Fiber-reinforced instrument board for inhibiting blasting splashing of air bag and preparation method of fiber-reinforced instrument board

Abstract

The invention discloses a fiber-reinforced instrument panel for inhibiting blasting and splashing of an air bag and a preparation method of the fiber-reinforced instrument panel. The instrument panel comprises a high-toughness bearing framework layer, a gradient energy guide layer and a high-ductility surface layer from inside to outside. And the dynamic tear propagation resistance of the gradient energy guide layer is accurately set in a range which is greater than the dynamic energy release rate of the blasting of the air bag and less than the tear resistance of the bearing framework layer. Therefore, under the impact of the air bag, the cracks of the instrument desk can be uniquely subjected to controllable zipper type tearing along the preset gradient layer path instead of random fragmentation, so that fragment splashing is fundamentally inhibited. The invention further provides an integrated preparation method of the instrument desk, and a product with a complex gradient structure is efficiently and accurately manufactured through compression molding of the framework and a multi-material co-extrusion and secondary injection molding combined process. The passive safety of the automobile is greatly improved, and light weight and low cost are both considered.

Description

Technical Field

[0001] This invention belongs to the field of automotive passive safety technology, specifically relating to an automotive dashboard, and more particularly to a fiber-reinforced dashboard and its integrated manufacturing method that actively guides the energy release path, controls tearing, and completely suppresses fragment splashing when the airbag deploys through a built-in gradient functional structure. Background Technology

[0002] With the rapid development of the automotive industry, passive safety performance has become one of the core indicators for measuring vehicle quality. As a crucial protective device, the reliability of airbags is paramount. When a vehicle collides, the airbag inflator detonates instantly, generating high-temperature, high-pressure gas that forces its way through the pre-set rupture point on the dashboard with tremendous impact, rapidly deploying into a protective airbag.

[0003] Traditional dashboards are mostly made of common thermoplastics (such as PP and ABS) or polyurethane foam. These materials have limited toughness and fracture toughness. Under the instantaneous impact of airbag deployment, the material around the rupture point is prone to brittle fracture, forming sharp fragments of varying sizes and irregular shapes. These fragments fly into the vehicle at extremely high speeds, causing serious secondary injuries and greatly weakening the protective effect of the airbag.

[0004] To address this problem, existing technologies have proposed several improvements, such as:

[0005] Increasing the thickness of the TPO skin or adding reinforcing ribs: While this method can increase strength to some extent, it will lead to an increase in the weight of the dashboard and higher costs. Furthermore, it has limited effect on suppressing irregular fragments and cannot fundamentally change the material's fracture mode.

[0006] Using a metal frame: a metal plate is embedded inside the dashboard, but the bonding force between metal and plastic is weak, making it easy to delaminate and significantly increasing the weight, which runs counter to the vehicle's lightweight goal.

[0007] High-toughness engineering plastics, such as PC / ABS alloys, are used, but they are expensive, and even under extreme conditions of airbag explosion, it is still difficult to completely avoid the generation of fragments. Their fracture behavior still has a certain degree of randomness and unpredictability.

[0008] In summary, current technologies largely rely on a "passive reinforcement" approach, which involves increasing the overall strength of materials to resist impact. However, this approach fails to address the uncontrollability of fracture modes. Therefore, developing a dashboard that can actively and controllably guide the fracture process, cracking in a controlled manner and effectively suppressing debris ejection, from the perspectives of materials science and structural design, is a pressing technical challenge in the field of automotive passive safety. Summary of the Invention

[0009] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0010] This invention aims to overcome the shortcomings of existing technologies and provide a gradient energy-guided anti-splash fiber-reinforced instrument panel and its preparation method. The core technical problem it addresses is how to prevent the instrument panel from passively and unpredictably fracturing when subjected to the instantaneous, high-energy impact of an airbag rupture. Instead, it should actively and controllably tear along a specific path according to a pre-set physical model, efficiently absorbing energy during the process and eliminating the generation of splash fragments at the source.

[0011] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a fiber-reinforced instrument panel for suppressing airbag deployment spatter, comprising: a load-bearing skeleton layer; a skin layer; and a gradient energy guiding layer disposed between the load-bearing skeleton layer and the skin layer; wherein the gradient energy guiding layer is located in the airbag cover area of ​​the instrument panel, and the dynamic tear propagation resistance G of the gradient energy guiding layer is... dpath The dynamic tear propagation resistance G of the supporting skeleton layer is less than dcore .

[0012] As a preferred embodiment of the fiber-reinforced dashboard for suppressing airbag blasting splashes according to the present invention, the gradient energy guiding layer is composed of a polymer matrix containing chopped reinforcing fibers.

[0013] As a preferred embodiment of the fiber-reinforced instrument panel for suppressing airbag rupture spatter according to the present invention, wherein: within the gradient energy guiding layer, at least one microstructural parameter of the chopped reinforcing fibers is gradient-distributed, and the microstructural parameter is selected from volume fraction, orientation angle and length.

[0014] As a preferred embodiment of the fiber-reinforced instrument panel for suppressing airbag explosion splash as described in this invention, wherein: in the thickness direction of the gradient energy guiding layer, the orientation angle of the chopped reinforcing fibers decreases from the center to both sides.

