Helicopter cabin door bubble type window forming method and system

Abstract

The invention relates to the technical field of helicopter cabin door manufacturing, and discloses a helicopter cabin door bubble type window forming method and system.The helicopter cabin door bubble type window forming method comprises the steps that a three-dimensional finite element analysis model of a helicopter cabin door bubble type window is built, and stress distribution after the bubble type window is reduced to the use temperature from the hot press forming temperature is analyzed; stress values and curvatures of all finite element nodes of the model are analyzed according to the three-dimensional finite element of the bubble type window; a clustering analysis method is adopted to divide a three-dimensional finite element analysis model into a plurality of cooling control areas and the cooling rate of each cooling control area meeting the internal stress limit value, the met cooling rate is determined through finite element analysis, regional precise cooling of different cooling control areas in the hot press forming process is achieved, and the cooling rate of each cooling control area is determined. The internal stress of the formed bubble type window structure is ensured to meet the control requirement, and particularly, the bubble type window is ensured not to easily generate larger temperature stress, so that the mechanical property of the bubble type window is improved.

Description

Technical Field

[0001] The invention relates to the technical field of helicopter cabin door manufacturing and discloses a method and system for forming a bubble-type window of a helicopter cabin door. Background Art

[0002] Existing helicopter doors feature a flat window structure. If a pilot needs to see below the fuselage to perform an operation, they must open the window and place their head as close to it as possible. The limited opening and closing width of the window restricts helmet-wearing pilots from performing various tasks. Forcing the helmet partially out of the window to perform operations would undoubtedly increase the pilot's difficulty and pose a significant safety risk. Therefore, a helicopter door design with full visibility is needed.

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

[0004] However, during the hot-pressing process of bubble-shaped windows, the bending conditions in different areas are inconsistent, which easily generates large temperature stresses during the cooling process, thereby reducing the mechanical properties of the bubble-shaped windows. How to control the cooling rate during the bubble-shaped window molding process to improve the mechanical properties of the bubble-shaped window is an urgent problem that needs to be solved. Summary of the Invention

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

[0006] In order to achieve the above technical effects, the technical solution adopted by the present invention is:

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

[0008] A three-dimensional finite element analysis model of the bubble-shaped window of the helicopter cabin door is constructed based on the structural dimensions and material performance parameters of the bubble-shaped window; the bubble-shaped window includes a mounting edge fixedly matched with the helicopter cabin door and a bubble-shaped window structure protruding from the helicopter cabin door;

[0009] According to the service temperature and hot pressing temperature of the bubble-shaped window, a finite element analysis method 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 temperature is cooled from the hot pressing temperature to the service temperature at a preset initial cooling rate;

[0010] Dividing the three-dimensional finite element analysis model into a plurality of cooling control areas using a K-means clustering analysis method according to 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;

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

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

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

[0014] Taking areas where the first internal stress values of all finite element nodes of the three-dimensional finite element analysis model are greater than the internal stress limit value as analysis areas, and determining the positions and number of the analysis areas;

[0015] Selecting the finite element node where the first internal stress maximum value is located in each analysis area as the cluster center, and calculating the Euclidean distance from each finite element node to each cluster center in the three-dimensional finite element analysis model 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;

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

[0017] Further, 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 is the Euclidean distance from the i-th finite element node to the j-th cluster center, L ij is the geometric distance from the i-th finite element node to the j-th cluster center, F iis the first internal stress value of the i-th finite element node, F j is the first internal stress value of the jth cluster center, K i is the curvature at the i-th finite element node, K j is the curvature at the j-th cluster center.

[0018] In order to achieve the above technical effects, the present invention also provides a helicopter door bubble window forming system, comprising:

[0019] A finite element model building module is used to build a three-dimensional finite element analysis model of the helicopter cabin door bubble-shaped window based on the structural dimensions and material performance parameters of the bubble-shaped window; the bubble-shaped window includes a mounting edge fixedly matched with the helicopter cabin door and a bubble-shaped window structure protruding from the helicopter cabin door;

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

[0021] a region division module, configured to divide the three-dimensional finite element analysis model into a plurality of cooling control regions using a K-means clustering analysis method according to 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;

