A damped sine wave application device for mechanical environmental testing

Abstract

The present application belongs to the field of mechanical environmental testing, and particularly relates to a damped sine wave application device for mechanical environmental testing. The device comprises: an elastic element (1), a damping element (2), a mounting frame (3), a release mechanism (7), and a timer (6). The first end of the elastic element (1) is fixed, and a stop mechanism (8) is provided on the elastic element (1); the damping element (2) is mounted on the elastic element (1) and can gradually attenuate the vibration of the elastic element (1); the top end of the mounting frame (3) is connected to the second end of the elastic element (1), and a test piece (4) and a weight (5) are mounted on the mounting frame (3); the release mechanism (7) is connected to the bottom end of the mounting frame (3); and the timer (6) is connected to the release mechanism (7) and the stop mechanism (8) respectively. The present application can significantly reduce the test cost and achieve a larger acceleration value at low frequency.

Description

Technical Field

[0001] The present application belongs to the field of mechanical environmental testing, and in particular relates to a damped sine wave application device for mechanical environmental testing. Background Art

[0002] If suitable on-site measurement data is unavailable, a transient sine wave can be used to simulate each ejection or takeoff process, based on the requirements of the shock environment test. In this case, the time history is simplified to a transient sine wave with a specific duration. The waveform is a damped sine wave, and the frequency is determined by the structural analysis of the given aircraft and the frequency of the first-order mode. The waveform damping (quality factor) is Q = 20, and the amplitude is determined by the structural analysis of the given aircraft, the frequency of the first-order mode, and the position of the equipment on the first-order mode vibration shape.

[0003] The key to achieving these experimental conditions lies in achieving a damped sine wave waveform. The difficulty lies in the limited travel range of a vibration table, which makes it impossible to achieve this under high acceleration conditions. Furthermore, this method relies primarily on active waveform control, resulting in complex equipment and high costs. To address this issue, numerous research efforts have been conducted, primarily based on improvements to the vibration table. However, few laboratories are currently capable of conducting this test, and the high cost and limited scope of testing are challenges.

[0004] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned deficiencies of the prior art. Summary of the Invention

[0005] The purpose of this application is to provide a damped sine wave application device for mechanical environmental testing to solve at least one problem existing in the prior art.

[0006] The technical solution of this application is:

[0007] A damped sine wave application device for mechanical environmental testing, comprising:

[0008] an elastic element, wherein a first end of the elastic element is fixed and a stop mechanism is provided on the elastic element;

[0009] a damping element, the damping element being mounted on the elastic element and capable of gradually attenuating the vibration of the elastic element;

[0010] a mounting frame, a top end of the mounting frame being connected to the second end of the elastic element, and a test piece and a weight being mounted on the mounting frame;

[0011] a release mechanism connected to the bottom end of the mounting frame;

[0012] A timer is connected to the release mechanism and the stop mechanism respectively.

[0013] In at least one embodiment of the present application, the elastic element is a metal spring, a rubber rope or a cantilever beam.

[0014] In at least one embodiment of the present application, the stiffness of the elastic element is:

[0015] k=mf 2

[0016] Where k is the stiffness of the elastic element, m is the total mass of the elastic element, damping element, mounting frame, test piece, and weight, and f is the natural frequency of the elastic element.

[0017] In at least one embodiment of the present application, the force F is applied by the release mechanism so that the mounting frame reaches an initial displacement. Then, the sinusoidal acceleration waveform generated by the mechanical environment test damping sine wave application device is:

[0018] a(t)=Asin(ωt)

[0019] Where A / ω 2 is the initial displacement, a is the acceleration, A is the acceleration amplitude, ω is the circular frequency, and t is the time.

[0020] In at least one embodiment of the present application, the release mechanism includes an electromagnetic suction cup and a hydraulic cylinder, one end of the electromagnetic suction cup is connected to the mounting frame, and the other end is connected to the hydraulic cylinder. When powered on, the electromagnetic suction cup adsorbs the mounting frame, and the hydraulic cylinder applies a pulling force to the electromagnetic suction cup, driving the mounting frame to reach an initial displacement. After the displacement reaches the target value, the electromagnetic suction cup is powered off, the adsorption force disappears, and the elastic element begins to vibrate.

