Mobile homestay with noise reduction structure

Abstract

This utility model discloses a mobile homestay with a noise reduction structure, including a composite shell. The composite shell includes a fiber-reinforced polymer outer shell layer and a load-bearing foam-filled core layer. The load-bearing foam-filled core layer is disposed inside the fiber-reinforced polymer outer shell layer. The load-bearing foam-filled core layer has a mesh-like skeleton inside and a microporous sound-absorbing lining layer disposed inside the load-bearing foam-filled core layer. The fiber-reinforced polymer outer shell layer, the load-bearing foam-filled core layer, and the microporous sound-absorbing lining layer are sequentially and fixedly connected. The composite noise reduction method, such as the composite wall composed of a fiber-reinforced polymer outer shell and a foam-filled core layer, blocks sound bridges and isolates mid-to-low frequency noise; the inner microporous sound-absorbing lining absorbs reverberation; the composite shell integrates load-bearing, heat insulation, sound insulation, and sound absorption functions, saving costs and space; and it is equipped with multi-layer hollow soundproof glass windows with double sealing to ensure sound insulation integrity and airtightness.

Description

Technical Field

[0001] This utility model relates to the field of mobile homestay technology, specifically a mobile homestay with a noise reduction structure. Background Technology

[0002] Mobile homestays, as a new business model combining prefabricated buildings and the cultural tourism industry, have received widespread attention in recent years due to their advantages such as reusability, environmental friendliness, and the ability to provide unique living experiences. Unlike traditional fixed buildings, mobile homestays place higher demands on their building envelopes in terms of lightweight construction, structural strength, and living comfort.

[0003] Currently, the existing solutions for mobile homestays mainly include the following: The first is to modify standard shipping containers. This solution utilizes the inherent high-strength steel structure of the container, which facilitates transportation and hoisting. The second is to use a light steel keel or wood frame structure, prefabricating the frame on-site or in a factory, then laying exterior wall panels on the outside and interior wall panels on the inside, with insulation materials such as rock wool, glass wool, or foam board filling the middle.

[0004] However, the aforementioned existing technical solutions all have insurmountable drawbacks in practical applications. For container conversion solutions, the metal shell itself is an excellent sound conductor, resulting in a significant sound bridge effect. External rainwater, wind noise, air conditioner outdoor unit vibration, or nearby noise can easily penetrate the interior through the metal shell, leading to poor acoustic quality. To achieve habitable sound insulation standards, complex secondary renovations are necessary, adding thick sound insulation layers, sound-absorbing layers, and vibration-damping structures. This not only significantly increases construction costs and time but also encroaches on limited interior space. For light steel keel or wood frame solutions, the walls are typically thin. Although insulation materials can be filled, rock wool's primary function is insulation, not sound insulation, resulting in insufficient overall sound insulation. It is particularly ineffective at isolating low- to mid-frequency noise such as traffic noise and human voices. More importantly, the load-bearing capacity of these structures relies mainly on the keel frame; the wall panels themselves, especially traditional color steel sandwich panels or decorative panels, lack load-bearing capacity, resulting in weak structural integrity. They are prone to deformation during repeated hoisting or relocation, affecting structural safety and airtightness.

[0005] Therefore, those skilled in the art need a new type of mobile homestay structure solution. The shell of this solution should be lightweight, have sufficient structural load-bearing capacity to reduce or replace reliance on heavy frames, and have good broadband noise reduction performance to achieve sound insulation and sound absorption, thereby providing users with a quiet and comfortable living environment without the need for complicated secondary renovations.

[0006] Therefore, this application is submitted. Utility Model Content

[0007] To address the problems existing in the prior art, the purpose of this utility model is to provide a mobile homestay with a noise reduction structure. This addresses the inherent limitations of existing solutions in practical applications. For container conversion solutions, the metal shell itself is an excellent sound conductor, exhibiting a significant sound bridge effect. External noise such as rain, wind, air conditioner vibrations, or nearby noise easily penetrates the interior through the metal shell, resulting in poor acoustic quality. To achieve habitable sound insulation standards, complex secondary renovations are necessary, adding thick sound insulation layers, sound-absorbing layers, and vibration-damping structures. This significantly increases construction costs and time, and also encroaches on limited interior space. For lightweight steel keel or wood frame solutions, the walls are typically thin. While insulation materials can be added, rock wool's primary function is insulation, not sound insulation, resulting in insufficient overall sound insulation. In particular, its ability to isolate low-to-mid-frequency noise, such as traffic noise and human voices, is poor. More importantly, the load-bearing capacity of the above-mentioned structure mainly relies on the keel frame. The wall panels themselves, especially traditional color steel sandwich panels or decorative panels, do not have load-bearing capacity. The overall structure is weak and is prone to deformation during multiple hoisting or moving processes, affecting structural safety and airtightness.

