Broadband high-sensitivity under-damped elastic wave pick-up

Abstract

The application provides a wideband high-sensitivity underdamped elastic wave pickup, and relates to the technical field of elastic wave pickup equipment. The wideband high-sensitivity underdamped elastic wave pickup comprises a shell, an elastic piezoelectric sheet and a counterweight. The bottom of the shell is provided with an arc-shaped underdamped sheet arched at the center. The elastic piezoelectric sheet is arranged on the arc-shaped underdamped sheet and fixedly connected with the arc-shaped underdamped sheet. The counterweight is arranged in the shell and placed on the elastic piezoelectric sheet, and the counterweight is used for being pressed on the elastic piezoelectric sheet under the action of gravity. Under the action of the elastic wave, the elastic piezoelectric sheet is used for outputting an electric signal based on different acting forces of the counterweight. The wideband high-sensitivity underdamped elastic wave pickup provided by the application can solve the technical problems of monitoring precision improvement and sensor self-resonance distortion in the prior art.

Description

Technical Field

[0001] This invention relates to the field of elastic wave pickup equipment technology, and more specifically, to a wideband, high-sensitivity, underdamped elastic wave pickup. Background Technology

[0002] In existing technologies, contact-based elastic wave pickup techniques mostly employ a second-order vibration system composed of an inertial body and an elastic element to pick up elastic waves. For a second-order vibration system, resonance is unavoidable. When resonance occurs, the elastic wave signal is nonlinearly amplified, leading to amplitude distortion and masking true defect characteristics. Furthermore, noise near the resonance peak is synchronously amplified, drowning out weak defect signals and reducing detection sensitivity. In FFT analysis, the resonant frequency is out of sync with the sampling frequency, causing spectral leakage and misinterpreting harmonic components as structural defect responses. Ideally, the acquired data should be a Ricker wavelet, exhibiting Gaussian pulse characteristics. This technique more accurately reflects the instantaneous vibration patterns within the elastic body. Summary of the Invention

[0003] The technical problem solved by this invention is how to improve the technical problem in the prior art where resonance affects the improvement of elastic wave pickup accuracy and the sensor's own resonance distortion, which is difficult to avoid. Embodiments of this invention can be implemented as follows:

[0004] This invention provides a wideband, high-sensitivity, underdamped elastic wave pickup, comprising:

[0005] The housing has an arc-shaped underdamped plate that is arched at the center of its bottom.

[0006] An elastic piezoelectric sheet is disposed on the arc-shaped underdamped sheet and fixedly connected to the arc-shaped underdamped sheet;

[0007] A counterweight is disposed inside the housing and placed on the elastic piezoelectric sheet, the counterweight being used to press against the elastic piezoelectric sheet under its own gravity;

[0008] Under the action of elastic waves, the elastic piezoelectric sheet is used to output electrical signals based on the different forces applied by the counterweight.

[0009] Optionally, the counterweight includes a counterweight portion and a connecting portion; the connecting portion is located at the center of one end face of the counterweight portion; the connecting portion contacts the elastic piezoelectric sheet to press it at the center of the elastic piezoelectric sheet.

[0010] Optionally, the connecting portion is magnetic, and the connecting portion is magnetically connected to the elastic piezoelectric sheet.

[0011] Optionally, the wideband high-sensitivity underdamped elastic wave pickup further includes a spring plate, wherein the elastic piezoelectric sheet is fixedly connected to the center position of the spring plate; the spring plate is fixedly connected to the center position of the arc-shaped underdamped sheet.

[0012] Optionally, the broadband high-sensitivity underdamped elastic wave pickup further includes a guide member, which is cylindrical and has a smooth sliding layer attached to its inner wall; the guide member is disposed inside the housing, and the counterweight is disposed inside the guide member and contacts the inner wall of the guide member.

[0013] Optionally, the arc-shaped underdamped sheet is arched into a spherical shape.

[0014] Optionally, the ratio of the height of the arc-shaped underdamped plate to the radius of the arc-shaped underdamped plate is in the range of 0.05 to 0.2.

[0015] Optionally, the housing includes a first outer shell and a base;

[0016] The base includes a seat body and a surrounding portion. The middle part of the seat body is arched to form the arc-shaped underdamped sheet. The surrounding portion is cylindrical and is disposed on the seat body and surrounds the outer periphery of the arc-shaped underdamped sheet. The elastic piezoelectric sheet and the counterweight are both disposed inside the surrounding portion.

[0017] The first outer shell covers the outside of the enclosure, and the enclosure, the elastic piezoelectric sheet, and the counterweight are all located inside the first outer shell.

[0018] Optionally, the inner diameter of at least part of the top of the first housing gradually decreases, and an inclined surface is formed inside the first housing facing the edge of the counterweight end face, with a gap formed between the inclined surface and the counterweight.

[0019] Optionally, the housing further includes a second outer shell, which covers the outside of the first outer shell.

[0020] The advantages of the broadband, high-sensitivity, underdamped elastic wave pickup provided by this invention compared to the prior art include:

[0021] This wideband, high-sensitivity, underdamped elastic wave pickup operates as follows: When an elastic wave reaches the pickup, its excitation causes the entire pickup to oscillate. The counterweight, due to its weight and inertia, exerts a change in the force on the piezoelectric element based on the elastic wave's vibration, thus outputting an electrical signal characterizing the elastic wave and enabling its monitoring. During this process, the piezoelectric element and counterweight are supported by a centrally arched underdamped element. The arched design of this underdamped element allows for precise control of its stiffness. Combined with the weight of the counterweight, this makes its natural frequency more controllable, facilitating the fixation of the frequency within a specified range and effectively avoiding resonance that could affect pickup accuracy. Meanwhile, the equivalent stiffness of this arc-shaped underdamped plate is more stable and controllable, reducing the impact of temperature, wear, and vibration. The system's natural frequency does not drift, and the resonance avoidance effect is long-lasting and stable, improving the problem of difficulty in improving pickup accuracy caused by resonance in existing technologies. Based on this, the broadband, high-sensitivity underdamped elastic wave pickup provided by this invention can improve the technical problem in existing technologies where resonance affects the pickup accuracy of elastic waves and is difficult to avoid.

