Railway vehicle cab hood glassy carbon mixed laying thickness optimization method

Abstract

The invention discloses a glassy carbon mixed paving thickness optimization method for a head cover of a railway vehicle cab, solves the problem that the thickness of each layer in a composite board in the prior art is not reasonably optimized, and has the beneficial effect of effectively controlling the thickness of each layer in the composite board on the premise of ensuring the quality and rigidity of the head cover. According to the specific scheme, the method for optimizing the glassy carbon mixed laying thickness of the railway vehicle cab hood comprises the steps that the railway vehicle cab hood is made of a composite material hood, and the bending rigidity of the composite material hood per unit width is obtained; substituting the total thickness of the railway vehicle cab hood into the bending rigidity of the composite material hood in unit width to obtain a rigidity optimization formula; calculating the relationship between the thickness of the outer carbon fiber layer and the thickness of the inner glass fiber layer according to a rigidity optimization formula; and determining the optimal solutions of the thickness of the outer carbon fiber layer and the thickness of the inner glass fiber layer based on the relationship between the thickness of the outer carbon fiber layer and the thickness of the inner glass fiber layer by taking a weight reduction set value compared with the glass fiber reinforced plastic hood as a target.

Description

Technical Field

[0001] This invention relates to the field of headgear thickness optimization technology, and in particular to a method for optimizing the thickness of glass-carbon composite paving in the headgear of a railway vehicle driver's cab. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] The driver's cab hood of a rail vehicle serves functions such as structural support, impact cushioning, sound insulation, and heat insulation. It requires a certain level of rigidity. Currently, most hoods use fiberglass sandwich composite materials, with a skin thickness of approximately 3.5mm to 4.5mm and a weight of approximately 200 to 400kg. Full fiberglass sandwich composite materials suffer from poor rigidity (easily deformed), large thickness, and high weight, making them unable to meet the increasingly stringent lightweight requirements of rail vehicles. The existing solution is to use carbon fiber composite materials as a replacement. Replacing the fiberglass skin with carbon fiber can significantly improve the hood's rigidity and reduce its deformation under vibration and oncoming air pressure impact conditions. However, full carbon fiber hoods suffer from high cost and performance redundancy. Existing technologies include solutions combining double-layer carbon fiber and a foam core; however, due to the cost of carbon fiber (approximately 10 times that of fiberglass), large-scale application would lead to a surge in hood manufacturing costs and also present performance redundancy issues.

[0004] Existing technologies have incorporated composite panels combining carbon fiber and glass fiber in other technical fields, but they have not been applied to driver's cab headgear. Moreover, they simply combine carbon fiber and glass fiber without addressing how to determine the optimal thickness of each component. This improper determination of the thickness of the carbon fiber and glass fiber cannot guarantee the bending stiffness of the driver's cab headgear, nor can it control the weight of the headgear, thus failing to meet the requirements of lightweight design. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method for optimizing the thickness of the carbon fiber and glass fiber composite layer in the driver's cab headgear of rail vehicles. This method rationally determines the thickness of the carbon fiber and glass fiber, ensuring not only the bending stiffness of the driver's cab headgear to guarantee safety, but also effectively controlling the quality of the driver's cab headgear.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: A method for optimizing the thickness of a glass-carbon composite paving layer in the head cover of a rail vehicle driver's cab includes the following: The headgear of the driver's cab of the rail vehicle is made of composite material, which includes an outer carbon fiber layer and an inner glass fiber layer. The bending stiffness of the composite headgear per unit width is obtained based on the thickness and modulus of each layer of the composite headgear. Under the boundary conditions of not changing the total thickness of the driver's cab headgear of the rail vehicle and not reducing the bending stiffness of the composite headgear, a lightweight design of the composite headgear is carried out. The stiffness optimization formula is obtained by substituting the total thickness of the driver's cab headgear of the rail vehicle into the bending stiffness of the composite headgear per unit width. The relationship between the thickness of the outer carbon fiber layer and the thickness of the inner glass fiber layer was calculated based on the stiffness optimization formula. With the goal of reducing weight compared to the fiberglass helmet, the optimal solution for the thickness of the outer carbon fiber layer and the inner fiberglass layer was determined based on the relationship between the thickness of the outer carbon fiber layer and the thickness of the inner fiberglass layer.