[0008] To address the aforementioned issues, this application proposes a mobile homestay with a noise reduction structure, comprising a composite shell. The composite shell includes a fiber-reinforced polymer outer shell layer and a load-bearing foam-filled core layer. The load-bearing foam-filled core layer is disposed inside the fiber-reinforced polymer outer shell layer. The load-bearing foam-filled core layer has a mesh-like skeleton inside and a microporous sound-absorbing inner lining layer filled on the mesh-like skeleton. The fiber-reinforced polymer outer shell layer, the load-bearing foam-filled core layer, and the microporous sound-absorbing inner lining layer are sequentially and fixedly connected.

[0009] Preferably, the mesh-like skeleton is welded from metal profiles or rigid composite material profiles.

[0010] Preferably, the fiber-reinforced polymer outer shell layer comprises a resin matrix and a glass fiber cloth or carbon fiber cloth disposed in the resin matrix.

[0011] Preferably, the glass fiber cloth or carbon fiber cloth has a multi-layer stacked structure.

[0012] Preferably, the microporous sound-absorbing liner is composed of a metal or polymer perforated panel and a non-woven sound-absorbing felt disposed between the perforated panel and the load-bearing foam-filled core layer.

[0013] Preferably, the load-bearing foam filling core layer is a rigid polyurethane foam layer or an extruded polystyrene foam layer.

[0014] Preferably, the composite housing is further provided with a window opening, and the window opening is fitted with a multi-layer hollow soundproof glass window, the frame of the glass window being sealed to the composite housing with sealant.

[0015] Preferably, the glass window comprises at least two layers of glass spaced apart, with a vacuum-sealed interlayer formed between the glass layers, or filled with argon gas.

[0016] Preferably, the glass window comprises three layers of glass spaced apart, with two interlayers formed between the glass panes.

[0017] Preferably, an EPDM rubber sealing strip is filled between the frame of the glass window and the inner wall of the window opening of the composite housing.

[0018] In summary, this utility model has the following beneficial effects: The noise reduction of this utility model is composite. First, the composite wall, composed of a fiber-reinforced polymer outer shell and a load-bearing foam-filled core layer, effectively blocks the sound bridge effect by combining materials of different densities, ensuring airborne sound insulation and effectively blocking external wind, rain, traffic, and other low-to-mid-frequency noise. Second, the microporous sound-absorbing lining layer on the innermost side absorbs reverberation noise entering the room or generated within the room, further improving comfort. Furthermore, the composite shell is integrally molded at the factory, integrating load-bearing, heat insulation, sound insulation, and sound absorption functions. This saves construction costs and time, and more importantly, avoids encroaching on the limited interior space of the mobile homestay. By installing multi-layered hollow sound-insulating glass windows on the composite shell and using sealant and EPDM rubber sealing strips for double sealing, the sound insulation performance of the traditionally weak acoustic components of the windows matches that of the wall, improving the overall sound insulation integrity and airtightness of the homestay. Attached Figure Description

[0019] Figure 1 A first-angle three-dimensional structural diagram of a mobile homestay with noise reduction features;

[0020] Figure 2 A second-angle three-dimensional structural diagram of a mobile homestay with noise reduction features;

[0021] Figure 3 A top-view structural diagram of a mobile homestay with noise reduction features;

[0022] Figure 4 A partial structural diagram of the installation of the load-bearing foam-filled core layer. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] A mobile homestay with a noise reduction structure includes a composite shell 1. The composite shell 1 includes a fiber-reinforced polymer outer shell layer 11 and a load-bearing foam-filled core layer 12. The load-bearing foam-filled core layer 12 is disposed inside the fiber-reinforced polymer outer shell layer 11. The load-bearing foam-filled core layer 12 has a mesh-like skeleton 121 and a microporous sound-absorbing inner lining layer 122 filled on the mesh-like skeleton 121. The fiber-reinforced polymer outer shell layer 11, the load-bearing foam-filled core layer 12, and the microporous sound-absorbing inner lining layer 122 are sequentially fixedly connected.

