An engine metal hose length simulation calculation method based on finite element method

Abstract

The application provides a length simulation calculation method for metal hoses for engines based on a finite element method, comprising the following steps: S1, importing a metal hose model into finite element software; S2, establishing a connection relationship between components; S3, calculating the maximum displacement of a servo actuator in the X direction under a follow-up coordinate system according to the maximum swing angle requirement of the engine; S4, setting the displacement-time load of the lower support point of the first servo actuator in the X direction under the first follow-up coordinate system, setting the displacement-time load of the lower support point of the second servo actuator in the X direction under the second follow-up coordinate system, and setting the total analysis step time; S5, performing transient dynamics analysis to simulate the maximum angle circle swing of the engine under the double servo actuators; and S6, observing the swing animation diagram according to the calculation result to analyze whether the length deformation of the metal hose is coordinated.

Description

Technical Field

[0001] This invention relates to the field of metal hose design technology for liquid rocket engines, and in particular to a method for simulating and calculating the length of metal hoses for engines based on the finite element method. Background Technology

[0002] In liquid rocket engines, flexible metal hoses, serving as fluid delivery lines, are crucial structures for compensating for deformation during engine oscillation. Currently, the length calculation method for flexible metal hoses in bidirectional oscillating engines primarily relies on a standard two-dimensional bending radius model, combined with the oscillation angle, to calculate the required total length. However, this calculation model fails to consider the three-dimensional spatial positions of the upper and lower support points on the engine. During engine oscillation, the flexible metal hose undergoes compensatory deformation in all directions, and this method, treating the hose only as a two-dimensional model, often results in a calculated length that is either too long or too short. This leads to over-compression or tautness of the flexible metal hose during engine oscillation, which is detrimental to product use. In such cases, the flexible metal hose length needs to be redesigned and production restarted, increasing costs and severely impacting engine development progress. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a simulation calculation method for the length of metal hoses for engines based on the finite element method, which addresses the shortcomings of the existing technology.

[0004] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A simulation calculation method for the length of a metal hose for an engine based on the finite element method, comprising: S1, importing the metal hose model into finite element software; S2, establishing the connection relationship between each component; S3, calculating the maximum X-direction displacement of the servo actuator in the following coordinate system according to the maximum swing angle requirement of the engine; S4, setting the displacement-time load of the lower support point of the first servo actuator in the X-direction in the first following coordinate system; setting the displacement-time load of the lower support point of the second servo actuator in the X-direction in the second following coordinate system; and setting the total analysis step time; S5, performing transient dynamic analysis to simulate the maximum angle circular swing of the engine under dual servo actuators; S6, observing the swing animation based on the calculation results and analyzing whether the deformation of the metal hose length is coordinated.

[0005] The beneficial effects of adopting the technical solution of this invention are that by designing a simulation method for calculating the length of metal hoses based on the finite element method, it guides the design of metal hose lengths during the R&D stage, avoids repeated production, and improves the engine development progress. It features simplicity, low cost, high efficiency, and small calculation deviation. It can simulate the swaying of various metal hoses on an engine, providing a basis for metal hose length design.

[0006] Further, step S1 includes: S11, obtaining a preliminary value for the length of the metal hose using a traditional metal hose calculation method; S12, drawing a metal hose model in a 3D design software based on the preliminary value for the length of the metal hose; S13, importing the metal hose model into a finite element software.

[0007] The beneficial effect of adopting the above-mentioned further technical solution is that, using the traditional metal hose calculation method, a preliminary value of the metal hose length can be obtained. Based on this preliminary value, a metal hose model can be drawn in 3D design software, and then imported into finite element software. This facilitates the simulation calculation of the length of metal hoses used in rocket engines.

[0008] Further, step S13 includes: extracting the centerline of the metal flexible mesh portion, which is equivalent to a metal wire beam element model of the same diameter.

[0009] The beneficial effect of adopting the above-mentioned further technical solution is that the centerline of the metal hose mesh section is extracted and equivalent to a metal wire beam element model of the diameter. This facilitates the simulation calculation of the length of the metal hose used in rocket engines.

[0010] Further, after step S13, the following is included: S14, in the finite element software, establishing the finite element models of the metal hose, the swing center point, the lower fulcrum of the first servo actuator, the lower fulcrum of the second servo actuator, the upper fulcrum of the first servo actuator, the upper fulcrum of the second servo actuator, the lower support of the first servo actuator, and the lower support of the second servo actuator.