[0022] a cooling rate determination module, configured to cool each cooling control region by reducing the cooling rate, and to obtain the second internal stress of each finite element node in the corresponding cooling control region using a finite element analysis method, and to determine the cooling rate at which the maximum value of the second internal stress in each cooling control region is less than or equal to the internal stress limit value as the cooling rate during the hot pressing forming process of the corresponding cooling control region;

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

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

[0025] Taking areas where the first internal stress values of all finite element nodes of the three-dimensional finite element analysis model are greater than the internal stress limit value as analysis areas, and determining the positions and number of the analysis areas;

[0026] Selecting the finite element node where the first internal stress maximum value is located in each analysis area as the cluster center, and calculating the Euclidean distance from each finite element node to each cluster center in the three-dimensional finite element analysis model 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;

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

[0028] Furthermore, in the area 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 is the Euclidean distance from the i-th finite element node to the j-th cluster center, L ij is the geometric distance from the i-th finite element node to the j-th cluster center, F i is the first internal stress value of the i-th finite element node, F j is the first internal stress value of the jth cluster center, K i is the curvature at the i-th finite element node, K j is the curvature at the j-th cluster center.

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

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

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

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention adopts a cluster analysis method to divide the three-dimensional finite element analysis model of the bubble-type window into multiple cooling control areas, as well as the cooling rate of each cooling control area that meets the internal stress limit value, and determines the satisfied cooling rate through finite element analysis, thereby realizing regional precise cooling of different cooling control areas during the hot pressing process, ensuring that the internal stress of the bubble-type window structure after molding meets the control requirements, and especially ensuring that the bubble-type window is not prone to generate large temperature stress, thereby improving the mechanical properties of the bubble-type window. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Flowchart of the method for forming the bubble-type window for a helicopter door in an embodiment;

[0034] Figure 2 This is a structural block diagram of the helicopter door bubble window molding system in an embodiment;

[0035] Figure 3 Schematic diagram of the installation structure of the helicopter door and bubble-shaped window in the embodiment;

[0036] Figure 4 Schematic diagram of the protruding bubble-shaped window in the embodiment;

[0037] Among them, 1. Finite element model construction module; 2. First internal stress analysis module; 3. Area division module; 4. Cooling rate determination module; 5. Temperature control module; 6. Helicopter cabin door; 7. Bubble-type window. DETAILED DESCRIPTION

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

[0039] Example

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

[0041] A three-dimensional finite element analysis model of the bubble-shaped window 7 of the helicopter door 6 is constructed based on the structural dimensions and material performance parameters of the bubble-shaped window 7; the bubble-shaped window 7 includes a mounting edge fixedly matched with the helicopter door 6 and a bubble-shaped window structure protruding from the helicopter door 6;

[0042] According to the use temperature and hot pressing temperature of the bubble-shaped window 7, a finite element analysis method is used to analyze and obtain the first internal stress of each finite element node of the three-dimensional finite element analysis model after cooling from the hot pressing temperature to the use temperature at a preset initial cooling rate;

[0043] Divide the three-dimensional finite element analysis model into multiple cooling control areas using a K-means clustering analysis method according to 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;

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

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

[0046] In this embodiment, a three-dimensional finite element analysis model of the bubble-type window 7 of the helicopter cabin door 6 is constructed, and the stress distribution of the bubble-type window 7 after the temperature drops from the hot pressing molding temperature to the use temperature is analyzed. According to the stress value and curvature of each finite element node of the three-dimensional finite element analysis model of the bubble-type window 7; a cluster analysis method is used to divide the three-dimensional finite element analysis model into multiple cooling control areas, and the cooling rate of each cooling control area that meets the internal stress limit value is determined by finite element analysis, and the satisfied cooling rate is determined through finite element analysis, so as to realize regional precise cooling of different cooling control areas during the hot pressing molding process, ensure that the internal stress of the bubble-type window 7 structure after molding meets the control requirements, especially ensure that the bubble-type window 7 is not prone to generate large temperature stress, thereby improving the mechanical properties of the bubble-type 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 the traditional hot-pressed window structure. The initial cooling rate is generally a cooling rate that satisfies the conditions that the overall structure of the traditional hot-pressed window does not deform or warp. The determination method is known to those skilled in the art and will not be repeated here.

