Unit body and structural panel assembly with enhanced impact and noise absorption properties

Abstract

A structural panel assembly includes an array of unit body assemblies. Each unit assembly includes: an outer frame member spaced apart from an inner frame member; a plurality of quasi-zero stiffness (QZS) spring members disposed between the inner frame member and the outer frame member; a phononic crystal disposed between the inner frame member and the outer frame member; and a plurality of locally resonant phononic crystal (LRPC) spring members disposed between the phononic crystal and one or more of the inner frame member and the outer frame member. The phononic crystal functions as a scattering phononic crystal (SPC) for attenuating high frequency sound waves within the unit assembly and as a vibration mass for the LRPC spring member for converting low frequency sound waves into thermal energy by vibration to attenuate low frequency sound waves within the unit assembly.

Description

Technical Field

[0001] The present disclosure generally relates to unit cells and structural panel assemblies with enhanced impact, noise absorption and insulation properties for use in automotive, aerospace, construction and other applications. The unit cells and structural panel assemblies incorporate quasi-zero stiffness (QZS) structures, scattering phononic crystals (SPCs) and locally resonant phononic crystals (LRPCs) that can be realized through additive manufacturing, molding and other techniques. Background Art

[0002] Impact tolerance and noise attenuation are important considerations when designing automotive, aerospace, architectural, and other structures. Conventional structures often struggle to withstand high-intensity impacts or sudden loads without sustaining significant damage. This can lead to safety hazards, structural failures, and increased maintenance costs. To avoid this, such structures often need to be made unnecessarily heavy and bulky, which is inefficient. Additionally, noise pollution is a pervasive problem across a variety of industries and in everyday environments. Excessive noise can adversely affect human health, productivity, and quality of life. Conventional noise reduction methods, such as noise barriers and insulation materials, can have limitations in effectively attenuating specific frequency ranges.

[0003] The need for structures to withstand impacts without sustaining significant damage has been a long-standing concern, especially in industries such as automotive, aerospace, and construction. As a result, rigid structures are typically used, which often results in a high degree of damage upon impact. Over time, researchers and engineers have explored the use of materials with improved impact resistance, such as high-strength alloys, composites, and energy-absorbing foams. These materials offer some improvements, but are not always sufficient to prevent damage or ensure the safety of the structure. Recently, the concept of QZS structures has emerged as a promising approach to effectively absorb and dissipate impact energy.

[0004] Likewise, traditional methods of mitigating noise include the use of noise barriers, soundproofing materials, and passive damping systems. While these methods are able to provide a certain level of noise reduction, they are often limited in effectively attenuating specific frequency ranges or selectively targeting specific noise sources. In addition, these methods may increase the weight, complexity, and cost of the system. Recently, automakers have experimented with using either SPC or LRPC, but not both.

[0005] This background is provided only as an illustrative environment and should not be construed as limiting in any way. It is obvious to those skilled in the art that the principles and concepts of the present disclosure can be implemented in other environment scenarios as well but not limited thereto. Summary of the invention

[0006] The present disclosure generally relates to unit cells and structural panel assemblies with enhanced impact, noise absorption and insulation properties for automotive, aerospace, construction and other applications. The unit cells and structural panel assemblies incorporate QZS structures, SPCs and LRPCs that can be achieved through additive manufacturing, molding and other techniques. This provides an improved method for enhancing impact tolerance and noise attenuation in various applications.