[0021] In at least one embodiment of the present application, the release mechanism includes a constant force rod and a hydraulic cylinder, one end of the constant force rod is connected to the mounting frame, and the other end is connected to the hydraulic cylinder. The hydraulic cylinder applies a pulling force to the constant force rod, driving the mounting frame to reach an initial displacement. After the displacement reaches the target value, the constant force rod breaks and the elastic element begins to vibrate.

[0022] In at least one embodiment of the present application, the stopping mechanism includes a stopping plate and an operating rod. When stopping, the operating rod drives the stopping plate to hold or clamp the elastic element.

[0023] The invention has at least the following beneficial technical effects:

[0024] The mechanical environment test damped sine wave application device of the present application can realize the damped sine wave through the elastic element-mass-damping system; can control the frequency of the damped sine wave through the stiffness and mass of the elastic element; can control the quality factor of the damped sine wave through the damping element; can control the acceleration of the damped sine wave through the initial position; can control the time length of the damped sine wave through a timer and a stop mechanism; the present application is easy to implement, can significantly reduce the test cost, and can achieve a larger acceleration value at low frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of a damped sine wave application device for a mechanical environmental test according to one embodiment of the present application;

[0026] Figure 2 This is a schematic diagram of damped sinusoidal wave waveform control according to one embodiment of the present application.

[0027] in:

[0028] 1- elastic element; 2- damping element; 3- mounting frame; 4- test piece; 5- weight; 6- timer; 7- release mechanism; 8- stop mechanism. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the drawings in the embodiments of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be understood as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0030] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as limiting the scope of protection of this application.

[0031] The following is combined with Figures 1 to 2 This application is described in further detail.

[0032] The present application provides a damped sine wave application device for a mechanical environment test, comprising: an elastic element 1, a damping element 2, a mounting bracket 3, a release mechanism 7 and a timer 6.

[0033] Specifically, such as Figure 1 As shown, the first end of the elastic element 1 is fixed, and a stopping mechanism 8 is provided on the elastic element 1. The stopping mechanism 8 can stop the elastic element 1. When stopping is not required, the stopping mechanism 8 is disengaged from the elastic element 1 and does not interfere with the movement. The damping element 2 is installed on the elastic element 1, which can gradually attenuate the vibration of the elastic element 1. The damping element 2 can be used to adjust the damping size of the system during movement to control the quality factor specified by the test conditions. The damping element 2 can be a viscoelastic damping material covered on the surface of the elastic element 1, or a particle damper can be added to the elastic element 1. The top of the mounting frame 3 is connected to the second end of the elastic element 1, and the test piece 4 and the weight are installed on the mounting frame 3. Code 5, mounting frame 3, test piece 4 and weight 5 together constitute the mass in the spring-mass-damping system. By adjusting the mass of weight 5, the frequency of the system movement can be adjusted. By adjusting the position of weight 5, the center of gravity of the mass can be adjusted to prevent adverse lateral movement caused by eccentricity; the release mechanism 7 is connected to the bottom end of the mounting frame 3; the timer 6 is connected to the release mechanism 7 and the stop mechanism 8 respectively. By connecting the release mechanism 7 to the timer 6, the timer 6 starts timing when the device is released from the initial position. When the time length specified by the test conditions is reached, the timer 6 outputs a signal to the stop mechanism 8. After receiving the signal, the stop mechanism 8 applies resistance to stop the device from moving.

[0034] In a preferred embodiment of the present application, the elastic element 1 may be in the form of a metal spring, a rubber rope, a cantilever beam, etc. In this embodiment, the elastic element 1 is a metal spring.