[0022] Furthermore, a magnetic connection is provided at the bottom of the counterweight. The counterweight rests on the elastic piezoelectric sheet based on its own weight, and the magnetic connection ensures that the counterweight and the elastic piezoelectric sheet do not detach. This avoids the lateral vibration interference caused by gaps in traditional mechanical connections (such as adhesives and bolts), and does not generate false resonance signals consistent with the system's natural frequency. It is only sensitive to vertical seismic wave vibrations, and the "effective triggering" of resonance comes only from real seismic waves without additional interference. In addition, it can also improve the problem of inaccurate monitoring data caused by the impact of the counterweight on the elastic piezoelectric sheet after it detaches from the elastic piezoelectric sheet, as well as the problem of the elastic piezoelectric sheet being easily damaged.

[0023] In addition, the guide can provide radial restraint to the counterweight, preventing it from shifting or tipping over. Furthermore, the sliding layer reduces the impact of lateral friction on the counterweight, thus ensuring an effective improvement in monitoring accuracy.

[0024] In addition, the inclined surface formed inside the first outer shell can provide a certain degree of restraint on the counterweight, which can prevent the counterweight from vibrating significantly during transportation, thus preventing damage to the elastic piezoelectric sheet. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a cross-sectional schematic diagram of the broadband, high-sensitivity, underdamped elastic wave pickup provided in the embodiments of this application;

[0027] Figure 2 This is an exploded structural diagram of the broadband, high-sensitivity, underdamped elastic wave pickup provided in the embodiments of this application;

[0028] Figure 3 This is a cross-sectional schematic diagram of the base provided in the embodiments of this application;

[0029] Figure 4 This is a schematic diagram of the counterweight block provided in the embodiments of this application.

[0030] Icon: Wideband high-sensitivity underdamped elastic wave pickup 10, housing 100, arc-shaped underdamped sheet 101, first outer shell 110, base 120, seat 121, enclosure 122, second outer shell 130, elastic piezoelectric sheet 200, spring sheet 210, counterweight block 300, counterweight part 310, connecting part 320, guide member 330. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0033] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0034] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0035] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0036] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0037] Please refer to the following: Figures 1 to 4 This application provides a broadband, high-sensitivity, underdamped elastic wave pickup 10, which is used to pick up elastic waves for subsequent analysis. For example, it can pick up seismic waves and then analyze them to determine the seismic source, amplitude, and magnitude. The broadband, high-sensitivity, underdamped elastic wave pickup 10 in this embodiment improves upon the technical problem of difficulty in improving pickup accuracy in existing technologies.

[0038] The following explanation uses seismic waves as an example of elastic waves to be picked up.

[0039] In existing technologies, spring-type detectors are commonly used to pick up seismic waves. The core structure of a spring-type detector consists of an inertial mass, a spring, and a damper, essentially forming a second-order vibration system. Resonance, a phenomenon where the amplitude of the vibration is drastically amplified under excitation close to the natural frequency, severely affects the amplitude, frequency, and phase accuracy of seismic wave pickup. Specifically, when the strata vibrate, the detector casing moves synchronously with the strata, while the inertial mass maintains its original motion due to inertia. The relative displacement between the casing and the mass is reflected by the spring deformation, which is then converted into an electrical signal output by an internal transducer (such as an electromagnetic induction device). The dynamic characteristics of this system are determined by three core parameters: natural frequency, damping coefficient, and damping ratio.

[0040] Wherein, the natural frequency f0 is determined by the spring stiffness k and the mass m of the mass block, and the formula is:

[0041] ;

[0042] Damping coefficient c: determines the rate at which the system's vibration decays. The smaller the damping, the more easily the system resonates. Damping ratio ζ: the ratio of actual damping to critical damping, is a key indicator for measuring the system's anti-resonance capability. ζ < 1 indicates an underdamped state, which is a common operating state for detectors.

[0043] Therefore, when the signal frequency f of the seismic wave approaches the natural frequency f0 of the detector, the system enters the resonance range, at which point the relative displacement amplitude of the mass block will show a peak. The smaller the damping ratio, the sharper the peak, and the more significant the resonance phenomenon.

[0044] When resonance occurs, amplitude distortion can occur, meaning that the amplitude is excessively amplified near the resonant frequency. Specifically, when seismic waves contain frequency components close to the detector's natural frequency, the signal amplitude corresponding to that frequency will be drastically amplified, far exceeding the amplitude of the actual formation vibration; while components far from the natural frequency will be attenuated or maintain a linear response. This results in a severely distorted amplitude spectrum of the seismic wave, failing to accurately reflect the true vibration intensity of the formation. For example, in seismic exploration, amplitude information is used to determine parameters such as formation lithology and porosity; amplitude distortion can lead to deviations in reservoir prediction results.

[0045] Furthermore, resonance also leads to frequency distortion, meaning it narrows the effective bandwidth and causes the loss of high- and low-frequency components. The effective operating bandwidth of a spring-loaded detector refers to the frequency range within which the output signal maintains a linear relationship with the input vibration; resonance compresses this bandwidth. Specifically, in the low-frequency range, when the signal frequency is much lower than f0, the system response is basically linear, but as it approaches f0, it enters the resonance region, and the response becomes nonlinear. In the high-frequency range, when the signal frequency is much higher than f0, the mass block, due to inertia, cannot follow the shell's movement, and the relative displacement approaches zero, resulting in significant attenuation of the high-frequency signal. Resonance causes the effective bandwidth to shrink towards the natural frequency, preventing the complete acquisition of broadband information from seismic waves. The frequency characteristics of seismic waves are the core basis for layer velocity calculation and reflector layer calibration; frequency distortion leads to errors in stratigraphic layering and deviations in structural interpretation.

[0046] Furthermore, resonance also leads to phase distortion, that is, signal phase shift and waveform distortion. Within the resonance range, the phase difference between the input and output signals changes drastically (in underdamped systems, the phase difference can rapidly transition from 0° to 180°); while in the linear response range, the phase difference is linearly related to the frequency. Phase distortion causes seismic wave waveform distortion, such as shifts in the starting point and peak position of reflected waves, affecting the superposition effect of seismic profiles and the continuity of the phase axis.

[0047] Furthermore, resonance amplifies environmental interference signals. When a detector is operating, it is subject to environmental vibrations (such as wind rustling through grass or instrument noise). If the frequency of these interference signals is close to the detector's natural frequency, resonance will amplify their amplitude, drowning out the weak, effective seismic wave signal. This results in a reduced signal-to-noise ratio (SNR), making it difficult to effectively separate the effective signal from noise in subsequent data processing.

