A mechanical pulse device and method for vibration excitation testing of a freely suspended test sample

Abstract

The invention relates to a mechanical pulse device and method for exciting vibration of a freely suspended test sample, comprising a sensor, a suspended / sliding moving part, an emergency braking part, a swing arm, a mass concentrator and a swing arm grabbing part, wherein the sensor detection position is on the freely suspended test sample; the emergency braking part is located at one side of the freely suspended test sample to brake the moving stroke of the suspended / sliding moving part; the upper end of the swing arm is swingably connected to the suspended / sliding moving part; the mass concentrator is connected to the lower end of the swing arm, and moves forward under the action of inertia after being braked by the emergency braking part during the movement of the suspended / sliding moving part, and collides with the freely suspended test sample to excite vibration; the swing arm grabbing part is fixed on the lower side of the suspended / sliding moving part, and corresponds to a side of the swing arm away from the freely suspended test sample to prevent the swing arm from swinging again after recovery, so that multiple excitations can be effectively avoided during the vibration excitation process, enabling high-quality pulse response signals, and the signals can be used for pulse excitation test equipment to calibrate the material properties of the freely suspended test sample.

Description

Technical Field

[0001] The present invention relates to a pulse excitation device, in particular to a mechanical pulse device and method for vibration excitation testing of a freely suspended test sample, and belongs to the application field of material engineering constant testing equipment. Background Art

[0002] Accurate material mechanical parameters are the premise for analyzing the deformation and stress of structural parts under load; the material mechanical testing method known as the pulse excitation test method is one of the methods for non-destructive calibration of material parameters. It is a widely recognized method of detecting mechanical parameters by inducing the vibration of the freely suspended test sample with a mechanical pulse, and then vibrating the freely suspended test sample. The sample vibration information can be collected through existing instruments such as accelerometers, microphones, and laser vibrometers. The mechanical parameters of the sample can be obtained by analyzing the vibration information through empirical formulas or special software.

[0003] The classic free-hanging test specimen is usually a rectangular plate, a rectangular beam, or a container containing the material to be tested. The important material parameters used to describe the mechanical properties of a material are the elastic modulus, Poisson's ratio, and shear modulus.

[0004] Usually, pulse excitation can be achieved manually by hitting the sample with a small hammer. However, in other cases, such as when the sample is placed in a closed environmental chamber to simulate pressure, humidity, high temperature and other environments, a remotely controlled mechanical device is required to achieve pulse excitation.

[0005] However, it is difficult for existing mechanisms to effectively excite the free vibration of suspended samples. One important reason is multiple excitation. Currently, there is an excitation device that uses a rod as a medium to accelerate the impact head to impact the sample at a certain speed. However, in actual applications, after the sample is excited, it will swing around the equilibrium position, and its relative distance from the impact head is difficult to control. When the sample moves towards the impact head, after the collision occurs, the sample will continue to move in the direction of the impact head under the action of inertia, while the impact head will continue to move according to the predetermined stroke. At this time, the interaction between the impact head and the sample hinders the free vibration of the sample. On the contrary, when the impact head is fired, the sample moves away from the impact head, and an under-excitation state occurs at this time, where the impact reaches the predetermined stroke but does not contact, or the contact force is insufficient.

[0006] In order to obtain clear and definite vibration information, multiple excitation and under-excitation need to be avoided. Therefore, the existing pulse excitation devices cannot meet the requirements of pulse excitation testing methods. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a mechanical pulse device and method for vibration excitation testing of a freely suspended test sample, thereby overcoming the problem in the prior art that multiple excitations and under-excitations cannot meet the requirements of the pulse excitation test method.