[0011] The beneficial effect of adopting the above-mentioned further technical solution is that it facilitates the simulation calculation of the length of metal hoses for engines based on the finite element method by establishing a finite element model.

[0012] Further, in step S14, the metal hose is a finite element model of the metal hose. The position of the metal hose in the finite element software is the same as its position coordinate on the engine, and the swing center point is the origin of the coordinate system. In the finite element model, the two ends of the metal hose wire are rigidly constrained to the upper connector and the lower connector of the metal hose, respectively. The upper connector of the metal hose is rigidly constrained to the lower lug of the first servo actuator and the swing center point, respectively. The lower connector of the metal hose is rigidly constrained to the lower lug of the second servo actuator and the swing center point, respectively. The swing center point is defined as follows. The hinge boundary conditions are defined as follows: the lower pivot of the first servo actuator is hinged to the lower lug of the first servo actuator, and the lower pivot of the second servo actuator is hinged to the lower lug of the second servo actuator. The upper pivot of the first servo actuator is defined as the hinge boundary condition, and the upper pivot of the second servo actuator is defined as the hinge boundary condition. A first follower coordinate system is established with the upper pivot of the first servo actuator as the origin and the X-axis pointing to the lower pivot of the first servo actuator. A second follower coordinate system is established with the upper pivot of the second servo actuator as the origin and the X-axis pointing to the lower pivot of the second servo actuator.

[0013] The beneficial effect of adopting the above-mentioned further technical solution is that it facilitates the simulation calculation of the length of metal hoses for engines based on the finite element method by establishing a finite element model.

[0014] Furthermore, the metal hose wire is a metal wire with a diameter of Φ0.5; in the finite element model, the upper and lower joints of the metal hose are made of stainless steel, the metal hose wire is made of stainless steel wire, and the lower lugs of the first and second servo actuators are made of stainless steel.

[0015] The beneficial effect of adopting the above-mentioned further technical solution is that it facilitates the simulation calculation of the length of metal hoses for engines based on the finite element method by establishing a finite element model, thereby improving the simulation accuracy.

[0016] Further, in step S4, the displacement-time load of the lower support point of the first servo actuator in the X direction under the first follower coordinate system is calculated by the following formula: x1=x0×sin(2π×t), where x1 is the displacement-time load of the lower support point of the first servo actuator in the X direction under the first follower coordinate system, x0 is the maximum displacement of the servo actuator in the X direction under the follower coordinate system, and t is the period time.

[0017] The beneficial effect of adopting the above-mentioned further technical solution is that, based on the maximum sway angle requirement of the engine, the maximum displacement of the servo actuator in the X direction under the follower coordinate system is calculated, and the displacement-time load of the lower support point of the first servo actuator in the X direction under the first follower coordinate system is set.

[0018] Further, in step S4, the displacement-time load of the lower support point of the second servo actuator in the X direction under the second follower coordinate system is calculated by the following formula: when t≤0.25s, x2=0, when t>0.25s, x2=x0×sin[2π×(t-0.25)], where x2 is the displacement-time load of the lower support point of the second servo actuator in the X direction under the second follower coordinate system, x0 is the maximum displacement of the servo actuator in the X direction under the follower coordinate system, and t is the period time.

[0019] The beneficial effect of adopting the above-mentioned further technical solution is that, based on the maximum sway angle requirement of the engine, the maximum displacement of the servo actuator in the X direction under the follower coordinate system is calculated, and the displacement-time load of the lower support point of the second servo actuator in the X direction under the second follower coordinate system is set.

[0020] Furthermore, in step S4, the total analysis step time is set to 5 seconds.

[0021] The beneficial effect of adopting the above-mentioned further technical solution is that, by setting the time analysis step t=5s, transient dynamic analysis is performed to simulate the maximum angle circular swing of the engine under dual servo actuators.

[0022] Furthermore, after step S6, step S7 includes: When there is an over-compression or taut state, the stress of the steel wire of the metal hose will increase instantaneously. It is necessary to readjust the length of the metal hose, re-import the metal hose model into the finite element software, replace the original metal hose, and re-simulate and calculate.