[0048] It should be noted that the fundamental reason why resonance affects seismic wave pickup lies in the inherent characteristics of the second-order system, the limitations of damping design, and the mismatch between the broadband characteristics of seismic waves and the detector's frequency band.

[0049] Specifically, regarding the inherent characteristics of a second-order system, the dynamic equation of the spring-type detector is:

[0050] ;

[0051] Where x is the relative displacement and F(t) is the formation excitation force. Its amplitude response function is:

[0052] ;

[0053] When f = f0, the denominator of the amplitude-frequency response is 2ζ. The smaller ζ is, the better. The larger the value, the more significant the amplitude amplification. Only when f is much smaller than f0 or much larger than f0 does the amplitude increase. The system only exhibits a linear response when it approaches a constant value.

[0054] Furthermore, regarding the limitations of damping design, in order to balance the detector's sensitivity and anti-resonance capability, the damping ratio ζ is usually designed between 0.5 and 0.7 (the optimal damping ratio is approximately 0.6), but resonance cannot be completely eliminated. If the damping is too large, the system sensitivity will decrease, making it unable to pick up weak seismic waves; if the damping is too small, the resonance phenomenon will intensify, and the accuracy will be severely reduced.

[0055] Furthermore, regarding the mismatch between the broadband characteristics of seismic waves and the frequency band of the detector, natural or artificially generated seismic waves are broadband signals containing frequency components ranging from a few hertz to several hundred hertz. However, the natural frequency of a spring-type detector is usually fixed (such as commonly used 10Hz or 28Hz detectors), which inevitably overlaps with some frequency components in the seismic waves, causing resonance.

[0056] Based on this, conventional solutions include: 1. Optimizing damping design by using electromagnetic or oil damping to precisely control the damping ratio to around 0.6, reducing the sharpness of resonance peaks and widening the effective frequency band; 2. Selecting a detector with a suitable natural frequency, choosing the detector based on the depth of the exploration target, using high-frequency detectors (e.g., 40Hz) for gradual exploration and low-frequency detectors (e.g., 5Hz) for deep exploration, avoiding overlap between the natural frequency and the target seismic wave frequency; 3. Signal processing compensation, correcting the amplitude and phase frequency responses of the detector through data processing methods such as deconvolution to restore the true characteristics of the seismic wave. However, these methods can only minimize the impact of resonance. In other words, even with the above methods, existing spring-type detectors are still affected by resonance, leading to reduced pickup accuracy.

[0057] Based on this, a wideband, high-sensitivity, underdamped elastic wave pickup 10 is provided in this embodiment to improve the effect of resonance during wave pickup.

[0058] In this embodiment, the broadband high-sensitivity underdamped elastic wave pickup 10 includes a housing 100, an elastic piezoelectric sheet 200, and a counterweight 300. The bottom of the housing 100 has an arc-shaped underdamped sheet 101 with a central arch. The elastic piezoelectric sheet 200 is disposed on and fixedly connected to the arc-shaped underdamped sheet 101. The counterweight 300 is disposed inside the housing 100 and placed on the elastic piezoelectric sheet 200, and is used to press against the elastic piezoelectric sheet 200 under its own weight. Under the action of seismic waves, the elastic piezoelectric sheet 200 outputs electrical signals based on different forces applied by the counterweight 300.

[0059] As described above, when the broadband high-sensitivity underdamped elastic wave pickup 10 is applied to seismic wave monitoring, it is buried in a designated location within a specified area. When a seismic wave reaches the broadband high-sensitivity underdamped elastic wave pickup 10, the oscillation of the seismic wave causes the pickup 10 to oscillate accordingly. Since the counterweight 300 has a certain weight, its own inertia causes a change in the force exerted by the counterweight 300 on the elastic piezoelectric element 200 based on the seismic wave vibration, thereby outputting an electrical signal that characterizes the seismic wave, thus completing the seismic wave monitoring. In this process, the elastic piezoelectric sheet 200 and the counterweight 300 are supported by the centrally arched underdamped plate 101. The arched design of the underdamped plate 101 allows for precise control of its stiffness. Combined with the weight of the counterweight, this makes its natural frequency more controllable, facilitating the fixation of the frequency within a specified frequency range. This effectively avoids the impact of resonance on the pickup accuracy. Simultaneously, the equivalent stiffness of the underdamped plate is more stable and controllable, reducing the influence of temperature, wear, and vibration. The system's natural frequency does not drift, resulting in a long-term and stable resonance avoidance effect. This improves upon the problem of difficulty in improving monitoring accuracy due to resonance effects in existing technologies. Therefore, the wideband, high-sensitivity underdamped elastic wave pickup 10 provided by this invention can improve the technical problem of resonance affecting elastic wave pickup accuracy in existing technologies, which is difficult to avoid.

[0060] It is worth noting that the counterweight 300 has a certain weight, ensuring that it remains in contact with the elastic piezoelectric element 200 even under the influence of seismic waves. This allows for seismic wave monitoring based on the change in force exerted on the elastic piezoelectric element 200 by the inertia of the counterweight 300. In other words, because the counterweight 300 has a certain weight, it is difficult for it to detach from the elastic piezoelectric element 200, thus avoiding the reduced monitoring effectiveness and damage to the elastic piezoelectric element 200 that would result from the counterweight detaching and impacting it.

[0061] It is worth noting that in this embodiment, the broadband high-sensitivity underdamped elastic wave pickup 10 is described in a vertically placed manner, so that it is mainly used to pick up longitudinal elastic waves. In other words, when using the broadband high-sensitivity underdamped elastic wave pickup 10 to pick up seismic waves, the broadband high-sensitivity underdamped elastic wave pickup 10 is mainly used to pick up seismic longitudinal waves.

[0062] Alternatively, in some embodiments, the counterweight 300 may be a solid metal block.

[0063] In addition, in this embodiment, the elastic piezoelectric sheet 200 is also provided with a wire for outputting an electrical signal. To facilitate the wire's lead-out, a hole or slot for the wire to lead out can be provided on the housing 100. Meanwhile, in this embodiment, to reduce the influence of DC current on the signal, a DC blocking capacitor is connected in series at one end of the output electrical signal wire, and an impedance matching resistor is connected in parallel with the DC blocking capacitor.