[0008] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a mechanical pulse device for vibration excitation testing of a freely suspended test sample, comprising a sensor, a suspended / sliding moving part, an emergency braking part, a swing arm, a mass concentrator and a swing arm grabber, wherein the sensor is fixed on the freely suspended test sample; the emergency braking part is located on one side of the freely suspended test sample to brake the moving stroke of the suspended moving part; the upper end of the swing arm is swingably connected to the suspended moving part; the mass concentrator is connected to the lower end of the swing arm to collide with the freely suspended test sample to excite vibration after being braked by the emergency braking part during the movement of the suspended moving part; the swing arm grabber is fixed on the lower side of the suspended moving part and corresponds to the side of the swing arm away from the freely suspended test sample to provide a damping force less than the inertia force of the mass concentrator and prevent the swing arm from swinging again after recovery.

[0009] Based on the above technical solution, the present invention can also be improved as follows.

[0010] As described above, in the mechanical pulse device for vibration excitation testing of a freely suspended test sample, further, the swing arm is a rigid swing arm.

[0011] As described above, a mechanical pulse device for vibration excitation testing of a freely suspended test sample, further, the swing arm is made of ferromagnetic material, the swing arm grabbing part includes an attachment plate and a magnet block, the attachment plate is fixed on the lower side of the suspended moving part, and the magnet block is fixed on the attachment plate.

[0012] The mechanical pulse device for vibration excitation testing of a freely suspended test sample as described above further includes a suspended mobile driving unit, a driving end of which is transmission-connected to an end of the suspended mobile member away from the freely suspended test sample.

[0013] The mechanical pulse device for vibration excitation testing of a freely suspended test sample as described above further includes a mounting frame, and the suspended movement drive unit is a pneumatic, electric or hybrid power drive unit and is mounted on the mounting frame.

[0014] As described above, in the mechanical pulse device for vibration excitation testing of a freely suspended test sample, further, the suspended moving part is a floating / sliding beam; the driving connecting rod or screw of the pneumatic, electric or hybrid power driving unit is directly connected to the floating / sliding beam.

[0015] As described above, in the mechanical pulse device for vibration excitation testing of a freely suspended test sample, further, the emergency brake portion is located between the freely suspended test sample and the floating / sliding beam.

[0016] As described above, a mechanical pulse device for vibration excitation testing of a freely suspended test sample, further, the suspended moving part includes a driving lever and a floating / sliding beam, the upper end of the driving lever is swingably connected to the mounting frame; one end of the floating / sliding beam is fastened to the lower part of the driving lever; the upper end of the swing arm is swingably connected to the other end of the floating / sliding beam.

[0017] As described above, a mechanical pulse device for vibration excitation testing of a freely suspended test sample, further, the emergency braking part is located between the driving lever and the swing arm, so as to brake the swing arm when the driving lever drives the floating / sliding beam to drive the swing arm to move.

[0018] As described above, a mechanical pulse device for vibration excitation testing of a freely suspended test sample, further, the swing arm, the mass concentrator, the swing arm grabber and the freely suspended test sample are located in a confined space, one end of the floating / sliding beam movably passes through the wall of the confined space and is tightly connected to the lower part of the driving lever, and the mounting frame is fixed on the outside of the wall of the confined space.

[0019] As described above, a mechanical pulse device for vibration excitation testing of a freely suspended test sample further includes a braking abutment portion, wherein the emergency braking portion is fixed to an end of the floating / sliding beam away from the swing arm, and the emergency braking portion is located between the braking abutment portion and the swing arm, and the braking abutment portion can move to contact the emergency braking portion for braking.

