Composite end frame structure tensile fixture device

Abstract

This invention relates to a tensile clamping device for composite material end-frame structures, comprising a pair of L-shaped clamping components and corresponding fastening assemblies placed at both ends of a thin-walled end-frame structure, a connecting base for fixing and connecting the L-shaped clamping components, an opening slot component for connecting the box-shaped end-frame structure, and connecting components. The L-shaped clamping components are used to fix the thin-walled end-frame structure. The connecting base has symmetrically arranged grooves, within which a slider movable along the slot direction is placed. The L-shaped clamping components and the connecting base are fixed to the slider via the assemblies. This tensile clamping device and fastening method can firmly clamp and fasten irregularly shaped components containing thin walls and box-shaped structures, thereby enabling various mechanical tests. The clamping device is simple to operate, easy to install and test, and adaptable to structural components of different thicknesses to achieve tensile loading. This invention is applicable to tensile testing of thin-walled composite material structures, and the design and connection of box-shaped structures and similar structural components.

Description

Technical Field

[0001] This invention relates to the field of workpiece clamping, and more particularly to a tensioning fixture device for composite material end frame structures. It also relates to clamping and connecting fixtures for thin-walled composite material structures and box-shaped structures. Background Technology

[0002] The development of new aerospace vehicles continuously pursues the goals of high efficiency, long lifespan, low cost, and high reliability, placing increasingly higher demands on the comprehensive requirements of materials and structures. Fiber-reinforced resin matrix composites, with their superior properties such as high specific strength, high specific modulus, strong designability, and good thermal stability, are widely used in the aerospace field. With the continuous development of composite material manufacturing technology, composite cylindrical structures have been gradually applied to the structures of aircraft, launch vehicles, missiles, etc. Among them, the end frame structure, as a key connection structure, plays a role in transferring loads and structural transitions, and its structural strength has important reference value for product reliability analysis.

[0003] The complete end frame structure is complex and large in size, resulting in high manufacturing costs. Therefore, experimental research was conducted on a simplified end frame model. The simplified end frame structural component is a flat model, such as... Figure 1 As shown, the structure consists of a thin-walled structure and a box-shaped structure. Based on the load characteristics of the end frame structure, an adaptive and highly flexible tensile loading fixture needs to be designed to realize the mechanical performance testing of the irregular structure. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of existing technologies and provide a tensile fixture device for composite material end-frame structures to meet the requirements of mechanical testing. The end-frame structure mainly includes thin-walled composite material structures and box-shaped structures. It meets the testing requirements for overall tensile testing and uniform load-bearing of the structural components.

[0005] The technical solution of this invention is:

[0006] A tensioning fixture device for a composite material end frame structure includes: an L-shaped clamping plate, a connecting base, and an opening slot component;

[0007] The L-shaped clamps are symmetrically arranged on both sides of the end frame of the test piece. The top of the L-shaped clamps is fixedly connected to the connecting base, and the side wall of the L-shaped clamps is fixedly connected to the thin-walled structural part of the end frame of the test piece.

[0008] The top of the slotted component is fixedly connected to the box-shaped structure of the end frame of the test piece;

[0009] The top of the connecting base and the bottom of the opening slot component are respectively fixedly connected to the static testing machine;

[0010] The L-shaped clamps symmetrically arranged on both sides of the end frame of the test piece can move relative to the connecting base along the thickness direction of the thin-walled structure, so that the axis of the connecting base of the symmetrical plane of the thin-walled structure coincides.

[0011] Preferably, the structural strength of the L-shaped clamp is higher than that of the thin-walled structure.

[0012] Preferably, the L-shaped clamping plate includes a long wall plate and a short wall plate;

[0013] The long wall panel is fixedly connected to the thin-walled structure, and the short wall panel is fixedly connected to the connecting base; the long wall panel and the short wall panel form an L-shaped structure.

[0014] Both the long and short walls have multiple through holes.

[0015] Preferably, the width of the long wall panel is the same as that of the thin-walled structure; the thickness of the long wall panel is greater than or equal to the thickness of the thin-walled structure.

[0016] Preferably, the upper surface of the short wall plate is provided with a positioning protrusion, and the lower surface of the connecting base is provided with a groove structure that corresponds to the protrusion. The protrusion and the groove structure work together to guide the assembly.

