Large transport aircraft body supports hoist joint heavy load strength test device and method

Abstract

The application discloses a large transport aircraft fuselage support lifting joint large load strength test device and method. The test base is fixedly connected with the chassis of the test frame, the test joint reverse model is fixed on the test base, and the test joint reverse model is fixedly connected with the test joint through a reverse model joint connecting piece; the fixing frame is fixedly connected with the column of the test frame through a fixing frame connecting piece, the actuating cylinder is fixedly connected with the fixing frame through an actuating cylinder connecting piece, and the ball head socket adapter is fixedly connected with the screw rod of the actuating cylinder; the ball head socket adapter is coaxial with the ball head mounting hole of the test joint. A B sleeve is installed in the trumpet mouth; a B sleeve is installed in the test joint ball head seat hole; a TB base assembly is installed on the upper surface plate of the test base; a strain gauge is attached to the root of the test joint ball head; one end of the adjustable pull rod is fixedly connected with the test base end ear seat, and the other end is fixedly connected with a U-shaped connecting piece. The application solves the problem that the conventional test equipment and method cannot complete the strength test in the large transport aircraft lifting support joint.

Description

Technical Field

[0001] This invention belongs to the field of aviation manufacturing technology, specifically relating to a test device and method for the high load strength of the lifting joint of the fuselage support of a large transport aircraft. Background Technology

[0002] In the development of a large transport aircraft, multiple fuselage support and lifting joints are crucial process components during fuselage manufacturing and assembly. They serve not only as vital support components during fuselage component development and as lifting joints, but also as critical support components during component assembly, impacting the assembly accuracy and safety. These joints are symmetrically located on both sides of the fuselage, their surfaces conforming to the fuselage profile and firmly connected to it via over one hundred bolts. The largest of these joints measures approximately 1000mm x 700mm x 500mm. They are assemblies consisting of a welded frame and supporting ball joints, with the ball joint axis perpendicular to the aircraft's horizontal plane. The rated load for these support and lifting joints is 12000 kgf. After manufacturing, the joints undergo static strength testing with a test load of 24000 kgf. Since passing the strength test of these support and lifting joints is a key indicator for aircraft product finalization, the strength verification of the joints is a mandatory process. Currently, the maximum load that the company's pressure testing machine can test can meet the joint testing requirements, but the maximum size of the parts that the test space can accommodate is 500mm x 500mm x 300mm, which is far from meeting the testing needs of such large joints. In order to solve the bottleneck problem of strength testing of these support and lifting joints, a testing method and device have been invented to meet the development needs of large aircraft. Summary of the Invention

[0003] The purpose of this invention is to provide a testing device and method for the high-load strength of lifting joints for fuselage supports in large transport aircraft. This invention solves the problem that conventional testing equipment and methods cannot complete strength tests on lifting support joints, which play an important role in large transport aircraft.

[0004] The technical solution of this invention is: a large load strength testing device for the lifting joint of a large transport aircraft fuselage support, comprising a test frame, a test base, a test joint inverse model, a fixed frame, an actuator cylinder connector, an actuator cylinder, an adjustable tie rod, an actuator cylinder support frame, a ball joint adapter, a fixed frame connector, a U-shaped connector, an inverse model joint connector, a test frame connector, and a measuring device; wherein, the test base is fixedly connected to the base frame of the test frame through the test frame connector, the test joint inverse model is fixed on the test base, and the test joint inverse model is fixedly connected to the test joint by the inverse model joint connector; the fixed frame is fixedly connected to the column of the test frame through the fixed frame connector, the actuator cylinder is fixedly connected to the fixed frame through the actuator cylinder connector, and the ball joint adapter is fixedly connected to the screw of the actuator cylinder; the ball joint adapter is coaxial with the ball joint mounting hole of the test joint; the testing device includes an A bushing, a B bushing, a TB seat assembly, strain gauges, and sensors. The A bushing is installed inside the flared opening of the ball joint adapter; the B bushing is installed inside the ball joint seat hole of the test joint; the TB seat assembly is installed on the upper surface plate of the test base, and its position conforms to the TB seat distribution principle; the strain gauge is attached to the root of the ball joint of the test joint and connected to the sensor; one end of the adjustable pull rod is fixedly connected to the end ear seat of the test base, and the other end is fixedly connected to the U-shaped connector fixed on the test frame; the base plate of the actuator support frame is fixed on the test base, and the upper recessed plane supports the bottom surface of the square head seat of the actuator.