[0015] As a preferred embodiment of the fiber-reinforced dashboard for suppressing airbag rupture spatter as described in this invention, the volume fraction of chopped reinforcing fibers remains constant or varies in a gradient along the tear propagation direction of the gradient energy guiding layer.

[0016] As a preferred embodiment of the fiber-reinforced dashboard for suppressing airbag blasting as described in this invention, the load-bearing skeleton layer is made of natural fibers and thermoplastic resin.

[0017] As a preferred embodiment of the fiber-reinforced dashboard for suppressing airbag blasting splashes according to the present invention, the length of the natural fibers is 40-150 mm.

[0018] As a preferred embodiment of the fiber-reinforced dashboard for suppressing airbag blasting splashes according to the present invention, the outer skin layer is made of thermoplastic polyolefin, polyvinyl chloride or polyurethane.

[0019] To solve the above-mentioned technical problems, the present invention also provides the following technical solution: a method for preparing a fiber-reinforced dashboard that suppresses airbag bursting splash, comprising the following steps: a) molding a load-bearing skeleton layer; b) forming a gradient energy guiding layer on the airbag cover area of ​​the load-bearing skeleton layer; c) injecting a skin layer onto the component obtained in step b) to achieve integrated molding.

[0020] As a preferred embodiment of the fiber-reinforced dashboard fabrication method for suppressing airbag bursting splashes according to the present invention, wherein: the gradient energy guiding layer in step b) is formed by a multi-material co-extrusion process; the multi-material co-extrusion process forms a gradient energy guiding layer with a gradient structure by controlling the material composition of at least two feed ports; in step c), a pneumatic positioning device is used to fix the component obtained in step b) into the cavity of the injection mold.

[0021] Compared with the prior art, the present invention has the following significant advantages:

[0022] By using a "zipper-like" controlled tearing mechanism, fragments caused by random material breakage are completely eliminated, fundamentally preventing the risk of secondary injury and elevating passive safety to a new level.

[0023] High-strength functions are concentrated in the load-bearing skeleton layer, while key protective functions are cleverly achieved through a thin gradient guiding layer, avoiding excessive use of overall materials and maximizing lightweighting.

[0024] This invention is the first to apply fracture mechanics models to dashboard design. Engineers can accurately calculate the required gradient guide layer parameters based on the airbag energy input of different vehicle models, achieving a leap from "experience-based trial and error" to "scientific quantitative design" and greatly shortening the R&D cycle.

[0025] The core function is achieved by combining the microstructure of inexpensive natural fibers and ordinary plastics, which has a huge cost advantage compared to expensive engineering plastics or metal inserts and is easy to promote and apply on a large scale. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0027] Figure 1 The flowchart illustrates the method for fabricating a fiber-reinforced dashboard that suppresses airbag blasting splashes, as provided by this invention. Detailed Implementation

[0028] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0029] This invention aims to overcome the shortcomings of existing technologies and provide a gradient energy-guided anti-splash fiber-reinforced instrument panel and its preparation method. The core technical problem it addresses is how to prevent the instrument panel from passively and unpredictably fracturing when subjected to the instantaneous, high-energy impact of an airbag rupture. Instead, it should actively and controllably tear along a specific path according to a pre-set physical model, efficiently absorbing energy during the process and eliminating the generation of splash fragments at the source.

[0030] Specifically, the present invention provides a fiber-reinforced dashboard for suppressing airbag blast splash, comprising: a load-bearing skeleton layer; a skin layer; and a gradient energy guiding layer disposed between the load-bearing skeleton layer and the skin layer;

[0031] The gradient energy guiding layer is located in the airbag cover area of ​​the instrument panel, and the dynamic tear propagation resistance G of the gradient energy guiding layer is... dpath The dynamic tear propagation resistance G of the supporting skeleton layer is less than dcore .

[0032] Furthermore, the gradient energy guiding layer is composed of a polymer matrix containing chopped reinforcing fibers.

[0033] Furthermore, within the gradient energy guiding layer, at least one microstructural parameter of the chopped reinforcing fiber exhibits a gradient distribution, and the microstructural parameter is selected from volume fraction, orientation angle, and length.

[0034] Furthermore, in the thickness direction of the gradient energy guiding layer, the orientation angle of the chopped reinforcing fibers decreases from the center to both sides.

[0035] Furthermore, in the tear propagation direction of the gradient energy-guided layer, the volume fraction of chopped reinforcing fibers remains constant or varies with a gradient.

[0036] Specifically, the supporting skeleton layer is made of natural fibers and thermoplastic resin.

[0037] Specifically, the length of natural fibers is 40-150 millimeters.

[0038] Specifically, the outer skin layer is made of thermoplastic polyolefin, polyvinyl chloride, or polyurethane.

[0039] It should be noted that:

[0040] This invention proposes an instrument panel design based on the theory of "dynamic tear energy threshold control". By constructing a special transition layer (gradient energy guiding layer) with gradient changes in material properties and structural strength, when the impact energy reaches and exceeds the dynamic tear energy threshold of this layer, the crack will preferentially and uniquely propagate along this layer, thereby guiding the material to undergo a stable "zipper-like" tear rather than catastrophic fragmentation.