[0007] The above-described method for optimizing the thickness of a glass-carbon composite head cover for a railway vehicle driver's cab includes an outer carbon fiber layer, an inner glass fiber layer, and an intermediate foam core material. The bending stiffness of the composite material headgear per unit width is obtained based on the thickness and modulus of the outer carbon fiber layer, the thickness and modulus of the inner glass fiber layer, and the thickness and modulus of the foam core material.

[0008] The method for optimizing the thickness of a glass-carbon composite hood for a rail vehicle driver's cab, as described above, calculates the unit width using an integral method along the y-axis of the coordinate system, with the thickness direction of the composite hood as the y-axis. b Flexural stiffness of sandwich composite materials D : (1) In the formula: I For the moment of inertia, E For elastic modulus, A For cross-sectional area, E core The modulus of the foam core material. h core For the thickness of the foam core material, E g The modulus of the inner glass fiber layer. h g The thickness of the inner glass fiber layer. E c The modulus of the outer carbon fiber layer. h c The thickness is the outer carbon fiber layer.

[0009] The above-described method for optimizing the thickness of a glass-carbon composite hood for a rail vehicle driver's cab obtains a simplified bending stiffness per unit width of the composite hood based on the thickness and modulus of the outer carbon fiber layer, the thickness and modulus of the inner glass fiber layer.

[0010] The simplified formula for the bending stiffness of the composite material headgear per unit width, as described above, in the method for optimizing the thickness of the glass-carbon composite paving in a railway vehicle driver's cab headgear is as follows: (2).

[0011] The method for optimizing the thickness of the glass-carbon composite paving for a railway vehicle driver's cab headgear, as described above, involves substituting the total thickness of the headgear (36mm) into the simplified formula for the bending stiffness of the composite headgear per unit width, resulting in the stiffness optimization formula: (3).

[0012] The above-described method for optimizing the thickness of the glass-carbon composite layer in the head cover of a rail vehicle driver's cab involves calculating the minimum required glass fiber thickness for different carbon fiber layer thicknesses using a Matlab program based on a stiffness optimization formula. This yields the relationship between the outer carbon fiber layer thickness and the inner glass fiber layer thickness.

[0013] The method for optimizing the thickness of the glass-carbon composite layer in the head cover of a rail vehicle driver's cab, as described above, has the following relationship between the thickness of the outer carbon fiber layer and the thickness of the inner glass fiber layer: the thickness of the glass fiber layer is 0.083 times the thickness of the outer carbon fiber layer. The total thickness of the composite material hood is 1.083 times the thickness of the outer carbon fiber layer.

[0014] The above-described method for optimizing the thickness of a fiberglass-carbon composite headgear for a rail vehicle aims to reduce weight by 20% compared to a fiberglass headgear. Based on the density of the outer carbon fiber layer and the inner glass fiber layer in the composite headgear, and the relationship between the thickness of the outer carbon fiber layer and the thickness of the inner glass fiber layer, the optimal solution for the thickness of the outer carbon fiber layer and the inner glass fiber layer is determined.

[0015] The above-described method for optimizing the thickness of a glass-carbon composite hood for a rail vehicle driver's cab involves using the relationship between the densities of the outer carbon fiber layer and the inner glass fiber layer in the composite hood, and the thicknesses of the outer carbon fiber layer and the inner glass fiber layer, to determine the weight of the composite hood. M With the thickness of the inner glass fiber layer h g Thickness of outer carbon fiber layer h c Functional relationship: (4) in, The density of the foam core material. The density of the inner glass fiber layer, This represents the density of the outer carbon fiber layer.

