A method and system for forming a bubble-type window for a helicopter door

Abstract

The application relates to the technical field of helicopter cabin door manufacturing, and discloses a forming method and system for a bubble-type window of a helicopter cabin door. A three-dimensional finite element analysis model of the bubble-type window of the helicopter cabin door is constructed, and stress distribution of the bubble-type window after the temperature of the bubble-type window is reduced from hot pressing forming to use temperature is analyzed. According to stress values and curvatures of each finite element node of the three-dimensional finite element analysis model of the bubble-type window, a clustering analysis method is used to divide the three-dimensional finite element analysis model into multiple cooling control areas, and a cooling rate of each cooling control area meeting an internal stress limit value is determined. The cooling rate meeting the requirement is determined through finite element analysis, precise cooling of different cooling control areas in the hot pressing forming process is realized, internal stress of the bubble-type window after forming is ensured to meet control requirements, and in particular, it can be ensured that the bubble-type window is not prone to generating large temperature stress, so that the mechanical property of the bubble-type window is improved.

Description

Technical Field

[0001] This invention relates to the field of helicopter cabin door manufacturing technology, and discloses a method and system for forming bubble-shaped windows for helicopter cabin doors. Background Technology

[0002] Existing helicopter door structures feature flat windows. If the pilot needs to work with a direct view of the area below the fuselage, they must open the window and bring their head as close to it as possible. However, the limited opening size of these windows significantly restricts the actions of helmet-wearing pilots. Forcing the helmet to protrude outside the window increases the difficulty of operations and poses considerable safety risks. Therefore, a full-view helicopter door design is necessary.

[0003] Our company's full-view helicopter door utilizes a one-piece molding process with high-strength transparent plastic material to create a bubble-shaped window. This bubble-shaped window structure not only provides a sealed space for the cockpit, reducing the impact of airflow on the pilot, but also increases the pilot's field of vision and viewing angle, effectively reducing the obstruction of vision caused by the original door partition. Especially during specific missions, such as rescue and hoisting operations, the protruding space provides the pilot with a suitable observation angle, helping them to observe targets more accurately and improving flight safety.

[0004] However, during the hot pressing process of bubble-shaped windows, the inconsistent bending conditions in different areas can easily lead to significant temperature stress during cooling, thereby reducing the mechanical properties of the bubble-shaped windows. Therefore, controlling the cooling rate during the bubble-shaped window molding process to improve its mechanical properties is a problem that urgently needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for forming a bubble-shaped window for a helicopter cabin door, which can ensure that the bubble-shaped window is not prone to generating large temperature stress, thereby improving the mechanical properties of the bubble-shaped window.

[0006] To achieve the above-mentioned technical effects, the technical solution adopted by the present invention is as follows:

[0007] A method for forming a bubble-shaped window for a helicopter cabin door, comprising:

[0008] Based on the structural dimensions and material performance parameters of the bubble-shaped window of the helicopter cabin door, a three-dimensional finite element analysis model of the bubble-shaped window is constructed; the bubble-shaped window includes a mounting edge that is fixedly fitted with the helicopter cabin door and a bubble-shaped window structure that protrudes from the helicopter cabin door.

[0009] Based on the operating temperature and hot pressing temperature of the bubble-shaped window, the first internal stress of each finite element node of the three-dimensional finite element analysis model is obtained by using the finite element analysis method after the hot pressing temperature is cooled to the operating temperature at a preset initial cooling rate.

[0010] Based on the first internal stress of each finite element node, the internal stress limit value of the bubble-shaped window, and the curvature at each finite element node, the three-dimensional finite element analysis model is divided into multiple cooling control regions using the K-means clustering analysis method.

[0011] For each cooling control area, the corresponding cooling control area is cooled by reducing the cooling rate, and the second internal stress of each finite element node in the corresponding cooling control area is obtained by finite element analysis. The cooling rate at which the maximum value of the second internal stress in each cooling control area is less than or equal to the internal stress limit value is determined as the cooling rate in the hot pressing process of the corresponding cooling control area.