[0007] In an illustrative embodiment, the present disclosure provides a unit cell assembly, comprising: an outer frame member separated from an inner frame member; a plurality of QZS spring members arranged between the inner frame member and the outer frame member; a phononic crystal arranged between the inner frame member and the outer frame member; and a plurality of LRPC spring members arranged between the phononic crystal and one or more of the inner frame member and the outer frame member. The outer frame member is an open frame member that allows sound waves to penetrate into the unit cell assembly through the outer frame member. The inner frame member is a closed frame member that includes a barrier material that attenuates the propagation of sound waves from the unit cell assembly through the inner frame member. The phononic crystal is a disk used as an SPC for attenuating high-frequency sound waves within the unit cell assembly. The phononic crystal is a disk that serves as a vibration mass for the LRPC spring member, and the vibration mass of the LRPC spring member is used to attenuate low-frequency sound waves within the unit cell assembly by converting low-frequency sound waves into heat energy through vibration. Optionally, a plurality of QZS spring members are arranged at the vertices of the inner frame member and the outer frame member. Optionally, a plurality of LRPC spring members are arranged between a plurality of QZS spring members. A plurality of LRPC spring members are arranged between the phononic crystal and the outer frame member. A plurality of LRPC spring members are each arranged at an inclined angle between the phononic crystal and one or more of the inner frame member and the outer frame member. The unit cell assembly is formed by one or more of an additive manufacturing technique and a molding technique.

[0008] In another illustrative embodiment, the present disclosure provides a structural panel assembly comprising an array of unit cell assemblies. Each unit cell assembly comprises: an outer frame member separated from an inner frame member; a plurality of QZS spring members arranged between the inner frame member and the outer frame member; a phononic crystal arranged between the inner frame member and the outer frame member; and a plurality of LRPC spring members arranged between the phononic crystal and one or more of the inner frame member and the outer frame member. The outer frame member is an open frame member that allows sound waves to penetrate into the unit cell assembly through the outer frame member. The inner frame member is a closed frame member that includes a barrier material that attenuates the propagation of sound waves from the unit cell assembly through the inner frame member. The phononic crystal is a disk used as an SPC for attenuating high-frequency sound waves within the unit cell assembly. The phononic crystal is a disk that serves as a vibration mass for the LRPC spring member, and the vibration mass of the LRPC spring member is used to attenuate low-frequency sound waves within the unit cell assembly by converting low-frequency sound waves within the unit cell assembly into heat energy through vibration. Multiple LRPC spring members are each arranged at an inclined angle between the phononic crystal and one or more of the inner frame member and the outer frame member. The array of unit body assemblies is one or both of an array of horizontally arranged unit body assemblies and an array of vertically arranged unit body assemblies, and the array of unit body assemblies is formed by one or more of additive manufacturing technology and molding technology. The array of unit body assemblies is arranged between the inner panel and the outer panel of the vehicle structure.

[0009] In another illustrative embodiment, the present disclosure provides a method for forming a unit cell assembly, the method comprising the following steps: providing an outer frame member separated from an inner frame member; providing a plurality of QZS spring members arranged between the inner frame member and the outer frame member; providing a phononic crystal arranged between the inner frame member and the outer frame member; and providing a plurality of LRPC spring members arranged between the phononic crystal and one or more of the inner frame member and the outer frame member; the providing step includes using one or more of an additive manufacturing technique and a molding technique. The outer frame member is an open frame member that allows sound waves to penetrate into the unit cell assembly through the outer frame member, and the inner frame member is a closed frame member, the closed frame member including a barrier material that attenuates the propagation of sound waves from the unit cell assembly through the inner frame member. The phononic crystal is a disk used as an SPC for attenuating high-frequency sound waves within the unit cell assembly, and is used as a disk for the vibration mass of the LRPC spring member, the vibration mass of the LRPC spring member being used to attenuate low-frequency sound waves within the unit cell assembly by converting low-frequency sound waves into heat energy through vibration. The method further includes arranging the unit cell assembly horizontally and vertically adjacent to one or more of a plurality of other unit cell assemblies to form an array of unit cell assemblies to form a structural panel assembly.

[0010] It will be apparent to one of ordinary skill in the art that elements of any illustrative embodiment provided herein may be used with any other illustrative embodiment without limitation thereto. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present disclosure is illustrated and described herein with reference to the accompanying drawings, in which like reference numerals are used to refer to like component parts / method steps where appropriate, and in which:

[0012] Figure 1 is a perspective view of an illustrative embodiment of a unit cell of the present disclosure;

[0013] Figure 2 is a perspective view of another illustrative embodiment of a unit cell of the present disclosure;

[0014] Figure 3 is a perspective view of an illustrative embodiment of a structural panel of the present disclosure;

[0015] Figure 4 is a flow chart of an illustrative embodiment of a method for forming a unit cell of the present disclosure; and

[0016] Figure 5 is a flow chart of one illustrative embodiment of a method for forming a structural panel of the present disclosure.