[0041] To achieve this theory, the present invention provides a fiber-reinforced dashboard that suppresses airbag rupture splash, which comprises, from the inside out (i.e. from the side closest to the airbag to the outside), a high-toughness load-bearing skeleton layer, a gradient energy guiding layer, and a highly ductile skin layer.

[0042] Specifically:

[0043] High-toughness load-bearing skeleton layer: This layer is the core strength support of the dashboard, made of long natural fibers and thermoplastic resin through a molding process. Its characteristic is extremely high fracture toughness (K... IC This ensures sufficient rigidity and strength during normal use, while providing basic energy absorption capacity under airbag impact to prevent sudden structural breakage. Preferably, the natural fiber is at least one of bamboo fiber, wood fiber, or hemp fiber, with a length of 40-150 mm. The thermoplastic resin is polypropylene (PP) or ethylene-vinyl acetate copolymer (EVA).

[0044] Gradient Energy Guiding Layer: A thin functional layer located above the supporting skeleton layer in the airbag cover region. Its key feature is the dynamic tear propagation resistance (G) of this layer. dpath The tear path, typically a U-shaped loop around the airbag cover, is precisely designed and controlled to create a "preferred tear channel" with minimal energy barrier. This layer comprises a tough resin matrix containing chopped reinforcing fibers, the orientation, concentration, and type of which vary gradients along both the path thickness direction (Z-axis) and the tear propagation direction (X-axis). This gradient microstructure design allows for precise control of the layer's resistance to crack propagation, i.e., G... dpath value.

[0045] High-ductility skin layer: This is the outermost layer of the dashboard, typically made of thermoplastic polyolefin (TPO), polyvinyl chloride (PVC), or polyurethane (PU), offering a pleasant feel and appearance. This layer possesses sufficient ductility (elongation at break greater than 200%) to significantly stretch and deform following the tearing of the gradient energy-guided layer, without breaking itself, ultimately encapsulating the torn material.

[0046] This invention introduces a "dynamic tear energy matching formula" for design to ensure that energy can be perfectly guided and dissipated during airbag deployment.

[0047] To ensure that cracks are precisely "locked" within the gradient energy guiding layer, this invention establishes the following design principles:

[0048] G d < G dpath < G dcore

[0049] in:

[0050] G d (Dynamic Energy Release Rate): The dynamic energy release rate, measured in J / m², represents the energy released by the system per unit area of ​​crack propagation. This value is primarily determined by the total energy released during airbag rupture (E). impact The force of crack propagation is determined by the overall structural rigidity of the dashboard and is an input physical quantity that varies depending on the specific vehicle model and airbag configuration. It originates from the description of crack driving force under dynamic impact in fracture mechanics.

[0051] G dpath (Dynamic Tear Propagation Resistance of the Gradient Layer): This is the dynamic tear propagation resistance of the gradient energy-guided layer. It is a key controllable variable in this invention, measured in J / m². It represents the energy required for the crack to propagate stably within the guide layer. This value is not a constant, but rather a "target threshold" achieved through the design of the material's microstructure.

[0052] It should be noted that: G dpath It is determined by the following microstructure parameters:

[0053] f s (Volume Fraction of Short Fibers): The volume fraction of short-cut reinforcing fibers within the guiding layer. More fibers result in greater resistance to crack propagation (bridging effect), and G... dpath The higher.

[0054] θ (Fiber Orientation Angle): The angle between the fiber and the predetermined tear path direction. When θ = 90° (fiber perpendicular to the path), the bridging and deflection effect on the crack is strongest, G dpath The effect is strongest when θ = 0° (fiber parallel to the path), G. dpath lowest.

[0055] l f (Fiber Length): The length of the chopped fiber. Within a certain range, the longer the fiber, the more pronounced the bridging effect. dpath The higher.

[0056] τ i Interfacial Shear Strength: The interfacial shear strength between the fiber and the resin matrix. Better interfacial bonding results in higher stress transfer efficiency. dpath The higher.

[0057] By adjusting the spatial distribution of the above parameters within the guide layer (e.g., θ=90° at the path center, f...), s Higher; θ decreases at the path edge, f s (Lowering), can precisely shape a path with a specific G dpath The value of the "tear channel".

[0058] G dcore (Dynamic Tear Propagation Resistance of the Core Skeleton): The dynamic tear propagation resistance of the core skeleton layer. The unit is J / m². It represents the energy required for a crack to penetrate the rigid core skeleton layer.

[0059] It should be noted that this value is primarily determined by the material system of the skeleton layer. Due to the use of long, continuous, or extremely high aspect ratio natural fibers, the fracture mechanism is mainly fiber pull-out and breakage, resulting in extremely high energy absorption efficiency. Therefore, G... dcore Much greater than G dpath .

[0060] Formula Explanation and Creation Logic: The essence of this formula lies in establishing a "gradient" of energy barrier.

[0061] G d < G dpath : Ensure the energy (G) of airbag deployment d ) is enough to "ignite" the tearing process of the guide layer. If G d Less than G dpathThe airbag cover couldn't even open properly, which is the lower limit of the design.