[0020] The beneficial effects of the present invention are as follows: the mass concentrator of the present invention moves toward the free hanging test sample at a certain initial speed under the drive of the swing arm, and transfers momentum to the free hanging test sample when in contact, thereby inducing free vibration of the free hanging test sample. The mass of the mass concentrator is smaller than the mass of the free hanging test sample to be tested. Therefore, the swing arm grabber of the present invention is smaller than the inertia force of the mass concentrator, ensuring that the mass concentrator collides with the tested free hanging test sample, and after the collision, kinetic energy is transferred, the mass concentrator and the swing arm are rebounded by the free hanging test sample, and the setting of the swing arm grabber prevents the swing arm from swinging again after recovery. The mechanical pulse device of the present invention can effectively avoid multiple excitations during the vibration excitation process, enabling high-quality pulse response signals, and the signal can be used in pulse excitation test equipment to calibrate the material properties of the free hanging test sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1This is a typical free hanging test sample suspension diagram;

[0022] Figure 2A It is a typical schematic diagram of the free hanging sample of a rectangular beam;

[0023] Figure 2B This is a typical schematic diagram of the hanging of a cylindrical free hanging sample;

[0024] Figures 3A to 3F This is a schematic diagram of the overall process of vibration excitation according to an embodiment of the present invention;

[0025] Figures 4A to 4G A schematic diagram of the overall process of vibration excitation according to another embodiment of the present invention;

[0026] Figures 5A to 5B It is a structural schematic diagram of a specific embodiment of the present invention.

[0027] Figure 6 It is a schematic diagram of the configuration of two types of mass concentrated bodies, spherical and cylindrical, used in the present invention;

[0028] Figure 7 The force and spectrum response after the flexible and rigid mass concentrators impact the sample are shown in the present invention.

[0029] Figures 8A to 8C It is a schematic diagram of the sliding connection structure between the floating / sliding beam and the driving lever in the mechanical pulse device of the present invention.

[0030] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0031] 1. Free hanging test specimen, 2. Frame, 3. Suspension wire, 4. Accelerometer, 5. Connection point, 6. Computer, 7A. Strip plate test beam, 7B. Columnar test beam, 8. Swing arm, 9. Mass concentration body, 10. Floating / sliding beam, 11. Brake block, 12. Strip hole, 13. Speed, 14. Collision braking point, 15. Collision point, 16. Rebound speed, 17. Buffer speed, 18. Outer wall of confined space, 19. Electromagnetic drive, 20. Core, 21. Driving lever swing connection end point, 22. Driving lever, 23. Mounting frame, 24. Motor, 25. Output shaft, 26. Magnet block, 27. Attachment plate, 28. Clamp. DETAILED DESCRIPTION

[0032] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0033] like Figure 1As shown, a typical free hanging test sample suspension diagram of the present invention is shown, showing a free hanging test sample 1 suspended on a frame 2 by a suspension line 3. A sensor / accelerometer 4 is attached to the free hanging test sample 1, and is connected to a computer 6 via a connection point 5. By testing the vibration response of the free hanging test sample 1 (test rectangular test plate), the engineering constants of the material sample can be calculated by using the existing pseudo-inverse method material parameter calculation software.

[0034] like Figure 2A As shown, a free-hanging test sample 1 is suspended on a frame 2 by a suspension line 3. An accelerometer 4 is attached to the free-hanging test sample 1, which is connected to a personal computer 6 via a connection point 5. The elastic modulus along the length direction can be calculated by the vibration response of the free-hanging test sample 1 (strip plate-shaped test beam 7A).

[0035] like Figure 2B As shown, a free-hanging test sample 1 is suspended on a frame 2 by a suspension line 3, and the free-hanging test sample 1 is a columnar test beam 7B. An accelerometer 4 is attached to the test board 1 and connected to a personal computer 6 via a connection point 5. The elastic modulus along the length direction can be calculated through the vibration response of the columnar test beam 7B.