[0017] Again, it will be apparent to one of ordinary skill in the art that elements of any illustrative embodiment provided herein may be used with any other illustrative embodiment, but are not limited thereto. DETAILED DESCRIPTION

[0018] Again, the present disclosure generally relates to unit cells and structural panel assemblies with enhanced impact, noise absorption and insulation properties for automotive, aerospace, construction and other applications. The unit cells and structural panel assemblies incorporate QZS structures, SPCs and LRPCs that can be realized through additive manufacturing, molding and other techniques. This provides an improved method for enhancing impact tolerance and noise attenuation in various applications.

[0019] Phononic crystals have gained significant interest in the automotive industry for their ability to manipulate and control the transmission of sound waves. Phononic crystals are periodic structures that exhibit spatial variations in their mechanical properties, enabling them to selectively filter, attenuate and / or guide sound waves. By exploiting the bandgap properties of phononic crystals, specific frequency ranges associated with noise can be effectively attenuated or blocked. The proposed design utilizes a combination of SPCs, which effectively attenuate high-frequency noise, and LRPCs, which are known for their effectiveness in converting low-frequency noise energy into heat through vibration. All frequencies at which the mode shapes occur can be programmed by varying the spring stiffness and mass of the vibrator.

[0020] QZS structures are engineered systems designed to exhibit extremely low stiffness under normal conditions while maintaining high stiffness when subjected to large deformations or impact forces. This unique property enables them to effectively absorb and dissipate energy during impact, thereby mitigating the effects of sudden loads and shocks.

[0021] Since QZS structures, SPCs, and LRPCs are generally known to those skilled in the art, they are not described in detail herein. Instead, the present disclosure focuses on specific uses of such materials.

[0022] As described in more detail below, the design of the present disclosure accommodates, among other things, a phononic crystal disk that serves as a scatterer for the SPC function and a vibrating mass for the LRPC function. The phononic crystal is connected to an outer frame using LRPC springs that have different spring stiffnesses that can be adjusted. The stiffness of the LRPC springs can be varied to change the resonant mode shape to target a specific frequency. For the same purpose, the vibrator mass can be varied, for example by changing the packing density. The outer and inner frames of the design are separated and held in place by load springs of the same stiffness, which serve as a QZS structure during impact.

[0023] The design also exploits the inherent shape memory behavior of common polymeric materials such as polylactic acid (PLA) and thermoplastic polyurethane (TPU) to recover the original shape after an impact using heat as a stimulus. The use of such materials along with meta-structures / architected materials provides a solution that is lightweight and compact compared to traditional approaches. The potential applications of this innovation are diverse, ranging from the automotive and aerospace industries (where impact resistance and noise control are critical) to the construction industry.

[0024] Thus, the proposed solution integrates the QZS structure, SPC and LRPCs into a single unit cell that can be programmed for each application given load and frequency isolation data. It offers the advantage of enhanced impact tolerance. Unlike conventional approaches that rely primarily on the strength and stiffness of the materials used, the QZS structure exhibits extremely low stiffness under normal conditions and effectively absorbs and dissipates impact energy, minimizing the force transmitted and reducing the risk of structural damage. The proposed solution also offers the advantage of targeted noise attenuation. The integration of phononic crystals in the unit cell enables precise control and manipulation of sound waves. Unlike conventional noise reduction methods that typically provide general noise attenuation, phononic crystals selectively attenuate or block specific frequency ranges associated with noise. The proposed solution further offers the advantages of versatility and integration. The unit cell offers versatility in its application and integration into existing structures. It can be seamlessly integrated into a variety of components, such as frame and body panels, door panels, machinery mounts, etc.

