Noise reduction device with square array of shape memory alloy three-spring resonant cells
Patent Information
- Application Number
- CN202610996481.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-06
- Publication Date
- 2026-08-28
AI Technical Summary
然而，利用压电或电磁变化来实现带隙调谐存在着性能不稳定、鲁棒性差等问题，因此在实际应用中受到一定限制
[0012]The noise reduction device with a square array of shape memory alloy three-spring resonant units provided by this invention has the following beneficial effects: it can utilize the temperature-induced phase change of the shape memory alloy spring to cause changes in the spring's elastic modulus and height, thereby enabling real-time and flexible tuning of the position and bandwidth of the bandgap of the vibration elastic wave of the noise reduction device with the square array of shape memory alloy three-spring resonant units. Therefore, compared with traditional planar wall panel acoustic noise reduction devices, it has vibration suppression and bandgap tuning capabilities over a wide frequency range. As the temperature of the shape memory alloy spring increases from 37℃ to 43.9℃, the spring transforms from martensitic to austenitic, and the elastic modulus of the spring increases from 65GPa to 76GPa. The height of the shape memory alloy three-spring resonant unit increases from 25mm to 32mm. The bandgap shifts to higher frequencies, with the bandgap range gradually changing from 89.08~125.23 Hz to 92.59~127.98Hz and 95.85~130.39 Hz. The center frequency of the bandgap increases from 107.16 Hz to 113.12 Hz. At the same time, the bandgap width slightly decreases from 36.15 Hz to 34.54 Hz, indicating that during the upward shift of the bandgap, its width remains basically stable, with only a slight contraction. Since the elastic modulus and transition temperature of shape memory alloys can be customized by changing the alloy composition and heat treatment, it is possible to select alloys with greater elastic modulus differences or to achieve bandgap tuning over a wider frequency range by utilizing ambient temperature. Therefore, this can provide a reference for further research on the tunable vibration reduction and noise reduction mechanism of aircraft panel structures and the development of engineering applications.
Smart Images
Figure CN122650150A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of planar wall panel vibration control technology, and specifically relates to a noise reduction device with a square array of shape memory alloy three-spring resonant units, which can be used for low-frequency vibration suppression, sound radiation reduction and elastic wave bandgap tuning of planar wall panel structures. Background Technology
[0002] With the increasing demands for passenger comfort in modern aircraft and the growing number of advanced onboard instruments and equipment, the vibration and noise environment of aircraft cabins faces more stringent standards. As a crucial component of the cabin structure, the periodic vibration of aircraft panels can seriously threaten the safety and reliability of local aircraft structures and onboard instruments. When the frequency of the elastic waves vibrating within the panel structure approaches its natural frequency, the panel will resonate, leading to structural fatigue damage and failure, instability and decreased sensitivity of precision instruments, and potentially even serious air crashes. Furthermore, the structural radiated noise generated by panel vibration significantly reduces passenger comfort; prolonged exposure to strong vibration and high noise environments can easily cause fatigue, irritability, rapid heartbeat, and elevated blood pressure, posing a significant threat to physical and mental health. Therefore, effectively suppressing the vibration of aircraft panel structures and improving the cabin acoustic environment has become one of the key technical problems urgently needing to be solved in the aviation field.
[0003] The frequency range in which elastic wave propagation is prohibited or suppressed is called the bandgap. Unlike Bragg scattering in phononic crystals, the elastic wave bandgap based on the local resonance mechanism is independent of the periodicity of the resonant unit array, but is closely related to the structural design and resonant frequency of the resonant unit. When the frequency of the elastic wave approaches the resonant frequency of the resonant unit, the elastic wave is significantly attenuated. Therefore, the position and width of the elastic wave bandgap and its ability to suppress wave propagation can be controlled by adjusting the geometry and material parameters of the resonant unit. However, traditional planar panel local resonance materials are composed of resonant units with fixed stiffness, and their structure lacks reconfigurability or self-adaptive characteristics, resulting in a typically narrow and untunable bandgap. To develop planar panel local resonance devices with tunable bandgap characteristics, many engineering applications have incorporated smart materials such as piezoelectric materials, dielectric / electrothermal elastomers, and electromagnetic structures into their active control designs, attracting widespread attention. However, using piezoelectric or electromagnetic changes to achieve bandgap tuning suffers from problems such as performance instability and poor robustness, thus limiting its practical application.
