavity is formed between the cylinder and the fixed piston (20); An air inlet hole (D) is provided on the side wall of the second impact hammer (19), and the air pump (18) is connected to the closed cavity inside the second impact hammer (19) through the air inlet hole (D). A universal push rod (21) is provided between the fixed piston (20) and the bottom of the water pool (1).

6. The buoyancy impact testing machine according to claim 5, characterized in that: Both ends of the universal push rod (21) are connected to the fixed piston (20) and the bottom of the pool (1) using ball hinge joints.

7. The buoyancy impact testing machine according to claim 1, characterized in that: The impact hammer is impact hammer three (22), and the impact hammer three (22) is mounted on the impact hammer guide rod (10). The lower part of the impact hammer three (22) is a cylindrical inner cavity with one end open; An inverted U-shaped jet piston (23) is provided in the cylindrical inner cavity of the impact hammer (22), and a closed cavity is formed between the cylindrical inner cavity and the inverted U-shaped jet piston (23). An air inlet hole (D) is opened on the side wall of the closed cavity, and the air pump (18) is connected to the inside of the closed cavity through the air inlet hole (D); a push rod (25) is also provided in the water pool directly below the jet piston (23).

8. The buoyancy impact testing machine according to claim 7, characterized in that: A locking portion is provided between the impact hammer 3 (22) and the inverted U-shaped jet piston (23) to enable the two to slide relative to each other at a predetermined position.

9. The buoyancy impact testing machine according to claim 8, characterized in that: The locking portion includes a pin (222) provided on the outer side wall of the impact hammer (22), the pin (222) being hinged with a pawl (223), a notch (221) being provided at a position corresponding to the outer side wall of the impact hammer (22) and the pawl (223), and a spring (224) being provided between the outer side wall of the impact hammer (22) and one end of the pawl (223); A hollow ring (231) is provided on the outer side wall of the lower middle portion of the jet piston (23), and the other end of the pawl (223) can pass through the notch (221) and extend into the interior of the hollow impact hammer (22), and support the jet piston (23) through the upper edge of the hollow ring (231); A stopper (24) is provided in the water pool (1), and the stopper (24) is located outside the impact hammer three (22). When the impact hammer three (22) and the inverted U-shaped jet piston (23) move upward together, the stopper (24) can press down one end of the pawl (223) with the spring (224), and the other end of the pawl (223) swings out from the hollow ring (231) around the pin (222).

10. The buoyancy impact testing machine according to claim 9, characterized in that: The spring (224) is a pre-compressed spring.

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