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

[0049] Taking areas where the first internal stress values of all finite element nodes of the three-dimensional finite element analysis model are greater than the internal stress limit value as analysis areas, and determining the positions and number of the analysis areas;

[0050] Selecting the finite element node where the first internal stress maximum value is located in each analysis area as the cluster center, and calculating the Euclidean distance from each finite element node to each cluster center in the three-dimensional finite element analysis model 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;

[0051] Each finite element node is clustered to the cluster center corresponding to the minimum Euclidean distance, forming a cooling control area including 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 ijis the Euclidean distance from the i-th finite element node to the j-th cluster center, L ij is the geometric distance from the i-th finite element node to the j-th cluster center, F i is the first internal stress value of the i-th finite element node, F j is the first internal stress value of the jth cluster center, K i is the curvature at the i-th finite element node, K j is the curvature at the jth 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 nodes and the cluster center, thereby improving the accuracy of cluster classification, facilitating the acquisition of more precise cooling rate control values, and enabling low-stress forming of the bubble-shaped window 7 of the helicopter door 6.

[0053] Based on the same inventive concept, this embodiment also provides a helicopter door 6 bubble-type window 7 molding system, comprising:

[0054] A finite element model building module 1 is used to build a three-dimensional finite element analysis model of the bubble-shaped window 7 of the helicopter cabin door 6 based on the structural dimensions and material performance parameters of the bubble-shaped window 7; the bubble-shaped window 7 includes a mounting edge fixedly matched with the helicopter cabin door 6 and a bubble-shaped window structure protruding from the helicopter cabin door 6;

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

[0056] A region division module 3 is configured to divide the three-dimensional finite element analysis model into a plurality of cooling control regions using a K-means clustering analysis method according to 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;

[0057] a cooling rate determination module 4 for cooling each cooling control region by reducing the cooling rate, obtaining the second internal stress of each finite element node in the corresponding cooling control region using a finite element analysis method, and determining the cooling rate at which the maximum value of the second internal stress in each cooling control region is less than or equal to the internal stress limit value as the cooling rate during the hot pressing forming process of the corresponding cooling control region;

[0058] The temperature control module 5 is used to cool down each cooling control area of the bubble-shaped window 7 in a zone-by-zone manner during the hot pressing process according to the cooling rate corresponding to each cooling control area.

[0059] In this embodiment, the temperature control module includes a cooling cavity disposed within the hot pressing mold. Each cooling cavity is connected to a feed conduit and a discharge conduit for introducing a cooling medium into the cooling cavity. A regulating valve is provided on the feed conduit or the discharge conduit for regulating the flow of the cooling medium. In this embodiment, the cooling medium is gaseous cold air or liquid coolant. Other refrigerants capable of being transported through the feed conduit and the discharge conduit are also suitable for use in the present invention.

[0060] In this embodiment, the temperature control module further includes an auxiliary heating mechanism for cooperating to achieve constant temperature, temperature increase or temperature decrease control of the temperature control module.

[0061] The above are only 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 in the scope of protection of the present invention.

Claims

1. A method for forming a bubble-type window for a helicopter door, characterized in that: include: A three-dimensional finite element analysis model of the bubble-shaped window of the helicopter cabin door is constructed based on the structural dimensions and material performance parameters of the bubble-shaped window; the bubble-shaped window includes a mounting edge fixedly matched with the helicopter cabin door and a bubble-shaped window structure protruding from the helicopter cabin door; According to the service temperature and hot pressing temperature of the bubble-shaped window, a finite element analysis method 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 temperature is cooled from the hot pressing temperature to the service temperature at a preset initial cooling rate; Dividing the three-dimensional finite element analysis model into a plurality of cooling control areas using a K-means clustering analysis method according to 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; For each cooling control region, the corresponding cooling control region is cooled by reducing the cooling rate, and the second internal stress of each finite element node in the corresponding cooling control region is obtained by a finite element analysis method, and the cooling rate at which the maximum value of the second internal stress in each cooling control region is less than or equal to the internal stress limit value is determined as the cooling rate of the corresponding cooling control region during the hot pressing forming process; According to the cooling rate corresponding to each cooling control area, each cooling control area of the bubble-shaped window is cooled in a zone-by-zone manner during the hot pressing process.