[0016] The beneficial effects of this invention are as follows: 1) The thickness optimization method provided by this invention includes a composite material headgear comprising a carbon fiber layer and an inner glass fiber layer. The bending stiffness of the composite material headgear is obtained, and the total thickness of the headgear for the rail vehicle driver's cab is substituted into the bending stiffness per unit width of the composite material headgear to obtain a stiffness optimization formula. The relationship between the thickness of the outer carbon fiber layer and the inner glass fiber layer is obtained through the stiffness optimization formula. Based on this, the optimal solution for the thickness of the outer carbon fiber layer and the inner glass fiber layer is determined. Based on the bending stiffness and with a target weight reduction compared to a fiberglass headgear, the high specific strength and high specific modulus characteristics of carbon fiber are fully utilized to achieve the optimal solution for lightweighting and stiffness constraints. This reasonable acquisition of the thickness of the carbon fiber layer and the inner glass fiber layer ensures the bending stiffness of the driver's cab headgear to guarantee safety and effectively controls the quality of the driver's cab headgear.

[0017] 2) The sandwich structure in this invention includes an outer carbon fiber layer, an inner glass fiber layer, and a middle foam core. The bending stiffness of the composite headgear per unit width is obtained based on the thickness and modulus of these three layers. Considering that the composite headgear mainly transmits tensile and compressive stress under bending load, the influence of the foam core modulus on the stiffness of the composite headgear is ignored, and a simplified formula for the bending stiffness of the composite headgear per unit width can be established.

[0018] 3) In this invention, based on the stiffness optimization formula, the minimum glass fiber thickness required for different carbon fiber layer thicknesses is calculated, that is, the relationship between the outer carbon fiber layer thickness and the inner glass fiber layer thickness is obtained. It can be seen that the lightweighting of composite headgear is not only achieved by reducing weight through low-density materials such as foam core materials, but also by utilizing the high modulus of carbon fibers to reduce the skin thickness.

[0019] 4) In this invention, the goal is to reduce the weight by 20% compared to fiberglass hoods. Based on the density of the outer carbon fiber layer and the inner glass fiber layer in the composite material hood, and the relationship between the thickness of the outer carbon fiber layer and the thickness of the inner glass fiber layer, the optimal solution for the thickness of the outer carbon fiber layer and the inner glass fiber layer is determined, thereby obtaining reasonable thicknesses of the outer carbon fiber layer, the inner glass fiber layer, and the foam core material. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0021] Figure 1 This is a schematic diagram of a fiberglass headgear in the prior art.

[0022] Figure 2 This is a schematic diagram of a composite material headgear in a method for optimizing the thickness of a glass-carbon composite headgear for a rail vehicle driver's cab according to one or more embodiments of the present invention.

[0023] Figure 3 This is a diagram showing the correspondence between the thickness of the outer carbon fiber layer and the thickness of the inner glass fiber layer in a method for optimizing the thickness of a glass-carbon composite layer in the head cover of a rail vehicle driver's cab according to one or more embodiments of the present invention.

[0024] Figure 4 This is a graph showing the relationship between the weight of the skin and the thickness of the outer carbon fiber layer in a composite material headgear, according to one or more embodiments of the present invention, in a method for optimizing the thickness of a glass-carbon composite headgear for a railway vehicle driver's cab.

[0025] Figure 5(a) is a displacement cloud map of a fiberglass head cover under a wind pressure load of 6000Pa in a method for optimizing the thickness of a fiberglass-carbon composite paving for a driver's cab head cover according to one or more embodiments of the present invention.

[0026] Figure 5(b) is a strain cloud diagram of a fiberglass head cover under a wind pressure load of 6000Pa, in a method for optimizing the thickness of a fiberglass-carbon composite paving for a driver's cab head cover according to one or more embodiments of the present invention.

[0027] Figure 5(c) is a stress cloud diagram of a fiberglass head cover under a wind pressure load of 6000Pa, in a method for optimizing the thickness of a fiberglass-carbon composite paving for a driver's cab head cover according to one or more embodiments of the present invention.