[0035] The damped sine wave application device for mechanical environmental testing of this application performs modal analysis and strength analysis based on the frequency value and test piece mass specified by the test conditions through mechanical formulas or finite element analysis. The natural frequency is mainly determined by the two parts of stiffness and mass. The stiffness is determined by the elastic element 1, and the mass includes the mass of the elastic element, the mass of the damping element, the mounting frame, the test piece, and the mass of the weight. For example, during the finite element analysis, the mass of the test piece has been determined. By adjusting the size of the elastic element 1 and the stiffness of the elastic element 1, the stiffness of the elastic element 1 is determined. The elastic element 1 must have a reasonable tensile and compressive stroke according to the test conditions and meet the strength requirements. Specifically, the stiffness of the elastic element 1 is:

[0036] k=mf 2

[0037] Where k is the stiffness of the elastic element, m is the total mass of the elastic element, damping element, mounting frame, test piece, and weight, and f is the natural frequency of the elastic element.

[0038] The damped sine wave application device for mechanical environmental testing of the present application applies a force F through a release mechanism 7, causing the elastic element 1, the damping element 2, the mounting frame 3, the test piece 4 and the weight 5 to generate an initial displacement (reach the initial position) as a whole, and the waveform of the damped sine wave is controlled by the size of the displacement (such as Figure 2 The acceleration value is shown in FIG. 1 . The sine wave acceleration waveform generated by the mechanical environment test damping sine wave application device of the present application is:

[0039] a(t)=Asin(ωt)

[0040] Where A / ω 2 is the initial displacement, a is the acceleration, A is the acceleration amplitude, ω is the circular frequency, and t is the time.

[0041] The mechanical environment test damping sinusoidal wave application device of the present application can have a variety of implementation methods for the release mechanism 7. In one embodiment of the present application, the release mechanism 7 includes an electromagnetic suction cup and a hydraulic cylinder. One end of the electromagnetic suction cup is connected to the mounting frame 3, and the other end is connected to the hydraulic cylinder. First, when the power is on, the mounting frame 3 is adsorbed by the electromagnetic suction cup, and then a pulling force is applied to the electromagnetic suction cup by the hydraulic cylinder, thereby driving the mounting frame 3 (the entirety of the elastic element 1, the damping element 2, the mounting frame 3, the test piece 4 and the weight 5) to reach the initial displacement. After the displacement reaches the target value, the electromagnetic suction cup is powered off, the adsorption force disappears, and the elastic element 2 begins to vibrate.

[0042] In another embodiment of the present application, the release mechanism 7 includes a tension rod and a hydraulic cylinder. One end of the tension rod is connected to the mounting bracket 3, and the other end is connected to the hydraulic cylinder. The hydraulic cylinder applies a tensile force to the tension rod, driving the mounting bracket 3 to an initial displacement. When the displacement reaches the target value, the tension rod breaks, and the elastic element 2 begins to vibrate. The tension rod is designed based on the mechanical properties of the material used, so that when subjected to tension, it will break under a predetermined load.

[0043] In the present invention's damped sine wave application device for mechanical environmental testing, the stop mechanism 8 includes a stop plate and a lever. During the stop operation, the lever drives the stop plate to clamp or grip the elastic element 1. The stop mechanism 8 acts like a brake, clamping or gripping the elastic element 1 when needed to prevent movement. During the damped sine wave operation, the stop mechanism 8 is completely disengaged from the elastic element 1, preventing any interference with movement.

[0044] The damped sine wave application device for mechanical environmental testing of this application has the following advantages:

[0045] a. Realize damped sine wave through elastic element-mass-damper system;

[0046] b. Design the stiffness coefficient of the elastic element 1 based on the mass of the test piece 4. By setting the weight 5, the mass size and center of gravity position can be adjusted to a certain extent. The mass size is adjusted to adjust the frequency, and the center of gravity is adjusted to prevent eccentricity from causing unnecessary lateral movement of the elastic element-mass-damper system. After matching the stiffness and mass, the frequency specified in the test conditions is achieved.