[0036] According to an embodiment of the present invention, a mechanical pulse device for vibration excitation testing of a freely suspended test sample includes a sensor, a suspended / sliding moving part, an emergency braking part, a swing arm 8, a mass concentrator 9 and a swing arm grabber, wherein the sensor is fixed on the freely suspended test sample; the emergency braking part is located on one side of the freely suspended test sample 1 to brake the moving stroke of the suspended / sliding moving part; the upper end of the swing arm 8 is swingably connected to the suspended / sliding moving part; the mass concentrator 9 is connected to the lower end of the swing arm to collide with the freely suspended test sample 1 to excite vibration after being braked by the emergency braking part during the movement of the suspended / sliding moving part; the swing arm grabber is fixed on the lower side of the suspended moving part and on the side of the corresponding swing arm away from the freely suspended test sample 1 to provide a damping force less than the inertia force of the mass concentrator 9 and prevent the swing arm 8 from swinging again after recovering.

[0037] In some embodiments, the swing arm 8 is a rigid swing arm, which means that the bending stiffness of the swing arm 8 is the highest; the suspension movement drive unit must drive the swing arm 8 to drive the mass concentration body connected to the swing arm 8 from the starting position to the specified speed in a short time, that is, the process is an acceleration process, and the bending stiffness of the swing arm 8 is high enough to transfer more momentum from the suspension / sliding movement drive unit to the mass concentration body 9. The mass concentration body 9 is accelerated by the suspension moving part, and its inertial force is equal to the product of the acceleration time and the mass. In order to ensure the transmission of controlled pulses, the deformation of the swing arm 8 should not exceed 1 / 10 of the length of the swing arm 8. Based on the prior knowledge of the acceleration of the suspension / sliding movement drive unit, the mass of the mass concentration body 9 and the length of the swing arm 8, the minimum bending stiffness required for the swing arm 8 can be calculated.

[0038] like Figure 3A As shown, the initial position according to the embodiment of the present invention. Specifically, the suspended / sliding moving part is a floating / sliding beam 10, one end of the swing arm 8 is connected to the mass concentrator 9, and the other end is connected to the floating / sliding beam 10; the swing arm is made of ferromagnetic material or has a magnet, the swing arm grabbing part is a magnet block 26 or a magnet block 26 fixed to the attachment plate 27, and the swing arm 8 is connected to the magnet block on the attachment plate 27 by magnetic force. Figure 3B As shown, the floating / sliding beam 10, the swing arm 8 and the mass concentrator 9 move toward the free hanging test sample 1 at a preset speed 13, wherein the emergency brake is a brake block 11 acting as an emergency brake to achieve emergency braking of the swing arm. Figure 3C As shown, at the moment of collision between the floating / sliding beam 10 and the brake block 11 at the collision braking point 14, that is, the end of the floating / sliding beam close to the swing arm is the braking contact part. In this process, the speed of the floating / sliding beam is reduced to zero, and the mass concentrator 9 drives the swing arm 8 to break away from the restraint of the magnet 26 under the action of inertia force and continue to swing around the other end of the swing arm 8. Figure 3D As shown, the mass concentrator 9 collides with the freely suspended test sample 1 at a point 15, during which the pulse energy is transferred to the sample by momentum transfer. Figure 3E As shown, after the collision, the mass concentrator 9 rebounds at a rebound speed 16, and the swing arm 8 contacts the magnet 26 again and is captured. Under the collision, the sample moves along the direction of movement of the mass concentrator before the collision, and vibrates at the same time. Figure 3F The floating / sliding beam 10, the swing arm 8 and the mass concentrator 9 are shown moving away from the sample at a buffering velocity 17 after the collision.

[0039] According to another specific embodiment of the mechanical pulse device for vibration excitation test of a freely suspended test sample of the present invention, it also includes a floating / sliding moving drive unit, and the driving end of the floating / sliding moving drive unit is transmission-connected to an end of the floating / sliding moving member away from the freely suspended test sample 1. Thus, under the action of the driving force of the floating / sliding moving drive unit, the swing arm 8 and the mass concentrator 9 move toward the freely suspended test sample together, the movement of the swing arm 8 is suddenly terminated by the emergency brake unit, and the mass concentrator 9 moves toward the freely suspended test sample 1 under the action of inertia, and excites vibration through momentum exchange during collision; the mass of the mass concentrator 9 needs to be less than the local apparent mass at the excitation point, so that the swing arm 8 is rebounded after vibration excitation, and the possibility of multiple excitations is avoided by setting a grabber for the swing arm 8.