[0064] Furthermore, in this embodiment, the counterweight 300 includes a counterweight portion 310 and a connecting portion 320; the connecting portion 320 is located at the center of one end face of the counterweight portion 310; the connecting portion 320 contacts the elastic piezoelectric sheet 200 to press against the center of the elastic piezoelectric sheet 200. The counterweight portion 310 is cylindrical, and the connecting portion 320 is located at the center of one end face of the counterweight portion 310, facilitating the engagement of the connecting portion 320 with the center of the elastic piezoelectric sheet 200, thereby ensuring a balanced force applied to the elastic piezoelectric sheet 200 and improving monitoring accuracy.

[0065] By establishing contact between the connecting portion 320 and the elastic piezoelectric element 200, the contact area between the counterweight 300 and the elastic piezoelectric element 200 can be reduced. This helps to increase the force applied to the elastic piezoelectric element 200, thereby amplifying the output level intensity of the elastic piezoelectric element 200 when seismic waves are generated, and thus improving monitoring sensitivity. It is worth noting that the connecting portion 320 is sheet-like. To facilitate improved monitoring sensitivity, the diameter of the connecting portion 320 is smaller than the diameter of the counterweight 310, and the connecting portion 320 and the elastic piezoelectric element 200 are in surface-to-surface contact. This avoids the situation where the contact area between the connecting portion 320 and the elastic piezoelectric element 200 is too small, which could easily damage the elastic piezoelectric element 200.

[0066] It should be understood that in other embodiments of this application, the connection portion 320 may also be configured in other ways. For example, the connection portion 320 may be configured as a ring structure. On the one hand, this can reduce the contact area between the connection portion 320 and the elastic piezoelectric sheet 200, thereby increasing the force applied by the connection portion 320 to the elastic piezoelectric sheet 200 and improving the monitoring sensitivity. On the other hand, it can also prevent the elastic piezoelectric sheet 200 from being damaged due to excessive force applied by the connection portion 320. As another example, the connection portion 320 may be configured as multiple protrusions arranged along a ring path, with the multiple protrusions together forming a structure similar to a ring.

[0067] Furthermore, the connecting part 320 is magnetic and is magnetically connected to the elastic piezoelectric sheet 200. Magnetic connection between the connecting part 320 and the elastic piezoelectric sheet 200 ensures a continuous connection between the counterweight 300 and the elastic piezoelectric sheet 200. While the counterweight 300 presses against the elastic piezoelectric sheet 200 under its own weight, the magnetic connection enhances the stability of the connection between the counterweight 300 and the elastic piezoelectric sheet 200. This ensures that the counterweight 300 and the elastic piezoelectric sheet 200 do not detach, avoiding lateral vibration interference caused by gaps in traditional mechanical connections (such as adhesives and bolts). It also prevents the generation of false resonance signals consistent with the system's natural frequency, is only sensitive to vertical seismic wave vibrations, and the "effective triggering" of resonance comes only from real seismic waves without additional interference. Additionally, it improves upon the inaccurate monitoring data caused by the impact on the elastic piezoelectric sheet 200 after the counterweight 300 detaches from it, and addresses the vulnerability of the elastic piezoelectric sheet 200.

[0068] In this embodiment, the wideband high-sensitivity underdamped elastic wave pickup 10 also includes a spring sheet 210, and an elastic piezoelectric sheet 200 is fixedly connected to the center position of the spring sheet 210; the spring sheet 210 is fixedly connected to the center position of the arc-shaped underdamped sheet 101.

[0069] In this embodiment, the broadband high-sensitivity underdamped elastic wave pickup 10 further includes a guide member 330. The guide member 330 is cylindrical, and a smooth sliding layer is attached to the inner wall of the guide member 330. Optionally, the sliding layer can be a smooth ceramic layer. The guide member 330 is disposed inside the housing 100, and the counterweight 300 is disposed inside the guide member 330 and contacts the inner wall of the guide member 330. By setting the guide member 330, a radial restraint effect can be provided to the counterweight 300, preventing the counterweight 300 from shifting laterally or tipping over. Furthermore, due to the sliding layer, the influence of lateral friction on the counterweight 300 can be reduced, ensuring an effective improvement in monitoring accuracy.

[0070] Because of the guide 330, the counterweight 300 can only exert force on the elastic piezoelectric sheet 200 in its axial direction, that is, it can exert force on the elastic piezoelectric sheet 200 in the direction perpendicular to the elastic piezoelectric sheet 200, which can avoid the monitoring distortion caused by the tilt or offset of the counterweight 300.

[0071] It is worth noting that after the guide 330, housing 100 and counterweight 300 are assembled, a sealant is injected between the guide 330 and housing 100 to stabilize the guide 330 and protect the elastic piezoelectric sheet 200.

[0072] In this embodiment, the arc-shaped underdamped plate 101 is arched into a spherical shape. Setting the arc-shaped underdamped plate 101 as a sphere allows the force to be dispersed when the arc-shaped underdamped plate 101 is subjected to force, thereby ensuring the overall stability of the arc-shaped underdamped plate 101 and avoiding reciprocating vibration of the arc-shaped underdamped plate 101, thus avoiding the problem of reduced monitoring accuracy caused by resonance.

[0073] It is worth noting that in some embodiments, a closure can be provided at the bottom of the arc-shaped underdamped plate 101, forming an air cavity between the closure and the arc-shaped underdamped plate 101. The air inside the air cavity provides a buffering effect, further improving the stability of the arc-shaped underdamped plate 101. The formation of the air cavity increases viscous air damping, enhances the total damping of the system, and further reduces the resonant peak value. The air inside the closed air cavity cannot flow freely. When the spherical metal part undergoes vertical elastic deformation under seismic wave excitation, it compresses / stretches the air inside the air cavity, causing viscous flow (friction between air molecules and the cavity wall, and between air molecules) within the cavity, forming additional viscous damping, which is superimposed on the total damping of the system. This damping is velocity-dependent viscous damping; the faster the metal part vibrates, the more intense the air compression / stretching, and the greater the viscous damping, effectively dissipating the mechanical energy of the vibration. In addition, the total damping ratio of the system will increase slightly (if it was already in the optimal range of 0.5 to 0.7, it will be closer to the optimal value; if it is slightly lower, it will move closer to the optimal range), the quality factor Q will decrease further, and the resonant peak value will be "flattened" more gently - even if the system has resonance in the ultra-high frequency band, its amplitude amplification effect will be weaker, with almost no actual interference.