[0005] In the aforementioned device, the test frame is a frame-type welded component with four symmetrically arranged columns at both ends. Each column consists of two [28 channel steels welded back-to-back through steel plates. The steel plates are evenly distributed along the column for 400mm and have through holes with a diameter of 31mm. The through holes are used for fastening the fasteners. The base frame of the test frame is a grid structure. Each crossbeam of the grid structure is composed of two [32 channel steels back-to-back with a spacing of 40mm, welded to the columns at both ends of the test frame. The longitudinal beams of the grid structure have the same structure as the crossbeams, are welded to adjacent crossbeams, and are equipped with several reinforcing plates.

[0006] In the aforementioned device, the test base is a structural welded component. Columns are symmetrically arranged between the upper and lower connecting plates of the test base. The columns are made of channel steel, arranged back-to-back, and welded from steel plates. Diagonal ribs are provided on the outer side of the columns. The shape and size of the lower connecting plate are designed to fit the test frame base. Several connecting holes are symmetrically arranged on the lower connecting plate for fixing to the test frame base. Several through holes are arranged on the upper connecting plate for fixing to the connectors of various specifications of inverted model connectors. U-shaped connectors are symmetrically arranged on one side of the test base for fixing to the adjustable tie rod.

[0007] In the aforementioned device, the test joint inverse model is a box-type welded component with multiple vertical ribs arranged therein and continuous welds are used; the upper surface of the test joint inverse model is a CNC-machined surface that matches the test joint surface, and several connecting holes are provided on the surface. The connecting holes are CNC-manufactured for connecting with the test joint. The CNC machining external tolerance is ±0.1mm, the hole position tolerance is ±0.05mm, and aging is performed after welding; the lower part of the test joint inverse model is a flat steel plate with several through holes, the positions of which correspond to the through holes on the connecting plate on the test base.

[0008] In the aforementioned device, the fixing frame is a symmetrical welded frame. The crossbeams and longitudinal beams of the frame are both made of [28 channel steel, arranged back to back and welded from steel plates. A U-shaped lug is provided in the middle area, and a connection hole is arranged on the U-shaped lug. After the single lug of the actuator is inserted into the U-shaped lug, it is fixed by the actuator connector. The length of the fixing frame is coordinated with the width of the test frame. The fixing frame has 8 fixing holes, and the hole positions are coordinated with the fixing hole positions on the test frame column.

[0009] In the aforementioned device, the actuator cylinder connector is made of 30CrMnSiA material, heat-treated to σb = 1080 ± 100 MPa, and surface-treated with bluing. Its smooth rod portion has a clearance fit with the connecting hole on the single lug of the actuator cylinder.

[0010] In the aforementioned device, the actuator support frame is an assembly, including a base frame and a gantry base, with the gantry base fixedly connected to the base frame; the base frame is a symmetrical welded component, with columns arranged between the upper and lower steel plates of the base frame, the columns being a face-to-face structure of channel steel, with reinforcing ribs symmetrically arranged on the outer side of the channel steel, and the bottom plate of the base frame being fixedly connected to the bottom plate of the test base and the test frame; the gantry base is used to limit the movement of the actuator.

[0011] In the aforementioned device, the ball-and-socket adapter is a stepped cylindrical structure. One end has an internal thread that is fixed to the screw of the actuating cylinder, and the other end is a ball-and-socket structure, which is the key part for the ball head of the test joint to be inserted. It is a hemispherical socket with an SΦ900+0.03 diameter and a 36° flared opening. The hemispherical socket and the flared opening are transitioned by an inner hole with a diameter of Φ900+0.1. The length is 35mm, and the inner surface Ra is 1.6. The ball-and-socket adapter is made of 30CrMnSiA material, heat treated with σb=1080±100MPa, and the surface treated with bluing.

[0012] In the aforementioned device, bushing A has a stepped circular structure, with the first cylinder being 4mm thick and the second cylinder having a clearance fit with the straight section of the ball socket of the ball joint adapter. It has an internal Φ8H7 through hole with an Ra value of 1.6 for holding a double-point target ball for measurement. The material is 45 steel, heat-treated to HRC28-32. Bushing B has a stepped structure, with the first cylinder being 4mm thick and the second cylinder fitting into the ball socket of the test connector. It also has an internal Φ8H7 through hole with an Ra value of 1.6 for holding a double-point target ball for measurement. The material is 45 steel, heat-treated to HRC28-32.