[0023] The beneficial effect of adopting the above-mentioned further technical solution is that, based on the calculation results and by observing the swing animation, it can be seen whether the deformation of the metal hose length is coordinated during the entire circular swing process of the engine. When over-compression or tautness occurs, the stress of the metal hose wire will increase instantaneously. At this time, it is necessary to readjust the length of the metal hose, re-import the metal hose model into the finite element software, replace the original metal hose, and re-simulate and calculate.

[0024] The advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A schematic flowchart illustrating the simulation calculation method for the length of metal hoses used in rocket engines based on the finite element method, provided in an embodiment of the present invention.

[0027] Figure 2 The finite element model structure for simulating the swinging motion of a metal hose is provided in an embodiment of the present invention.

[0028] Figure 3 The finite element model structure of the metal hose provided in the embodiment of the present invention.

[0029] Explanation of reference numerals: 11. Metal hose; 12. Swing center point; 13. Lower fulcrum of the first servo actuator; 14. Lower fulcrum of the second servo actuator; 15. Upper fulcrum of the first servo actuator; 16. Upper fulcrum of the second servo actuator; 17. Lower support lug of the first servo actuator; 18. Lower support lug of the second servo actuator; 21. Upper connector of the metal hose; 22. Lower connector of the metal hose; 23. Steel wire of the metal hose. Detailed Implementation

[0030] The principles and features of the present invention are described below with reference to the accompanying drawings. The embodiments described are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0033] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0034] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0035] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0036] This invention provides a method for simulating the length of a metal hose for an engine based on the finite element method, including: S1, importing the metal hose model into finite element software; S2, establishing the connection relationships between various components; S3, calculating the maximum X-direction displacement of the servo actuator in the following coordinate system according to the maximum swing angle requirement of the engine; S4, setting the displacement-time load of the lower support point of the first servo actuator in the X-direction in the first following coordinate system; setting the displacement-time load of the lower support point of the second servo actuator in the X-direction in the second following coordinate system; and setting the total analysis step time; S5, performing transient dynamic analysis to simulate the maximum angle circular swing of the engine under dual servo actuators; S6, observing the swing animation based on the calculation results and analyzing whether the deformation of the metal hose length is coordinated.

[0037] The beneficial effects of adopting the technical solution of this invention are that by designing a simulation method for calculating the length of metal hoses based on the finite element method, it guides the design of metal hose lengths during the R&D stage, avoids repeated production, and improves the engine development progress. It features simplicity, low cost, high efficiency, and small calculation deviation. It can simulate the swaying of various metal hoses on an engine, providing a basis for metal hose length design.

[0038] Further, step S1 includes: S11, obtaining a preliminary value for the length of the metal hose using a traditional metal hose calculation method; S12, drawing a metal hose model in a 3D design software based on the preliminary value for the length of the metal hose; S13, importing the metal hose model into a finite element software.

[0039] The beneficial effect of adopting the above-mentioned further technical solution is that, using the traditional metal hose calculation method, a preliminary value of the metal hose length can be obtained. Based on this preliminary value, a metal hose model can be drawn in 3D design software, and then imported into finite element software. This facilitates the simulation calculation of the length of metal hoses used in rocket engines.

[0040] Further, step S13 includes: extracting the centerline of the metal flexible mesh portion, which is equivalent to a metal wire beam element model of the same diameter.

[0041] The beneficial effect of adopting the above-mentioned further technical solution is that the centerline of the metal hose mesh section is extracted and equivalent to a metal wire beam element model of the diameter. This facilitates the simulation calculation of the length of the metal hose used in rocket engines.

[0042] Further, after step S13, the following steps are included: S14, in the finite element software, establishing finite element models of the metal hose 11, the swing center point 12, the lower fulcrum of the first servo actuator 13, the lower fulcrum of the second servo actuator 14, the upper fulcrum of the first servo actuator 15, the upper fulcrum of the second servo actuator 16, the lower support lug of the first servo actuator 17, and the lower support lug of the second servo actuator 18.

[0043] The beneficial effect of adopting the above-mentioned further technical solution is that it facilitates the simulation calculation of the length of metal hoses for engines based on the finite element method by establishing a finite element model.