[0074] In addition, the enclosed air cavity forms a physical barrier at the bottom of the arc-shaped underdamped plate 101, isolating it from surface dust, water vapor, and small particles. It also reduces the direct interference of surface micro-vibrations (such as soil particle collisions) to the arc-shaped underdamped plate 101 through solid conduction. External interference is an important cause of triggering false resonance. The isolation effect of the air cavity allows the arc-shaped underdamped plate 101 to respond only to the vertical vibration of seismic waves, reducing meaningless vibration excitation and reducing the probability of resonance being accidentally triggered from the source.

[0075] In some implementations, ventilation holes may be provided on the closure to achieve stability without affecting viscous damping and air pressure, thereby eliminating the influence of additional aerodynamic stiffness in the air cavity on the system's natural frequency.

[0076] Furthermore, in this embodiment, the ratio of the height of the arched underdamped plate 101 to the radius of the horizontal direction of the arched underdamped plate 101 ranges from 0.05 to 0.2. In other words, the value of the above ratio can be 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, or 0.2, etc.

[0077] Preferably, the ratio of the height of the arched underdamped plate 101 to its horizontal radius can be set to a range of 0.15 to 0.2. In other words, the preferred values ​​for this ratio are 0.15, 0.16, 0.17, 0.18, 0.19, or 0.2. It should be noted that high-precision wave pickup requires meeting requirements such as zero resonance interference, high and stable sensitivity, uniform stiffness, reasonable stress distribution, strong anti-interference capability, and good deformation linearity. Setting the ratio within the range of 0.15 to 0.2 can simultaneously satisfy multiple requirements, achieving a range of accuracy across all dimensions.

[0078] Specifically, when the ratio is set to 0.15 to 0.2, the stiffness of the arc-shaped underdamped plate 101 is moderate, the pickup sensitivity is sufficient and stable, and there is no signal attenuation. The transducer signal of the elastic piezoelectric plate 200 is positively correlated with the elastic deformation of the arc-shaped underdamped plate 101. If the deformation is too small, the signal amplitude will be low and the signal-to-noise ratio will be poor. However, the ratio of 0.15 to 0.2 ensures that the vertical elastic deformation of the arc-shaped underdamped plate 101 under the excitation of seismic waves is within the "effective pickup range," which can ensure sufficient amplitude of the transducer signal and avoid nonlinear distortion caused by excessive deformation. Among them, the arch height ratio is weakly positively correlated with the bending stiffness. Compared with the ratio set to 0.05 to 0.15, setting the ratio to 0.15 to 0.2 increases the stiffness by 2.5 to 3 times, but it still falls within the category of "low bending stiffness." With the help of the large-mass counterweight 300, f0 can still be kept below 5Hz, without affecting the avoidance of resonance. Furthermore, moderate stiffness means optimal force-deformation matching. The minute excitation force of seismic waves (micro-stress of ground vibration) can be converted into detectable elastic deformation, and the elastic piezoelectric sheet can stably output charge signals. However, the low ratio end (0.05-0.15) has smaller stiffness and is more susceptible to environmental micro-vibration interference compared to the high ratio end (0.15-0.2), resulting in large fluctuations in signal amplitude.

[0079] Furthermore, compared to the low-ratio end, the high-ratio end exhibits the most uniform three-dimensional stiffness distribution on the spherical surface, with no deviation in wave pickup response across different directions and higher signal consistency. Specifically, the stiffness uniformity of the spherical structure depends on the matching degree between the arch height and the curvature of the spherical surface: when the arch height ratio is <0.15, compared to the high-ratio end, the arch height of the spherical surface at the low-ratio end is too shallow, more like a "planar metal sheet," resulting in localized weak areas in its three-dimensional stiffness distribution (the stiffness at the edge of the spherical surface is slightly lower than that at the top of the arch), leading to slight deviations in wave pickup response across different directions. At the high-ratio end, the curvature of the spherical surface perfectly matches the arch height, and the radial / circumferential bending stiffness is completely uniform. Regardless of the vertical direction from which the seismic wave is excited, the deformation of the metal components is consistent, and the transduction signal of the elastic piezoelectric sheet has no directional deviation, which is crucial for high-precision wave pickup.

[0080] Furthermore, compared to the low-ratio end, the high-ratio end exhibits a more uniform stress distribution with no significant stress concentration, exhibits no stiffness drift during long-term vibration, and maintains high signal fidelity. Specifically, compared to the low-ratio end, the bending deformation of the spherical surface in the high-ratio end is more evenly distributed across the entire arch surface, with the arch crown as the stress center. The stress gradient in the transition zone is gentle, and the stress concentration factor is reduced to below 1.2, approaching a uniform stress state. This results in a 5 to 8-fold improvement in the fatigue resistance of the metal components, no stiffness drift during long-term vibration, and high signal fidelity.

[0081] Furthermore, compared to the low-ratio end, the high-ratio end has higher lateral stiffness, effectively suppressing environmental micro-vibrations / transverse wave interference and maximizing the signal-to-noise ratio. Specifically, the lateral stiffness (radial / circumferential) of the spherical structure is positively correlated with the arch height ratio. The high-ratio end has 3 to 4 times higher lateral stiffness than the low-ratio end, which can more effectively resist horizontal shear forces, allowing the counterweight 300 to vibrate only in the vertical direction without lateral displacement. With sufficiently high lateral stiffness, environmental micro-vibrations and transverse wave interference can be completely filtered out, and the elastic piezoelectric sheet 200 only picks up the effective signal of the seismic P-wave, with a signal-to-noise ratio far exceeding the requirements for high-precision wave pickup.

[0082] Meanwhile, compared to the low-ratio end, the high-ratio end exhibits superior linearity in elastic deformation, with no nonlinear distortion and higher signal fidelity. While linear elastic deformation of metallic materials has a definite upper limit, the high-ratio end allows the deformation of the arc-shaped underdamped plate 101 under maximum seismic wave excitation to be only 30% to 50% of the linear elastic upper limit, falling within the "small deformation linear elastic range," where deformation is strictly linearly related to force. Under the same excitation, the deformation of the low-ratio end is closer to the linear elastic upper limit than the high-ratio end. Therefore, compared to the low-ratio end, the high-ratio end is less prone to nonlinear softening and exhibits higher signal fidelity.