[0013] A method for testing the high load strength of a lifting joint for a fuselage support of a large transport aircraft, used in the aforementioned high load strength testing device for the lifting joint for a fuselage support of a large transport aircraft, the method comprising:

[0014] According to the requirements of the large load strength test of the fuselage support lifting joint of the large transport aircraft, the vertical compression state is converted to the horizontal compression state for the test. The test joint with the ball head part structure removed is placed horizontally on the test joint inverse model and fixed with the inverse model joint connector to ensure reliable connection.

[0015] The A bushing is installed in the ball socket hole of the ball socket adapter, and the B bushing is installed in the ball seat mounting hole of the test joint;

[0016] Remove the cover plate of the TB seat assembly, place an Φ8 target ball, and establish a measurement coordinate system; place a double-point target ball in the A bushing and the B bushing;

[0017] Adjust the position of the actuator cylinder so that the center line of the actuator cylinder is collinear with the center line of the ball head of the test joint, to ensure the correct direction of the applied force of the actuator cylinder;

[0018] Remove the target ball, bushing A and bushing B, install the test joint ball head, install a strain gauge on the ball head base, and connect the strain gauge to the sensor;

[0019] The actuator moves towards the ball head of the test connector, causing the ball head of the test connector to be positioned in the ball socket of the ball socket adapter that is fixed to the actuator.

[0020] Loading begins along the axis of the supporting ball head. The test load is strictly executed according to the specified test load. When the system is loaded to 50% of the test load, loading is stopped. After holding the load for 5 minutes, strain monitoring confirms safety, and then loading continues to the test load of the joint under test. After the loading system is loaded to the specified load, the holding time is 20 minutes.

[0021] The strain is measured by the change in resistance of the strain gauge using a sensor. The strain is then determined to determine whether the deformation of the test joint is within the design allowable range. If it is within the allowable range, the test joint is qualified; otherwise, it is unqualified, and the test is completed.

[0022] The advantages of this invention are as follows: Compared with the prior art, this invention solves the problem that conventional testing equipment and methods cannot complete the strength test of the lifting support joint, which plays an important role in large transport aircraft, thus meeting design requirements and ensuring the lifting safety, docking accuracy, and docking safety of aircraft fuselage components. The testing device uses a horizontal loading method to simulate the vertical stress state of the test joint, avoiding the safety hazards of difficult positioning of large test joints with complex structures and instability caused by excessively high vertical loading heights, ensuring the safety of large load tests. The structural design of the testing device ensures that the test load is accurately transferred to the ball joint of the test joint, effectively simulating the usage scenario of the test joint. The ball joint adapter further facilitates the ball joint insertion of the test joint. The measuring device uses laser measurement to improve the accuracy of the installation of the testing device, ensuring the accuracy of the loading force direction along the ball joint axis during the test and avoiding additional bending moments. The use of sensors and strain gauges for measurement makes the judgment of test results more accurate. The test device has a compact structure, is easy to install and adjust, has reliable joint positioning, safe test loading, and accurate test result measurement. It effectively solves the production bottleneck problem of large-load test of large aircraft support lifting joints, achieves satisfactory results, and ensures the model development of large transport aircraft. Attached Figure Description

[0023] Figure 1 A schematic diagram of the installation of the large load strength testing device for the fuselage support lifting joint of a large transport aircraft provided in this application;

[0024] Figure 2 for Figure 1 The diagram shown is a schematic representation of the structure from the front view.

[0025] Figure 3 for Figure 2 The diagram shown is a left-view view of the structure.