[0025] The proposed design consists of an inner frame and an outer frame connected to each other by QZS load springs, and the size / lattice constant of such a unit cell can be calculated from the Bragg frequency using the general equation:

[0026] f c =c / 2a

[0027] The design features tilted / skewed LRPC springs connecting the diffuser / vibrator to the outer frame. Using finite element analysis (FEM), the modal shapes of the vibrator can be simulated and adjusted accordingly. The design uses materials such as PLA and TPU, which are readily available and exhibit little-known shape memory behavior when heated. The unit cells are used to form an array that can fill a defined space, such as the space between the inner and outer door panels of a vehicle.

[0028] Now specific reference Figure 1In one illustrative embodiment, the unit cell assembly 10 includes an outer frame member 12 that is spaced apart from an inner frame member 14. In this embodiment, each of the outer frame member 12 and the inner frame member 14 is a generally rectangular or square frame member having a length of approximately 95 mm, a width of approximately 95 mm, and a thickness of approximately 2.5 mm, although other shapes and sizes may also be used. The outer frame 12 is spaced apart from the inner frame by a distance of approximately 35 mm. The outer frame member 12 is an open frame member that defines an opening 16 and allows sound waves to penetrate into the unit cell assembly 10 through the outer frame member 12. The inner frame member 14 is a closed frame member that includes a barrier material 18, such as PLA, TPU, etc., inside thereof for attenuating the propagation of sound waves from the unit cell assembly 10 through the inner frame member 14. Each of the outer frame member 12 and the inner frame member may be made of PLA, TPU, etc.

[0029] A plurality of QZS spring members 20 are arranged between the inner frame member 14 and the outer frame member 12. Each QZS spring member 20 is made of PLA, TPU, etc. and includes a thin-walled Schwarz triple periodic minimum surface (TPMS) lattice structure. As shown, optionally, a plurality of QZS spring members 20 are arranged at the vertices of the inner frame member 14 and the outer frame member 12 and have a length of approximately 35 mm. The QZS spring member 20 is a volume of a rectangular parallelepiped with dimensions x, y and z (e.g., 10 mm, 10 mm and 35 mm, depending on the application), which is filled with a Schwarz TPMS lattice structure with lattice constants a, b and c and a wall thickness t. It is worth noting that the dimensions may vary depending on the application.

[0030] The phononic crystal 22 is arranged between the inner frame member 14 and the outer frame member 12. The phononic crystal 22 is made of PLA or the like, and in this embodiment, has a disk shape with a diameter of about 76 mm, a thickness of about 12 mm at the axis, and a thickness of about 2 mm at the periphery, although other shapes and sizes may also be used. The phononic crystal 22 is suspended in a cavity 24 formed by the inner frame 14, the outer frame 12, and a plurality of QZS spring members 20. The phononic crystal 22 is used as an SPC for tunably attenuating high-frequency sound waves between about 1700 Hz and about 1900 Hz in the unit cell assembly 10. The phononic crystal 22 is also used as a vibration mass for the LRPC spring member 26 for attenuating low-frequency sound waves and harmonic waves between about 200 Hz and about 700 Hz in the unit cell assembly 10 by converting the low-frequency sound waves into heat energy through vibration.

[0031] A plurality of LRPC spring members 26 are arranged between the phononic crystal 22 and one or more of the inner frame member 14 and the outer frame member 12. In this embodiment, optionally, a plurality of LRPC spring members 26 are arranged between a plurality of QZS spring members 20 and between the phononic crystal 22 and the outer frame member 12. According to the frame structure, a plurality of LRPC spring members 26 are each arranged between the phononic crystal 22 and the outer frame member 12 at an inclination angle of approximately 62 degrees. Each LRPC spring member 26 is made of TPU or the like, includes a thin-walled Schwarz TPMS lattice structure, and has a length of approximately 25 mm. The LRPC spring member 26 is a volume of a rectangular parallelepiped shape with dimensions x, y, and z, which is filled with a Schwarz TPMS lattice structure having lattice constants a, b, and c and a wall thickness of t. It is worth noting that the dimensions may vary depending on the application.