[0044] Further, in step S14, the metal hose 11 is a finite element model of the metal hose. The position of the metal hose 11 in the finite element software is the same as its position coordinate on the engine, and the swing center point 12 is the origin of the coordinate system. In the finite element model, the two ends of the metal hose wire 23 are rigidly constrained to the upper connector 21 and the lower connector 22 of the metal hose, respectively. The upper connector 21 of the metal hose is rigidly constrained to the lower support lug 17 of the first servo actuator and the swing center point 12, respectively. The lower connector 22 of the metal hose is rigidly constrained to the lower support lug 18 of the second servo actuator and the swing center point 12, respectively. The swing center point 12 is rigidly constrained to the lower support lug 18 of the second servo actuator and the swing center point 12, respectively. 2 is defined as a hinged boundary condition; the lower pivot point 13 of the first servo actuator is hinged to the lower support lug 17 of the first servo actuator, the lower pivot point 14 of the second servo actuator is hinged to the lower support lug 18 of the second servo actuator, the upper pivot point 15 of the first servo actuator is defined as a hinged boundary condition, and the upper pivot point 16 of the second servo actuator is defined as a hinged boundary condition; with the upper pivot point 15 of the first servo actuator as the origin and X pointing to the lower pivot point 13 of the first servo actuator, a first follower coordinate system is established, and with the upper pivot point 16 of the second servo actuator as the origin and X pointing to the lower pivot point 14 of the second servo actuator, a second follower coordinate system is established.

[0045] The beneficial effect of adopting the above-mentioned further technical solution is that it facilitates the simulation calculation of the length of metal hoses for engines based on the finite element method by establishing a finite element model.

[0046] The coordinate system includes an X-axis, a Y-axis, and a Z-axis.

[0047] Furthermore, the metal hose wire 23 is a metal wire with a diameter of Φ0.5; in the finite element model, the upper connector 21 and the lower connector 22 of the metal hose are both made of stainless steel, the metal hose wire 23 is made of stainless steel wire, and the lower support lug 17 of the first servo actuator and the lower support lug 18 of the second servo actuator are made of stainless steel.

[0048] The beneficial effect of adopting the above-mentioned further technical solution is that it facilitates the simulation calculation of the length of metal hoses for engines based on the finite element method by establishing a finite element model, thereby improving the simulation accuracy.

[0049] One end of the metal flexible hose 11 is connected to the swing center point 12, which serves as the rotation reference for the swing.

[0050] First servo actuator: The upper fulcrum 15 of the first servo actuator is connected to the relevant structure, and the lower fulcrum 13 of the first servo actuator is installed on the lower support ear 17 of the first servo actuator, forming a transmission link of "upper fulcrum-actor-lower fulcrum-lower support ear".

[0051] Second servo actuator: The upper fulcrum 16 of the second servo actuator is connected to the relevant structure, and the lower fulcrum 14 of the second servo actuator is installed on the lower lug 18 of the second servo actuator to form a corresponding transmission link.

[0052] The entire system is driven by the coordinated displacement of two servo actuators, with the swing center point 12 as the rotation center, to realize the circular swing motion of the engine.

[0053] Further, in step S4, the displacement-time load of the lower support point of the first servo actuator in the X direction under the first follower coordinate system is calculated by the following formula: x1=x0×sin(2π×t), where x1 is the displacement-time load of the lower support point of the first servo actuator in the X direction under the first follower coordinate system, x0 is the maximum displacement of the servo actuator in the X direction under the follower coordinate system, and t is the period time.

[0054] The beneficial effect of adopting the above-mentioned further technical solution is that, based on the maximum sway angle requirement of the engine, the maximum displacement of the servo actuator in the X direction under the follower coordinate system is calculated, and the displacement-time load of the lower support point of the first servo actuator in the X direction under the first follower coordinate system is set.

[0055] Further, in step S4, the displacement-time load of the lower support point of the second servo actuator in the X direction under the second follower coordinate system is calculated by the following formula: when t≤0.25s, x2=0, when t>0.25s, x2=x0×sin[2π×(t-0.25)], where x2 is the displacement-time load of the lower support point of the second servo actuator in the X direction under the second follower coordinate system, x0 is the maximum displacement of the servo actuator in the X direction under the follower coordinate system, and t is the period time.

[0056] The beneficial effect of adopting the above-mentioned further technical solution is that, based on the maximum sway angle requirement of the engine, the maximum displacement of the servo actuator in the X direction under the follower coordinate system is calculated, and the displacement-time load of the lower support point of the second servo actuator in the X direction under the second follower coordinate system is set.

[0057] Furthermore, in step S4, the total analysis step time is set to 5 seconds.