[0026] Figure 4 A schematic diagram of the test rack structure provided in this application;

[0027] Figure 5 A schematic diagram of the test base structure provided in this application;

[0028] Figure 6 This is a schematic diagram of the inverse model structure of the test joint provided in this application;

[0029] Figure 7 This is a schematic diagram of the fixing frame structure provided in this application;

[0030] Figure 8 A schematic diagram of the actuator cylinder structure provided in this application;

[0031] Figure 9 A schematic diagram of the adjustable tie rod structure provided in this application;

[0032] Figure 10 This is a schematic diagram of the actuator support frame structure provided in this application;

[0033] Figure 11 This is a schematic diagram of the actuator support frame and actuator installation provided in this application;

[0034] Figure 12 This is a schematic diagram of the ball joint adapter provided in this application;

[0035] Figure 13 This is a schematic diagram of the installation of the measuring device provided in this application;

[0036] Figure 14 This is a schematic diagram of the installation of the measuring device provided in this application;

[0037] Figure 15 This is a schematic diagram of the installation of the measuring device provided in this application;

[0038] Figure 16 The coordinate values ​​of the TB point of the measuring device provided in this application;

[0039] Figure 17 The coordinate values ​​of the bushing A and the double-point target ball in the bushing of the measuring device provided in this application.

[0040] Figure Labels

[0041] 1-Test frame, 2-Test base, 3-Test joint reverse model, 4-Fixed frame, 5-Actuator cylinder connector, 6-Actuator cylinder, 7-Adjustable tie rod, 8-Actuator cylinder support frame, 81-Base frame, 82-Gantry base, 9-Ball head socket adapter, 10-Fixed frame connector, 11-U-shaped connector, 12-Reverse model joint connector, 13-Test frame connector, 14-Measuring device, 141-A bushing, 142-B bushing, 143-TB seat assembly, 144-Strain gauge, 145-Sensor. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0043] Example 1. A large load strength testing device for the fuselage support lifting joint of a large transport aircraft, using a certain type of large transport aircraft as a platform, includes: a test frame, a test base, a test joint inverse model, a fixed frame, an actuator cylinder connector, an actuator cylinder, an adjustable tie rod, an actuator cylinder support frame, a ball joint adapter, a fixed frame connector, a U-shaped connector, an inverse model joint connector, a test frame connector, a measuring device, and several hexagonal head bolts.

[0044] Please see Figure 1 This is a schematic diagram of the installation of a large load strength test device for the fuselage support lifting joint of a large transport aircraft. The test device is installed on the floor of the laboratory building. The test frame 1 is installed on the factory floor. The test base 2 is fixedly connected to the base frame of the test frame 1 through the test frame connector 13. The test joint inverse model 3 is fixed to the test base 2 with hexagonal head bolts. The test joint and the test joint inverse model 3 are fixedly connected with the inverse model connector connector 12. The fixed frame 4 is fixedly connected to the column of the test frame 1 through the fixed frame connector 10. The actuator 6 is fixedly connected to the fixed frame 4 through the actuator connector 5. The ball head socket adapter 9 is fixedly connected to the screw of the actuator 6. One end of the adjustable pull rod 7 is fixedly connected to the end ear seat of the test base 2, and the other end is fixedly connected to the U-shaped connector 11 fixed on the test frame 1. The bottom plate of the actuator support frame 8 is fixed on the test base 2. The upper concave plane supports the bottom surface of the square head seat of the actuator 6 to achieve the support of the actuator 6. The center line of the actuator support frame 8 is collinear with the axis of the actuator 6. The TB seat assembly of the measuring device 14 is set on the upper plane of the test base 2. The A bushing is placed in the ball socket of the ball socket adapter 9, the B bushing is placed in the ball socket mounting hole of the test joint, and the strain gauge is attached to the root of the ball joint and connected to the sensor. Figure 2 for Figure 1 The diagram shown is a schematic representation of the structure from the front view. Figure 3 for Figure 2 The diagram shown is a left-view view of the structure.

[0045] Please see Figure 4 This is a schematic diagram of the test frame structure. The test frame 1 is a frame-type welded component, serving as the final load-bearing component for the strength test. It has four symmetrically arranged columns at both ends. Each column consists of two [28 channel steels welded back-to-back to steel plates. The steel plates are evenly distributed along both sides of the columns at 405mm intervals. Through holes in the steel plates are used for fixing the frame. The base of the test frame 1 is a grid structure with several horizontal beams and several vertical beams. Each horizontal beam is welded to the columns at both ends of the test frame 1, and the vertical beams are butt-welded to the horizontal beams. Each horizontal beam and vertical beam consists of two [32 channel steels arranged back-to-back at 40mm intervals. This spacing facilitates the fixing of the test base 2 and the base of the test frame 1.

