Design method and device for pneumatically separating push rod flexible support

Abstract

The application provides a design method of pneumatic separation push rod flexible support, comprising the following steps: obtaining dynamic parameters and response parameters of a main structure of a pneumatic separation push rod; determining configuration parameters of a support structure and obtaining modal parameters of the support structure; establishing a combined model composed of the main structure and the support structure and obtaining acceleration response parameters of the main structure and load parameters transmitted by the support structure in the combined model; and performing size optimization on the support structure by taking cross-sectional dimensions of the support structure as optimization variables, taking minimization of mass of the support structure as an optimization target and taking the modal parameters, the acceleration response parameters and the load parameters satisfying preset constraint conditions as constraints. The design method realizes the technical effects of significantly reducing the mass of the support structure, effectively reducing the transmitted load, inhibiting the acceleration response of the main structure and avoiding resonance.

Description

Technical Field

[0001] This invention relates to the field of aerospace separation technology, specifically to a flexible support structure for a pneumatic separation push rod and its design method. Background Technology

[0002] In spacecraft, missiles, and other aircraft, aerodynamic separation push rods are used to achieve critical actions such as interstage separation, fairing separation, or payload release. To ensure the reliability and stability of the separation process, traditional designs typically employ high-rigidity support structures to constrain the displacement of the push rod under flight vibration environments.

[0003] However, high-rigidity support structures have the following inherent drawbacks: first, their large structural mass hinders aircraft weight reduction; second, they transmit significant dynamic loads to the connection interface under vibration, placing higher demands on the strength of surrounding structures; and third, they occupy considerable installation space, hindering system integration. Therefore, a novel support design method is urgently needed that can reduce structural mass, decrease transmitted loads, and adapt to vibration environments while ensuring separation functionality. Summary of the Invention

[0004] The present invention aims to solve the technical problems of existing high-rigidity support structures for pneumatic separation push rods, such as large mass, large load transmission, and large space occupation, and provides a design method and device for flexible support of pneumatic separation push rods that can achieve high damping and low load transmission effect.

[0005] To achieve the above objectives, the present invention provides a design method for a flexible support for a pneumatic separation push rod, comprising: Obtain the dynamic and response parameters of the main structure of the pneumatic separator push rod; Determine the configuration parameters of the support structure and obtain its modal parameters; Establish a model of the combined structure consisting of the main structure and the supporting structure, and obtain the acceleration response parameters of the main structure and the load parameters transmitted by the supporting structure in the combined structure. The cross-sectional dimensions of the supporting structure are used as optimization variables, the minimum mass of the supporting structure is used as the optimization objective, and the modal parameters, acceleration response parameters and load parameters are subject to preset constraints to optimize the dimensions of the supporting structure.

[0006] Furthermore, the dynamic parameters include at least the first natural frequency of the main structure; the response parameters include at least the maximum acceleration response of the main structure under vibration conditions; and the modal parameters include at least the first two natural frequencies of the supporting structure.

[0007] Furthermore, the supporting structure is symmetrically arranged at the connection points of the main structure.

[0008] Furthermore, when obtaining the modal parameters of the support structure, the boundary conditions at both ends of the support structure are consistent with the boundary conditions at both ends of the support structure in the composite.

[0009] Furthermore, when obtaining the acceleration response parameters of the main structure in the assembly, the elastic modulus of the supporting structure material on one side of the vibration direction is reduced, and its elastic modulus is restored when calculating the load transmitted by the supporting structure.

[0010] Furthermore, the elastic modulus is reduced to one-tenth of its actual value.

[0011] Furthermore, the preset constraints include: the absolute value of the difference between the first two natural frequencies of the support structure and the first natural frequency of the main structure is greater than a preset threshold, and the first natural frequency of the support structure is lower than the first natural frequency of the main structure.

[0012] Furthermore, the preset constraint conditions also include: the maximum acceleration response of the main structure in the assembly is less than the product of the maximum acceleration response of the independent main structure and the load reduction coefficient.

[0013] Furthermore, the preset constraint condition also includes: the load transmitted by the support structure is less than the bearing limit load of its connection position.

[0014] The present invention also provides a pneumatic separation push rod flexible support device, which is obtained by adopting the design method of the pneumatic separation push rod flexible support as described above.