[0017] Preferably, the positioning protrusion is positioned at the upper end of any through hole in the short wall plate.

[0018] Preferably, it further includes: a slider;

[0019] The bottom surface of the connecting base is symmetrically machined with two sets of through grooves as slide rails;

[0020] The slider is set in the slide groove, and the slide groove can slide along the length direction of the slider; the length direction of the slider is perpendicular to the surface of the short wall plate.

[0021] The slider has threaded holes machined on it, and the short wall plate and the slider are fixedly connected by the first bolt.

[0022] Preferably, the slider and the slide groove are fitted with a clearance.

[0023] Preferably, the material grade of the L-shaped clamp is 40Cr.

[0024] Preferably, it further includes: a locking screw ring;

[0025] The top of the connecting base and the bottom of the opening slot component are fixed to the static testing machine by pins and tightened by locking bolts.

[0026] The advantages of this invention compared to the prior art are:

[0027] This tensile clamp has a wide range of applications, enabling the connection and fastening of composite end-frame structural components to the testing machine, and facilitating mechanical property testing. It is suitable for the design and connection of thin-walled composite structures, box-shaped structures, and similar structures. This tensile clamp is simple to operate, easy to install and test, and adaptable to tensile tests on end-frame structural components of varying thicknesses. Attached Figure Description

[0028] Figure 1 Simplified 3D view of the composite material end frame structure.

[0029] Figure 2 This is a front view of the composite material end frame structure tensioning fixture device of the present invention.

[0030] Figure 3 This is a left view of the composite material end frame structure tension clamp device of the present invention.

[0031] Figure 4 This is a front view of the L-shaped clamp of the present invention.

[0032] Figure 5 This is a cross-sectional view of the slider of the present invention.

[0033] Explanation of reference numerals in the attached drawings: Locking ring 1; Connecting base 2; First washer 3; Second nut 4; Left clamping plate 5; Second washer 6; First bolt 7; Second bolt 8; Right clamping plate 9; First nut 10; Third washer 11; Third bolt 8; Opening slot component 13; Slider 14; Protruding key 15; Fastening assembly 100 is a fastening assembly composed of second bolt 8, first washer 3, and second nut 4; Fastening assembly 200 is a fastening assembly composed of first bolt 7 and second washer 6. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0035] A tensile clamping device for composite material end frame structures is used to clamp and fix thin-walled end frame components and box-shaped components on a testing machine. It includes a pair of L-shaped clamping plates (left clamping plate 5 and right clamping plate 9) for clamping and fixing the thin-walled structure, a connecting base 2, an opening slot component 13, and related fastening components 100, 200, and connectors.

[0036] The L-shaped clamps are used to fix the thin-walled structure of the end frame and are connected and fixed by fastening components 100. Each L-shaped clamp includes a long wall plate and a short wall plate. The long wall plate of the L-shaped clamp is uniformly provided with connecting through holes, the size and number of which are calculated according to theoretical strength. The short wall plate of the L-shaped clamp is symmetrically provided with connecting through holes for connecting with the slider 14 in the groove of the connecting base 2. This is used for connecting the L-shaped clamp and the connecting base 2 and for transferring load. The connecting base 2 is symmetrically marked with scales along the loading center line for centering the structure. The width of the L-shaped clamp is the same as that of the thin-walled structure, and the thickness of the L-shaped clamp is greater than or equal to the thickness of the thin-walled structure. The connecting base 2 is symmetrically provided with slide grooves, and a movable slider 14 is provided in the groove. The movement direction of the slider 14 is perpendicular to the surface of the end frame. The opening groove component 13 has a deep groove along the side, the size of which should allow the connecting bolts to be installed and tightened. The box-shaped structure of the end frame is connected to the open slot component 13 by bolts to transfer loads. The size of the slot is based on the length of the bolts and includes pre-installed installation space. This clamping and fastening method allows for the testing of mechanical properties of irregularly shaped structures. It effectively clamps and fastens thin-walled structures, transfers loads to the box-shaped structure using a fixed load, and then conducts relevant mechanical property tests. The flexible connection method allows for adaptation to the thickness of the sample, especially the thickness of thin-walled structures.

[0037] The L-shaped clamping plate has symmetrically and uniformly arranged connecting through holes. The number and size of the connecting through holes can be calculated and adjusted according to theoretical results. At the same time, the spacing between the threaded holes is the same, which can better fix the thin-walled structure.