[0083] Furthermore, the arc-shaped underdamped plate 101 at the high-proportion end ensures that the system's natural frequency remains stable in the extremely low-frequency range of 2Hz to 4Hz, completely outside the effective frequency band of seismic waves. The system always operates in the quasi-static linear response region, with no distortion in amplitude or phase, thus eliminating resonance interference. Specifically, at the high-proportion end, although the bending stiffness of the arc-shaped underdamped plate 101 is higher than that at the low-proportion end, it is still considered "low stiffness." Combined with the heavy counterweight 300, f0 remains far below the lower limit of the effective frequency band of seismic waves, and the stiffness is stable, with a deviation of less than 2% for f0 and no frequency drift, fundamentally avoiding the impact of resonance on accuracy.

[0084] The high-proportion arc-shaped underdamped plate 101, serving as the upper limit of the spherical shallow arch, is essentially the "effective range of bending stiffness." It neither exceeds the boundary of the shallow arch, thus avoiding activation of tensile stiffness and an increase in natural frequency, nor does it fully utilize the bending stiffness characteristics of the shallow arch, achieving a golden balance between sufficient stiffness to support accuracy and sufficient stiffness to avoid resonance. Specifically, in terms of stiffness, the bending stiffness lies at the intersection of "low stiffness (avoiding resonance) + moderate stiffness (supporting accuracy)," a stiffness range that simultaneously satisfies resonance avoidance and high-precision wave pickup. Simultaneously, in terms of structure, the curvature of the sphere, arch height, stress distribution, and deformation linearity reach their optimal values ​​across all dimensions within this range, with no performance shortcomings, representing the optimal mechanical solution for the spherical shallow arch structure. Furthermore, it is highly compatible with the structural design of the magnetically attracted large counterweight; the moderate stiffness allows for sufficient relative displacement of the counterweight block 300, and the magnetic clamping force provides stable contact damping without signal fluctuations.

[0085] In this embodiment, the housing 100 includes a first outer shell 110 and a base 120. The base 120 includes a seat body 121 and a retaining portion 122. The middle of the seat body 121 is arched to form an arc-shaped underdamped plate 101. A guide member 330 is located between the counterweight 300 and the retaining portion 122, and the retaining portion 122 can provide a limiting effect to the guide member 330. The retaining portion 122 is cylindrical and is disposed on the seat body 121 and surrounds the outer periphery of the arc-shaped underdamped plate 101. The elastic piezoelectric sheet 200 and the counterweight 300 are both disposed inside the retaining portion 122. It is worth noting that in some embodiments, the retaining portion 122 and the base 120 can be integrally molded. In other embodiments, the retaining portion 122 and the base 120 can be connected by fitting or snap-fitting. The first outer shell 110 covers the outside of the enclosure portion 122, and the enclosure portion 122, the elastic piezoelectric sheet 200 and the counterweight 300 are all located inside the first outer shell 110.

[0086] Furthermore, the inner diameter of at least a portion of the top of the first outer shell 110 gradually decreases, and an inclined surface is formed inside the first outer shell 110 facing the edge of the end face of the counterweight 300, with a gap between the inclined surface and the counterweight 300. The inclined surface formed inside the first outer shell 110 can provide a certain degree of restraint on the counterweight 300, preventing damage to the elastic piezoelectric sheet 200 caused by large-scale vibration of the counterweight 300 during transportation.

[0087] It is worth noting that the first outer shell 110 is made of materials such as plastic. On the one hand, this reduces the rigidity of the first outer shell 110, thereby preventing the counterweight 300 from being squeezed and deformed. On the other hand, it also reduces the overall mass of the broadband high-sensitivity underdamped elastic wave pickup 10. In addition, the gap formed between the inclined plane and the counterweight 300 is small. This is to prevent the counterweight 300 from undergoing large displacement during transportation, which could impact the elastic piezoelectric sheet 200. It also prevents the broadband high-sensitivity underdamped elastic wave pickup 10 from having the first outer shell 110 restrict the counterweight 300, thus avoiding a decrease in detection accuracy during use.

[0088] In addition, housing 100 also includes a second outer shell 130, which covers the outside of housing 110. The second outer shell 130 can provide protection for the entire broadband high-sensitivity underdamped elastic wave pickup 10.

[0089] In the broadband high-sensitivity underdamped elastic wave pickup 10 provided in this embodiment, the magnetic connection between the arc-shaped underdamped plate 101 with a central arched spherical shape, the counterweight 300 with a certain weight, and the elastic piezoelectric plate 200 can significantly improve the influence of resonance on the pickup accuracy, thereby achieving the purpose of improving the pickup accuracy.

[0090] Specifically, in the first aspect, in this broadband, high-sensitivity, underdamped elastic wave pickup 10, a large-weight counterweight reduces the total system mass M. totalThe system's natural frequency f0 is significantly improved. Combined with the three-dimensional structural stiffness of the spherical arched metal component (far exceeding that of the planar arc-shaped metal sheet), the system's natural frequency f0 is pulled to an extremely low value (typically below 5Hz, or even close to 0), completely deviating from the effective exploration frequency range of seismic waves (5~30Hz for deep layers, 30~100Hz for mid-layers, and 100~500Hz for shallow layers). When the effective frequency f of the seismic wave is much greater than f0, the system operates in the quasi-static linear response region, with an amplitude-frequency response close to a constant, and almost no distortion in amplitude and phase. The amplification / attenuation effect of resonance does not affect the core exploration signal at all. Secondly, the total damping of the structure formed by the arc-shaped underdamped sheet 101, the counterweight 300, and the elastic piezoelectric sheet 200 is significantly higher than that of traditional structures. The damping ratio easily reaches the optimal range of 0.5 to 0.7, and the quality factor Q is significantly reduced. Even if the system's natural frequency overlaps with a certain high frequency, the resonance peak will be significantly "flattened," without sharp amplitude amplification, only slight signal attenuation, and the impact on pickup accuracy is negligible. Thirdly, the counterweight 300 and the elastic piezoelectric sheet 200 are magnetically connected, fitting tightly without mechanical gaps. This avoids the lateral vibration interference caused by gaps in traditional mechanical connections (such as adhesives and bolts), and does not generate false resonance signals consistent with the system's inherent frequency. It is only sensitive to seismic wave vibrations in the vertical direction, and the "effective triggering" of resonance comes only from real seismic waves without additional interference. At the same time, the radial and circumferential stiffness of the spherically arched underdamped sheet 101 is uniform and much higher than that of a planar arc-shaped metal sheet. It can effectively suppress horizontal and oblique vibrations, providing elastic restoring force only in the vertical direction. This makes the vibration mode of the system highly singular, avoiding "composite resonance caused by the superposition of multi-directional vibrations." The influence range of resonance is strictly limited to the main pickup direction. Based on this, the influence of harmonics on the pickup accuracy can be improved, thereby significantly improving the pickup accuracy of this wideband high-sensitivity underdamped elastic wave pickup 10.