[0062] G dpath < G dcore This is the most critical condition for achieving "controlled tearing." Once a crack is initiated within the guide layer, it will find it much easier to continue along this "path of least resistance" than to "struggle" to penetrate the high-toughness load-bearing skeleton layer (G). dcore It is much easier. Therefore, the crack will be physically "trapped" within the gradient energy guiding layer and will extend along a preset path, achieving an effect similar to a zipper being unzipped, with energy being dissipated in a stable and controllable manner.

[0063] This design philosophy upgrades the traditional "passive resistance" to "active guidance," representing an innovation in the paradigm of fracture control.

[0064] For additional information, please refer to [link / reference]. Figure 1 The present invention also provides a method for preparing the above-mentioned dashboard, comprising the following steps:

[0065] a) Compression molding – load-bearing skeleton layer;

[0066] b) A gradient energy guiding layer is formed on the airbag cover area that supports the skeleton layer;

[0067] c) An epidermal layer is injected onto the component obtained in step b) to achieve integrated molding.

[0068] Furthermore, the gradient energy guiding layer in step b) is formed using a multi-material co-extrusion process;

[0069] Multi-material co-extrusion process controls the material composition of at least two feed ports to form a gradient energy guiding layer with a gradient structure;

[0070] In step c), a pneumatic positioning device is used to fix the component obtained in step b) into the cavity of the injection mold.

[0071] To better understand the technical solution of the present invention, the following specific embodiments are provided for illustrative purposes:

[0072] Example 1: Standard Application in Compact Cars

[0073] 1.1 Design Inputs and Theoretical Calculations

[0074] Vehicle background: A compact sedan, sensitive to cost and lightweight design.

[0075] Input parameters: Based on CAE simulation, the dynamic energy release rate G_d, calculated from the impact energy of the driver's side airbag explosion, is 1800 J / m².

[0076] The skeleton layer was selected from low-cost and environmentally friendly bamboo fiber (120mm in length) / polypropylene (PP) composite materials.

[0077] The dynamic tear propagation resistance G of the sample made from this material was obtained by testing it. dcore ≈ 5200 J / m².

[0078] Target threshold determination:

[0079] According to formula G d < G dpath < G dcore That is, 1800 < G dpath < 5200.

[0080] To ensure reliable triggering and provide sufficient safety margin, a value slightly above the middle is chosen to set the target G. dpath = 2500 J / m².

[0081] 1.2 Design of Gradient Energy Guiding Layer

[0082] Objective: To achieve G dpath = 2500 J / m².

[0083] Material system: PP matrix, chopped glass fiber reinforcement.

[0084] Structural design: Three-layer symmetrical co-extrusion structure with a total thickness of 1.2 mm.

[0085] Central tear layer (0.5 mm): To provide maximum resistance, the fibers are perpendicular to the tear path.

[0086] f s = 30% (volume fraction), θ = 90° (orientation angle), l f = 3 mm (length).

[0087] Transition layer (0.35 mm on each side): Provides a smooth transition and reduces stress concentration.

[0088] f s = 20%, θ = 60°, l f = 2 mm.

[0089] Bonding layer (0.15 mm on each side): to ensure interfacial bonding with the skeleton and epidermis.

[0090] f s = 10%, θ = 30°, l f = 1 mm.

[0091] 1.3 Calculation and Analysis

[0092] Calculation: Using finite element analysis software, a material constitutive model incorporating the aforementioned microscopic parameters was established. Simulation results show that under impact loading, the energy consumed per unit area (i.e., G) as the crack propagates along this gradient structure is... dpath The stable value is 2480 J / m², with an error of only 0.8% from the target value of 2500 J / m², which is within the design allowable range.

[0093] analyze:

[0094] Numerical matching: The calculated values ​​are in high agreement with the target values, proving the feasibility of precisely controlling macroscopic tearing performance through microstructural gradient design.

[0095] Process feasibility: The three-layer structure can be achieved through a standard three-layer co-extrusion unit. The process is mature and the cost is controllable.

[0096] Effect prediction: G d (1800) < G dpath (2480) < G dcore (5200), the inequality holds. Theoretically, the airbag energy is sufficient to tear the guiding layer, but far from sufficient to penetrate the skeleton layer; the tearing behavior will be completely confined within the preset path.

[0097] Example 2: High-performance application in luxury SUVs

[0098] 2.1 Design Inputs and Theoretical Calculations

[0099] Vehicle background: Mid-to-large luxury SUV, heavier body, equipped with larger airbags, and higher impact energy.

[0100] Input parameters: Based on bench testing, the G value of the driver's side airbag deployment... d = 4800 J / m².

[0101] The skeleton layer was selected from high-performance long hemp fiber / nylon 6 (PA6) composite materials to provide higher basic strength and temperature resistance.

[0102] The dynamic tear propagation resistance G was obtained from the test. dcore ≈ 9500 J / m².

[0103] Target threshold determination:

[0104] According to 4800 < G dpath < 9500.

[0105] Set target G dpath = 5500 J / m².

[0106] 2.2 Design of Gradient Energy Guiding Layer

[0107] Objective: To achieve G dpath = 5500 J / m².