[0040] Specifically, it also includes a mounting frame 23, and the suspension movement driving part is a pneumatic, electric or hybrid driving part and is installed on the mounting frame 23. Specifically, the suspension / sliding moving part can also include a driving lever 22 and a floating / sliding beam 10, the upper end of the driving lever 22 is swingably connected to the mounting frame 23; one end of the floating / sliding beam 10 is tightly connected to the lower part of the driving lever 22; the upper end of the swing arm 8 is swingably connected to the other end of the floating / sliding beam 10.

[0041] The emergency brake part is located between the driving lever 22 and the swing arm 8 to brake the swing arm 8 when the driving lever 22 drives the floating / sliding beam to move the swing arm 8. The lower end of the driving lever 22 is a brake abutment part.

[0042] like FIG. 4A to FIG. 4G As shown, the swing arm 8, the mass concentrator 9, the swing arm grabber and the free hanging test sample 1 are located in a confined space, one end of the floating / sliding beam 10 movably passes through the wall of the confined space and is fastened to the lower part of the driving lever 22, and the mounting frame 23 is fixed to the outer side of the wall of the confined space.

[0043] Figure 4A As shown, the free-hanging test sample 1 with the accelerometer 4 attached is freely suspended in the closed space 18 through the suspension wire 3. The swing arm 8 and the free-hanging test sample 9 used to excite vibration can pass through the outer wall 18 of the closed space and are connected to the floating / sliding beam 10 connected to the external swingable driving lever 22. The magnet 26 used to fix and grab the swing arm has a mounting plate 27 for fixing the magnet 26. The driving lever fixed on the frame 23 moves and can contact the brake block 11 to be braked urgently. The suspension / sliding moving driving part is composed of an electromagnetic driver 19 and a core 20. Figure 4B The electromagnetic driver 19 of the suspension / sliding movement driving unit shown in the figure excites its core 20 to push the driving lever 22 to swing around the driving lever swing connection end 21, thereby pushing the floating / sliding beam 10 to drive the swing arm 8 and the mass concentrator 9 to move toward the freely suspended test sample 12 at a speed v. Figure 4C As shown in FIG. 1 , the driving lever 22 is pushed by the core 20, separated from the core, and collides with the brake block 11 on the outer wall of the enclosed space. Before the collision occurs, the mass concentration body 9 maintains the speed v and moves forward. Figure 4D As shown in FIG. 1 , after the driving lever 22 is braked by the brake block 11, the mass concentrator 9 drives the swing arm 8 to break away from the restraint of the magnet 26 under the action of the inertial force and move toward the freely suspended test sample 1. Figure 4E As shown in the figure, after the collision occurs, the mass concentrator 9 is rebounded, and at the same time, the freely suspended test sample 12 is rigidly swung and vibrated around the suspension point 3 in the direction before the collision of the mass concentrator 9. Figure 4F As shown in FIG. 1 , the driving lever 22 is restored under the action of its own weight and contacts the core 19 again, and the swing arm 8 and the mass concentrator 9 are captured by the magnet 26 under the action of their own weight. Figure 4G As shown, the driving lever 22 pushes the core 9 back to the initial position under its own weight. During the system recovery process, the freely suspended test sample 1 will produce a slight swing, but it is still far away from the mass concentrator 9, so the device based on the invention has no risk of multiple excitation.