[0025] Please see Figure 1-4 This utility model provides a mobile homestay with a noise reduction structure, the core of which lies in the integrated composite shell 1. This composite shell 1 simultaneously solves the contradictions of the sound bridge effect of the container solution and the weak structural load-bearing capacity and poor sound insulation performance of the light steel and wood frame solutions in the prior art.

[0026] like Figure 4 As shown, the composite shell 1 includes a fiber-reinforced polymer outer shell layer 11, a load-bearing foam-filled core layer 12, and a microporous sound-absorbing inner lining layer 122.

[0027] In terms of spatial relationship, the fiber-reinforced polymer outer shell layer 11 constitutes the outermost layer of the composite shell 1, providing weather resistance, impact resistance, and waterproofing. The load-bearing foam-filled core layer 12 is disposed inside the fiber-reinforced polymer outer shell layer 11. The microporous sound-absorbing inner lining layer 122 is disposed inside the load-bearing foam-filled core layer 12. These three layers are sequentially fixed and connected through methods such as bonding, co-curing, or integral foaming molding to form a high-strength, lightweight, and integrated overall enclosure structure.

[0028] To address the issues of insufficient load-bearing capacity and weak overall integrity in existing light steel or wood frame wall panels, this invention incorporates a grid-like skeleton 121 within the load-bearing foam-filled core layer 12. In this embodiment, the grid-like skeleton 121, along with the fiber-reinforced polymer outer shell layer 11 and the foam core layer 12 itself, works synergistically to form a stress-skin composite structure. The grid-like skeleton 121, as the primary load-bearing structure, ensures the rigidity and strength of the mobile homestay during hoisting, transportation, and use, while the foam-filled core layer 12 provides shear support. This structural design allows the composite shell 1 to function as a load-bearing structure itself, eliminating the need for an additional heavy-duty frame and improving structural efficiency.

[0029] To address the issues of sound bridging in shipping containers and insufficient sound insulation in light steel frames, this invention utilizes the acoustic properties of composite materials. The combination of a high-density fiber-reinforced polymer outer shell layer 11 and a low-density porous load-bearing foam-filled core layer 12 creates an interface with different acoustic impedances, effectively reflecting and attenuating externally transmitted sound energy. In particular, the foam material itself possesses excellent sound insulation properties, and the mesh-like skeleton 121 is completely encased in foam, avoiding sound bridging caused by rigid connections, thus effectively blocking external wind, rain, and traffic noise.

[0030] To address the issue of poor indoor acoustic quality, a microporous sound-absorbing lining layer 122 is installed on the innermost side to absorb indoor sound or a small amount of noise that penetrates the wall, thereby reducing indoor reverberation and improving speech clarity and living comfort.

[0031] More specifically, in terms of spatial relationship, the fiber-reinforced polymer outer shell layer 11, as the outermost layer, possesses high strength far exceeding that of ordinary plastics, along with corrosion resistance and impact resistance, forming the first physical barrier for the guesthouse against the external environment. The load-bearing foam-filled core layer 12 is located inside the outer shell layer 11 in this embodiment. The microporous sound-absorbing inner lining layer 122 serves as the interior finishing layer and is located inside the foam core layer 12. Specifically, after precisely positioning the fiber-reinforced polymer outer shell layer 11, the microporous sound-absorbing inner lining layer 122, and their internal mesh-like skeleton 121 in the mold, liquid foam material, such as polyurethane, is injected into the cavity between them. During the foaming and expansion process, the foam generates extremely strong self-adhesion, thereby firmly bonding the fiber-reinforced polymer outer shell layer 11, the mesh-like skeleton 121, and the microporous sound-absorbing inner lining layer 122 to form an integral structure. The high-strength fiber-reinforced polymer outer shell layer 11 and the mesh-like skeleton 121 primarily bear tensile and compressive stresses. The lightweight load-bearing foam-filled core layer 12 serves as the core material, and its key role is to provide shear support and prevent the high-strength outer shell layer 11 from buckling locally under pressure.