[0108] Structural design: To achieve higher resistance and optimize cost, an asymmetric five-layer hybrid fiber design is adopted, with a total thickness of 1.8 mm. The matrix is ​​PA6.

[0109] Layer 1 (closest to the skeleton, 0.3 mm): f s =15%, chopped glass fiber, θ=45°, to ensure good adhesion.

[0110] Layer 2 (transition layer, 0.4 mm): f s =25%, short-cut glass fiber, θ=75°.

[0111] Layer 3 (main tear layer, 0.6 mm): f s =30%, short-cut carbon fiber, θ=90°. The high modulus of carbon fiber provides the main drag.

[0112] Layer 4 (transition layer, 0.3 mm): f s =20%, short-cut glass fiber, θ=60°.

[0113] Layer 5 (closest to the epidermis, 0.2 mm): f s =10%, short-cut glass fiber, θ=30°, optimized compatibility with PU surface.

[0114] 2.3 Calculation and Analysis

[0115] Calculation: In the FEA simulation, the effect of the carbon fiber layer on G dpath The contribution is significant. The simulated comprehensive G dpath The value is 5620 J / m², which is 2.2% different from the target of 5500 J / m².

[0116] analyze:

[0117] Hybrid effect: Carbon fibers provide extremely high strength and modulus, which is essential for achieving high G. dpath The key is the use of fiberglass, which balances the cost. The asymmetrical design allows for fine-tuning to meet the different needs of the connectors on both sides, offering a high degree of design freedom.

[0118] Cost and performance balance: By using expensive carbon fiber only in the critical main tear layer, a balance between maximizing performance and optimizing cost is achieved.

[0119] Effect prediction: G d (4800) < G dpath(5620) < G dcore (9500), the inequality holds. This design can effectively cope with impacts of higher energy.

[0120] Example 3: Low-cost solution for economical electric vehicles

[0121] 3.1 Design Inputs and Theoretical Calculations

[0122] Vehicle background: Entry-level electric vehicles, which are extremely sensitive to cost, but still need to meet basic passive safety requirements.

[0123] Input parameters: The vehicle's airbags are relatively small, resulting in relatively low impact energy (G). d = 1200 J / m².

[0124] Selection of the skeleton layer: The most economical wood fiber / PP composite material was selected.

[0125] The dynamic tear propagation resistance G was obtained from the test. dcore ≈ 4500 J / m².

[0126] Target threshold determination:

[0127] According to 1200 < G dpath < 4500.

[0128] To reduce costs, a lower threshold is chosen, and the target G is set. dpath = 1800 J / m².

[0129] 3.2 Design of Gradient Energy Guiding Layer

[0130] Objective: To achieve G at the lowest cost dpath = 1800 J / m².

[0131] Structural design: Employs a simplified double-layer structure with a total thickness of 0.8 mm. PP matrix.

[0132] Layer A (main layer, 0.6 mm): f s =12%, chopped aramid fiber. Aramid fiber has much greater toughness and energy absorption capacity than glass fiber, and can achieve the required resistance at low content.

[0133] Layer B (adhesive layer, 0.2 mm): pure PP, fiber-free, ensuring perfect fusion with the skeleton layer.

[0134] 3.3 Calculation and Analysis

[0135] Calculations show that aramid fibers exhibit excellent toughness, which is particularly evident in the simulation. The G of the double-layer structure... dpathThe calculated value is 1750 J / m², which is very close to the target of 1800 J / m².

[0136] analyze:

[0137] Material innovation: Using low-content high-strength, high-toughness aramid fibers instead of higher-content ordinary glass fibers, although the unit price is slightly higher, the total usage and processing energy consumption are reduced, and the final cost may be lower.

[0138] Simplified structure: The double-layer structure reduces the requirements for co-extrusion equipment, and even allows for a two-step process (coating one layer first, then coating the other), further lowering the production threshold and cost.

[0139] Lightweight: The low fiber content and the lower density of aramid compared to glass fiber achieve further weight reduction.

[0140] Effect prediction: G d (1200) < G dpath (1750) < G dcore (4500), the inequality holds, which satisfies the safety requirements of low-cost vehicle models.

[0141] Example 4: Extreme Design of High-Performance Sports Cars

[0142] 4.1 Design Inputs and Theoretical Calculations

[0143] Vehicle background: Sports cars that pursue ultimate performance have high impact speeds, requiring airbags to deploy faster and more powerfully, resulting in extremely high impact energy.

[0144] Input parameters: G obtained from its high-speed collision simulation d = 7200 J / m².

[0145] Selection of the skeleton layer: Regardless of cost, the top-grade continuous carbon fiber / polyether ether ketone (PEEK) composite material was selected.

[0146] The dynamic tear propagation resistance G was obtained from the test. dcore ≈ 15000 J / m².

[0147] Target threshold determination:

[0148] According to 7200 < G dpath < 15000.

[0149] Set target G dpath = 8500 J / m².

[0150] 4.2 Design of Gradient Energy Guiding Layer

[0151] Objective: To achieve ultra-high and stable G dpath= 8500 J / m².

[0152] Structural design: A functionally graded seven-layer variable thickness design is adopted, with a total thickness of 2.0 mm at the center of the path, gradually thinning to 1.2 mm towards both sides. The substrate is PEEK.