[0012] According to the cooling rate corresponding to each cooling control area, the cooling control area of ​​the bubble-shaped window is cooled in sections during the hot pressing process.

[0013] Furthermore, the method of dividing the three-dimensional finite element analysis model into multiple cooling control regions using K-means clustering analysis includes:

[0014] The region in which the first internal stress value of all finite element nodes in the three-dimensional finite element analysis model is greater than the internal stress limit value is taken as the analysis region, and the location and number of the analysis regions are determined.

[0015] The finite element node containing the first maximum internal stress in each analysis region is selected as the cluster center. Based on the first internal stress value at each finite element node, the curvature at each finite element node, and the geometric distance from each finite element node to each cluster center, the Euclidean distance from each finite element node to each cluster center in the three-dimensional finite element analysis model is calculated.

[0016] Each finite element node is clustered to the cluster center corresponding to the minimum Euclidean distance, forming a cooling control region that includes the cluster center and the finite element nodes clustered to the corresponding cluster center.

[0017] Furthermore, according to Calculate the Euclidean distance from each finite element node to each cluster center in the three-dimensional finite element analysis model, where d ij Let L be the Euclidean distance from the i-th finite element node to the j-th cluster center. ij F is the geometric distance from the i-th finite element node to the j-th cluster center. iLet F be the first internal stress value of the i-th finite element node. j K represents the first internal stress value of the j-th cluster center. i Let K be the curvature at the i-th finite element node. j Let be the curvature at the j-th cluster center.

[0018] To achieve the above-mentioned technical effects, the present invention also provides a helicopter cabin door bubble-shaped window forming system, comprising:

[0019] The finite element model construction module is used to construct a three-dimensional finite element analysis model of the bubble-shaped window based on the structural dimensions and material performance parameters of the helicopter cabin door bubble-shaped window; the bubble-shaped window includes an installation edge that is fixedly fitted to the helicopter cabin door and a bubble-shaped window structure that protrudes from the helicopter cabin door;

[0020] The first internal stress analysis module is used to analyze and obtain the first internal stress of each finite element node of the three-dimensional finite element analysis model after the hot pressing temperature is cooled to the operating temperature at a preset initial cooling rate, based on the operating temperature and hot pressing temperature of the bubble-shaped window.

[0021] The region division module is used to divide the three-dimensional finite element analysis model into multiple cooling control regions based on the first internal stress of each finite element node, the internal stress limit value of the bubble-shaped window, and the curvature at each finite element node, using the K-means clustering analysis method.

[0022] The cooling rate determination module is used to cool down each cooling control area by reducing the cooling rate, and to obtain the second internal stress of each finite element node in the corresponding cooling control area using the finite element analysis method. The cooling rate at which the maximum value of the second internal stress in each cooling control area is less than or equal to the internal stress limit value is determined as the cooling rate in the hot pressing process of the corresponding cooling control area.

[0023] The temperature control module is used to cool each cooling control area of ​​the bubble-shaped window in sections during the hot pressing process according to the cooling rate corresponding to each cooling control area.

[0024] Furthermore, in the region partitioning module, the method of dividing the three-dimensional finite element analysis model into multiple cooling control regions using K-means clustering analysis includes:

[0025] The region in which the first internal stress value of all finite element nodes in the three-dimensional finite element analysis model is greater than the internal stress limit value is taken as the analysis region, and the location and number of the analysis regions are determined.

[0026] The finite element node containing the first maximum internal stress in each analysis region is selected as the cluster center. Based on the first internal stress value at each finite element node, the curvature at each finite element node, and the geometric distance from each finite element node to each cluster center, the Euclidean distance from each finite element node to each cluster center in the three-dimensional finite element analysis model is calculated.

[0027] Each finite element node is clustered to the cluster center corresponding to the minimum Euclidean distance, forming a cooling control region that includes the cluster center and the finite element nodes clustered to the corresponding cluster center.