[0046] Please see Figure 5This is a schematic diagram of the test base structure. The test base 2 is a welded frame structure with symmetrical columns between its upper and lower connecting plates. The columns are made of channel steel, arranged back to back, and welded with steel plates. The outer side of the columns is provided with diagonal ribs, and the structure meets the test load requirements. The structural dimensions of the lower connecting plate are designed to be compatible with the base frame of the test frame 1, which facilitates its fixed connection with the base frame of the test frame 1. The upper connecting plate is larger in size, suitable for strength testing of test joints of multiple specifications. Several through holes on it are used for fixed connection with the inverse model joint. The test base 2 has U-shaped joints symmetrically arranged on one side for fixed connection with the adjustable tie rod 7, realizing the pull of the adjustable tie rod 7 on it.

[0047] Please see Figure 6 This is a schematic diagram of the inverse model 3 of the test joint. It is a box-type welded component and a crucial transitional part for positioning and load transfer of the test joint. The box structure has multiple vertical ribs arranged internally, using continuous welds to prevent deformation under test loads. The upper profile is a CNC-machined surface that matches the test joint profile, with several connection holes. These holes are CNC-manufactured with a surface tolerance of ±0.1mm and a hole position tolerance of ±0.05mm, and undergo post-weld aging to facilitate connection with the test joint. The lower part of the inverse model 3 is a flat steel plate with rectangular holes to reduce the weight of the inverse model and facilitate the welding of the multiple vertical ribs inside the box structure, as well as the dissipation of processing heat.

[0048] Please see Figure 7 This is a schematic diagram of the fixed frame structure. The fixed frame 4 is a symmetrical welded frame, mainly used for fixing the actuator cylinder. Both the crossbeams and longitudinal beams are made of [28 channel steel, arranged back-to-back and welded from steel plates. A U-shaped lug, made of 45 steel, is provided in the middle area. The lug has connection holes for single-ear fixing of the actuator cylinder connector 5 and the actuator cylinder 6. The length of the fixed frame 4 is coordinated with the width of the test frame 1. Eight fixing holes are provided, and their positions are coordinated with the fixing holes on the column.

[0049] Please see Figure 8 This is a schematic diagram of the actuator cylinder structure. The actuator cylinder 6 is the loading device of the test apparatus, using a 400KN servo hydraulic cylinder with a length of approximately 1400mm and a rated working pressure of 21MPa. It has a pressure resistance of 28MPa and a stroke of 500mm, with an optimal stroke not exceeding 300mm. One end is a single-ear connector, and the other end is a screw, with a square boss at the root of the screw. The square boss is placed in the recessed plane on the upper part of the actuator cylinder support frame 8 to provide auxiliary support. The single-ear connector of the actuator cylinder 5 is fixedly connected to the U-shaped lug of the fixed frame 4 as the actuator cylinder connector 5, and the screw part is fixedly connected to the internal thread of the ball-head adapter 9.

[0050] Please see Figure 9This is a schematic diagram of the adjustable pull rod structure. The adjustable pull rod 7 is an assembly, symmetrically distributed on both sides of the test base, and serves as an auxiliary pulling device for the test base. It includes: a left screw 71, left and right threaded sleeves 72, and a right screw 73. The left screw 71 has a left-hand thread, and the right screw 73 has a right-hand thread. One end of the left and right threaded sleeves 72 has a left-hand internal thread, and the other end has a right-hand internal thread. A handle is fitted in the middle for easy adjustment. The left-hand internal thread is screwed to the left screw 71, and the right-hand internal thread is screwed to the right screw 73. The adjustable pull rod 7 is made of 45 steel, heat-treated to HRC28-32, and has a bluing finish.

[0051] Please see Figure 10 This is a schematic diagram of the actuator support frame structure. The actuator support frame 8 is an assembly that supports and limits the actuator 6. It includes a base frame 81, a gantry base 82, and several connecting parts. The gantry base 82 is fixedly connected to the base frame 81. The base frame 81 is a symmetrical welded component with columns arranged between the upper and lower steel plates. The columns are channel steel with face-to-face structure, and reinforcing ribs are symmetrically arranged on the outer side of the channel steel to ensure the strength requirements of the base. The bottom plate of the base frame 81 is fixedly connected to the bottom plate of the test base 2 and the test frame 1 to achieve the positioning of the actuator support frame 8. The gantry base 82 is used to limit and fix the actuator 6. Figure 11 This is a schematic diagram of the actuator support frame and actuator installation.