[0091] It is worth noting that the arched, spherical underdamped plate 101 in the center is the only elastic element in this seismic pickup system. Its equivalent stiffness is one of the core parameters determining the system's natural frequency, and the spherical structure makes the stiffness more stable and controllable. Specifically, the stiffness of the arched, spherical underdamped plate 101 is determined by the radius of curvature of the spherical surface, the metal thickness, and the elastic modulus of the material. It belongs to three-dimensional structural stiffness, which is more uniform and stable than the bending / tensile stiffness of a planar arc-shaped metal plate. It is minimally affected by temperature, wear, and vibration, and the system's natural frequency will not drift, resulting in a long-term and stable resonance avoidance effect. In addition, the spherical stiffness is highly adjustable. By adjusting the radius of curvature (arch height) and the metal thickness, the stiffness can be precisely controlled. In conjunction with the mass of the counterweight, the natural frequency can be stably pulled to an extremely low frequency range below 5Hz, completely escaping the effective frequency band of seismic waves.

[0092] Of course, when dealing with elastic waves other than seismic waves, the curvature radius (arch height), metal thickness, and selected materials of the arc-shaped underdamped plate 101 can be adjusted according to the effective frequency range of the actual picked-up elastic waves. This will adjust the natural frequency of the system, allowing the system's natural frequency to deviate from the effective frequency range of the actual picked-up elastic waves. This will significantly improve the impact of resonance on the picking accuracy and enhance the picking precision.

[0093] Furthermore, the counterweight 300, with its considerable weight, constitutes the dominant inertial mass of the system. Its mass is significantly greater than the equivalent mass of the arc-shaped underdamped plate 101, meaning the total mass of the system is approximately equal to the mass of the counterweight 300. Therefore, the mass of the counterweight 300 directly affects the natural frequency of the system. The formula for the system's natural frequency is as follows:

[0094] ;

[0095] At the stiffness k of the arc-shaped underdamped plate 101 eq Under fixed conditions, the larger the mass of the counterweight 300, the easier it is to escape the effective frequency band of seismic waves at the end of the month.

[0096] Furthermore, the large mass also increases the system's inertia, making it better resistant to interference from environmental micro-vibrations. Even when encountering small frequency fluctuations, it will not easily trigger resonance, resulting in a wider linear response range for the system.

[0097] Furthermore, since the total damping of this structure is a superposition of internal material damping, air damping, magnetic contact damping, and piezoelectric damping, and the magnetic connection makes the damping more controllable and stable, the total damping ratio ζ is much higher than that of traditional structures. Specifically, the tight fit of the magnetic connection makes the contact friction damping between the counterweight 300 and the elastic piezoelectric sheet 200, and between the elastic piezoelectric sheet 200 and the arc-shaped underdamped sheet 101 more stable. The "dry friction-wet friction" switching without mechanical gaps avoids abrupt changes in damping, keeping the system damping stable within the optimal range. Moreover, the internal material damping of the arc-shaped underdamped sheet 101 (more thorough three-dimensional deformation of the grain friction), the mechanical resistance damping of the elastic piezoelectric sheet 200 (which can be precisely controlled by adjusting the load resistance), and the air damping (the spherical structure of the arc-shaped underdamped sheet 101 has a uniform windward area distribution, resulting in more stable damping) significantly increase the total damping, effectively reducing the resonant peak value, and preventing strong distortion even when encountering resonance at high frequencies.

[0098] Meanwhile, the core value of magnetic connection is to ensure the connection stability of the counterweight 300 with a certain weight (preventing the counterweight 300 from detaching due to seismic wave vibration), and to eliminate false resonance caused by contact gaps, but without changing the physical nature of resonance. Specifically, the magnetic force only provides normal clamping force and does not change the system's stiffness or mass, therefore it does not affect the system's natural frequency. Secondly, the magnitude of the magnetic force only affects the magnitude of contact damping, not the form of damping, therefore it can only adjust the sharpness of the resonance peak, not eliminate resonance.

[0099] In summary, this structure significantly reduces the resonance impact on seismic wave pickup, with virtually no resonance distortion in the core exploration frequency band (above 5Hz), and only resonance with no practical impact in the ultra-high frequency band. The stability of the wave pickup accuracy is far superior to that of traditional spring-type wave pickups.

[0100] It is worth noting that the core advantage of this wideband, high-sensitivity, underdamped elastic wave pickup 10 lies in transferring the influence of resonance to the ultra-low frequency / ultra-high frequency bands where seismic waves have no effective signal. Simultaneously, through stable stiffness, large mass, and high damping, the resonance avoidance and retention effects are long-term and stable, without resonance drift or false resonance signals. In other words, when facing different effective frequency bands of the elastic waves to be picked up, this wideband, high-sensitivity, underdamped elastic wave pickup 10 can adjust parameters such as the weight of the counterweight 300 and the arch height of the arc-shaped underdamped plate 101 to transfer the influence of resonance to the range of ineffective signals outside the effective frequency band of the elastic wave to be picked up. This improves the impact of resonance on the elastic wave pickup accuracy, effectively enhancing the elastic wave pickup accuracy.