[0028] Figure 6(a) is a displacement cloud map of the composite material head cover under a wind pressure load of 6000Pa in a method for optimizing the thickness of glass-carbon composite paving of a driver's cab head cover according to one or more embodiments of the present invention.

[0029] Figure 6(b) is a strain cloud diagram of the composite material head cover under a wind pressure load of 6000Pa in a method for optimizing the thickness of glass-carbon composite paving in a driver's cab head cover according to one or more embodiments of the present invention.

[0030] Figure 6(c) is a stress cloud diagram of the composite material head cover under a wind pressure load of 6000Pa in a method for optimizing the thickness of glass-carbon composite paving in a driver's cab head cover according to one or more embodiments of the present invention.

[0031] Figure 7 This is a flowchart of a method for optimizing the thickness of a glass-carbon composite paving for a driver's cab headgear according to one or more embodiments of the present invention. Detailed Implementation

[0032] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0033] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. As introduced in the background section, in the prior art, the driver's cab head cover is mostly made of two layers of carbon fiber sandwiching the internal core material. The thickness of each layer in the composite board of carbon fiber and glass fiber has not been reasonably optimized. In order to solve the above technical problems, this invention proposes a method for optimizing the thickness of glass-carbon fiber mixed paving in the driver's cab head cover of rail vehicles.

[0034] In a typical embodiment of the present invention, reference is made to Figure 7 As shown, a method for optimizing the thickness of a glass-carbon composite paving for a rail vehicle driver's cab head cover includes the following: The headgear of the driver's cab of the rail vehicle is made of composite material, which includes an outer carbon fiber layer and an inner glass fiber layer. The bending stiffness of the composite headgear per unit width is obtained based on the thickness and modulus of each layer of the composite headgear. Under the boundary conditions of not changing the total thickness of the driver's cab headgear of the rail vehicle and not reducing the bending stiffness of the composite headgear, a lightweight design of the composite headgear is carried out. The stiffness optimization formula is obtained by substituting the total thickness of the driver's cab headgear of the rail vehicle into the bending stiffness of the composite headgear per unit width. The relationship between the thickness of the outer carbon fiber layer and the thickness of the inner glass fiber layer was calculated based on the stiffness optimization formula. With the goal of reducing weight compared to the fiberglass helmet, the optimal solution for the thickness of the outer carbon fiber layer and the inner fiberglass layer was determined based on the relationship between the thickness of the outer carbon fiber layer and the thickness of the inner fiberglass layer.

[0035] Existing fiberglass helmet configuration reference Figure 1 As shown, a sandwich structure composite material of 4.5mm fiberglass + 27mm foam core + 4.5mm fiberglass is used, with a total thickness of 36mm and a total inner and outer skin area of ​​10.5m². 2 The fiberglass helmet weighs approximately 202 kg, of which the skin weighs 178 kg and the foam weighs 24 kg.

[0036] In this embodiment, the composite material headgear includes an outer carbon fiber layer, an inner glass fiber layer, and a middle foam core material; the performance parameters of the outer carbon fiber layer, the inner glass fiber layer, and the middle foam core material are shown in Table 1: Table 1 Material performance parameters for headgear

[0037] As can be seen from Table 1, the modulus of the outer carbon fiber layer is about twice that of the inner glass fiber layer, and the density is 20% lower than that of the inner glass fiber layer, which has considerable potential for weight reduction.

[0038] The bending stiffness of the composite hood per unit width is obtained based on the thickness and modulus of the outer carbon fiber layer, the thickness and modulus of the inner glass fiber layer, and the thickness and modulus of the foam core material. The y-axis of the coordinate system is defined along the thickness direction of the composite hood, and the stiffness per unit width is calculated using an integral method. b Flexural stiffness of sandwich composite materials D : (1) In the formula: I For the moment of inertia, E For elastic modulus, A For cross-sectional area, E core The modulus of the foam core material. h core For the thickness of the foam core material, E g The modulus of the inner glass fiber layer. h g The thickness of the inner glass fiber layer. E c The modulus of the outer carbon fiber layer. h c y represents the thickness of the outer carbon fiber layer, and dy refers to the differential along the thickness direction of the composite material.