[0058] The beneficial effect of adopting the above-mentioned further technical solution is that, by setting the time analysis step t=5s, transient dynamic analysis is performed to simulate the maximum angle circular swing of the engine under dual servo actuators.

[0059] Among them, the maximum displacement in the X direction is calculated by using geometric relationships to calculate the maximum displacement x0 in the X direction under the following coordinate system, based on the maximum sway angle requirement of the engine.

[0060] Displacement-time load: Lower fulcrum 13 of the first servo actuator: x1=x0×sin(2π×t), which is a standard sinusoidal periodic load with a period of 1s.

[0061] The second servo actuator lower fulcrum 14: when t≤0.25s, x2=0, when t>0.25s, x2=x0×sin[2π×(t-0.25)], this load is delayed by 0.25s (i.e. a quarter cycle) compared to the first servo actuator, and the phase difference between the two is π / 2, which can synthesize the motion trajectory of drawing a circle.

[0062] Time analysis step: The total analysis step time is set to t=5s. Transient dynamic analysis is performed to simulate the swaying process of 5 cycles and observe the maximum angle of the engine swaying in a circular motion.

[0063] Simulation results analysis: In transient dynamics simulation, the phase difference of the displacement load of the two servo actuators is π / 2, which will drive the structure with the swing center as the rotation center to perform circular motion in the plane (swinging in a circle).

[0064] Throughout the movement, the metal hose will swing along with the structure. It is necessary to pay attention to its stress, deformation, and the smoothness of its movement trajectory to verify whether it meets the design requirements for the maximum swing angle of the engine.

[0065] Connection relationship: The metal hose is connected to the swing center point. The two servo actuators are respectively connected to the corresponding lugs (lower lugs 17 and 18 of the first servo actuator and the second servo actuator) and the structure through the upper and lower fulcrums (lower fulcrum 13 of the first servo actuator, lower fulcrum 14 of the second servo actuator, upper fulcrum 15 of the first servo actuator and upper fulcrum 16 of the second servo actuator). The phase difference π / 2 drives the circular motion.

[0066] Displacement load: Second servo actuator x2 delay 0.25s.

[0067] Analysis step: Total time 5s, transient dynamics simulation realizes the engine drawing a circle and swinging.

[0068] The maximum angle circular swing simulation of the engine is completed by using the phase difference displacement load of dual servo actuators.

[0069] Furthermore, after step S6, step S7 includes: When there is an over-compression or taut state, the stress of the steel wire of the metal hose will increase instantaneously. It is necessary to readjust the length of the metal hose, re-import the metal hose model into the finite element software, replace the original metal hose, and re-simulate and calculate.

[0070] The beneficial effect of adopting the above-mentioned further technical solution is that, based on the calculation results and by observing the swing animation, it can be seen whether the deformation of the metal hose length is coordinated during the entire circular swing process of the engine. When over-compression or tautness occurs, the stress of the metal hose wire will increase instantaneously. At this time, it is necessary to readjust the length of the metal hose, re-import the metal hose model into the finite element software, replace the original metal hose, and re-simulate and calculate.

[0071] This invention provides a finite element method-based simulation calculation method for the length of metal hoses used in liquid rocket engines (hereinafter referred to as engines). The calculation model includes a metal hose 11, a swing center point 12, a lower fulcrum of a first servo actuator 13, a lower fulcrum of a second servo actuator 14, an upper fulcrum of a first servo actuator 15, an upper fulcrum of a second servo actuator 16, a lower support lug of a first servo actuator 17, and a lower support lug of a second servo actuator 18. This invention features simplicity, low cost, high efficiency, and small calculation deviation. It can simulate the swinging motion of various metal hoses on engines, providing a basis for the design of metal hose lengths. This invention designs a finite element method-based simulation method for calculating the length of metal hoses, guiding the design of metal hose lengths during the R&D stage, avoiding repeated production, and improving the engine development progress.

[0072] This invention provides a simulation method for calculating the length of metal hoses used in engines, based on the finite element method, which can be used in the research and development stage. This invention features simplicity, low cost, high efficiency, and small calculation deviation, laying the foundation for rapid engine development and iteration.

[0073] The technical solution adopted in this invention mainly includes: establishing finite element models of the metal hose 11, the swing center point 12, the lower support point of the first servo actuator 13, the lower support point of the second servo actuator 14, the upper support point of the first servo actuator 15, the upper support point of the second servo actuator 16, the lower support lug of the first servo actuator 17, and the lower support lug of the second servo actuator 18 in finite element software.