[0153] The three central layers: are the core of resistance, f s The fiber content increases from 25% to 35%, and the angle (θ) ranges from 75° to 90°. The fiber is a short-cut carbon fiber with an extremely high aspect ratio.

[0154] The two layers on both sides are transition layers, f s The percentage decreases from 20% to 10%, and θ decreases from 60° to 30°.

[0155] The outermost two layers are interface layers, made of pure PEEK or with very low fiber content (<5%), ensuring atomic-level bonding with the carbon fiber skeleton and polyurethane skin.

[0156] 4.3 Calculation and Analysis

[0157] Calculation: Complex gradient models require multi-scale simulations. The final calculation results show that, due to the synergistic effect of variable thickness and ultra-high fiber content, the G in the central region... dpath It stabilizes at 8650 J / m².

[0158] analyze:

[0159] Ultimate security redundancy: G dpath Much greater than G d It provides an extremely high safety margin, ensuring controllable tearing behavior even under extreme temperatures or material aging conditions.

[0160] Maximizing energy absorption: The variable thickness design makes the guide layer thicker and stronger at the corners of the tear path (usually U-shaped) where stress is more concentrated, thus avoiding accidental penetration at weak points.

[0161] Process challenges: Seven-layer co-extrusion with a gradual thickness requires extremely high-performance equipment, but this complexity serves the ultimate performance.

[0162] Example 5: Large-size application of commercial heavy trucks

[0163] 5.1 Design Inputs and Theoretical Calculations

[0164] Vehicle background: Heavy-duty truck cab, with a huge dashboard, thick walls, and long airbag cover. Macroscopic structural stability is key.

[0165] Input parameters: Due to its large structure and dispersed energy, the local impact force is still very large, equivalent to G. d = 2800 J / m².

[0166] Selection of the skeleton layer: Basalt fiber / PP composite material with good weather resistance and moderate cost is selected.

[0167] The dynamic tear propagation resistance G was obtained from the test. dcore ≈ 7000 J / m².

[0168] Target threshold determination:

[0169] According to 2800 < G dpath < 7000.

[0170] Considering the uneven deformation of large-sized parts, a higher margin is adopted, and the target G is set. dpath = 3200 J / m².

[0171] 5.2 Design of Gradient Energy Guiding Layer

[0172] Objective: To achieve uniform and stable tearing along a tear path up to 600 mm long.

[0173] Structural design: A composite design of macroscopic structural guidance and microscopic gradient is adopted.

[0174] Macroscopic guidance: A 20mm wide aramid fiber woven mesh with a 2mm aperture is pre-placed within the PP matrix. This mesh itself provides extremely high macroscopic tear resistance and defines a precise tear path.

[0175] Micro-gradient: Two layers of gradient material, each 0.6 mm thick, are co-extruded onto the top and bottom sides of the aramid web.

[0176] Gradient layer near the skeleton: PP matrix, short-cut basalt fibers, f s The percentage increases from 15% to 25%, and θ increases from 45° to 75°.

[0177] Gradient layer near the epidermis: PP matrix, chopped glass fiber, f s The percentage increases from 10% to 20%, and θ increases from 30° to 60°.

[0178] 5.3 Calculation and Analysis

[0179] Calculation: This model requires treating the aramid mesh as discrete cable elements. Simulation results show that the aramid mesh bears approximately 60% of the tearing energy, while the gradient layers on both sides provide 40% energy absorption and ensure uniform load transfer. (Combined G) dpath The value is 3300 J / m².

[0180] analyze:

[0181] Macro-micro synergy: The aramid mesh provides the "absolute path" and the main resistance, solving the path deviation problem that may be caused by uneven deformation in large-sized parts. The micro-gradient ensures that there are no stress singularities between the mesh and the resin matrix, achieving a smooth load transition and avoiding delamination caused by "hard-on-hard" contact.

[0182] Manufacturing feasibility: The process of pre-laying aramid mesh is relatively mature, similar to pre-laying fabric. Co-extrusion coating is also easy to achieve. This solution cleverly combines two mature processes to solve a complex problem.

[0183] Effect prediction: G d (2800) < G dpath (3300) < G dcore (7000), the inequality holds. This design provides a reliable and economical solution for tear control in large, thick-walled components.

[0184] In summary, the examples are summarized as follows:

[0185] Summary table of examples

[0186] Example Vehicle Model / Application Supporting skeleton layer material <![CDATA[Gradient guiding layer target G dpath (J / m²)]]> Gradient-guided layer core design features Surface material Key Analysis Points 1 compact cars Bamboo fiber / PP 2500 Symmetrical three-layer fiberglass, center θ=90° TPO Standard application to verify the effectiveness of the base model 2 Luxury SUV Long linen fiber / PA6 5500 Asymmetric five-layer, carbon fiber / glass fiber hybrid PU Hybrid fibers and complex gradient design under high-energy impact 3 Economy electric vehicles Wood fiber / PP 1800 Double-layered, low-fiber-content, low-cost aramid PVC Low-cost solutions for lightweight applications of aramid fibers 4 high-performance sports car Carbon fiber / PEEK 8500 Functional gradient seven layers, variable thickness polyurethane Refined safety redundancy design under extreme energy impact 5 Commercial heavy trucks Basalt fiber / PP 3200 Macro-structure guidance, large-size mesh fabric TPO Macro- and micro-level coordinated control of large-size, thick-walled components

[0187] In addition, to verify the effectiveness of this invention, the following simulation experiments were conducted, and the report is as follows:

[0188] Experimental objective:

[0189] The "controllable tearing" mechanism of this invention was quantitatively verified, compared with the "random fragmentation" mode of traditional materials.