[0032] The unit cell assembly 10 is formed by one or more of an additive manufacturing technique and a molding technique.

[0033] Now specific reference Figure 2 In another illustrative embodiment, the unit cell assembly 10 also includes an outer frame member 12 that is separated from an inner frame member 14. In this embodiment, each of the outer frame member 12 and the inner frame member 14 is a generally hexagonal frame member having a side length of about 55 mm and a thickness of about 2.5 mm, depending on the lattice constant, although other shapes and sizes may also be used. The outer frame 12 is spaced apart from the inner frame by a distance of about 35 mm. The outer frame member 12 is an open frame member that defines an opening 16 and allows sound waves to penetrate into the unit cell assembly 10 through the outer frame member 12. The inner frame member 14 is also an open frame member that defines an opening 16 and allows sound waves to be transmitted out of the unit cell assembly 10 through the inner frame member 14. Each of the outer frame member 12 and the inner frame member can be made of PLA, TPU, etc.

[0034] A plurality of QZS spring members 20 are arranged between the inner frame member 14 and the outer frame member 12. Each QZS spring member 20 is made of PLA, TPU, etc. and includes a thin-walled Schwarz triple periodic minimum surface (TPMS) lattice structure. As shown, optionally, a plurality of QZS spring members 20 are arranged at the vertices of the inner frame member 14 and the outer frame member 12 and have a length of approximately 35 mm. The QZS spring member 20 is a volume of a rectangular parallelepiped with dimensions x, y and z (e.g., 10 mm, 10 mm and 35 mm, depending on the application), which is filled with a Schwarz TPMS lattice structure with lattice constants a, b and c and a wall thickness t. It is worth noting that the dimensions may vary depending on the application.

[0035] The phononic crystal 22 is arranged between the inner frame member 14 and the outer frame member 12. The phononic crystal 22 is made of PLA or the like, and in this embodiment has a disk shape with a diameter of about 76 mm, a thickness of about 12 mm at the axis, and a thickness of about 2 mm at the periphery, although other shapes and sizes may also be used. The phononic crystal 22 is suspended in a cavity 24 formed by the inner frame 14, the outer frame 12, and a plurality of QZS spring members 20. The phononic crystal 22 is used as an SPC for tunably attenuating high-frequency sound waves between about 1700 Hz and about 1900 Hz in the unit cell assembly 10. The phononic crystal 22 is also used as a vibration mass for the LRPC spring member 26 for attenuating low-frequency sound waves and harmonic waves between about 200 Hz and about 700 Hz in the unit cell assembly 10 by converting the low-frequency sound waves into heat energy through vibration.

[0036] A plurality of LRPC spring members 26 are arranged between the phononic crystal 22 and one or more of the inner frame member 14 and the outer frame member 12. In this embodiment, optionally, a plurality of LRPC spring members 26 are arranged between a plurality of QZS spring members 20 and between the phononic crystal 22 and the outer frame member 12. A plurality of LRPC spring members 26 are each arranged between the phononic crystal 22 and the outer frame member 12 at an inclination angle of approximately 62 degrees according to the frame structure. Each LRPC spring member 26 is made of TPU or the like, includes a thin-walled Schwarz TPMS lattice structure, and has a length of approximately 25 mm. The LRPC spring member 26 is a volume of a cuboid shape with dimensions x, y, and z, which is filled with a Schwarz TPMS lattice structure having lattice constants a, b, and c and a wall thickness t. It is worth noting that the dimensions may vary depending on the application.

[0037] Likewise, the unit cell assembly 10 is formed by one or more of an additive manufacturing technique and a molding technique.