[0038] The connecting base 2 has symmetrically opened sliding grooves, and each groove contains two sliders 14. The L-shaped clamp and the connecting base 2 can be connected and fixed by the sliders 14 in the sliding grooves. Therefore, this tensile device is suitable for connection testing of thin-walled parts of different thicknesses. That is, the connecting base 2 has symmetrically opened grooves, and the grooves contain freely movable sliders 14. The sliders 14 are fitted with the grooves in a gap within the base grooves, which can better fix the sample and the fixture.

[0039] like Figure 4 As shown, a positioning key 15 is provided on the short wall plate of the L-shaped clamp. Through the cooperation of the key 15 and the groove, Figure 2 The central convex key 15 can move left and right along the groove. This allows for accurate positioning of the relative movement between the L-shaped clamping plate and the base, as well as for secure connection. A positioning convex key 15 is provided at any threaded through hole of the L-shaped clamping plate.

[0040] The open slot component 13 has an open hole at one end that connects to the end frame box structure, and is connected by bolts to provide load-bearing force. The open slot component 13 is made of thicker metal material to prevent deformation of the tooling, especially the slot opening. The dimensions of the deep groove on the side of the open slot component 13 are determined based on the length of the connecting third bolt 8.

[0041] Fastening assembly 100 includes a set of second bolts 8, first washers 3, and second nuts 4. Fastening assembly 200 includes a set of first bolts 7 and second washers 6. It is recommended that the bolts of the fastening assemblies be made of 45# steel or 40Cr material, which has a high strength grade. This allows the various components to cooperate and transfer loads.

[0042] The materials used for the L-shaped clamps and the open slot component 13 must have high strength and hardness to prevent deformation of the through holes or tooling during loading. 40Cr is recommended. The strength level of the left and right clamps should be higher than that of the thin-walled structure. Based on the stress analysis of the composite material end frame, the failure location of the structure should be on the box-shaped structure. To better fix the thin-walled structure and provide continuous load, the thickness of the left and right clamps is recommended to be greater than the thickness of the end frame structure.

[0043] The preferred connection method between the end frame tensile structure and the testing machine of this invention is a pin connection, followed by fastening with a locking screw 1 to ensure that there are no gaps between the tooling connections.

[0044] Example

[0045] Figure 1 , Figure 2 These are, respectively, the front view and the left view of the composite material end frame structure tension clamp device of the present invention. Figure 3This is a partially enlarged view of the L-shaped clamping plate of the present invention. The end-frame structure tensile clamping device is used to clamp and fix the thin-walled structure and box-shaped structure of the end-frame structure onto a testing machine. It mainly includes a pair of L-shaped clamping plates for fixing the thin-walled structure, a connecting base 2 connected to the testing machine, an opening slot component 13 for connecting and fixing the box-shaped structure, and various bolt fastening assemblies at different positions. The pair of L-shaped clamping plates includes a left clamping plate 5 and a right clamping plate 9 with identical structures. The long walls of the clamping plates are evenly provided with connecting through holes, and are simultaneously connected and fixed to the thin-walled structure of the end frame through fastening assemblies 100. Fastening assemblies 100 include a set of second bolts 8, first washers 3, and second nuts 4. The size and location of the connecting holes are determined based on the theoretical load and safety factor. For example, the theoretical strength of the end frame structure is 8000N. With a safety factor of 3, the connecting bolts are determined to be M12. According to the design manual, the compressive strength of 45# steel bolts is approximately 240MPa. After calculation, there should be 3 connecting bolts. To ensure uniform force distribution and load transfer, the optimal recommendation is to evenly distribute the connecting holes to avoid stress concentration. In this example, there are 3 connecting holes in one row, evenly distributed according to the width of the thin plate.

[0046] The connecting base 2 includes a pin connector for connection to the testing machine and a base with grooves on the side. Four sliders 14 are respectively installed in the side grooves, such as... Figure 5 As shown. The slider 14 is fitted with the groove with a clearance fit, and the short wall plate of the clamping plate is connected to the connecting base 2 by the first bolt 7 for load transfer. (Front view of connecting base 2) Figure 1 The scale lines are drawn symmetrically along the loading center line.