[0190] Quantitatively evaluate the technical effectiveness of this invention in suppressing debris splash.

[0191] Verification of the "Dynamic Tear Energy Matching Formula" (G d < G dpath < G dcore The effectiveness in practical applications.

[0192] Test sample:

[0193] The present invention sample (sample A): an instrument panel assembly prepared using the scheme of Example 1 (bamboo fiber / PP skeleton, three-layer glass fiber gradient guiding layer, TPO skin).

[0194] Comparison Sample 1 (Sample B): An instrument panel assembly injection molded from ordinary PP material, representing traditional technology.

[0195] Comparison Sample 2 (Sample C): An instrument panel assembly injection molded from 30% long glass fiber reinforced PP material (LFT-PP), representing a high-strength solution in the prior art.

[0196] Test equipment:

[0197] High-speed camera (shooting rate of at least 10,000 fps)

[0198] Airbag Deployment Test Bench

[0199] Load sensor (for measuring explosive impact force)

[0200] Standardized debris collection device (adhesive pads arranged around the test area)

[0201] Electronic balance (accuracy 0.01g)

[0202] Microscope (used for analyzing fracture morphology)

[0203] Experimental process and data analysis

[0204] Experiment 1: Observation of blasting process behavior and debris statistics

[0205] The experiment aims to visually compare the differences in the physical behavior of different samples during airbag bursting.

[0206] Experimental steps:

[0207] Samples A, B, and C were installed on the standard test bench.

[0208] Debris collection devices are arranged around the sample.

[0209] The airbags are triggered to deploy, and the high-speed camera and load sensor are activated simultaneously.

[0210] After the explosion, collect all the material fragments that have separated from the parent body.

[0211] The fragments are weighed, counted, and their dimensions are measured.

[0212] Experimental data recording:

[0213] Test Project unit Sample (A) of the present invention Comparative sample (B - ordinary PP) Comparative sample (C-LFT-PP) Explosion - Controllable "zipper-like" tearing, the cover opens completely along a U-shaped path. Catastrophic fracturing, with radial fracturing in the cover plate area. Localized fragmentation and penetration resulted in large, irregularly shaped pieces. Number of fragments generated indivual 0 > 50 3 Total weight of collected fragments g 0.00 12.35 5.78 Maximum fragment mass g - 0.85 2.10 Maximum fragment length mm - 45.2 62.5 Maximum distance of debris splash mm 0 > 800 450

[0214] Data Analysis and Conclusions:

[0215] Behavioral differences: High-speed video clearly shows that the tearing process of sample A was smooth and followed a single path, fully meeting the design expectations of "controlled tearing". Sample B produced a large number of high-speed, sharp fragments, which were extremely dangerous. Although sample C was better than B, it still produced several large and hard fragments, which also posed a safety threat.

[0216] Quantitative results: Sample A produced zero debris and had a total debris weight of zero, perfectly achieving the core objective of "suppressing splashing." In contrast, both control samples produced significant splashing, and the data clearly demonstrates the advantages of this invention.

[0217] Experiment 2: Energy Absorption Characteristics and Impact Load Analysis

[0218] The experiment aims to verify the role of gradient energy guiding layers in energy dissipation.

[0219] Experimental steps:

[0220] During the experiment, the impact force-time curves of each sample during the blasting process were collected using a load sensor.

[0221] Integrate the curve to calculate the total energy (E) absorbed by the sample during the impact process. absorbed = ∫F(t)·v(t)dt, or the energy absorption efficiency can be evaluated by analyzing the peak impact force and duration.

[0222] Test Project unit Sample (A) of the present invention Comparative sample (B - ordinary PP) Comparative sample (C-LFT-PP) <![CDATA[Peak impact force (F max )]]> kN 8.2 15.6 11.5 <![CDATA[Effective time of impact force action (t eff )]]> ms 18.5 6.2 9.8 Impact force-time waveform - Wide and gentle camel hump Sharp, towering pulses sharper pulse Energy absorption efficiency assessment - high Low medium

[0223] Experimental data recording:

[0224] Data Analysis and Conclusions:

[0225] Impact force management: The peak impact force of sample A (8.2 kN) was significantly lower than that of the control sample, and the impact time (18.5 ms) was longer. This indicates that the "zipper-like" tearing process of the present invention transforms the instantaneous violent impact into a continuous and controllable energy dissipation process, reducing the instantaneous impact load on occupants and surrounding structures.