[0028] Furthermore, in the region division module, according to Calculate the Euclidean distance from each finite element node to each cluster center in the three-dimensional finite element analysis model, where d ij Let L be the Euclidean distance from the i-th finite element node to the j-th cluster center. ij F is the geometric distance from the i-th finite element node to the j-th cluster center. i Let F be the first internal stress value of the i-th finite element node. j K represents the first internal stress value of the j-th cluster center. i Let K be the curvature at the i-th finite element node. j Let be the curvature at the j-th cluster center.

[0029] Furthermore, the temperature control module includes a cooling cavity disposed on the hot pressing mold, each of the cooling cavities being connected to a feed conduit and a discharge conduit for introducing a cooling medium into the cooling cavity, and the feed conduit or the discharge conduit being provided with a regulating valve for controlling the flow rate of the cooling medium.

[0030] Furthermore, the temperature control module also includes an auxiliary heating mechanism.

[0031] Furthermore, the cooling medium is either gaseous cold air or liquid coolant.

[0032] Compared with the prior art, the beneficial effects of this invention are as follows: This invention uses cluster analysis to divide the three-dimensional finite element analysis model of the bubble-shaped window into multiple cooling control regions, and determines the cooling rate of each cooling control region that meets the internal stress limit value. The cooling rate that meets the limit is determined through finite element analysis, thereby achieving precise regional cooling of different cooling control regions during hot pressing. This ensures that the internal stress of the bubble-shaped window structure after molding meets the control requirements, and in particular, it ensures that the bubble-shaped window is not prone to generating large temperature stress, thereby improving the mechanical properties of the bubble-shaped window. Attached Figure Description

[0033] Figure 1 This is a flowchart of the method for forming a bubble-shaped window for a helicopter cabin door in the embodiment;

[0034] Figure 2 This is a structural block diagram of the helicopter cabin door bubble-shaped window forming system in the embodiment;

[0035] Figure 3 This is a schematic diagram of the installation structure of the helicopter cabin door and the bubble-shaped window in the embodiment;

[0036] Figure 4 This is a schematic diagram of the protruding bubble-shaped window in the embodiment;

[0037] The module includes: 1. Finite element model construction module; 2. First internal stress analysis module; 3. Region division module; 4. Cooling rate determination module; 5. Temperature control module; 6. Helicopter door; 7. Bubble-shaped window. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the above-described subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0039] Example

[0040] See Figures 1 to 4 A method for forming a bubble-shaped window for a helicopter cabin door, comprising:

[0041] Based on the structural dimensions and material performance parameters of the bubble-shaped window 7 of the helicopter door 6, a three-dimensional finite element analysis model of the bubble-shaped window 7 is constructed; the bubble-shaped window 7 includes an installation edge that is fixedly fitted with the helicopter door 6 and a bubble-shaped window structure that protrudes from the helicopter door 6.

[0042] Based on the operating temperature and hot pressing temperature of the bubble-shaped window 7, the first internal stress of each finite element node of the three-dimensional finite element analysis model is obtained by using the finite element analysis method after the hot pressing temperature is cooled to the operating temperature at a preset initial cooling rate from the hot pressing temperature.

[0043] Based on the first internal stress of each finite element node, the internal stress limit value of the bubble-shaped window 7, and the curvature at each finite element node, the three-dimensional finite element analysis model is divided into multiple cooling control regions using the K-means clustering analysis method.

[0044] For each cooling control area, the corresponding cooling control area is cooled by reducing the cooling rate, and the second internal stress of each finite element node in the corresponding cooling control area is obtained by finite element analysis. The cooling rate at which the maximum value of the second internal stress in each cooling control area is less than or equal to the internal stress limit value is determined as the cooling rate in the hot pressing process of the corresponding cooling control area.