[0038] Now specific reference Figure 3In an illustrative embodiment, a structural panel assembly 30 includes a plurality of unitary assemblies 10 formed or connected together to form an integral structural member that is integrated into a vehicle, structure, etc., so as to provide enhanced impact tolerance, noise absorption and insulation for the vehicle, structure, etc. The structural panel assembly 30 composed of an array of unitary assemblies 10 can be one or both of an array of unitary assemblies 10 arranged horizontally and an array of unitary assemblies 10 arranged vertically, and the array of unitary assemblies has any suitable length, width and depth shape and / or size for a given application. For example, the structural panel assembly 30 can be arranged between an inner panel 32 and an outer panel 34 of a vehicle structure 36 (e.g., a door). The impact tolerance is improved, and the noise from the outside of the door can be captured in the structural panel assembly 30 and dissipated by it, thereby isolating the vehicle's cabin from the noise. Many other uses are also possible. In this example, the structural panel 30 can be adhered to one or more of the inner panel 32 and the outer panel 34, and / or other intermediate structures, layers and / or materials can be utilized.

[0039] Figure 4 is a flow chart of an illustrative embodiment of a method 40 for forming a unit cell assembly 10 of the present disclosure. The method includes the following steps: providing an outer frame member separated from an inner frame member (step 42), providing a plurality of QZS spring members arranged between the inner frame member and the outer frame member (step 44), providing a phononic crystal arranged between the inner frame member and the outer frame member (step 46), and providing a plurality of LRPC spring members arranged between the phononic crystal and one or more of the inner frame member and the outer frame member (step 48). For example, these steps are performed using one or more of additive manufacturing techniques and molding techniques. Similarly, the outer frame member is an open frame member that allows sound waves to penetrate into the unit cell assembly through the outer frame member, and the inner frame member is a closed frame member that includes a barrier material that attenuates the propagation of sound waves that propagate out of the unit cell assembly through the inner frame member. The phononic crystal is a disk-shaped piece that acts as an SPC for attenuating high frequency sound waves within the unit cell assembly and as a vibrating mass of an LRPC spring member for attenuating low frequency sound waves within the unit cell assembly by converting the low frequency sound waves into heat energy through vibration.

[0040] Figure 5 is a flow chart of an illustrative embodiment of a method 50 for forming a structural panel assembly 30 of the present disclosure. The method includes the steps of arranging the unit cell assembly horizontally and vertically adjacent to one or more of a plurality of other unit cell assemblies to form an array of unit cell assemblies that constitute a structural panel assembly (step 52), and optionally arranging the structural panel assembly between inner and outer panels of a vehicle or other structure (step 54).

[0041] Thus, the disclosed design accommodates a phononic crystal disk, etc., that serves as a scatterer for the SPC function and a vibrating mass for the LRPC function. The phononic crystal is connected to an outer frame using LRPC springs, where the LRPC springs have different spring stiffnesses that can be adjusted. The stiffness of the LRPC springs can be changed to change the resonance mode shape to a target specific frequency. For the same purpose, the vibrator mass can be changed, for example, by changing the packing density. The outer and inner frames of the design are separated and held in place by load springs of the same stiffness, which serve as a QZS structure during impact.

[0042] This design also exploits the inherent shape memory behavior of common polymeric materials such as PLA and TPU to recover the original shape after an impact with heat as the stimulus. The use of this material along with meta-structural / architectural materials provides a lightweight and compact solution compared to traditional approaches. The potential applications of this innovation are diverse, ranging from the automotive and aerospace industries (where impact resistance and noise control are crucial) to the construction industry.

[0043] Thus, the proposed solution integrates the QZS structure, SPC and LRPC into a single unit cell that can be programmed for each application given load and frequency isolation data. It offers the advantage of enhanced impact withstandability. Unlike conventional approaches that rely primarily on the strength and stiffness of the materials used, the QZS structure exhibits extremely low stiffness under normal conditions and effectively absorbs and dissipates impact energy, minimizing the transmitted forces and reducing the risk of structural damage. The proposed solution also offers the advantage of targeted noise attenuation. The integration of phononic crystals within the unit cell enables precise control and manipulation of sound waves. Unlike conventional noise reduction approaches that typically provide general noise attenuation, phononic crystals selectively attenuate or block specific frequency ranges associated with noise. The proposed solution further offers the advantages of versatility and integration. The unit cell offers versatility in its application and integration into existing structures. It is able to be seamlessly integrated into a variety of components such as frame and body panels, door panels, mechanical mountings, etc.

