A rapid analysis method of overturning stability of an aircraft panel transport vehicle under crosswind

Abstract

The application discloses a kind of overturn stability quick analysis method of aircraft panel transport vehicle under crosswind, it includes the following steps: establishing reasonable simplified aircraft panel transport vehicle finite element model;Calculate wind pressure distribution rule;Finite element simulation calculation;Establish overturn stability judgment basis.This method can be for the overturn stability of large aircraft panel under the influence of crosswind in the process of transportation Quick calculation, with the evaluation method established, the design stability of aircraft panel transport vehicle can be quickly evaluated.The real wind pressure distribution rule is introduced into the calculation, the overturn stability of aircraft panel transport vehicle under different wind force levels can be calculated by the application, the counterweight design of transport vehicle can be optimized through the calculation result, further improve the safety design of large aircraft panel transport vehicle, prevent the overturn phenomenon of aircraft panel transport vehicle caused by crosswind, it is a kind of quick, effective evaluation calculation method.

Description

Technical Field

[0001] This invention relates to a rapid analysis method for the overturning stability of an aircraft panel transport vehicle under crosswinds, specifically a rapid calculation and determination method for whether a large aircraft panel transport vehicle will overturn under crosswinds. Background Technology

[0002] With the continuous development of large aircraft and the increasing size of wings, the transportation of large wing panels has become a major challenge. To ensure safe transportation of large aircraft panels, the transport vehicle must be designed to resist overturning. During transport, the large wing panels are fixed to the transport vehicle. Crosswinds act on the windward side of the wing panels. The wind pressure varies at different locations on the wing panels and changes over time, causing continuous changes in the forces and moments within the transport vehicle. When these forces and moments exceed critical values, the crosswinds will cause the entire transport vehicle to overturn, resulting in significant economic losses. Therefore, an evaluation method is needed that can quickly calculate the overturning stability of large aircraft panels during transportation by considering factors such as the crosswind distribution, crosswind speed, ground friction, and force and moment balance, in order to evaluate the design stability of the aircraft panel transport vehicle. Based on the calculation results, the design of the transport vehicle was optimized to further improve the safety of the large aircraft panel transport vehicle and prevent the aircraft panel transport vehicle from overturning due to crosswinds. Summary of the Invention

[0003] To address the aforementioned issues, this invention establishes an efficient calculation method and evaluation criteria based on the finite element method. By incorporating the actual wind pressure distribution pattern into the calculation, the counterweight design of the transport vehicle can be optimized using the calculation results, further improving the safety design of large aircraft panel transport vehicles and preventing overturning of aircraft panel transport vehicles due to crosswinds.

[0004] The technical solution of this invention is: a rapid analysis method for the overturning stability of an aircraft panel transport vehicle under crosswinds, comprising the following steps:

[0005] Step 1: Establish a reasonably simplified finite element model of the aircraft panel transport vehicle:

[0006] 1-1 A three-dimensional geometric model of the aircraft panel transport vehicle was created using CAD software. All parts except the aircraft panel, counterweight, and transport vehicle were deleted from the aircraft panel transport vehicle model to create a simplified model. The simplified model was made to have the same length, width, and height as the actual aircraft panel transport vehicle. The position of the counterweight in the simplified model was consistent with the position of the counterweight on the actual aircraft panel transport vehicle. The four wheels of the transport vehicle were simplified into four small pillars, and the diameter of the wheel was equal to the height of the small pillar.

[0007] 1-2 Build a ground model below the simplified model. The length and width of the ground model should be no less than 1.5 times the actual length and width of the aircraft panel transport vehicle, and the height should be equal to the actual transport road surface.

[0008] Step 2: Calculate the wind pressure distribution pattern:

[0009] 2-1 Calculate the basic wind pressure value F according to Formula 1

[0010]

[0011] Where c is the air resistance coefficient; ρ is the air density; s is the windward area of ​​the wall panel; and v is the relative velocity between the object and the air.