[0074] like Figures 1-2 As shown, the metal hose 11 is a finite element model of the metal hose. The position of the metal hose 11 in the finite element software is the same as its position coordinate on the engine, and the swing center point 12 is the origin of the coordinate system. The metal hose wire 23 is a metal wire with a diameter of Φ0.5.

[0075] In the finite element model, the metal wire mesh (metal hose wire 23) is rigidly constrained with the two end connectors (metal hose upper connector 21 and metal hose lower connector 22). The metal hose lower connector 22 is rigidly constrained with the lower support lug 17 of the first servo actuator, the lower support lug 18 of the second servo actuator, and the swing center point 12. The swing center point 12 is defined as a hinged boundary condition. The lower support point 13 of the first servo actuator is hinged to the lower support lug 17, and the lower support point 14 of the second servo actuator is hinged to the lower support lug 18. The upper support point 15 of the first servo actuator and the upper support point 16 of the second servo actuator are defined as hinged boundary conditions.

[0076] In the finite element model, a first follower coordinate system is established with the upper support point 15 of the first servo actuator as the origin and the X-axis pointing to the lower support point 13 of the first servo actuator. A second follower coordinate system is established with the upper support point 16 of the second servo actuator as the origin and the X-axis pointing to the lower support point 14 of the second servo actuator.

[0077] In the finite element model, the upper and lower connectors of the metal hose (upper connector 21 and lower connector 22) are made of stainless steel, the metal hose wire 23 is made of stainless steel wire, and the lower support lug 17 of the first servo actuator and the lower support lug 18 of the second servo actuator are made of stainless steel.

[0078] First, the traditional metal hose calculation method is used to obtain the preliminary value of the metal hose length. In the 3D design software, the metal hose model is drawn based on the preliminary value of the metal hose length. The metal hose model is then imported into the finite element software to extract the center line of the metal hose mesh part, which is equivalent to a metal wire beam element model with diameter.

[0079] According to the technical plan, establish the connection relationship between the various components.

[0080] Based on the maximum sway angle requirement of the engine, the maximum X-direction displacement x0 of the servo actuator in the follower coordinate system is calculated. The displacement-time load of the lower support point 13 of the first servo actuator in the X-direction in the first follower coordinate system is set as x1 = x0 × sin(2π × t). The displacement-time load of the lower support point 14 of the second servo actuator in the X-direction in the second follower coordinate system is set as follows: when t ≤ 0.25s, x2 = 0; when t > 0.25s, x2 = x0 × sin[2π × (t - 0.25)]. The time analysis step (analysis step time) is set to t = 5s. Transient dynamic analysis is performed to simulate the maximum angle circular sway of the engine under dual servo actuators.

[0081] Based on the calculation results and by observing the swing animation, it can be seen whether the deformation of the metal hose length is coordinated during the entire circular swing process of the engine. When over-compression or tautness occurs, the stress on the steel wire of the metal hose will increase instantaneously. In this case, it is necessary to readjust the length of the metal hose, re-import the metal hose model into the finite element software, replace the original metal hose, and recalculate the simulation.

[0082] This invention provides a simulation method for calculating the length of metal hoses used in engines, based on the finite element method, which can be used in the research and development stage. This invention features simplicity, low cost, high efficiency, and small calculation deviation, laying the foundation for rapid engine development and iteration.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for simulating and calculating the length of a metal hose for an engine based on the finite element method, characterized in that, include: S1. Import the metal hose model into the finite element software; S2. Establish the connection relationships between the components; S3. Based on the maximum sway angle requirement of the engine, calculate the maximum X-direction displacement of the servo actuator in the follower coordinate system; S4. Set the displacement-time load of the lower support point of the first servo actuator in the X direction in the first follower coordinate system; Set the displacement-time load of the lower support point of the second servo actuator in the X direction in the second follower coordinate system; and set the total analysis step time. S5. Perform transient dynamics analysis to simulate the maximum angle circular swing of the engine under dual servo actuators. S6. Based on the calculation results, observe the swing animation and analyze whether the deformation of the metal hose length is coordinated.