[0044] Figure 5A As shown, in some specific embodiments, the driving connecting rod or screw of the pneumatic, electric or hybrid driving unit is directly connected to the floating / sliding beam; the emergency brake unit is located between the free suspension test sample and the floating / sliding beam, or further includes a brake abutment unit, the brake block 11 is fixed to the end of the floating / sliding beam away from the swing arm, the brake block 11 is located between the brake abutment unit and the swing arm, and the emergency brake unit and the brake abutment unit can contact and brake. Specifically, the floating / sliding beam 10 can be directly driven by the output shaft of the pneumatic, hydraulic, or motor 24, and the diameter of the output shaft 25 is larger than the diameter of the floating / sliding beam, which can serve as a brake abutment unit. Figure 5B The figure shows that the braking abutment part is a connecting rod or an output shaft 25 of a motor 24 with a diameter larger than that of the floating / sliding beam 10. After colliding with the brake block 11, the mass concentrator 9 drives the swing arm to separate from the magnet and move toward the target 12 at a speed v under the action of inertia force.

[0045] Figure 6 As shown, there are two mass concentrator configurations, spherical and cylindrical. The drawings are only for illustrating the diversity of configurations of the mass concentrator 9 and are not limited to these two configurations. Figure 7The effect of the contact time between the mass concentrator 9 and the sample on the frequency response is shown. A longer contact time is more likely to generate a low-frequency signal, while a shorter contact time is more likely to generate a high-frequency signal. FIG8 shows a connection method between a floating / sliding beam 10 and a driving lever 22 in a specific embodiment of the present invention. In this connection, one end of the driving lever 22 clamps one end of the floating / sliding beam 10, that is, the floating / sliding beam is provided with a strip hole 12 along the length direction of the driving lever 22, and the driving lever 22 has two clamping members 28 on both sides of the floating / sliding beam. The floating / sliding beam 10 can slide within a certain range along the length direction of the driving lever 22, and the clamping member 28 can be a positioning member such as a nut.

[0046] The specific embodiment of the device of the present invention is used to test the vibration response of a freely suspended test sample 1 in a confined space 18. In the confined space, the temperature, humidity and other possible chemical and physical factors to be applied to the test sample can be set. The freely suspended test sample 1 obtains mechanical pulse energy through the device proposed by the invention, thereby generating vibrations. Then, its material mechanical parameter information is calculated by the software system. In the software system, a digital twin of the freely suspended test sample 1 is created, and the virtual sample vibration information is obtained by modifying the material parameters of the virtual sample, and compared with the measured information, thereby obtaining the sample material parameters.

[0047] The swing arm 8 of the present invention can be made of ferromagnetic material and can be grasped by magnetic force. The grasping force provided by the electromagnetic mechanism needs to be less than the inertia force of the mass concentration body 9 and sufficient to prevent the swing arm 8 from swinging again. The mass concentration body moves toward the free hanging test sample 1 at a certain initial speed under the drive of the swing arm 8. When in contact, the momentum is transferred to the free hanging test sample 1, thereby inducing the free vibration of the free hanging test sample 1. The mass of the mass concentration body 9 is less than the mass of the free hanging test sample 1 to be tested. Therefore, the grabbing member of the swing arm 8 of the present invention is less than the inertia force of the mass concentration body 9, ensuring that the mass concentration body collides with the free hanging test sample 1 to be tested. After the collision occurs, kinetic energy is transferred, and the mass concentration body 9 and the swing arm are rebounded by the free hanging test sample 1. Due to the setting of the swing arm grabbing member, the swing arm 8 is prevented from swinging again after recovery. The mechanical pulse device of the present invention can effectively avoid multiple excitations during the vibration excitation process, enabling high-quality pulse response signals, and the signal can be used in pulse excitation test equipment to calibrate the material properties of the free hanging test sample.

[0048] When the mechanical pulse acts on the center of gravity of the rigid free suspension test sample, the apparent mass is the same as the total mass of the rigid free suspension test sample; when it acts on other points, the apparent mass is less than the total mass of the rigid free suspension test sample. For deformable elastic bodies, the apparent mass is related to the excitation position and the natural mode. At this time, the apparent mass can be obtained using professional vibration analysis software or through experiments.