[0039] Considering that the composite hood primarily transmits tensile and compressive stresses under bending loads, the modulus of the inner glass fiber layer is... E g Thickness of outer carbon fiber layer E c The E1 value of the skin in Table 1 is used for approximate calculation. The influence of the foam core material modulus on the bending stiffness of the composite headgear is ignored. The simplified bending stiffness of the composite headgear per unit width is obtained based on the thickness and modulus of the outer carbon fiber layer, the thickness and modulus of the inner glass fiber layer.

[0040] The simplified formula for the bending stiffness of a composite hood per unit width is: (2) In the Matlab program, input the glass fiber layer modulus as a material parameter. E g Thickness of outer carbon fiber layer E c The modulus of the inner glass fiber layer Eg =23900MPa, inner glass fiber layer thickness h g =4.5mm, foam core material thickness h core =27mm, substitute into the original structure (fiberglass helmet) stiffness Calculation formula: (5) The bending stiffness of the 4.5mm thick glass fiber layer, i.e., the glass limiting skin, is approximately 5.37 × 10⁻⁶ using formula (3). 7 N·mm 2 .

[0041] Without changing the total thickness of the hood (36mm) and without reducing its rigidity D =5.37×10 7 N·mm 2 Under the boundary conditions, a glass-carbon composite method was used to achieve a lightweight design for the fiberglass helmet. The total thickness was reduced to 2... h c +2 h g + h core Substituting 36mm into formula (1) yields... (4) Starting from 0, with a step size of 0.02 mm, and ending at 4.5 mm, the calculation is performed iteratively for different carbon fiber layer thicknesses. h c =0:0.02:4.5, with D= As boundary conditions, the minimum required inner glass fiber layer thickness for different carbon fiber layer thicknesses is calculated according to formula (4). The calculation results are as follows Figure 3 As shown.

[0042] from Figure 3 As can be seen, the thickness of the inner glass fiber layer and the total skin thickness both decrease significantly with the increase of the outer carbon fiber layer thickness. When the outer carbon fiber layer thickness increases to 1.8 mm, the inner glass fiber layer thickness can be reduced to 0.15 mm, and the total skin thickness is only 1.95 mm. This demonstrates that the lightweighting of the glass fiber-carbon hybrid hood is achieved not only through weight reduction using low-density materials but also by utilizing the high modulus of carbon fiber to reduce skin thickness. However, the extensive use of carbon fiber leads to a significant increase in hood cost; therefore, the thickness of the carbon fiber layer and the inner glass fiber layer needs to be optimized to balance performance, weight, and cost.

[0043] Establish the weight of composite material hood M With the thickness of the inner glass fiber layer h g carbon fiber layer thicknessh c Functional relationship: (5) This embodiment aims to reduce the weight by 20% compared to the fiberglass helmet (i.e., the weight of the skin needs to be reduced to 137.6 kg). , The weight of the composite material hood. The weight of the fiberglass hood is based on Figure 3 The proportional relationships in the table and the densities in Table 1, The density of the foam core material. The density of the inner glass fiber layer, Given the density of the outer carbon fiber layer, Matlab programming was used to find the optimal solution that balances performance, weight reduction, and cost. The calculation results are as follows: Figure 4 As shown.

[0044] from Figure 4 As the thickness of the outer carbon fiber layer increases, the weight of the skin is significantly reduced. When the thickness of the outer carbon fiber layer increases to more than 0.5 mm, the weight of the skin can be reduced to below 137.6 kg while maintaining the same rigidity as the original fiberglass hood. When the thickness of the outer carbon fiber layer increases to 1.8 mm, the weight is reduced to 63.5 kg, a 64.3% reduction compared to the original fiberglass skin. Since the single-layer thickness of commonly used carbon fiber cloth is 0.2 mm, in this embodiment, the preferred composite material hood layer is 0.6 mm carbon fiber layer + 2.8 mm fiberglass layer + 29.2 mm foam core material + 2.8 mm fiberglass layer + 0.6 mm carbon fiber layer, with a weight of 153.9 kg (a weight reduction of 23.8%).