[0052] Please see Figure 12 This is a schematic diagram of the ball-and-socket adapter. The ball-and-socket adapter 9 is the receiving component for the ball head insertion of the test joint, a key component of the test device. It has a stepped cylindrical structure with an internal thread at one end and a ball-and-socket structure at the other end. The material is 30CrMnSiA, heat-treated to σb=1080±100MPa, and surface-treated with bluing. The internal thread at one end is fixedly connected to the screw at one end of the actuator cylinder 6, with the thread size and length matching the screw. The ball-and-socket structure at the other end is the key part for the ball head insertion of the test joint. It consists of a hemispherical socket of SΦ900+0.03 and a 36° flared opening. The hemispherical socket and the flared opening are transitioned by a Φ900+0.1 inner hole, with a length of 35mm and an inner surface Ra of 1.6.

[0053] Please see Figures 13 to 15This is a schematic diagram of the measuring device installation. The measuring device 14 is used for adjusting the position of the test device before testing and for measuring during the test. It includes an A bushing 141, a B bushing 142, a TB seat assembly 143, a strain gauge 144, and a sensor 145. The A bushing 141 is installed inside the flared opening of the ball joint adapter 9, and the B bushing 142 is installed inside the ball joint seat hole of the test joint, so as to ensure that the center line of the actuator 9 is collinear with the center line of the ball joint through the double-point target ball, ensuring the correct direction of the force. The TB seat assembly 143 is installed on the upper surface plate of the test base 2, and its position conforms to the TB seat distribution principle to facilitate the establishment of a measurement coordinate system. The strain gauge 144 is attached to the root of the ball joint, so that it expands and contracts with the strain of the test joint. The strain gauge 144 is connected to the sensor 145. The strain is determined by measuring the change in resistance, thereby determining the deformation of the test joint.

[0054] Please see Figure 16 , which is the coordinate value of the TB point of the measuring device, and is the theoretical data for establishing the measuring coordinate system.

[0055] Please see Figure 17 It refers to the coordinate values ​​of the bushing of measuring device A and the double-point target ball in the bushing, which are the theoretical data of the double-point target ball for adjusting the collinearity of the center line of the actuator cylinder and the center line of the ball head of the test joint.

[0056] The following is a test method for the high load strength of the lifting joint of the fuselage support of a large transport aircraft provided by the present invention. (See below) Figure 1 , Figure 2 , Figure 13 , Figure 14 , Figure 16 and Figure 17 The process is as follows:

[0057] Step 1: According to the requirements of the large load strength test of the lifting joint of the fuselage support of the large transport aircraft, the test joint with the ball head structure removed is placed horizontally on the test joint inverse model, and fixed with the inverse model joint connector to ensure reliable connection.

[0058] Step 2: Install bushing A into the ball socket of the ball joint adapter, and install bushing B into the ball head mounting hole of the test joint.

[0059] Step 3: Remove the cover plate of the TB seat assembly, place the Φ8 target ball, and establish a measurement coordinate system; place the double-point target ball in bushings A and B.

[0060] Step 4: Adjust the position of the actuator cylinder so that the center line of the actuator cylinder is collinear with the center line of the ball head of the test joint, ensuring the correct direction of the loading force of the actuator cylinder.

[0061] Step 5: Remove the target ball, bushing A and bushing B, install the test joint ball head, install the strain gauge on the ball head base, and connect the strain gauge to the sensor.

[0062] Step 6: The actuator moves towards the ball head of the test joint, causing the ball head of the test joint to be positioned in the ball socket of the ball head socket adapter that is fixed to the actuator.

[0063] Step 7: Start loading in the direction shown in the diagram. The test load shall be strictly executed according to the specified test load. When the system is loaded to 50% of the test load (i.e. the rated service load of the test joint), the loading shall be stopped. After holding the load for 5 minutes, and after the strain monitoring confirms that it is safe, the loading shall be continued to the test load of the test joint. After the loading system is loaded to the specified load, the holding time shall be 20 minutes.

[0064] Step 8: Measure the change in resistance using a sensor to determine the strain and whether the deformation of the test joint is within the design allowable range. If it is within the allowable range, the test joint is qualified; otherwise, it is unqualified, and the test is completed.