[0012] 2-2 Based on the calculated basic wind pressure value F, the wind pressure distribution pattern is calculated using Formula 2.

[0013] F(x,y)=F·η(x,y) (2)

[0014] Where η(x,y) is a three-dimensional spatial distribution function.

[0015] Step 3: Finite element simulation calculation:

[0016] 3-1 Set Young's modulus, Poisson's ratio, and density for each physical object, including the aircraft panel, transport vehicle, counterweight, and ground. In the simplified model, the transport vehicle is density-equivalent based on its mass, so that the total mass of the transport vehicle in the simplified model is equal to the total mass of the physical transport vehicle.

[0017] 3-2 Boundary Condition Setting: Set a constraint of 6 degrees of freedom at the bottom of the ground in the ground model; provide support force from the friction between the transport vehicle and the ground in the simplified model, and input the friction coefficient between the ground and the wheels;

[0018] 3-3 Mesh Generation: The maximum dimensions of the mesh in the ground model and the simplified model shall not exceed 1% of the length, width, and height of the transport vehicle;

[0019] 3-4 The wind pressure calculated using Formula 2 is then introduced into the statics module of the finite element software for solution. The displacement and stress fields of the transport vehicle under crosswind are calculated. The displacement field results are as follows: Figure 2 As shown.

[0020] Step 4: Establish the criteria for judging overturning stability:

[0021] 4-1: The vertical support reaction force T of the ground in the ground model on the transport vehicle tire in the simplified model is obtained by integrating the contact stress using Formula 3. z

[0022] T z =-∫σ 33dA (3)

[0023] Where, σ 33 For each element, the stress component along the vertical direction is, as follows: Figure 3 As shown; A is the contact area; the vertical support reaction force T is obtained by integrating over the entire contact area. z ;

[0024] 4-2 Repeat step 4-1 to calculate the vertical support reactions on the left and right sides of the front wheels of the transport vehicle. and Vertical support reaction forces on the left and right sides of the rear wheel and The results are as follows Figure 4 As shown;

[0025] 4-3 Establish the overturning judgment criteria based on Formula 4:

[0026]

[0027] Where ε is the overturning probability of the panel transport vehicle; when the calculated result of ε is equal to 1, the overturning probability is 100%. In this case, it is necessary to add the mass of the counterweight to the simplified model and repeat steps 3-4 until the calculated overturning probability ε meets the actual requirements, such as... Figure 5 As shown. Attached Figure Description

[0028] Figure 1 This is a finite element model of the aircraft panel transport vehicle, counterweight, and ground in step one of this invention;

[0029] Figure 2 The displacement result calculated by finite element method in step three of this invention;

[0030] Figure 3 The stress components along the vertical direction of each wheel of the transport vehicle calculated in step three of this invention.

[0031] Figure 4 The result of the vertical support reaction force of each wheel of the transport vehicle calculated in step three of this invention;

[0032] Figure 5 This refers to the overturning probability of the panel transport vehicle under different counterweights, calculated in step four of this invention.

[0033] Numbering in the diagram: 1. Aircraft panel; 2. Counterweight; 3. Transport vehicle; 4. Ground Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0035] like Figure 1-5As shown, a rapid analysis method for the overturning stability of an aircraft panel transport vehicle under crosswinds includes the following steps:

[0036] Step 1: Establish a reasonably simplified finite element model of the aircraft panel transport vehicle:

[0037] 1-1 A three-dimensional geometric model of the aircraft panel transport vehicle was created using CAD software. All parts except for the aircraft panel 1, counterweight 2, and transport vehicle 3 were deleted from the aircraft panel transport vehicle model to create a simplified model. The simplified model was made to have the same length, width, and height as the actual aircraft panel transport vehicle. The position of counterweight 2 in the simplified model was consistent with the position of the counterweight on the actual aircraft panel transport vehicle. The four wheels of transport vehicle 3 were simplified into four small pillars, and the diameter of the wheels was equal to the height of the small pillars.