[0101] In summary, during the elastic wave pickup process of the wideband high-sensitivity underdamped elastic wave pickup 10, when the elastic wave reaches the wideband high-sensitivity underdamped elastic wave pickup 10, the elastic wave excitation causes the wideband high-sensitivity underdamped elastic wave pickup 10 to oscillate accordingly. Since the counterweight 300 has a certain weight, under its own inertia, the force applied by the counterweight 300 to the elastic piezoelectric sheet 200 based on the vibration of the elastic wave changes, thereby outputting an electrical signal that can characterize the elastic wave, so as to complete the monitoring of the elastic wave. In this process, the elastic piezoelectric sheet 200 and the counterweight 300 are supported by the centrally arched underdamped plate 101. The arched design of the underdamped plate 101 allows for precise control of its stiffness. Combined with the weight of the counterweight 300, this makes its natural frequency more controllable, facilitating the fixation of the frequency within a specified frequency range. This effectively avoids the impact of resonance on the pickup accuracy. Simultaneously, the equivalent stiffness of the underdamped plate 101 is more stable and controllable, reducing the influence of temperature, wear, and vibration. The system's natural frequency does not drift, resulting in a long-term and stable resonance avoidance effect. This improves upon the problem of difficulty in improving pickup accuracy caused by resonance effects in existing technologies. Therefore, the wideband, high-sensitivity underdamped elastic wave pickup 10 provided by this invention can improve the technical problem of resonance affecting elastic wave pickup accuracy in existing technologies, which is difficult to avoid. Furthermore, a magnetic connecting part 320 is provided at the bottom of the counterweight 300. The connecting part 320 is magnetically connected to the elastic piezoelectric sheet 200. The counterweight 300 rests on the elastic piezoelectric sheet 200 based on its own weight. The magnetic connection ensures that the counterweight 300 and the elastic piezoelectric sheet 200 do not detach. This avoids the lateral vibration interference caused by gaps in traditional mechanical connections (such as adhesives and bolts). It will not generate false resonance signals consistent with the system's natural frequency. It is only sensitive to vertical seismic wave vibrations. The "effective triggering" of resonance comes only from real seismic waves without additional interference. In addition, it can also improve the problem of inaccurate monitoring data caused by the impact of the counterweight 300 on the elastic piezoelectric sheet 200 after it detaches from the elastic piezoelectric sheet 200, as well as the problem of the elastic piezoelectric sheet 200 being easily damaged. Furthermore, the guide member 330 provides radial restraint to the counterweight 300, preventing lateral displacement or tipping. The sliding layer also reduces the impact of lateral friction on the counterweight 300, ensuring improved monitoring accuracy. Additionally, the inclined surface formed inside the first housing 110 provides further restraint to the counterweight 300, preventing damage to the elastic piezoelectric sheet 200 due to significant vibrations during transport.

[0102] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A broadband, high-sensitivity, underdamped elastic wave pickup (10), characterized in that, include: The housing (100) has an arc-shaped underdamped plate (101) arched at the center at its bottom. An elastic piezoelectric sheet (200) is disposed on the arc-shaped underdamped sheet (101) and fixedly connected to the arc-shaped underdamped sheet (101); A counterweight (300) is disposed inside the housing (100) and placed on the elastic piezoelectric sheet (200). The counterweight (300) is used to press against the elastic piezoelectric sheet (200) under its own gravity. Under the action of elastic waves, the elastic piezoelectric sheet (200) is used to output electrical signals based on the different forces applied by the counterweight (300).

2. The broadband, high-sensitivity, underdamped elastic wave pickup (10) according to claim 1, characterized in that, The counterweight (300) includes a counterweight part (310) and a connecting part (320); the connecting part (320) is located at the center of one end face of the counterweight part (310); the connecting part (320) contacts the elastic piezoelectric sheet (200) to press it at the center of the elastic piezoelectric sheet (200).

3. The broadband, high-sensitivity, underdamped elastic wave pickup (10) according to claim 2, characterized in that, The connecting part (320) is magnetic and is magnetically connected to the elastic piezoelectric sheet (200).

4. The broadband, high-sensitivity, underdamped elastic wave pickup (10) according to claim 1, characterized in that, The wideband high-sensitivity underdamped elastic wave pickup (10) also includes a spring sheet (210), and the elastic piezoelectric sheet (200) is fixedly connected to the center of the spring sheet (210); the spring sheet (210) is fixedly connected to the center of the arc-shaped underdamped sheet (101).

5. The broadband, high-sensitivity, underdamped elastic wave pickup (10) according to claim 1, characterized in that, The broadband high-sensitivity underdamped elastic wave pickup (10) further includes a guide (330), which is cylindrical and has a smooth sliding layer attached to its inner wall; the guide (330) is located inside the housing (100), and the counterweight (300) is located inside the guide (330) and contacts the inner wall of the guide (330).

6. The broadband, high-sensitivity, underdamped elastic wave pickup (10) according to claim 1, characterized in that, The arc-shaped underdamped sheet (101) is arched into a spherical shape.

7. The broadband, high-sensitivity, underdamped elastic wave pickup (10) according to claim 6, characterized in that, The ratio of the height of the arched underdamped plate (101) to the radius of the arched underdamped plate (101) is in the range of 0.05 to 0.

2.

8. The broadband, high-sensitivity, underdamped elastic wave pickup (10) according to any one of claims 1-7, characterized in that, The housing (100) includes a first outer shell (110) and a base (120); The base (120) includes a seat body (121) and a retaining part (122). The middle part of the seat body (121) is arched to form the arc-shaped underdamped plate (101). The retaining part (122) is cylindrical and is disposed on the seat body (121) and surrounds the outer periphery of the arc-shaped underdamped plate (101). The elastic piezoelectric plate (200) and the counterweight (300) are both disposed inside the retaining part (122). The first outer shell (110) covers the outside of the enclosure (122), and the enclosure (122), the elastic piezoelectric sheet (200) and the counterweight (300) are all located inside the first outer shell (110).

9. The broadband, high-sensitivity, underdamped elastic wave pickup (10) according to claim 8, characterized in that, The inner diameter of at least part of the top of the first outer shell (110) gradually decreases, and an inclined surface is formed inside the first outer shell (110) facing the edge of the end face of the counterweight (300), and a gap is formed between the inclined surface and the counterweight (300).

10. The broadband, high-sensitivity, underdamped elastic wave pickup (10) according to claim 8, characterized in that, The housing (100) also includes a second outer shell (130) which covers the outside of the first outer shell (110).

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