2. The method for forming a helicopter door bubble-type window according to claim 1, characterized in that: The method of dividing the three-dimensional finite element analysis model into multiple cooling control areas using the K-means cluster analysis method includes: Taking areas where the first internal stress values of all finite element nodes of the three-dimensional finite element analysis model are greater than the internal stress limit value as analysis areas, and determining the positions and number of the analysis areas; Selecting the finite element node where the first internal stress maximum value is located in each analysis area as the cluster center, and calculating the Euclidean distance from each finite element node to each cluster center in the three-dimensional finite element analysis model 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; Each finite element node is clustered to the cluster center corresponding to the minimum Euclidean distance, forming a cooling control area including the cluster center and the finite element nodes clustered to the corresponding cluster center.

3. The method for forming a helicopter door bubble-type window 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 is the Euclidean distance from the i-th finite element node to the j-th cluster center, L ij is the geometric distance from the i-th finite element node to the j-th cluster center, F i is the first internal stress value of the i-th finite element node, F j is the first internal stress value of the jth cluster center, K i is the curvature at the i-th finite element node, K j is the curvature at the j-th cluster center.

4. A helicopter door bubble window molding system, characterized in that: include: A finite element model building module is used to build a three-dimensional finite element analysis model of the helicopter cabin door bubble-shaped window based on the structural dimensions and material performance parameters of the bubble-shaped window; the bubble-shaped window includes a mounting edge fixedly matched with the helicopter cabin door and a bubble-shaped window structure protruding from the helicopter cabin door; a first internal stress analysis module for analyzing, based on the operating temperature and the hot pressing temperature of the bubble-shaped window, using a finite element analysis method to obtain a first internal stress at each finite element node of the three-dimensional finite element analysis model after the model is cooled from the hot pressing temperature to the operating temperature at a preset initial cooling rate; a region division module, configured to divide the three-dimensional finite element analysis model into a plurality of cooling control regions using a K-means clustering analysis method according to 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; a cooling rate determination module, configured to cool each cooling control region by reducing the cooling rate, and to obtain the second internal stress of each finite element node in the corresponding cooling control region using a finite element analysis method, and to determine the cooling rate at which the maximum value of the second internal stress in each cooling control region is less than or equal to the internal stress limit value as the cooling rate during the hot pressing forming process of the corresponding cooling control region; The temperature control module is used to cool each cooling control area of the bubble-shaped window in a zone-by-zone manner during the hot pressing process according to the cooling rate corresponding to each cooling control area.

5. The helicopter door bubble window molding system according to claim 4, characterized in that: In the region division module, the method of dividing the three-dimensional finite element analysis model into multiple cooling control regions using the K-means cluster analysis method includes: Taking areas where the first internal stress values of all finite element nodes of the three-dimensional finite element analysis model are greater than the internal stress limit value as analysis areas, and determining the positions and number of the analysis areas; Selecting the finite element node where the first internal stress maximum value is located in each analysis area as the cluster center, and calculating the Euclidean distance from each finite element node to each cluster center in the three-dimensional finite element analysis model 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; Each finite element node is clustered to the cluster center corresponding to the minimum Euclidean distance, forming a cooling control area including the cluster center and the finite element nodes clustered to the corresponding cluster center.

6. The helicopter door bubble window molding system according to claim 5, characterized in that: In the regional 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 is the Euclidean distance from the i-th finite element node to the j-th cluster center, L ij is the geometric distance from the i-th finite element node to the j-th cluster center, F i is the first internal stress value of the i-th finite element node, F j is the first internal stress value of the jth cluster center, K i is the curvature at the i-th finite element node, K j is the curvature at the j-th cluster center.

7. The helicopter door bubble window molding system according to claim 4, characterized in that: The temperature control module includes a cooling cavity arranged on the hot pressing mold, each of the cooling cavities is connected to a feed conduit and a discharge conduit for introducing a cooling medium into the cooling cavity, and a regulating valve for regulating the flow of the cooling medium is provided on the feed conduit or the discharge conduit.

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

9. The helicopter door bubble window molding system according to claim 7, characterized in that: The cooling medium is gaseous cold air or liquid coolant.

Images