[0045] According to the cooling rate corresponding to each cooling control area, the cooling control area of ​​the bubble-shaped window 7 is cooled in sections during the hot pressing process.

[0046] In this embodiment, a three-dimensional finite element analysis model of the bubble-shaped window 7 of the helicopter cabin door 6 is constructed, and the stress distribution of the bubble-shaped window 7 after cooling from the hot pressing temperature to the operating temperature is analyzed. Based on the stress value and curvature of each finite element node in the three-dimensional finite element analysis model of the bubble-shaped window 7, a cluster analysis method is used to divide the three-dimensional finite element analysis model into multiple cooling control regions, and the cooling rate of each cooling control region that meets the internal stress limit value is determined. The required cooling rate is determined through finite element analysis, so as to achieve precise regional cooling of different cooling control regions during the hot pressing process, ensuring that the internal stress of the bubble-shaped window 7 structure after molding meets the control requirements. In particular, it can ensure that the bubble-shaped window 7 is not prone to generating large temperature stress, thereby improving the mechanical properties of the bubble-shaped window 7.

[0047] In this embodiment, the preset initial cooling rate can be set according to the material of the window structure and with reference to the cooling rate data of traditional hot-pressed window structures. The initial cooling rate is generally the cooling rate that meets the condition that the overall structure of the traditional hot-pressed window does not deform or warp. The method of determining it is known to those skilled in the art and will not be described here.

[0048] In this embodiment, the method of dividing the three-dimensional finite element analysis model into multiple cooling control regions using K-means clustering analysis includes:

[0049] The region in which the first internal stress value of all finite element nodes in the three-dimensional finite element analysis model is greater than the internal stress limit value is taken as the analysis region, and the location and number of the analysis regions are determined.

[0050] The finite element node containing the first maximum internal stress in each analysis region is selected as the cluster center. Based on the first internal stress value at each finite element node, the curvature at each finite element node, and the geometric distance from each finite element node to each cluster center, the Euclidean distance from each finite element node to each cluster center in the three-dimensional finite element analysis model is calculated.

[0051] Each finite element node is clustered to the cluster center corresponding to the minimum Euclidean distance, forming a cooling control region that includes the cluster center and the finite element nodes clustered to the corresponding cluster center.

[0052] In this embodiment, according to Calculate the Euclidean distance from each finite element node to each cluster center in the three-dimensional finite element analysis model, where d ijLet L be the Euclidean distance from the i-th finite element node to the j-th cluster center. ij F is the geometric distance from the i-th finite element node to the j-th cluster center. i Let F be the first internal stress value of the i-th finite element node. j K represents the first internal stress value of the j-th cluster center. i Let K be the curvature at the i-th finite element node. j Let be the curvature at the j-th cluster center. This Euclidean distance takes into account the geometric distance from the finite element node to the cluster center, the stress value at each finite element node, and the influence of curvature. It can more accurately reflect the actual relationship between the finite element node and the cluster center, thereby improving the accuracy of cluster classification. This facilitates obtaining a more precise cooling rate control value and enables low-stress molding of the bubble-shaped window 7 of the helicopter cabin door 6.

[0053] Based on the same inventive concept, this embodiment also provides a helicopter cabin door 6 bubble-shaped window 7 forming system, including:

[0054] Finite element model construction module 1 is used to construct a three-dimensional finite element analysis model of the bubble-shaped window 7 based on the structural dimensions and material performance parameters of the bubble-shaped window 7 of the helicopter door 6; the bubble-shaped window 7 includes an installation edge that is fixedly fitted to the helicopter door 6 and a bubble-shaped window structure that protrudes from the helicopter door 6.

[0055] The first internal stress analysis module 2 is used to analyze and obtain the first internal stress of each finite element node of the three-dimensional finite element analysis model after the hot pressing temperature is cooled to the operating temperature at a preset initial cooling rate, based on the operating temperature and hot pressing temperature of the bubble-shaped window 7, using the finite element analysis method.