[0032] Understandably, the mesh-like frame 121 constitutes the main three-dimensional load-bearing network. Its function is no longer to independently bear all loads, but to serve as the rigid foundation of the mobile homestay, specifically designed to resist critical bending moments, torques, and concentrated loads generated during hoisting, transportation, and other operating conditions.

[0033] The load-bearing foam-filled core layer 12, with its own shear stiffness, provides continuous elastic support for the members of the mesh-like skeleton 121. This improves the local stability of the skeleton members and effectively prevents buckling or instability under compression or bending, thus allowing the use of lighter profiles for the skeleton. Secondly, it can act as a shear force transmission medium, uniformly transferring the uniformly distributed load on the fiber-reinforced polymer outer shell layer 11 and the concentrated load on the skeleton 121 to the entire composite structure, ensuring that all components participate in load-bearing, thereby improving the overall structural stiffness and strength.

[0034] By adopting the above structure, the entire composite shell 1 can be used as a whole to bear the load collaboratively, and its structural stiffness, strength, and weight ratio exceed those of traditional light steel frames or containers of the same weight. This solves the problems of weak load-bearing capacity and easy deformation of light steel or wooden frame structures in the prior art. When the composite shell 1 of this embodiment is manufactured, it simultaneously integrates the functions of load-bearing structure, external wall protection, foam core insulation, and internal wall sound absorption. It can be understood that the microporous sound-absorbing inner lining layer 122 itself is an interior finishing layer, requiring no further decoration. This solves the problem in the prior art where container solutions must add a thick sound-absorbing layer to achieve sound insulation standards, thus encroaching on limited internal space, and maximizes space utilization. Furthermore, the structure of this embodiment achieves both sound insulation and sound absorption. The combination of the high-density outer shell layer 11 and the low-density foam core layer 12 creates a difference in acoustic impedance, which can block external noise. The foam core material 12 itself is a porous material and completely encloses the internal skeleton 121, avoiding the sound bridge effect of the metal shell or light steel keel of the container in the prior art. The innermost sound-absorbing lining layer 122 is specifically designed to absorb room reverberation and residual noise that penetrates.

[0035] Preferably, the mesh-like skeleton 121 is welded from metal profiles or rigid composite material profiles. Specifically, metal profiles are used, and in one embodiment, for example, high-strength Q235 / Q355 thin-walled square steel, lightweight aluminum alloy profiles, or rigid composite material profiles are used. Preferably, for example, pultruded fiberglass profiles are used to ensure high elastic modulus and high yield strength.

[0036] The aforementioned structure ensures that the mesh-like skeleton 121 possesses both rigidity and load-bearing capacity. This allows the composite shell 1 to effectively resist the severe dynamic loads caused by concentrated forces at the lifting points during hoisting and by torque and shear forces resulting from road bumps during transportation, ensuring structural safety and stability, and guaranteeing the structure's integrity and fatigue durability. Furthermore, welding creates rigid nodes between the members, making the entire mesh-like skeleton 121 a monolithic structure. Compared to bolt or rivet connections, rigid connections enhance the overall torsional stiffness of the skeleton. This is particularly crucial for structures like mobile homes that require repeated transportation and hoisting, effectively preventing loosening or fatigue failure at connections due to long-term vibration, thus ensuring long-term structural durability.

[0037] In addition, profiles can be I-shaped, C-shaped, or hollow tubular, which can provide the maximum moment of inertia with the least amount of material.

[0038] When aluminum alloy or composite material profiles are selected, the weight of the frame itself can be reduced to the greatest extent while ensuring the aforementioned high strength. This lightweight design not only reduces transportation costs and the requirements for hoisting equipment, but also alleviates the shear force burden on the foam core layer 12.

[0039] Understandably, when foam raw materials such as polyurethane are subsequently injected into the mold cavity for foaming, the foaming process will generate certain expansion pressure and chemical reaction heat. Using a rigid, dimensionally stable mesh skeleton 121 as an inner mold can ensure that the geometry of the entire composite shell 1 remains accurate and undeformed during the foaming process, and ensure that the foam can be uniformly and densely filled around the skeleton.