[0065] This invention provides a high-load strength test method for the fuselage support lifting joint of a large transport aircraft. The test method is flexible, convenient, safe, and feasible. It effectively solves the problem of strength verification for large support lifting joints, enabling accurate simulation and verification of the stress conditions of the joint and accurate measurement of deformation. This provides accurate verification data for determining whether the support lifting joint meets design requirements, ensuring the support stability and docking accuracy requirements of large transport aircraft fuselage components during assembly, as well as the safety during fuselage component lifting.

Claims

1. A large load strength testing device for the lifting joint of a fuselage support of a large transport aircraft, characterized in that, The system includes a test frame, a test base, a test joint inverse model, a fixing frame, an actuator cylinder connector, an actuator cylinder, an adjustable tie rod, an actuator cylinder support frame, a ball-and-socket adapter, a fixing frame connector, a U-shaped connector, an inverse model connector, a test frame connector, and a measuring device. The test base is fixed to the base frame of the test frame via the test frame connector. The test joint inverse model is fixed to the test base, and the test joint inverse model is fixed to the test joint using the inverse model connector. The fixing frame is fixed to the column of the test frame via the fixing frame connector. The actuator cylinder is fixed to the fixing frame via the actuator cylinder connector. The ball-and-socket adapter is fixed to the screw of the actuator cylinder. The ball-and-socket adapter is coaxial with the ball-and-socket mounting hole of the test joint. The measuring device includes an A bushing, a B bushing, a TB seat assembly, strain gauges, and sensors. The A bushing is installed at the flared end of the ball-and-socket adapter. The inner B bushing is installed inside the ball head seat hole of the test joint; the TB seat assembly is installed on the upper surface plate of the test base, and its position conforms to the TB seat distribution principle; the strain gauge is attached to the root of the ball head of the test joint and connected to the sensor; one end of the adjustable pull rod is fixedly connected to the end ear seat of the test base, and the other end is fixedly connected to the U-shaped connector fixed on the test frame; the base plate of the actuator support frame is fixed on the test base, and the upper recessed plane supports the bottom surface of the square head seat of the actuator; the ball head socket adapter is a stepped cylindrical structure, one end of which has an internal thread and is fixedly connected to the screw of the actuator, and the other end is a ball socket structure, which is the key part for the ball head of the test joint to be inserted. It is an SΦ900+0.03 hemispherical socket and a 36° flared mouth. The hemispherical socket and the flared mouth are transitioned by an Φ900+0.1 inner hole, with a length of 35mm and an inner surface Ra of 1.

6. Bushing A has a stepped circular structure. The first cylinder is 4mm thick, and the second cylinder is clearance-fitted with the straight section of the ball socket of the ball head socket adapter. An 8H7 through hole with Ra of 1.6 is provided inside to hold the double-point target ball for measurement. The B bushing has a stepped structure. The first cylinder is 4mm thick, and the second cylinder is inside the ball head hole of the test connector. An 8H7 through hole with Ra of 1.6 is provided inside to hold the double-point target ball for measurement. The actuator moves towards the ball head of the test joint, causing the ball head of the test joint to enter the ball socket of the ball head socket adapter fixed to the actuator.

2. The apparatus according to claim 1, characterized in that, The test frame is a welded frame structure with four symmetrical columns at both ends. Each column consists of two [28 channel steels welded back-to-back to a steel plate. The steel plate is evenly distributed along the column for 400mm and has through holes with a diameter of 31mm. The through holes are used for fastening the fasteners. The base frame of the test frame is a grid structure. Each crossbeam of the grid structure consists of two [32 channel steels welded back-to-back with a spacing of 40mm, and is welded to the columns at both ends of the test frame. The longitudinal beams of the grid structure have the same structure as the crossbeams and are welded to adjacent crossbeams. Several reinforcing plates are also provided.

3. The apparatus according to claim 1, characterized in that, The test base is a welded structural component. Columns are symmetrically arranged between the upper and lower connecting plates of the test base. The columns are made of channel steel, arranged back-to-back, and welded from steel plates. Diagonal ribs are provided on the outer side of the columns. The shape and size of the lower connecting plate are designed to fit the base frame of the test frame. Several connecting holes are symmetrically arranged on the lower connecting plate for fixing to the base frame of the test frame. Several through holes are arranged on the upper connecting plate for fixing to the connectors of various sizes of inverted model connectors. U-shaped connectors are symmetrically arranged on one side of the test base for fixing to the adjustable tie rod.

