Large-deformation flexible static force loading system

Abstract

The utility model belongs to the technical field of airplane structural strength ground tests, and particularly relates to a large-deformation flexible static force loading system. The device consists of a loading motor, a loading control subsystem, a steel wire rope, a pulley block, a spring group, a force sensor and a portal frame, the loading motor is used for providing required driving force, and any displacement can be provided through the loading motor; the loading control subsystem is used for controlling a loading motor, carrying out structure loading according to a loading scheme, and simultaneously realizing coordinated loading of each loading point; the steel wire rope is connected with the loading motor and the spring group and transmits driving force to extend the spring; the pulley block is used for changing the trend of the steel wire rope; the spring set serves as a flexible part of the loading system and provides low rigidity needed by the system. The force sensor is used for monitoring the applied load; the portal frame is used for hanging the loading system. The utility model provides a flexible static loading system, so that loading of a dynamic load is realized under the condition of preloading the required static load, and the influence of the rigidity of the static loading system on the dynamic response of the structure is reduced, thereby obtaining more real dynamic response data.

Description

Technical Field

[0001] This utility model belongs to the field of aircraft structural strength ground testing technology, specifically relating to a large deformation flexible static loading system. Background Technology

[0002] With the evolving needs of ground-based verification of aircraft structures, the requirement for combined ground mechanical tests under various loads has emerged, such as mechanical-thermal combined tests, thermal-vibration combined tests, and static-dynamic combined tests. In static aircraft tests, hydraulic actuators are typically used for static loading. However, in combined static-dynamic tests, applying static loads using hydraulic actuators introduces significant additional stiffness to the structure, altering its dynamic characteristics. Therefore, hydraulic actuators are unsuitable for combined static-dynamic tests, necessitating the development of low-stiffness static loading systems. Existing flexible static loading systems mostly utilize rubber ropes to reduce system stiffness, applying static loads via hydraulic actuators or motors. Similar systems are commonly used in missile or aircraft control surface tests. Due to the limited stroke of hydraulic actuators, the deformation provided in flexible static loading systems for large structures is limited. Therefore, the low-stiffness requirement of the loading system is often difficult to meet when using hydraulic actuators in combined static-dynamic tests of large structures, whereas motor loading can provide arbitrary deformation amounts. For flexible loading systems using rubber ropes, the stiffness of the rubber ropes changes with the elongation. During use, the elongation of the rubber ropes is usually no more than 60%. When it is necessary to reduce the stiffness of the loading system, it can only be achieved by increasing the original length of the rubber ropes, which increases the demand for test space. In contrast, the space required by static loading systems is mainly used to provide the deformation required by the flexible components. By increasing the elongation of the flexible components, the demand for test space of the loading system can be effectively reduced. Utility Model Content

[0003] The purpose of this invention is to propose a flexible static loading system to meet the requirements of ground static-dynamic load combined testing of large aircraft structures. This system enables the loading of dynamic loads under the condition of pre-applied static loads, and reduces the influence of the stiffness of the static loading system on the dynamic response of the structure, thereby obtaining more realistic dynamic response data.

[0004] The technical solution of this utility model is as follows: To achieve the above objectives, the flexible static loading system proposed in this utility model consists of a loading motor, a loading control subsystem, a wire rope, a pulley block, a spring block, a force sensor, and a gantry frame. The loading motor provides the required driving force and can provide any displacement. The loading control subsystem controls the loading motor, performs structural loading according to the loading scheme, and simultaneously achieves coordinated loading at each loading point. The wire rope connects the loading motor and the spring block, transmitting the driving force to stretch the springs. The pulley block changes the direction of the wire rope, allowing for flexible arrangement of the loading system according to the test site. The spring block, as a flexible component of the loading system, provides the required low stiffness. The force sensor monitors the applied load. The gantry frame suspends the loading system.

[0005] Furthermore, a large deformation flexible static loading system includes a spring assembly, a force sensor, a gantry frame, a loading motor subsystem, a fixed pulley assembly, a wire rope, and a loading control subsystem;

[0006] One end of the spring assembly is connected to the loading point of the test piece, and the other end is connected to one end of the steel wire rope; the other end of the steel wire rope passes around the fixed pulley assembly and connects to the loading motor subsystem; a force sensor is also arranged between the spring assembly and the loading point of the test piece to monitor the application of static load in real time and participate in load loading control, and send the monitoring information to the loading control subsystem; the gantry frame is used to suspend the spring assembly and the loading motor subsystem; fixed pulleys are fixed at the upper and lower ends of the gantry frame respectively, forming a fixed pulley assembly.

[0007] Furthermore, the gantry crane comprises two sets, which are placed side by side.

[0008] Furthermore, a first fixed pulley is fixed to the upper end of the gantry frame of the suspension spring assembly, and a second fixed pulley is fixed to the lower end of the suspension loading motor subsystem.

[0009] Furthermore, the loading motor subsystem can be an electric hoist, or a self-made loading system consisting of a motor, a reduction mechanism, and a coil.

[0010] Furthermore, the spring assembly comprises two symmetrically distributed groups. In the specific design, each spring assembly is designed with springs of different stiffness but the same free height. Based on the load size at each loading point, springs of different stiffness are combined to ensure the loading capacity of each spring assembly and to obtain the lowest possible spring assembly stiffness.