[0015] The design method for a pneumatically separated push rod flexible support provided by this invention achieves a comprehensive technical effect by minimizing the mass of the support structure and optimizing dimensions by combining preset constraints on modal parameters, acceleration response parameters, and load parameters. This significantly reduces the mass of the support structure while effectively reducing the transmitted load, suppressing the acceleration response of the main structure, and avoiding resonance. Furthermore, this solution integrates multiple objectives (lightweight, low load, vibration suppression, and frequency avoidance) into a quantifiable dimension optimization problem, with a clear process that facilitates engineering implementation.

[0016] It should be understood that the above general description and the following specific embodiments are merely exemplary and illustrative, and do not limit the scope of the invention. Attached Figure Description

[0017] The accompanying drawings, which are part of the specification of this invention, illustrate exemplary embodiments of the invention. The drawings, together with the description in the specification, serve to illustrate the principles of the invention.

[0018] Figure 1 This is an overall flowchart of the pneumatic separation push rod flexible support design method described in this invention; Figure 2This is a schematic diagram of a typical configuration of the pneumatic separation push rod main structure and flexible support structure combination. Figure 3 This is a schematic diagram of the instability of the flexible support structure in the composite structure. Detailed Implementation

[0019] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and to exemplify the principles of the present invention, and are not configured to limit the present invention. In addition, the structural components in the drawings are not necessarily drawn to scale. For example, the dimensions of some structural components or regions in the drawings may be enlarged for other structural components or regions to aid in the understanding of the embodiments of the present invention.

[0020] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of the embodiments of the present invention. In the description of the present invention, it should be noted that, unless otherwise stated, the terms "installation," "connection," and "joining" 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 direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0021] Furthermore, the terms "comprising," "including," "having," or any other variations thereof are intended to cover non-exclusive inclusion, such that a structure or component that includes a list of elements includes not only those elements but also other structural elements that are not expressly listed or inherent to the structure or component. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the article or apparatus that includes the element.

[0022] Spatial relation terms such as "below," "under," "under," "low," "above," "on," and "high" are used for descriptive convenience to explain the positioning of one element relative to a second element, indicating that these terms are intended to cover different orientations of the device, in addition to those different from those shown in the figure. Furthermore, phrases such as "one element on / below another element" can indicate that two elements are in direct contact, or that there are other elements between the two elements. In addition, terms such as "first" and "second" are also used to describe individual elements, areas, parts, etc., and should not be considered limiting. Similar terms are used throughout the description to refer to similar elements.

[0023] It will be apparent to those skilled in the art that the present invention can be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention.

[0024] Figure 1 This is an overall flowchart of the flexible support design method for the pneumatic separation push rod described in this invention. Figure 2 This is a schematic diagram of a typical configuration of the pneumatic separation push rod main structure and the flexible support structure combination. Figure 3 This is a schematic diagram of the instability of the flexible support structure in the composite structure.

[0025] Implementation Method 1: Specific Implementation Steps of the Design Method like Figure 1 As shown, this embodiment provides a design method for a flexible support for a pneumatic separation push rod, specifically including the following steps: Step S1: Obtain the main structural parameters of the separation push rod.

[0026] A finite element model of the main structure of the pneumatic separator push rod was established. The first-order natural frequencies of the main structure were obtained through modal analysis. f_qd By analyzing the vibration response (e.g., applying acceleration power spectral density or sinusoidal sweep vibration conditions under flight conditions), the maximum acceleration response of the main structure under vibration conditions is obtained. A_qd .

[0027] Step S2: Preliminarily determine the configuration parameters of the flexible support structure.

[0028] Based on the installation space and interface requirements, the preliminary configuration parameters of the flexible support structure are determined, including: connection positions (preferably symmetrical arrangement to improve multi-directional vibration resistance), cross-sectional shape (e.g., rectangular, circular, or I-shaped), and materials (e.g., aluminum alloy, titanium alloy, or composite materials). A finite element model of the support structure is established, and boundary constraints consistent with the actual assembly connection form are applied at both ends. Its first two natural frequencies are then calculated. f_zc1 and f_zc2 .

[0029] Step S3: Establish the combined model and obtain the acceleration response and load parameters.