[0045] from Figure 5a , Figure 6a It can be seen that the maximum deformation of the fiberglass hood and the fiberglass-carbon composite hood under a wind pressure load of 6000Pa is 4.87mm and 4.16mm, respectively. At this time, the maximum deformation is located on the lower side of the windshield. The deformation of the fiberglass-carbon composite hood is 14.5% smaller than that of the fiberglass hood, indicating that the overall stiffness of the fiberglass-carbon composite hood is slightly improved. Figure 5b , Figure 6b It was observed that the maximum strain of the fiberglass hood and the fiberglass-carbon composite hood were 920. με and 751 με Located in the upper rounded corner area of ​​the windshield, the strain of the glass-carbon composite hood was reduced by 18.4%. Figure 5c , Figure 6c The maximum stresses observed for the fiberglass and glass-carbon composite hoods were 22.7 MPa and 33.2 MPa, respectively, with the glass-carbon composite hood showing a 46.3% increase in maximum stress. This is in accordance with Hooke's Law in mechanics of materials. σ = E ε Under the same strain ε Below, elastic modulus E The higher the stress σ The larger.

[0046] Since the modulus of the carbon fiber composite material used in this embodiment is approximately 2.1 times that of glass fiber, under wind pressure load, when the deformation of the fiberglass-carbon fiber composite hood causes the same strain, the carbon fiber layer has a higher modulus and transmits greater stress than the inner glass fiber layer. Correspondingly, under the same wind pressure load, the resultant force on the fiberglass-carbon fiber composite hood and the fiberglass hood is equal, but the stress transmitted by the inner glass fiber layer in the fiberglass-carbon fiber composite hood is lower, therefore the stress in its outer carbon fiber layer is higher than that of the fiberglass hood. Referring to Table 1, the tensile strength of the carbon fiber skin (603.0 MPa) is 33.2% higher than that of the fiberglass skin (452.8 MPa). Therefore, the fiberglass-carbon fiber composite hood can fully utilize the advantages of carbon fiber's high modulus and high strength.

[0047] The strength of the glass-carbon composite hood was checked using Abaqus (finite element method for engineering simulation), and the calculation results are shown in Table 2.

[0048] Table 2 Strength Verification Results of Glass-Carbon Composite Headliner

[0049] Table 2 shows that the maximum strain and maximum stress of the glass-carbon composite headgear under vibration acceleration impact load are 81.9 g / cm³. με And 2.2 MPa, which is much lower than the wind pressure load shown in Figure 5, and both are lower than the allowable design strain of vacuum-formed fiberglass (5500). με ( ), meeting the operating conditions requirements.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for optimizing the thickness of a glass-carbon composite paving for a railway vehicle driver's cab head cover, characterized in that, Includes the following: The headgear of the driver's cab of the rail vehicle is made of composite material, which includes an outer carbon fiber layer and an inner glass fiber layer. The bending stiffness of the composite headgear per unit width is obtained based on the thickness and modulus of each layer of the composite headgear. Under the boundary conditions of not changing the total thickness of the driver's cab headgear of the rail vehicle and not reducing the bending stiffness of the composite headgear, a lightweight design of the composite headgear is carried out. The stiffness optimization formula is obtained by substituting the total thickness of the driver's cab headgear of the rail vehicle into the bending stiffness of the composite headgear per unit width. The relationship between the thickness of the outer carbon fiber layer and the thickness of the inner glass fiber layer was calculated based on the stiffness optimization formula. With the goal of reducing weight compared to the fiberglass helmet, the optimal solutions for the thickness of the outer carbon fiber layer and the inner fiberglass layer were determined based on the relationship between the thickness of the outer carbon fiber layer and the thickness of the inner fiberglass layer.