[0044] Although the present disclosure is illustrated and described herein with reference to illustrative embodiments and specific examples thereof, it will be apparent to one of ordinary skill in the art that other embodiments and examples may perform similar functions and / or achieve the same results. All such equivalent embodiments and examples are within the spirit and scope of the present disclosure and are therefore contemplated and intended to be covered by the following non-limiting claims for all purposes.

Claims

1. A unit body assembly, comprising: an outer frame member spaced from the inner frame member; a plurality of quasi-zero stiffness (QZS) spring members disposed between the inner frame member and the outer frame member; a phononic crystal disposed between the inner frame member and the outer frame member; and A plurality of locally resonant phononic crystal (LRPC) spring members are disposed between the phononic crystal and one or more of the inner and outer frame members.

2. The unit cell assembly of claim 1, wherein the outer frame member is an open frame member that allows sound waves to penetrate into the unit cell assembly through the outer frame member; and / or The inner frame member is a closed frame member including a barrier material that attenuates the propagation of sound waves from the unit cell assembly through the inner frame member.

3. The unit cell assembly of claim 1 or 2, wherein the phononic crystal is a disk used as a scattering phononic crystal (SPC) for attenuating high-frequency acoustic waves within the unit cell assembly; or The phononic crystal is a disk used as a vibrating mass for the LRPC spring member, the vibrating mass being used to attenuate low frequency sound waves within the unit cell assembly by converting low frequency sound waves into heat energy through vibration.

4. The unit cell assembly according to claim 1 or 2, wherein: The plurality of QZS spring members are arranged at vertices of the inner frame member and the outer frame member; The plurality of LRPC spring members are disposed between the plurality of QZS spring members; and The plurality of LRPC spring members are disposed between the phononic crystal and the outer frame member.

5. The unit cell assembly of claim 1 or 2, wherein each of the plurality of LRPC spring members is arranged at an inclined angle between one or more of the inner frame member and the outer frame member and the phononic crystal; and / or The unit body assembly is formed by one or more of additive manufacturing technology and molding technology.

6. A structural panel assembly comprising an array of unit cell assemblies as claimed in any one of claims 1 to 5.

7. The structural panel assembly of claim 6, wherein the array of unit cell assemblies is one or both of an array of horizontally arranged unit cell assemblies and an array of vertically arranged unit cell assemblies, and wherein the array of unit cell assemblies is formed by one or more of an additive manufacturing technique and a molding technique; and / or The array of unit cell assemblies is arranged between inner and outer panels of a vehicle structure.

8. A method for forming a unit cell assembly, the method comprising the following steps: providing an outer frame member spaced from the inner frame member; providing a plurality of quasi-zero stiffness (QZS) spring members disposed between the inner frame member and the outer frame member; providing a phononic crystal disposed between the inner frame member and the outer frame member; and providing a plurality of locally resonant phononic crystal (LRPC) spring members disposed between one or more of the inner and outer frame members and the phononic crystal; The providing step comprises using one or more of additive manufacturing technology and molding technology.

9. The method of claim 8, wherein the outer frame member is an open frame member that allows sound waves to penetrate through the outer frame member into the unit cell assembly, and wherein the inner frame member is a closed frame member that includes a barrier material that attenuates the propagation of sound waves out of the unit cell assembly through the inner frame member; and / or The phononic crystal is a disk used as a scattering phononic crystal (SPC) and as a vibration mass for an LRPC spring component, wherein the scattering phononic crystal (SPC) is used to attenuate high-frequency sound waves within the unit cell assembly, and the vibration mass of the LRPC spring component is used to attenuate low-frequency sound waves within the unit cell assembly by converting the low-frequency sound waves into heat energy through vibration.

10. The method according to claim 8 or 9, further comprising arranging the unit cell assembly horizontally or vertically adjacent to one or more of a plurality of other unit cell assemblies to form an array of unit cell assemblies constituting a structural panel assembly.

Images