[0056] The region division module 3 is used to divide the three-dimensional finite element analysis model into multiple cooling control regions based on the first internal stress of each finite element node, the internal stress limit value of the bubble-shaped window 7, and the curvature at each finite element node, using the K-means clustering analysis method.

[0057] The cooling rate determination module 4 is used to cool down each cooling control area by reducing the cooling rate, and to obtain the second internal stress of each finite element node in the corresponding cooling control area by using the finite element analysis method. The cooling rate at which the maximum value of the second internal stress in each cooling control area is less than or equal to the internal stress limit value is determined as the cooling rate in the hot pressing process of the corresponding cooling control area.

[0058] Temperature control module 5 is used to cool each cooling control area of ​​the bubble-shaped window 7 in sections according to the cooling rate corresponding to each cooling control area during the hot pressing process.

[0059] In this embodiment, the temperature control module includes cooling chambers disposed on the hot-pressing mold. Each cooling chamber is connected to an inlet conduit and an outlet conduit for introducing a cooling medium into the cooling chamber. A regulating valve is provided on the inlet conduit or the outlet conduit for controlling the flow rate of the cooling medium. In this embodiment, the cooling medium is gaseous cold air or liquid coolant; other refrigerants that can be transported through the inlet and outlet conduits are also applicable to this invention.

[0060] In this embodiment, the temperature control module further includes an auxiliary heating mechanism, which is used to cooperate in realizing the constant temperature, heating or cooling control of the temperature control module.

[0061] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for forming a bubble-shaped window for a helicopter cabin door, characterized in that, include: Based on the structural dimensions and material performance parameters of the bubble-shaped window of the helicopter cabin door, a three-dimensional finite element analysis model of the bubble-shaped window is constructed; the bubble-shaped window includes a mounting edge that is fixedly fitted with the helicopter cabin door and a bubble-shaped window structure that protrudes from the helicopter cabin door. Based on the operating temperature and hot pressing temperature of the bubble-shaped window, the first internal stress of each finite element node of the three-dimensional finite element analysis model is obtained by using the finite element analysis method after the hot pressing temperature is cooled to the operating temperature at a preset initial cooling rate. Based on the first internal stress of each finite element node, the internal stress limit value of the bubble-shaped window, and the curvature at each finite element node, the three-dimensional finite element analysis model is divided into multiple cooling control regions using the K-means clustering analysis method. For each cooling control area, the corresponding cooling control area is cooled down by reducing the cooling rate, and the second internal stress of each finite element node in the corresponding cooling control area is obtained by finite element analysis. The cooling rate at which the maximum value of the second internal stress in each cooling control area is less than or equal to the internal stress limit value is determined as the cooling rate in the hot pressing process of the corresponding cooling control area. According to the cooling rate corresponding to each cooling control area, the cooling control area of ​​the bubble-shaped window is cooled in sections during the hot pressing process.

2. The method for forming a bubble-shaped window for a helicopter cabin door according to claim 1, characterized in that, The method of dividing the three-dimensional finite element analysis model into multiple cooling control regions using K-means clustering analysis includes: The region in which the first internal stress value of all finite element nodes in the three-dimensional finite element analysis model is greater than the internal stress limit value is taken as the analysis region, and the location and number of the analysis regions are determined. The finite element node containing the first maximum internal stress in each analysis region is selected as the cluster center. Based on the first internal stress value at each finite element node, the curvature at each finite element node, and the geometric distance from each finite element node to each cluster center, the Euclidean distance from each finite element node to each cluster center in the three-dimensional finite element analysis model is calculated. Each finite element node is clustered to the cluster center corresponding to the minimum Euclidean distance, forming a cooling control region that includes the cluster center and the finite element nodes clustered to the corresponding cluster center.