[0030] like Figure 2 As shown, the finite element model of the main structure and the finite element model of the supporting structure are assembled to establish a combined model. Vibration response analysis is then performed on this combined model. Specifically, the acceleration response parameters of the main structure are extracted. A_zh To simulate the potential local instability or nonlinear softening effect of a flexible support structure on one side of the vibration direction, the elastic modulus of the material of the support structure on that side is reduced to one-tenth of its actual value. E'=E / 10), by reducing the elastic modulus to simulate the effect of support structure instability in a vibration environment. Simultaneously, when calculating the load transmitted by the support structure, its elastic modulus is restored, and the transmitted load at the connection point between the support structure and the mounting interface is extracted. Q_zc .

[0031] Step S4: Optimize the dimensions of the support structure using preset constraints.

[0032] Using the cross-sectional dimensions of the supporting structure (such as wall thickness, flange width, and web height) as optimization variables, the optimization objective is to minimize the total mass M of the supporting structure. The following optimization constraints are set: Frequency constraint: | f_zc1 - f_qd |>5Hz, | f_zc2 - f_qd |>5Hz, and f_zc1 < f_qd By optimizing the constraints to control the natural frequency of the support structure, resonance between the support structure and the main structure of the release pusher is avoided, ensuring that the stiffness of the support structure is much smaller than that of the main structure of the release pusher, thus allowing the support structure to become unstable under vibration.

[0033] Acceleration response constraints: A_zh < A_qd * k ,in k The load reduction factor is pre-set according to the task requirements (e.g.) k =0.7). Sufficient damping effect generated by the flexible support structure can absorb vibration energy, reduce the acceleration response of the main structure of the release push rod in a vibration environment, and improve the reliability and life of the push rod itself.

[0034] Load constraints: Q_zc < Q_sj ,in Q_sj The maximum design load that the supporting structure connection points (such as bulkheads and supports) can withstand.

[0035] Through iterative optimization, the lightest support structure cross-sectional dimensions that satisfy all constraints are obtained. In this embodiment, the design of the separate push rod support structure is independent of the main separate push rod structure and is designed separately. The designed support structure is a flexible structure with low stiffness, and the load transmitted to the support location is small.

[0036] This invention provides a design method for a high-damping, low-load aerodynamic release pusher flexible support. By optimizing the dimensions of the support structure with mass minimization as the optimization objective, the mass of the support structure is further reduced, thereby improving structural efficiency. Constraints in the dimensional optimization ensure that the support structure and the main structure of the release pusher are at different natural frequencies, preventing resonance. This also ensures that the goals of reducing the acceleration response of the main structure of the release pusher and reducing the load on the support location are achieved. The flexible support device designed using this method has low stiffness, allowing for instability under vibration. Besides significantly reducing structural mass, it also reduces the load transmitted by the release pusher through the support structure. The damping effect of the flexible support device significantly reduces the acceleration response of the main structure of the release pusher.

[0037] Implementation Method Two: Typical Application Examples Step S1: Obtain the parameters of the separation push rod. The main structure cylinder is a cylinder with an outer diameter of 195mm and an inner diameter of 187mm. Calculate its first-order natural frequency. f_qd =10.2 Hz, maximum acceleration response under vibration environment A_qd =352m / s 2 ; Step S2: As Figure 3 As shown, based on the installation space and interface requirements, a total of four support structures are determined, evenly distributed around the cylinder's central axis at 90° intervals. The material selected for the support structures is 30CrMnSiA. The initial cross-section of the support structures is set as a ring with an outer diameter of 50mm and an inner diameter of 40mm. A separate finite element model of the support structures is established for modal calculations, and the first two natural frequencies are extracted. f_zc1 , f_zc2 ; Step S3: Assemble the finite element models of the main structure and the support structure of the separate push rod to establish the finite element model of the combined body. For example... Figure 3 As shown, during vibration, the diagonal brace on the compression side of the assembly will become unstable due to its low stiffness. After instability, the supporting effect weakens. Therefore, the elastic modulus of the supporting structure material is reduced to 1 / 10 of the original elastic modulus. The response of the assembly under the vibration environment in step S1 is calculated, and the maximum acceleration response of the pneumatic push rod main structure is extracted. A_ zh .