[0004] Shape memory alloys, as smart materials, possess advantages such as high strength, good stability, strong driving force, and long service life. Their unique shape memory effect can also be applied to the active control design of aircraft panel vibrations. These designs can generally be divided into two categories: one is based on bandgap tuning through changes in the elastic modulus during phase transformation. Generally, shape memory alloys exhibit martensite with a lower elastic modulus at low temperatures and austenite with a higher elastic modulus at high temperatures. The change in elastic modulus caused by temperature-induced phase transformation is used to alter the position and bandwidth of the bandgap. The other category is based on reversible deformation caused by the shape memory effect, which can significantly change the resonant frequency of the resonant unit, thereby altering the bandgap position and bandwidth. Therefore, using resonators based on shape memory alloys and rationally designing their structural shape can provide a solution for effectively suppressing the vibrations of aircraft panel structures with low-frequency broadband characteristics. Summary of the Invention
[0005] To address the aforementioned problems, the present invention aims to provide a noise reduction device with a square array of shape memory alloy three-spring resonant units.
[0006] To achieve the above objectives, the noise reduction device with a square array of shape memory alloy three-spring resonant units provided by the present invention is composed of multiple shape memory alloy three-spring resonant units periodically fixed on a flat wall panel in a square array. Each shape memory alloy three-spring resonant unit includes a copper column and three shape memory alloy springs. The three shape memory alloy springs are evenly arranged at 120° along the circumference, with their lower ends fixed to one side of the flat wall panel and their upper ends connected to the bottom of the copper column, forming a spatially symmetrical support system.
[0007] The distance between the square arrays is 80mm, the height varies from 25 to 32mm, and the oscillator arrangement of the square array is 6×6.
[0008] The distance between adjacent shape memory alloy three-spring resonant units in each square array is 80mm.
[0009] The planar wall panel is made of aluminum alloy, with a side length of 650mm and a thickness of 2.5mm. It consists of a skin and frame ribs and stringers attached to the inside of the skin. The frame ribs have a C-shaped cross section, and the stringers have a Z-shaped cross section. The distance between the frame ribs is 480mm, and the distance between the stringers is 160mm.
[0010] The copper pillar has a height of 5mm and a radius of 7.5mm.
[0011] The shape memory alloy spring has a wire diameter of 1.15 mm, a mean diameter of 12.6 mm, an effective number of coils of 6.5, and a pitch variation range of 1–3 mm.
[0012] The noise reduction device with a square array of shape memory alloy three-spring resonant units provided by this invention has the following beneficial effects: it can utilize the temperature-induced phase change of the shape memory alloy spring to cause changes in the spring's elastic modulus and height, thereby enabling real-time and flexible tuning of the position and bandwidth of the bandgap of the vibration elastic wave of the noise reduction device with the square array of shape memory alloy three-spring resonant units. Therefore, compared with traditional planar wall panel acoustic noise reduction devices, it has vibration suppression and bandgap tuning capabilities over a wide frequency range. As the temperature of the shape memory alloy spring increases from 37℃ to 43.9℃, the spring transforms from martensitic to austenitic, and the elastic modulus of the spring increases from 65GPa to 76GPa. The height of the shape memory alloy three-spring resonant unit increases from 25mm to 32mm. The bandgap shifts to higher frequencies, with the bandgap range gradually changing from 89.08~125.23 Hz to 92.59~127.98Hz and 95.85~130.39 Hz. The center frequency of the bandgap increases from 107.16 Hz to 113.12 Hz. At the same time, the bandgap width slightly decreases from 36.15 Hz to 34.54 Hz, indicating that during the upward shift of the bandgap, its width remains basically stable, with only a slight contraction. Since the elastic modulus and transition temperature of shape memory alloys can be customized by changing the alloy composition and heat treatment, it is possible to select alloys with greater elastic modulus differences or to achieve bandgap tuning over a wider frequency range by utilizing ambient temperature. Therefore, this can provide a reference for further research on the tunable vibration reduction and noise reduction mechanism of aircraft panel structures and the development of engineering applications. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of the shape memory alloy three-spring resonant unit structure in this invention.
[0014] Figure 2 A schematic diagram of the noise reduction device structure of the square array of shape memory alloy three-spring resonant units provided by the present invention.
[0015] Figure 3 The diagram shows the vibration transmission response in the 0-500Hz frequency band of the planar wall panel with a square array of shape memory alloy three-spring resonant units provided by the present invention and the original wall panel, as measured by vibration reduction experiments. (a) is the band structure diagram, (b) is a comparison of vibration transmission characteristics, and (c) is a comparison of sound insulation characteristics. Detailed Implementation
[0016] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.
[0017] like Figure 1 , Figure 2As shown, the noise reduction device with a square array of shape memory alloy three-spring resonant units is composed of multiple shape memory alloy three-spring resonant units 1 periodically fixed on a planar wall panel 6 in a square array. Each shape memory alloy three-spring resonant unit 1 includes a copper column 4 and three shape memory alloy springs 5. The three shape memory alloy springs 5 are evenly arranged at 120° along the circumference, with their lower ends fixed to one side of the planar wall panel 6 and their upper ends connected to the bottom of the copper column 4, forming a spatially symmetrical support system.