3. The method for forming a bubble-shaped window for a helicopter cabin door according to claim 1, characterized in that, according to Calculate the Euclidean distance from each finite element node to each cluster center in the three-dimensional finite element analysis model, where d ij Let L be the Euclidean distance from the i-th finite element node to the j-th cluster center. ij F is the geometric distance from the i-th finite element node to the j-th cluster center. i Let F be the first internal stress value of the i-th finite element node. j K represents the first internal stress value of the j-th cluster center. i Let K be the curvature at the i-th finite element node. j Let be the curvature at the j-th cluster center.

4. A bubble-shaped window forming system for a helicopter cabin door, characterized in that, include: The finite element model construction module is used to construct a three-dimensional finite element analysis model of the bubble-shaped window based on the structural dimensions and material performance parameters of the helicopter cabin door bubble-shaped window; the bubble-shaped window includes an installation edge that is fixedly fitted to the helicopter cabin door and a bubble-shaped window structure that protrudes from the helicopter cabin door; The first internal stress analysis module is used to analyze and obtain the first internal stress of each finite element node of the three-dimensional finite element analysis model after the hot pressing temperature is cooled to the operating temperature at a preset initial cooling rate, based on the operating temperature and hot pressing temperature of the bubble-shaped window. The region division module is used to divide the three-dimensional finite element analysis model into multiple cooling control regions based on the first internal stress of each finite element node, the internal stress limit value of the bubble-shaped window, and the curvature at each finite element node, using the K-means clustering analysis method. The cooling rate determination module is used to cool down each cooling control area by reducing the cooling rate, and to obtain the second internal stress of each finite element node in the corresponding cooling control area using the finite element analysis method. The cooling rate at which the maximum value of the second internal stress in each cooling control area is less than or equal to the internal stress limit value is determined as the cooling rate in the hot pressing process of the corresponding cooling control area. The temperature control module is used to cool each cooling control area of ​​the bubble-shaped window in sections during the hot pressing process according to the cooling rate corresponding to each cooling control area.

5. The helicopter cabin door bubble-shaped window forming system according to claim 4, characterized in that, In the region partitioning module, the method for dividing the three-dimensional finite element analysis model into multiple cooling control regions using K-means clustering analysis includes: The region in which the first internal stress value of all finite element nodes in the three-dimensional finite element analysis model is greater than the internal stress limit value is taken as the analysis region, and the location and number of the analysis regions are determined. The finite element node containing the first maximum internal stress in each analysis region is selected as the cluster center. Based on the first internal stress value at each finite element node, the curvature at each finite element node, and the geometric distance from each finite element node to each cluster center, the Euclidean distance from each finite element node to each cluster center in the three-dimensional finite element analysis model is calculated. Each finite element node is clustered to the cluster center corresponding to the minimum Euclidean distance, forming a cooling control region that includes the cluster center and the finite element nodes clustered to the corresponding cluster center.

6. The helicopter cabin door bubble-shaped window forming system according to claim 5, characterized in that, In the region division module, according to Calculate the Euclidean distance from each finite element node to each cluster center in the three-dimensional finite element analysis model, where d ij Let L be the Euclidean distance from the i-th finite element node to the j-th cluster center. ij F is the geometric distance from the i-th finite element node to the j-th cluster center. i Let F be the first internal stress value of the i-th finite element node. j K represents the first internal stress value of the j-th cluster center. i Let K be the curvature at the i-th finite element node. j Let be the curvature at the j-th cluster center.

7. The helicopter cabin door bubble-shaped window forming system according to claim 4, characterized in that, The temperature control module includes a cooling cavity disposed on the hot pressing mold. Each cooling cavity is connected to a feed pipe and a discharge pipe for introducing a cooling medium into the cooling cavity. The feed pipe or the discharge pipe is provided with a regulating valve for regulating the flow rate of the cooling medium.

8. The helicopter cabin door bubble-shaped window forming system according to claim 7, characterized in that, The temperature control module also includes an auxiliary heating mechanism.

9. The helicopter cabin door bubble-shaped window forming system according to claim 7, characterized in that, The cooling medium is either gaseous cold air or liquid coolant.

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