[0011] The beneficial effects of this utility model are as follows: The flexible static loading system of this utility model has been successfully applied to the static-dynamic load combined test of a certain wing. During the loading test, it can achieve coordinated loading at 4 loading points, with a maximum load of 37kN, a loading error of no more than 0.2%, a spring design elongation rate of 80% to 100%, and a maximum deformation of 2m, which effectively reduces the stiffness of the static loading system. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0013] Among them, 1-spring assembly; 2-force sensor; 3-test piece; 4-gantry frame; 5-loading motor subsystem; 6-fixed pulley assembly; 7-wire rope; 8-loading control subsystem. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0015] The flexible static loading system in this invention is used to apply static loads to a structure in a combined static and dynamic test. Due to the low stiffness of the loading system, the influence of the additional stiffness of the static loading system on the stiffness of the test piece is reduced, thereby enabling the acquisition of more realistic dynamic response data of the structure under dynamic load.

[0016] The system of this utility model consists of a spring assembly, a force sensor, a gantry frame, a loading motor subsystem, a fixed pulley assembly, a loading control subsystem, and a steel wire rope.

[0017] Spring assembly 1 is the flexible component in this invention, and its low stiffness characteristic is achieved through the spring assembly. Springs with different stiffnesses but the same free height are designed, and springs of different stiffnesses are combined according to the load magnitude at each loading point, thereby ensuring the loading capacity of each spring assembly and obtaining the lowest possible spring assembly stiffness.

[0018] Force sensor 2 is used to monitor the application of static load and participate in load loading control. One force sensor is arranged at each loading point, with one end of the force sensor connected to the test piece and the other end connected to the spring assembly, thereby ensuring that the load measured by the force sensor is the actual load applied to the structure.

[0019] Gantry 4 is used to suspend the spring assembly and load the motor subsystem. The height of the gantry must be able to accommodate the deformation of the spring assembly and the structure.

[0020] The loading motor subsystem 5 is used to apply the static force required by the structure. The loading motor subsystem pulls back the wire rope, and the wire rope pulls the spring assembly to load the structure. In this utility model, the loading motor subsystem can be an electric hoist, or a self-made loading system composed of a motor, a reduction mechanism, and a coil.

[0021] The fixed pulley block 6 is used to change the direction of the wire rope, so as to make reasonable arrangements of the loading system according to the test site.

[0022] The wire rope 7 is used to transmit static loads, and the direction of the wire rope can be changed by the fixed pulley block to flexibly arrange the test system.

[0023] The loading control subsystem 8 is used to collect force sensor signals and control the operation of the loading motor subsystem, thereby realizing the specified loading scheme and controlling the loading accuracy, and coordinating the loads at each loading point during the loading process.

[0024] During the test, according to the loading scheme, a loading signal is issued to drive the motors at each loading point, pulling the steel wire ropes and springs to load the structure. After each loading point reaches its maximum load, the dynamic load loading system is connected to the test piece, and subsequent dynamic load loading is performed. After the dynamic load loading is completed, the connection between the dynamic load loading system and the test piece is disconnected, and an unloading signal is issued to control the loading motors to unload the static load.

[0025] The loading system designed in this utility model can be modified according to the number of loading points, such as the number of spring groups in the loading system, to meet different loading requirements; the stiffness of the spring groups at each loading point is matched to ensure that the deformation of the spring groups is approximately the same under the maximum load at each loading point, thereby ensuring that the test space is fully utilized and that coordinated loading control is easier to implement.

[0026] The above description is merely a specific embodiment of this utility model, providing a detailed description of the utility model. Parts not covered in detail are conventional techniques. However, the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this utility model should be included within the protection scope of this utility model. The protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A large deformation flexible static loading system, characterized in that, Includes spring assembly, force sensor, gantry frame, loading motor subsystem, fixed pulley assembly, wire rope, and loading control subsystem; One end of the spring assembly is connected to the loading point of the test piece, and the other end is connected to one end of the steel wire rope; the other end of the steel wire rope passes around the fixed pulley assembly and connects to the loading motor subsystem; a force sensor is also arranged between the spring assembly and the loading point of the test piece to monitor the application of static load in real time and participate in load loading control, and send the monitoring information to the loading control subsystem; the gantry frame is used to suspend the spring assembly and the loading motor subsystem; fixed pulleys are fixed at the upper and lower ends of the gantry frame respectively, forming a fixed pulley assembly.

2. The large deformation flexible static loading system as described in claim 1, characterized in that, The gantry crane consists of two sets, which are placed side by side.

3. The large deformation flexible static loading system as described in claim 2, characterized in that, The upper end of the gantry frame of the suspension spring assembly is fixed with a first fixed pulley, and the lower end of the suspension loading motor subsystem is fixed with a second fixed pulley.

4. The large deformation flexible static loading system as described in claim 1, characterized in that, The loading motor subsystem is an electric hoist, or a self-made loading system consisting of a motor, a reduction gear and a coil.

5. The large deformation flexible static loading system as described in claim 1, characterized in that, The spring assembly comprises two groups, symmetrically distributed.

6. The large deformation flexible static loading system as described in claim 5, characterized in that, Each spring group is designed with springs of different stiffness but the same free height. Springs of different stiffness are combined according to the load size at each loading point to ensure the loading capacity of each spring group and to obtain the lowest possible spring group stiffness.

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