[0018] The distance between the square arrays is 80mm, the height varies from 25 to 32mm, and the oscillator arrangement of the square array is 6×6.
[0019] The distance between adjacent shape memory alloy three-spring resonant units 1 in each square array is 80mm.
[0020] The planar wall panel 6 is made of aluminum alloy, with a side length of 650mm and a thickness of 2.5mm. It consists of a skin and frame ribs and stringers attached to the inner side of the skin. The frame ribs have a C-shaped cross section, and the stringers have a Z-shaped cross section. The distance between the frame ribs is 480mm, and the distance between the stringers is 160mm. The density of the aluminum alloy skin is ρ = 2800kg / m3, the elastic modulus is E = 68GPa, and the Poisson's ratio is ν = 0.33.
[0021] The copper pillar 4 has a height of 5 mm, a radius of 7.5 mm, a density of ρ = 8960 kg / m3, an elastic modulus of E = 110 GPa, and a Poisson's ratio of ν = 0.35.
[0022] The shape memory alloy spring 5 has a wire diameter of 1.15 mm, a mean diameter of 12.6 mm, an effective number of coils of 6.5, and a pitch variation range of 1–3 mm. Its density ρ = 6500 kg / m³, martensitic modulus E = 65 GPa, austenitic modulus E = 76 GPa, Poisson's ratio ν = 0.3, and transformation temperatures of 29°C (martensite completion temperature), 42°C (martensite initiation temperature), 43°C (austenitic initiation temperature), and 58°C (austenitic completion temperature). Its initial state is non-twinned martensite that has undergone a reorientation process, and all shape memory alloy springs 5 have the same transformation temperature, elastic modulus, and height.
[0023] The working principle of the noise reduction device with a shape memory alloy three-spring resonant unit provided by the present invention is described below:
[0024] When the temperature of the shape memory alloy spring 5 was 20°C (below the austenite initiation temperature) and 70°C (above the austenite termination temperature), the inventors conducted vibration tests on the noise reduction device with the square array of the shape memory alloy three-spring resonant units 1. Figure 2No. 2 indicates the excitation point location of this noise reduction device, and No. 3 indicates the response point location. The four boundaries of the noise reduction device are set as fixed boundaries. The vibration excitation is a concentrated point force applied to excitation point 2, with position coordinates (150mm, 150mm). The excitation acceleration is 600mm / s, and the direction is perpendicular to the plane wall 6. The excitation time interval is 1 second. The acceleration of the vibration response is measured at response point 3, with position coordinates (500mm, 500mm).
[0025] This invention utilizes the temperature phase transition characteristics of shape memory alloys to achieve structural vibration reduction and noise control by arranging shape memory alloy three-spring resonant units 1 on a planar wall panel 6. The inventors conducted vibration tests on the planar wall panel 6 equipped with a square array of shape memory alloy three-spring resonant units 1 under two conditions: 20℃ (below the austenite initiation temperature, where the springs are in the martensitic phase) and 70℃ (above the austenite termination temperature, where the springs are completely transformed into the austenitic phase). The experiment used fixed boundaries on the four sides of the planar wall panel 6, applying a concentrated point force excitation perpendicular to the panel surface at a distance of 600 mm / s with a 1-s interval at the (150 mm, 150 mm) position. Vibration responses were collected at the far end (500 mm, 500 mm). This invention alters the stiffness and inherent dynamic characteristics of the resonant units through temperature changes, dissipating and suppressing the energy transfer of thin-plate vibration through local resonance effects. This effectively weakens the airborne sound radiation caused by structural vibration, achieving controllable vibration reduction and noise control, overcoming the drawback of traditional vibration reduction structures having unadjustable frequency bands.