[0040] Preferably, the fiber-reinforced polymer outer shell layer 11 includes a resin matrix and a glass fiber cloth or carbon fiber cloth disposed in the resin matrix.

[0041] Specifically, glass fiber cloth or carbon fiber cloth are high-performance reinforcing materials, far exceeding the tensile strength of steel; while the resin matrix, such as epoxy resin or unsaturated polyester, serves to bond the fibers, transfer loads, and protect them. In this embodiment, the fiber-reinforced polymer outer shell layer 11 achieves high specific strength and specific modulus after combining the two. It is understood that this provides equal or even higher structural strength and stiffness at a much lighter weight than steel or aluminum alloys. This allows the fiber-reinforced polymer outer shell layer 11 to effectively withstand tensile, compressive, and bending stresses, while also ensuring an overall lightweight design.

[0042] It should be noted that the fiber-reinforced polymer outer shell layer 11 possesses corrosion-resistant and waterproof properties. It can resist erosion from various harsh weather conditions such as ultraviolet radiation, acid rain, and salt spray. This ensures the mobile homestay's enclosure structure has a long service life and extremely low maintenance costs. Furthermore, by incorporating fiberglass or carbon fiber cloth into the resin matrix, the multidirectional fiber weave structure of the fiberglass or carbon fiber cloth allows stress to be rapidly dispersed in multiple directions upon impact. This gives the fiber-reinforced polymer outer shell layer 11 high toughness and impact resistance, enabling it to absorb a large amount of impact energy and maintain structural integrity.

[0043] Preferably, the glass fiber cloth or carbon fiber cloth has a multi-layer stacked structure.

[0044] It is understood that this embodiment employs multi-layer stacking to increase its bending stiffness. This enhances the overall bending and buckling resistance of the entire composite shell 1. When the outer shell layer 11 is subjected to external point impacts, such as from flying stones or tools during transportation, the impact energy is dissipated between layers through minute interlayer delamination. Crack propagation is confined to a single layer, preventing potentially penetrating failure as seen in single-layer thick plates or brittle materials. This improves the durability and safety of the building.

[0045] Preferably, the microporous sound-absorbing inner lining 122 is composed of a metal or polymer perforated panel and a non-woven sound-absorbing felt disposed between the perforated panel and the load-bearing foam-filled core layer 12.

[0046] Specifically, the microporous sound-absorbing inner lining 122 is made of a perforated metal or polymer panel. When indoor noise, especially mid-frequency noise such as human voices and television sounds, is incident, it excites the air columns in these micropores to resonate. At this time, the non-woven sound-absorbing felt placed behind it dissipates the resonant sound energy and converts it into heat energy through the viscous friction and thermal conduction of its internal fibers. This absorbs indoor reverberation noise in a specific frequency band, solves the defect of poor sound absorption capacity of traditional materials, and improves indoor speech intelligibility.

[0047] Preferably, the load-bearing foam filling core layer 12 is a rigid polyurethane foam layer or an extruded polystyrene foam layer.

[0048] Specifically, rigid polyurethane foam and extruded polystyrene, unlike ordinary EPS foam, can act as rigid connectors, transmitting shear forces between the inner and outer skins to ensure overall structural integrity.

[0049] This invention automatically integrates the functions of a thermal insulation core material while selecting the structural core material. It avoids the cumbersome, multi-step process of first constructing the structural frame and then separately filling it with insulation cotton, as is required with light steel or wood frames in the prior art. This embodiment provides thermal comfort while ensuring structural performance.

[0050] Preferably, the composite housing 1 is further provided with a window opening 2, and the window opening 2 is fitted with a multi-layer hollow soundproof glass window 3, the frame of the glass window 3 is sealed to the composite housing 1 by sealant.

[0051] Specifically, continuous and seamless filling and bonding using sealants such as polyurethane or silicone weather-resistant sealants ensures the sound insulation integrity of the entire building envelope, making the sound insulation performance of the windows match that of the walls. To accommodate differential deformation between different materials, it should be noted that the frames of the composite shell 1 and the glass window 3 are typically made of aluminum alloy or PVC, which have different coefficients of thermal expansion. If rigid connections are used with cement mortar, the joints will crack and fail under thermal expansion and contraction. However, sealant is a highly elastic material. Its own elastic deformation can absorb and buffer differential deformation between different materials, ensuring that the sealed connection remains intact and effective even under long-term diurnal temperature variations, thus improving the durability of the structure.