4. The apparatus according to claim 1, characterized in that, The test joint inverse model is a box-type welded component with multiple vertical ribs arranged in it and continuous welds. The upper surface of the test joint inverse model is a CNC-machined surface that matches the test joint surface. Several connecting holes are provided on the surface. The connecting holes are CNC-manufactured for connecting with the test joint. The CNC machining tolerance is ±0.1mm and the hole position tolerance is ±0.05mm. Post-weld aging is required. The lower part of the test joint inverse model is a flat steel plate with several through holes. The hole positions correspond to the through holes on the connecting plate on the test base.

5. The apparatus according to claim 1, characterized in that, The fixing frame is a symmetrical welded frame. The crossbeams and longitudinal beams of the frame are made of [28 channel steel, back to back, and welded from steel plates. A U-shaped lug is provided in the middle area. The U-shaped lug has a connection hole. After the single lug of the actuator is inserted into the U-shaped lug, it is fixed by the actuator connector. The length of the fixing frame is coordinated with the width of the test frame. The fixing frame has 8 fixing holes, and the hole positions are coordinated with the fixing holes on the test frame column.

6. The apparatus according to claim 1, characterized in that, The actuator cylinder connector is made of 30CrMnSiA material, heat treated with σb=1080±100MPa, and surface treated with bluing; its smooth rod part is clearance-fitted with the connecting hole on the single ear of the actuator cylinder.

7. The apparatus according to claim 1, characterized in that, The actuator support frame is an assembly, including a base frame and a gantry base, with the gantry base fixedly connected to the base frame. The base frame is a symmetrical welded component, with columns arranged between the upper and lower steel plates of the base frame. The columns are channel steel with face-to-face structure, and reinforcing ribs are symmetrically arranged on the outer side of the channel steel. The bottom plate of the base frame is fixedly connected to the bottom plate of the test base and the test frame. The gantry base is used to limit the movement of the actuator.

8. The apparatus according to claim 1, characterized in that, The ball joint adapter is made of 30CrMnSiA, with a heat treatment pressure of σb = 1080 ± 100 MPa and a bluing finish.

9. The apparatus according to claim 1, characterized in that, The bushing is made of 45 steel and heat-treated to HRC28-32.

10. A method for testing the high load strength of a lifting joint for a fuselage support of a large transport aircraft, characterized in that... The method using the large load strength testing device for the lifting joint of the fuselage support of a large transport aircraft as described in any one of claims 1 to 9 includes: According to the requirements of the large load strength test of the fuselage support lifting joint of the large transport aircraft, the vertical compression state is converted to the horizontal compression state for the test. The test joint with the ball head part structure removed is placed horizontally on the test joint inverse model and fixed with the inverse model joint connector to ensure reliable connection. The A bushing is installed in the ball socket hole of the ball socket adapter, and the B bushing is installed in the ball seat mounting hole of the test joint; Remove the cover plate of the TB seat assembly, place an Φ8 target ball, and establish a measurement coordinate system; place a double-point target ball in the A bushing and the B bushing; Adjust the position of the actuator cylinder so that the center line of the actuator cylinder is collinear with the center line of the ball head of the test joint, to ensure the correct direction of the applied force of the actuator cylinder; Remove the target ball, bushing A and bushing B, install the test joint ball head, install a strain gauge on the ball head base, and connect the strain gauge to the sensor; The actuator moves towards the ball head of the test connector, causing the ball head of the test connector to be positioned in the ball socket of the ball socket adapter that is fixed to the actuator. Loading begins along the axis of the supporting ball head. The test load is strictly executed according to the specified test load. When the system is loaded to 50% of the test load, loading is stopped. After holding the load for 5 minutes, strain monitoring confirms safety, and then loading continues to the test load of the joint under test. After the loading system is loaded to the specified load, the holding time is 20 minutes. The strain is measured by the change in resistance of the strain gauge using a sensor. The strain is then determined to determine whether the deformation of the test joint is within the design allowable range. If it is within the allowable range, the test joint is qualified; otherwise, it is unqualified, and the test is completed.

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