[0038] Next, the elastic modulus of the supporting structure material is restored to its original elastic modulus, and the response of the assembly under the vibration environment described in step S1 is calculated to extract the load transmitted by the supporting structure. Q_zc .

[0039] Determine the load reduction factor k =0.7, determine the maximum load that the supporting structure connection location can withstand. Q_sj =15000N; Step S4: Optimize the inner and outer diameters of the supporting structure cross-section using optimization software. The optimization constraints include: 1. f_zc1 < f_qd And| f_zc1 - f_qd 5. | f_zc2 - f_qd| >5; 2. A_zh < A_qd * k ; 3. Q_zc < Q_sj .

[0040] The optimization objective was set to minimize the mass of the supporting structure.

[0041] After running the optimization program and iterating, a support structure cross-section with an outer diameter of 25mm and an inner diameter of 21mm was finally obtained. f_ zc1 =1.23hz, f_zc2 =4.96hz, which satisfies f_zc1 < f_qd And| f_zc1 - f_qd 5. | f_zc2 - f_qd 5. A_zh =231m / s², which satisfies the condition. A_zh < A_qd * k . Q_zc =14894N, which satisfies the condition. Q_zc < Q_sj .

[0042] Implementation Method 3: Pneumatic Separation Push Rod Flexible Support Device This embodiment provides a flexible support device for a pneumatic separation push rod obtained using any of the above-described design methods. The device includes at least two flexible support arms, symmetrically arranged circumferentially or laterally on the main structure of the pneumatic separation push rod. One end of each support arm is connected to the main push rod structure, and the other end is connected to the aircraft cabin or mounting bracket. The cross-sectional dimensions of the support arms are determined by the aforementioned dimensional optimization method, and their stiffness is lower than that of traditional support structures, allowing for controllable elastic deformation or local instability under vibration conditions, thereby playing a role in damping energy dissipation and load isolation.

[0043] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A design method for a flexible support for a pneumatic separation push rod, characterized in that, include: Obtain the dynamic and response parameters of the main structure of the pneumatic separator push rod; The configuration parameters of the support structure were initially determined, and its modal parameters were obtained; Establish a model of the combined structure consisting of the main structure and the supporting structure, and obtain the acceleration response parameters of the main structure and the load parameters transmitted by the supporting structure in the combined structure. The cross-sectional dimensions of the supporting structure are used as optimization variables, the minimum mass of the supporting structure is used as the optimization objective, and the modal parameters, acceleration response parameters and load parameters are subject to preset constraints to optimize the dimensions of the supporting structure.

2. The method according to claim 1, characterized in that: The dynamic parameters include at least the first natural frequency of the main structure; the response parameters include at least the maximum acceleration response of the main structure under vibration conditions; and the modal parameters include at least the first two natural frequencies of the supporting structure.

3. The method according to claim 1, characterized in that: The supporting structure is arranged symmetrically at the connection points of the main structure.

4. The method according to claim 1, characterized in that: When obtaining the modal parameters of the support structure, the boundary conditions at both ends of the support structure are consistent with the boundary conditions at both ends of the support structure in the composite.

5. The method according to claim 1, characterized in that: When obtaining the acceleration response parameters of the main structure in the assembly, the elastic modulus of the supporting structure material on one side of the vibration direction is reduced, and its elastic modulus is restored when calculating the load transmitted by the supporting structure.

6. The method according to claim 5, characterized in that: The elastic modulus is reduced to one-tenth of its actual value.

7. The method according to claim 2, characterized in that: The preset constraints include: the absolute value of the difference between the first two natural frequencies of the support structure and the first natural frequency of the main structure is greater than a preset threshold, and the first natural frequency of the support structure is lower than the first natural frequency of the main structure.

8. The method according to claim 1, characterized in that: The preset constraint conditions also include: the maximum acceleration response of the main structure in the assembly is less than the product of the maximum acceleration response of the independent main structure and the load reduction coefficient.

9. The method according to claim 1, characterized in that: The preset constraint conditions also include: the load transmitted by the support structure is less than the bearing limit load of its connection position.

10. A flexible support device for a pneumatic separation push rod, characterized in that, The device adopts the design method of flexible support for pneumatic separation push rod as described in any one of claims 1-9.

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