[0047] One end of the slotted component 13 is a pin joint that connects to the testing machine, and the other end is slotted along the side and has a through hole in the slot wall. It is connected to the box-shaped structure of the end frame and transmits load through the fastening assembly 200. The fastening assembly 200 includes a set of first bolts 7 and second washers 6. The bolts are connected to the slider 14.

[0048] The assembly process of the tensile fixture with end frame structure is as follows: First, install the connecting base 2 and the slotted part 13 on the upper and lower joints of the testing machine, and lock the locking screw 1 to prevent tooling gaps. Place the box-shaped structure of the end frame structure on the slotted part 13, aligning the upper and lower through holes. Insert the third bolt 8 into the through hole from bottom to top, and connect and tighten the third washer 11 to the first nut 10. Then, the long wall plates of the L-shaped clamps 5 and 9 clamp the thin-walled structure of the end frame, aligning the through holes from left to right. Insert the second bolt 8, and tighten the first washer 3 and the second nut 4 from right to left. Slowly start the testing machine, allowing the protruding key 15 of the L-shaped clamp to slide into the groove of the connecting base 2, and ensuring that the connecting base 2 and the short wall plate of the L-shaped clamp are in contact but not under load. Adjust the position of the slider 14 in the groove, screw the first bolt 7 into the groove opening and connect it to the slider 14, and tighten them to prevent slippage. Thus, a set of tensile fixtures with end frame structure is assembled and testing can begin.

[0049] The tooling surface of the L-shaped clamping plate long wall panel is required to have a certain degree of smoothness to avoid uneven stress after fastening with the thin-walled end frame structure.

[0050] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

[0051] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A tensile fixture device for a composite material end frame structure, wherein the end frame of the test piece comprises a thin-walled structure and a box-shaped structure, characterized in that, include: L-shaped clamp, connecting base (2) and opening slot component (13); The L-shaped clamps are symmetrically set on both sides of the end frame of the test piece. The top of the L-shaped clamps is fixedly connected to the connecting base (2), and the side wall of the L-shaped clamps is fixedly connected to the thin-walled structure part of the end frame of the test piece. The top of the slotted component (13) is fixedly connected to the box-shaped structure of the end frame of the test piece; The top of the connecting base (2) and the bottom of the opening slot component (13) are respectively fixedly connected to the static testing machine; The L-shaped clamps symmetrically set on both sides of the end frame of the test piece can move relative to the connecting base (2) along the thickness direction of the thin-walled structure, so that the axis of the connecting base (2) of the symmetrical surface of the thin-walled structure coincides. The structural strength of L-shaped clamps is higher than that of thin-walled structures. L-shaped panels include long side panels and short side panels; The long wall panel is fixedly connected to the thin wall structure, and the short wall panel is fixedly connected to the connecting base (2); the long wall panel and the short wall panel form an L-shaped structure; Multiple through holes are evenly distributed on both the long and short wall panels; The width of the long wall panel is the same as that of the thin wall structure; the thickness of the long wall panel is greater than or equal to the thickness of the thin wall structure. The upper surface of the short wall plate is provided with a positioning protrusion (15), and the lower surface of the connecting base (2) is provided with a groove structure that is in conjunction with the protrusion (15). The protrusion (15) and the groove structure work together to guide the assembly. Also includes: slider (14); The bottom surface of the connecting base (2) is symmetrically machined with two sets of through grooves as slide grooves; The slider (14) is set in the slide groove, and the slide groove can slide along the length direction of the slider (14); the length direction of the slider (14) is perpendicular to the surface of the short wall plate; The slider (14) has threaded holes, and the short wall plate and the slider (14) are fixedly connected by the first bolt (7); The slider (14) is fitted with the slide groove with a clearance.

2. The composite material end frame structural member tensioning fixture device according to claim 1, characterized in that, The positioning key (15) is positioned at the upper end of any through hole in the short wall plate.

3. A tensile clamping device for composite material end frame structures according to claim 1 or 2, characterized in that, The material grade of the L-shaped clamp is 40Cr.

4. A tensile clamping device for composite material end frame structures according to claim 1 or 2, characterized in that, Also includes: Locking screw (1); The top of the connecting base (2) and the bottom of the opening slot component (13) are respectively fixed to the static testing machine by pins and tightened by locking screws (1).

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