[0052] Preferably, the glass window 3 comprises at least two layers of glass spaced apart, with a vacuum-sealed interlayer formed between the glass panes, or filled with argon gas.

[0053] Specifically, argon is an inert gas with a density much greater than air and a thermal conductivity much lower than air. Filling the glass window with argon can greatly suppress gas convection within the glass interlayer and reduce heat transfer. Both vacuum and argon filling improve the thermal insulation performance of the glass window 3. Furthermore, the glass window 3 comprises at least two layers of glass spaced apart, forming a vacuum-sealed interlayer or a structure filled with argon, thus enhancing its sound insulation performance.

[0054] Preferably, the glass window 3 comprises three layers of glass spaced apart, with two interlayers formed between the glass panes.

[0055] Understandably, different glass thicknesses, such as 6mm, 4mm, and 6mm, or different interlayer thicknesses, such as 12mm + 16mm, can be used to stagger the resonant frequency points of different combinations. This allows the window to have stable sound insulation performance throughout the entire mid-to-low frequency range.

[0056] To ensure the airtightness and sound insulation integrity of the window installation, the frame of the glass window 3 is sealed to the composite shell 1 with a sealant (such as weather-resistant silicone sealant) for the first layer of sealing. Furthermore, an EPDM rubber sealing strip is filled between the frame of the glass window 3 and the inner wall of the window opening 2 of the composite shell 1 as a second layer of elastic sealing, ensuring a seamless connection and completely eliminating sound and air leakage.

[0057] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the scope of protection of the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the scope of protection of the present utility model.

Claims

1. A mobile homestay with a noise reduction structure, characterized in that, The device includes a composite shell, comprising a fiber-reinforced polymer outer shell layer and a load-bearing foam-filled core layer. The load-bearing foam-filled core layer is disposed inside the fiber-reinforced polymer outer shell layer. The load-bearing foam-filled core layer has a mesh-like skeleton inside and a microporous sound-absorbing liner layer filled on the mesh-like skeleton. The fiber-reinforced polymer outer shell layer, the load-bearing foam-filled core layer, and the microporous sound-absorbing liner layer are sequentially and fixedly connected.

2. The mobile homestay with noise reduction structure according to claim 1, characterized in that, The mesh-like frame is welded from metal profiles or rigid composite material profiles.

3. The mobile homestay with noise reduction structure according to claim 1, characterized in that, The fiber-reinforced polymer outer shell layer includes a resin matrix and glass fiber cloth or carbon fiber cloth disposed in the resin matrix.

4. The mobile homestay with noise reduction structure according to claim 3, characterized in that, The glass fiber cloth or carbon fiber cloth has a multi-layer stacked structure.

5. The mobile homestay with noise reduction structure according to claim 1, characterized in that, The microporous sound-absorbing liner is composed of a metal or polymer perforated panel and a non-woven sound-absorbing felt disposed between the perforated panel and the load-bearing foam-filled core layer.

6. The mobile homestay with noise reduction structure according to claim 1, characterized in that, The load-bearing foam filling core layer is a rigid polyurethane foam layer or an extruded polystyrene foam layer.

7. The mobile homestay with noise reduction structure according to claim 1, characterized in that, The composite shell is also provided with a window opening, and the window opening is fitted with a multi-layer hollow soundproof glass window. The frame of the glass window is sealed to the composite shell with sealant.

8. The mobile homestay with noise reduction structure according to claim 7, characterized in that, The glass window comprises at least two layers of glass spaced apart, with a vacuum-sealed interlayer between the glass layers, or filled with argon gas.

9. The mobile homestay with noise reduction structure according to claim 8, characterized in that, The glass window comprises three layers of glass spaced apart, with two interlayers formed between the glass panes.

10. The mobile homestay with noise reduction structure according to claim 8, characterized in that, An EPDM rubber sealing strip is filled between the frame of the glass window and the inner wall of the window opening of the composite housing.

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