2. The method for optimizing the thickness of glass-carbon composite paving in the head cover of a rail vehicle driver's cab according to claim 1, characterized in that, The composite material headgear includes an outer carbon fiber layer, an inner glass fiber layer, and a middle foam core material. The bending stiffness of the composite material headgear per unit width is obtained based on the thickness and modulus of the outer carbon fiber layer, the thickness and modulus of the inner glass fiber layer, and the thickness and modulus of the foam core material.

3. The method for optimizing the thickness of glass-carbon composite paving in the head cover of a rail vehicle driver's cab according to claim 2, characterized in that, The unit width is calculated using an integral method along the y-axis of the coordinate system, with the thickness direction of the composite hood as the coordinate axis. b Flexural stiffness of sandwich composite materials D : （1） In the formula: I For the moment of inertia, E For elastic modulus, A For cross-sectional area, E core The modulus of the foam core material. h core For the thickness of the foam core material, E g The modulus of the inner glass fiber layer. h g The thickness of the inner glass fiber layer. E c The modulus of the outer carbon fiber layer. h c The thickness is the outer carbon fiber layer.

4. The method for optimizing the thickness of glass-carbon composite paving in the head cover of a rail vehicle driver's cab according to claim 2, characterized in that, The simplified bending stiffness of the composite headgear per unit width is obtained by using the thickness and modulus of the outer carbon fiber layer, the thickness and modulus of the inner glass fiber layer.

5. The method for optimizing the thickness of glass-carbon composite paving in the head cover of a rail vehicle driver's cab according to claim 4, characterized in that, The simplified formula for the bending stiffness of the composite material hood per unit width is: （2）。 6. The method for optimizing the thickness of glass-carbon composite paving in the head cover of a rail vehicle driver's cab according to claim 5, characterized in that, Substituting the total thickness of the rail vehicle driver's cab hood, which is 36mm, into the simplified formula for the bending stiffness of the composite material hood per unit width, we obtain the stiffness optimization formula: （3）。 7. The method for optimizing the thickness of glass-carbon composite paving in the head cover of a rail vehicle driver's cab according to claim 1, characterized in that, Based on the stiffness optimization formula, the minimum required glass fiber thickness for different carbon fiber layer thicknesses is calculated, thus obtaining the relationship between the outer carbon fiber layer thickness and the inner glass fiber layer thickness.

8. The method for optimizing the thickness of glass-carbon composite paving in the head cover of a rail vehicle driver's cab according to claim 7, characterized in that, The relationship between the thickness of the outer carbon fiber layer and the thickness of the inner glass fiber layer is as follows: the thickness of the glass fiber layer is 0.083 times the thickness of the outer carbon fiber layer. The total thickness of the composite material hood is 1.083 times the thickness of the outer carbon fiber layer.

9. The method for optimizing the thickness of glass-carbon composite paving in the head cover of a rail vehicle driver's cab according to claim 1, characterized in that, With the goal of reducing weight by 20% compared to fiberglass helmets, the optimal solutions for the thickness of the outer carbon fiber layer and the inner glass fiber layer in the composite helmet are determined based on the relationship between the density of the outer carbon fiber layer and the thickness of the inner glass fiber layer.

10. The method for optimizing the thickness of glass-carbon composite paving in the head cover of a rail vehicle driver's cab according to claim 9, characterized in that, The relationship between the density of the outer carbon fiber layer and the inner glass fiber layer in the composite material hood, and the thickness of the outer carbon fiber layer and the inner glass fiber layer, is used to determine the weight of the composite material hood. M With the thickness of the inner glass fiber layer h g Thickness of outer carbon fiber layer h c Functional relationship: （4） in, The density of the foam core material. The density of the inner glass fiber layer, This represents the density of the outer carbon fiber layer.

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