[0038] 1-2 Build a ground model below the simplified model. The length and width of the ground model should be no less than 1.5 times the actual length and width of the aircraft panel transport vehicle 3, and the height should be equal to the actual transport road surface height. In this embodiment, the length, width, and height of the ground model are 20000mm, 10000mm, and 100mm, respectively.

[0039] Step 2: Calculate the wind pressure distribution pattern:

[0040] 2-1 Calculate the basic wind pressure value F according to Formula 1

[0041]

[0042] Where c is the air drag coefficient, taken as 0.045; ρ is the air density, taken as 1.293 kg / m³. 3 ; s represents the windward area of ​​the wall panel, taken as 1900×15000mm. 2 Considering that the wall panel moves slowly during transportation and is relatively stationary compared to the crosswind, v is the relative speed of the object and the air, and the wind speed is taken as 5.56 m / s.

[0043] 2-2 Based on the calculated basic wind pressure value F, the wind pressure distribution pattern is calculated using Formula 2.

[0044] F(x,y)=F·η(x,y) (2)

[0045] Where η(x,y) is a three-dimensional spatial distribution function, and x and y are the coordinates of each point on the aircraft panel, respectively. In this embodiment, η(x,y) is taken as a standard two-dimensional normal distribution function, i.e. In this example, the mean μ and variance σ 2 Take values ​​of 0 and 1 respectively.

[0046] Step 3: Finite element simulation calculation:

[0047] 3-1 Young's modulus, Poisson's ratio, and density are assigned to each of the following physical components: aircraft panel 1, transport vehicle 3, counterweight 2, and ground 4. In the simplified model, the transport vehicle 3 is density-equivalent based on its mass, ensuring that the total mass of the transport vehicle 3 in the simplified model equals the total mass of the physical transport vehicle. In this embodiment, the Young's modulus of aircraft panel 1, transport vehicle 3, and counterweight 2 is 210 GPa, and the Poisson's ratio is 0.30. The density of the transport vehicle is 7.1 × 10⁻⁶. -10 t / mm 3 The density of the aircraft wall panels is 2.7 × 10⁻⁶. -9 t / mm 3 The density of counterweight 2 is 7.8 × 10⁻⁶. -9 t / mm 3 Ground surface 4 is considered a rigid surface with a Young's modulus of 210 × 10⁻⁶. 5 GPa, Poisson's ratio is 0.30, and density is 4×10 - 9 t / mm 3 ;

[0048] 3-2 Boundary Condition Setting: Set a constraint of 6 degrees of freedom at the bottom of ground 4 in the ground model; provide support force from the friction between the transport vehicle 3 and ground 4 in the simplified model, and input the friction coefficient μ = 0.2 between ground 4 and the wheel;

[0049] 3-3 Mesh Generation: The maximum dimensions of the mesh in the ground model and the simplified model shall not exceed 1% of the dimensions of the transport vehicle.

[0050] 3-4 The wind pressure calculated using Formula 2 is then used in the statics module of the finite element software AQBAQUS 6.14 to solve for the displacement and stress fields of transport vehicle 3 under crosswind conditions. The resulting displacement contour plot is shown below. Figure 2 As shown.

[0051] Step 4: Establish the criteria for judging overturning stability:

[0052] 4-1: The contact stress (i.e., CPRESS compressive stress) results are obtained through Formula 3, such as... Figure 3 (As shown) Integrating, we obtain the vertical reaction force T of the ground in the ground model on the three tires of the transport vehicle in the simplified model. z

[0053] T z =-∫σ 33 dA (3)

[0054] Where, σ 33 For each element, the stress component along the vertical direction, in this embodiment, the σ of the first element... 33 = 3.201 MPa, where A is the contact area of ​​the unit, which is 100 mm². 2By summing up each element and integrating over the entire contact area, the vertical support reaction force T on the ground where the wheel is located can be obtained. z =9288N, such as Figure 4 As shown.