[0026] Figure 3 This diagram illustrates the vibration transmission response in the 0-500Hz frequency band obtained from vibration reduction experiments of a planar wall panel with a square array of shape memory alloy three-spring resonant units, as provided by this invention, compared to the original wall panel. The vibration transmission response is characterized by the vibration transmissibility (FRF). A smaller FRF value indicates a greater degree of vibration attenuation within the planar thin plate 6, and a better vibration suppression effect of the shape memory alloy three-spring resonant unit 1. The calculation formula is as follows:
[0027] FRF=20log10|uo(ω)ui(ω)|
[0028] Where ω is the excitation frequency, ui(ω) is the acceleration at the excitation point, and uo(ω) is the acceleration at the response point. As the temperature of the shape memory alloy spring 5 increases from 20℃ to 70℃, the spring transforms from martensitic to austenitic, the elastic modulus increases from 65GPa to 76GPa, the height of the shape memory alloy three-spring resonant unit 1 increases from 25mm to 32mm, and the band gap shifts to higher frequencies. The sound transmission loss curve of the noise reduction device with a square array of shape memory alloy three-spring resonant units is shown in the figure. Figure 3As shown in (b), there is a sharp sound insulation peak and a wide-band sound insulation platform of 89-125 Hz is formed. The average sound insulation in the platform reaches 48 dB, with a maximum value of 75.9 dB. The wide-band sound insulation platform feature allows the planar wall panel 6 to cover the low-frequency noise band of the aircraft in multiple flight phases, achieving wide-band and high-efficiency sound insulation without precise tuning.
[0029] To more clearly demonstrate the tuning effect of the shape memory alloy three-spring resonant unit 1 on the vibration bandgap of the planar wall plate 6, the frequency position and bandwidth of the bandgap of the planar wall plate 6 obtained from experiments and simulations were compared. Regarding the experimental results, the inventors found that when the shape memory alloy spring 5 is in the martensitic phase, the first-order bandgap frequency range of the planar wall plate 6 is 88–123 Hz, and the bandgap bandwidth is 35 Hz; when the shape memory alloy spring 5 is in the austenitic phase, the first-order bandgap frequency range is tuned to 94–129 Hz, the bandgap bandwidth is 35 Hz, and the adjustable frequency range reaches 88–129 Hz. Simulation results show that as the temperature of the shape memory alloy spring 5 increases from 20℃ to 70℃, the spring transforms from martensite to austenite, and the bandgap shifts to higher frequencies. Specifically, the first-order bandgap frequency range for the martensitic phase is 89.08–125.23 Hz, with a bandwidth of 36.15 Hz; the first-order bandgap frequency range for the austenitic phase is 95.85–130.39 Hz, with a bandwidth of 34.54 Hz, resulting in an adjustable frequency range of 89.08–130.39 Hz. These simulation results are largely consistent with the experimental results regarding the first-order bandgap position and bandwidth.
[0030] The simulation and experimental results above verify that the noise reduction device with a square array of shape memory alloy three-spring resonant units provided by the present invention can achieve bandgap tuning of planar thin plate vibration, overcoming the shortcomings of traditional thin plate acoustic noise reduction devices with narrow and fixed vibration reduction bandgap and excessive size. Although the adjustable range of the bandgap is still limited by the properties of the specific shape memory alloy material used in the present invention, the provided structure and tuning method are not lacking in generality. The shape memory alloy springs required for a specific vibration frequency range can be customized by alloy composition and heat treatment process to further expand the bandgap tuning range and optimize vibration reduction performance.
Claims
1. A noise reduction device with a square array of shape memory alloy three-spring resonant units, characterized in that: The noise reduction device is composed of multiple shape memory alloy three-spring resonant units (1) periodically fixed on the flat wall panel (6) in a square array. Each shape memory alloy three-spring resonant unit (1) includes a copper column (4) and three shape memory alloy springs (5). The three shape memory alloy springs (5) are evenly arranged at 120° along the circumference, with their lower ends fixed on one side of the flat wall panel (6) and their upper ends connected to the bottom of the copper column (4), forming a spatially symmetrical support system.
2. The noise reduction device with a square array of shape memory alloy three-spring resonant units according to claim 1, characterized in that: The distance between the square arrays is 80mm, the height varies from 25 to 32mm, and the oscillator arrangement of the square array is 6×6.
3. The noise reduction device with a square array of shape memory alloy three-spring resonant units according to claim 1, characterized in that: The distance between adjacent shape memory alloy three-spring resonant units (1) in each square array is 80 mm.
4. The noise reduction device with a square array of shape memory alloy three-spring resonant units according to claim 1, characterized in that: The planar wall panel (6) is made of aluminum alloy material, with a side length of 650mm and a thickness of 2.5mm. It consists of a skin and frame ribs and stringers attached to the inside of the skin. The frame ribs have a C-shaped cross section, and the stringers have a Z-shaped cross section. The distance between the frame ribs is 480mm, and the distance between the stringers is 160mm.
5. The noise reduction device with a square array of shape memory alloy three-spring resonant units according to claim 1, characterized in that: The copper pillar (4) has a height of 5 mm and a radius of 7.5 mm.
6. The noise reduction device with a square array of shape memory alloy three-spring resonant units according to claim 1, characterized in that: The shape memory alloy spring (5) has a wire diameter of 1.15 mm, a mean diameter of 12.6 mm, an effective number of coils of 6.5, and a pitch variation range of 1-3 mm.