[0049] Due to the non-destructive nature of the test, the vibration information of the sample can be continuously collected at different times and in different environments, and then the software can obtain the material parameters at different times and in different environments. The device proposed by Fang Ming makes this test possible. Because the mechanical parameters of composite materials are greatly affected by the environment, this invention is crucial for composite material testing. The mechanical pulse excitation method proposed in this invention will not produce multiple excitations, nor will it introduce the vibration characteristics of the excitation device itself into the target sample.

[0050] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A mechanical pulse device for vibration excitation testing of a freely suspended test specimen, characterized in that: It includes a sensor, a suspended / sliding moving part, an emergency braking part, a swing arm, a mass concentrator and a swing arm grabbing part, wherein the sensor detection position is on the free hanging test sample; the emergency braking part is located at one side of the free hanging test sample to brake the moving stroke of the suspended / sliding moving part; the upper end of the swing arm is swingably connected to the suspended / sliding moving part; the mass concentrator is connected to the lower end of the swing arm to collide with the free hanging test sample to stimulate vibration after being braked by the emergency braking part during the movement of the suspended moving part; the swing arm grabbing part is fixed on the lower side of the suspended / sliding moving part and corresponds to the side of the swing arm away from the free hanging test sample to provide a force less than the inertia force of the mass concentrator, and the force can prevent the swing arm from swinging again after recovery.

2. A mechanical pulse device for vibration excitation testing of a freely suspended test sample according to claim 1, characterized in that: The swing arm is a rigid swing arm.

3. A mechanical pulse device for vibration excitation testing of a freely suspended test sample according to claim 2, characterized in that: The swing arm is made of ferromagnetic material, and the swing arm grabbing member includes an attachment plate and a magnet block. The attachment plate is fixed on the lower side of the suspension / sliding moving member, and the magnet block is fixed on the attachment plate.

4. A mechanical pulse device for vibration excitation testing of a freely suspended test sample according to claim 1, characterized in that: It also includes a suspension / sliding movement driving unit, a driving end of which is drivingly connected to an end of the suspension / sliding moving member away from the freely suspended test sample.

5. A mechanical pulse device for vibration excitation testing of a freely suspended test sample according to claim 4, characterized in that: It also includes a mounting frame, and the suspended mobile driving unit is a pneumatic, electric or hybrid power driving unit and is mounted on the mounting frame.

6. A mechanical pulse device for vibration excitation testing of a freely suspended test sample according to claim 5, characterized in that: The suspended / sliding moving part is a floating / sliding beam; the driving connecting rod or screw rod of the pneumatic, electric or hybrid power driving part is directly connected to the floating / sliding beam.

7. A mechanical pulse device for vibration excitation testing of a freely suspended test sample according to claim 6, characterized in that: The emergency stop is located between the free hanging test specimen and the floating / sliding beam.

8. A mechanical pulse device for vibration excitation testing of a freely suspended test sample according to claim 4, characterized in that: The suspended moving part includes a driving lever and a floating / sliding beam, the upper end of the driving lever is swingably connected to the mounting frame; one end of the floating / sliding beam is firmly connected to the lower part of the driving lever; the upper end of the swing arm is swingably connected to the other end of the floating / sliding beam.

9. A mechanical pulse device for vibration excitation testing of a freely suspended test sample according to claim 8, characterized in that: The emergency brake part is located between the driving lever and the swing arm to brake the swing arm when the driving lever drives the floating / sliding beam to drive the swing arm to move.

10. A mechanical pulse device for vibration excitation testing of a freely suspended test sample according to claim 9, characterized in that: The swing arm, the mass concentrator, the swing arm grabber and the free hanging test sample are located in a confined space; one end of the floating / sliding beam movably passes through the wall of the confined space and is fastened to the lower part of the driving lever; the mounting frame is fixed on the outer side of the wall of the confined space.

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