[0226] Energy dissipation mechanism: The broad and gentle curve morphology is typical of ductile fracture and stable crack propagation. This demonstrates that the gradient energy guiding layer efficiently absorbs the burst energy of the airbag through multiple mechanisms, including fiber pull-out, matrix plastic deformation, and stable crack propagation. In contrast, the sharp pulse of the control sample corresponds to sudden material failure, indicating low energy absorption efficiency.

[0227] Experiment 3: Experimental Verification of Dynamic Tear Energy Matching Formula

[0228] This experiment is the core verification of the scientific validity of this invention, aiming to prove that the actually measured G_d value does indeed conform to G. d <G dpath < G dcore The relationship.

[0229] Experimental steps:

[0230] G dMeasurement: The dynamic energy release rate G driving tearing was determined by conducting high-speed impact tests on intact samples on standard instruments and analyzing the energy release at the moment of crack initiation. d .

[0231] G dpath Measurement: A standard sample (such as a pure tear sample) containing a gradient energy guiding layer was precisely cut from sample A of the present invention, and a high-speed dynamic tear test was performed to measure the dynamic tear propagation resistance G of the layer. dpath .

[0232] G dcore Measurement: A standard specimen was cut from a load-bearing skeleton without a gradient layer, and its dynamic tear propagation resistance G was measured using the same method. dcore .

[0233] Test data record (taking Sample A of Example 1 as an example):

[0234] parameter symbol Measured value (J / m²) Target / Theoretical value (J / m²) error Does it meet the design guidelines? Dynamic energy release rate <![CDATA[G d ]]> 1850 1800 (input) +2.8% - Gradient guiding layer tear resistance <![CDATA[G dpath ]]> 2480 2500 (Target) -0.8% - Bearing skeleton layer tear resistance <![CDATA[G dcore ]]> 5150 5200 (test value) -1.0% - Design principles verification <![CDATA[G d < G dpath < G dcore ]]> 1850 < 2480 < 5150 1800 < 2500 < 5200 - satisfy

[0235] Data Analysis and Conclusions:

[0236] High consistency: measured G d G dpath and G dcore The three key parameters closely match the input, target, and test values ​​from the design phase, with errors all within the allowable ±3% range.

[0237] Criterion holds: Measured data perfectly satisfy G. d < G dpath < G dcore This is a core design principle. This has been strongly demonstrated experimentally:

[0238] The airbag has enough energy to trigger a tear in the guiding layer (1850 < 2480).

[0239] The guide layer is the path of least resistance (2480).

[0240] The cracks were unable to penetrate the supporting skeleton layer (2480 < 5150), and were therefore firmly "locked" in the preset path.

[0241] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A fiber-reinforced dashboard for suppressing airbag blast debris, characterized in that, It includes: a support skeleton layer; an epidermal layer; and a gradient energy guiding layer disposed between the support skeleton layer and the epidermal layer; The gradient energy guiding layer is located in the airbag cover area of ​​the instrument panel, and the dynamic tear propagation resistance G of the gradient energy guiding layer is... dpath The dynamic tear propagation resistance G of the supporting skeleton layer is less than dcore .

2. The fiber-reinforced instrument panel for suppressing airbag rupture spatter according to claim 1, characterized in that: The gradient energy guiding layer is composed of a polymer matrix containing chopped reinforcing fibers.

3. The fiber-reinforced dashboard for suppressing airbag blast spatter according to claim 2, characterized in that: Within the gradient energy guiding layer, at least one microstructural parameter of the chopped reinforcing fiber exhibits a gradient distribution, and the microstructural parameter is selected from volume fraction, orientation angle, and length.

4. The fiber-reinforced dashboard for suppressing airbag blast spatter according to claim 3, characterized in that: In the thickness direction of the gradient energy guiding layer, the orientation angle of the chopped reinforcing fibers decreases from the center to both sides.

5. The fiber-reinforced dashboard for suppressing airbag blast spatter according to claim 4, characterized in that: In the tear propagation direction of the gradient energy-guided layer, the volume fraction of chopped reinforcing fibers remains constant or varies with a gradient.

6. The fiber-reinforced dashboard for suppressing airbag blast spatter according to claim 5, characterized in that: The supporting skeleton layer is made of natural fibers and thermoplastic resin.

7. The fiber-reinforced dashboard for suppressing airbag blast spatter according to claim 6, characterized in that: The length of natural fibers is 40-150 mm.

8. The fiber-reinforced dashboard for suppressing airbag blast spatter according to claim 7, characterized in that: The outer skin layer is made of thermoplastic polyolefin, polyvinyl chloride, or polyurethane.

9. A method for manufacturing an instrument panel as described in any one of claims 1-8, characterized in that, Includes the following steps: a) Compression molding – load-bearing skeleton layer; b) A gradient energy guiding layer is formed on the airbag cover area that supports the skeleton layer; c) An epidermal layer is injected onto the component obtained in step b) to achieve integrated molding.

10. The method for preparing a fiber-reinforced instrument panel to suppress airbag blast spatter according to claim 9, characterized in that: The gradient energy guiding layer in step b) is formed using a multi-material co-extrusion process; Multi-material co-extrusion process controls the material composition of at least two feed ports to form a gradient energy guiding layer with a gradient structure; In step c), a pneumatic positioning device is used to fix the component obtained in step b) into the cavity of the injection mold.

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