[0047] c. Adjust the quality factor of the damped sine wave by using damping element 2 so that the quality factor reaches the value specified by the test conditions;

[0048] d. Control the acceleration of the damped sine wave by applying an initial displacement (or initial force);

[0049] e. It has a timing function, and the timing starts from the moment the elastic element 1 is released from the initial position;

[0050] f. The elastic element-mass-damping system can be stopped by the stop mechanism 8, and the stopping process does not generate a greater load on the test piece 4;

[0051] g. The duration of the damped sine wave is controlled by the timing function and the stop mechanism 8.

[0052] The damped sine wave application device for mechanical environmental testing in this application can conveniently achieve the damped sine wave required for the test, especially when low-frequency acceleration is high. This application is easy to implement, can significantly reduce testing costs, and can achieve greater acceleration values ​​at low frequencies.

[0053] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A damped sine wave application device for mechanical environmental testing, characterized in that: include: An elastic element (1), wherein a first end of the elastic element (1) is fixed, and a stop mechanism (8) is provided on the elastic element (1); A damping element (2), the damping element (2) being mounted on the elastic element (1) and capable of gradually attenuating the vibration of the elastic element (1); the damping element (2) is a viscoelastic damping material covering the surface of the elastic element (1), or a particle damper being added to the elastic element (1); A mounting frame (3), wherein the top end of the mounting frame (3) is connected to the second end of the elastic element (1), and a test piece (4) and a weight (5) are mounted on the mounting frame (3). The frequency of the system movement is adjusted by adjusting the mass of the weight (5), and the center of gravity of the mass is adjusted by adjusting the position of the weight (5) to prevent adverse lateral movement caused by eccentricity; a release mechanism (7), the release mechanism (7) being connected to the bottom end of the mounting frame (3); A timer (6), wherein the timer (6) is connected to the release mechanism (7) and the stop mechanism (8) respectively.

2. The damped sine wave applying device for mechanical environment testing according to claim 1, characterized in that: The elastic element (1) is a metal spring, a rubber rope or a cantilever beam.

3. The damped sine wave applying device for mechanical environment testing according to claim 2, characterized in that: The stiffness of the elastic element (1) is: k=mf 2 Where k is the stiffness of the elastic element, m is the total mass of the elastic element, damping element, mounting frame, test piece, and weight, and f is the natural frequency of the elastic element.

4. The damped sine wave applying device for mechanical environment testing according to claim 3, characterized in that: A force F is applied by the release mechanism (7) so that the mounting frame (3) reaches an initial displacement. Then, the sinusoidal acceleration waveform generated by the mechanical environment test damping sinusoidal wave applying device is: a(t)=Asin(ωt) Where A / ω 2 is the initial displacement, a is the acceleration, A is the acceleration amplitude, ω is the circular frequency, and t is the time.

5. The damped sine wave applying device for mechanical environment testing according to claim 4, characterized in that: The release mechanism (7) includes an electromagnet sucker and a hydraulic cylinder. One end of the electromagnet sucker is connected to the mounting frame (3), and the other end is connected to the hydraulic cylinder. When the power is on, the electromagnet sucker absorbs the mounting frame (3). The hydraulic cylinder applies a pulling force to the electromagnet sucker, driving the mounting frame (3) to reach an initial displacement. After the displacement reaches a target value, the electromagnet sucker is powered off, the adsorption force disappears, and the elastic element (2) begins to vibrate.

6. The damped sine wave applying device for mechanical environment testing according to claim 4, characterized in that: The release mechanism (7) comprises a fixed force rod and a hydraulic cylinder. One end of the fixed force rod is connected to the mounting frame (3), and the other end is connected to the hydraulic cylinder. The hydraulic cylinder applies a pulling force to the fixed force rod, driving the mounting frame (3) to reach an initial displacement. After the displacement reaches a target value, the fixed force rod breaks, and the elastic element (2) begins to vibrate.

7. The damped sine wave applying device for mechanical environment testing according to claim 4, characterized in that: The stopping mechanism (8) comprises a stopping plate and an operating rod. When stopping, the operating rod drives the stopping plate to hold or clamp the elastic element (1).

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