[0055] 4-2 Repeat step 4-1 to calculate the vertical support reactions on the left and right sides of the front wheel. and Vertical support reaction forces on the left and right sides of the rear wheel and like Figure 4 As shown;

[0056] 4-3 Establish the overturning judgment criteria based on Formula 4:

[0057]

[0058] Where ε is the overturning probability of the panel transport vehicle; when the calculated result of ε is equal to 1, the overturning probability is 100%. In this case, it is necessary to increase the mass of the counterweight in step 3, from 300kg to 600kg. At this time, the overturning probability ε of the panel transport vehicle decreases, and the calculated overturning probability ε meets the actual requirements, such as... Figure 5 As shown.

[0059] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

[0060] The parts not covered in this invention are the same as or can be implemented using existing technologies.

Claims

1. A rapid analysis method for the overturning stability of an aircraft panel transport vehicle under crosswinds, characterized in that, Includes the following steps: Step 1 involves establishing a reasonably simplified finite element model of the aircraft panel transport vehicle. The specific process is as follows: 1-1 A three-dimensional geometric model of the aircraft panel transport vehicle was created using CAD software. All parts except the aircraft panel, counterweight, and transport vehicle were deleted from the aircraft panel transport vehicle model to create a simplified model. The simplified model was made to have the same length, width, and height as the actual aircraft panel transport vehicle. The position of the counterweight in the simplified model was consistent with the position of the counterweight on the actual aircraft panel transport vehicle. The four wheels of the transport vehicle were simplified into four small pillars, and the diameter of the wheel was equal to the height of the small pillar. 1-2 Build a ground model below the simplified model. The length and width of the ground model should be no less than 1.5 times the actual length and width of the aircraft panel transport vehicle, and the height should be equal to the actual transport road surface. Step two, calculating the wind pressure distribution pattern, includes the following steps: 2-1 Calculate the basic wind pressure value according to Formula 1 F （1） in, c This refers to the air drag coefficient; air density; This refers to the windward area of ​​the wall panel; v The relative velocity of an object to the air; 2-2 Based on the calculated basic wind pressure values F The wind pressure distribution pattern is calculated using Formula 2. （2） in, It is a three-dimensional spatial distribution function; Step 3, finite element simulation calculation, includes the following steps: 3-1 Set Young's modulus, Poisson's ratio, and density for each physical object, including the aircraft panel, transport vehicle, counterweight, and ground. In the simplified model, the transport vehicle is density-equivalent based on its mass, so that the total mass of the transport vehicle in the simplified model is equal to the total mass of the physical transport vehicle. 3-2 Boundary Condition Setting: Set a constraint of 6 degrees of freedom at the bottom of the ground in the ground model; provide support force from the friction between the transport vehicle and the ground in the simplified model, and input the friction coefficient between the ground and the wheels; 3-3 Mesh Generation: The maximum dimensions of the mesh in the ground model and simplified model shall not exceed 1% of the length, width, and height of the transport vehicle; 3-4 The wind pressure calculated by Formula 2 is introduced into the statics module of the finite element software for solution, and the displacement field and stress field of the transport vehicle under crosswind are calculated. Step four establishes the criteria for judging overturning stability, including the following steps: 4-1 The vertical support reaction force of the ground on the transport vehicle tire in the simplified model is obtained by integrating the contact stress using Formula 3. （3） in, Let each element be a stress component along the vertical direction. A The contact area is given; the vertical support reaction force is obtained by integrating over the entire contact area. ; 4-2 Repeat step 4-1 to calculate the vertical support reactions on the left and right sides of the front wheels of the transport vehicle. and Vertical support reaction forces on the left and right sides of the rear wheel and ; 4-3 Establish the overturning judgment criteria based on Formula 4: （4） in, The probability of the panel transport vehicle overturning; when If the calculated result is 1, then the overturning probability is 100%. In this case, it is necessary to add the mass of the counterweight to the simplified model and repeat steps three and four until the calculated overturning probability is obtained. Meet actual needs.

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