2. The method for simulating and calculating the length of a metal hose for an engine based on the finite element method according to claim 1, characterized in that, Step S1 includes: S11, using the traditional metal hose calculation method to obtain the preliminary value of the metal hose length; S12. In the 3D design software, draw the metal hose model based on the preliminary value of the metal hose length; S13. Import the metal hose model into the finite element software.

3. The method for simulating and calculating the length of a metal hose for an engine based on the finite element method according to claim 2, characterized in that, Step S13 includes: extracting the centerline of the metal flexible mesh portion, which is equivalent to a metal wire beam element model of the same diameter.

4. The method for simulating and calculating the length of a metal hose for an engine based on the finite element method according to claim 2, characterized in that, Step S13 is followed by: S14, in the finite element software, establishing the finite element models of the metal hose (11), the swing center point (12), the lower fulcrum of the first servo actuator (13), the lower fulcrum of the second servo actuator (14), the upper fulcrum of the first servo actuator (15), the upper fulcrum of the second servo actuator (16), the lower support of the first servo actuator (17), and the lower support of the second servo actuator (18).

5. The method for simulating and calculating the length of a metal hose for an engine based on the finite element method according to claim 4, characterized in that, In step S14, the metal hose (11) is a finite element model of the metal hose. The position of the metal hose (11) in the finite element software is the same as its position coordinate on the engine. The swing center point (12) is the origin of the coordinate system. In the finite element model, the two ends of the metal hose wire (23) are rigidly constrained by the upper connector (21) and the lower connector (22) of the metal hose, respectively. The upper connector (21) of the metal hose is rigidly constrained by the lower lug (17) of the first servo actuator and the swing center point (12), respectively. The lower connector (22) of the metal hose is rigidly constrained by the lower lug (18) of the second servo actuator and the swing center point (12), respectively. The first servo actuator lower pivot (13) is hinged to the first servo actuator lower lug (17), the second servo actuator lower pivot (14) is hinged to the second servo actuator lower lug (18), the first servo actuator upper pivot (15) is defined as the hinge boundary condition, and the second servo actuator upper pivot (16) is defined as the hinge boundary condition; with the first servo actuator upper pivot (15) as the origin and X pointing to the first servo actuator lower pivot (13), a first follower coordinate system is established; with the second servo actuator upper pivot (16) as the origin and X pointing to the second servo actuator lower pivot (14), a second follower coordinate system is established.

6. The method for simulating and calculating the length of a metal hose for an engine based on the finite element method according to claim 5, characterized in that, The metal hose wire (23) is a metal wire with a diameter of Φ0.

5. In the finite element model, the upper connector (21) and the lower connector (22) of the metal hose are made of stainless steel, the metal hose wire (23) is made of stainless steel wire, and the lower support lug (17) of the first servo actuator and the lower support lug (18) of the second servo actuator are made of stainless steel.

7. The method for simulating and calculating the length of a metal hose for an engine based on the finite element method according to claim 1, characterized in that, In step S4, the displacement-time load of the lower support point of the first servo actuator in the X direction in the first follower coordinate system is calculated using the following formula: x1 = x0 × sin(2π × t). Where x1 is the displacement-time load of the lower support point of the first servo actuator in the X direction in the first follower coordinate system, x0 is the maximum displacement of the servo actuator in the X direction in the follower coordinate system, and t is the period time.

8. The method for simulating and calculating the length of a metal hose for an engine based on the finite element method according to claim 1, characterized in that, In step S4, the displacement-time load of the lower support point of the second servo actuator in the X direction in the second follower coordinate system is calculated using the following formula: When t ≤ 0.25s, x2 = 0. When t > 0.25s, x2 = x0 × sin[2π × (t - 0.25)], Where x2 is the displacement-time load of the lower support point of the second servo actuator in the X direction in the second follower coordinate system, x0 is the maximum displacement of the servo actuator in the X direction in the follower coordinate system, and t is the period time.

9. The method for simulating and calculating the length of a metal hose for an engine based on the finite element method according to claim 1, characterized in that, In step S4, the total analysis step time is set to 5 seconds.

10. The method for simulating and calculating the length of a metal hose for an engine based on the finite element method according to claim 1, characterized in that, Step S6 is followed by: S7. When there is over-compression or tautness, the stress on the steel wire of the metal hose will increase instantaneously. The length of the metal hose needs to be readjusted, the metal hose model needs to be re-imported into the finite element software, the original metal hose needs to be replaced, and the simulation calculation needs to be re-performed.

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