Impact test system and test piece fixing device thereof

Abstract

An object of the present invention is to provide a test piece fixing device capable of fixing a test piece in an impact test while applying a preload to the test piece. Another object of the present invention is to provide an impact test system that uses the aforementioned test piece fixing device to fix a test piece. The test piece fixing device for achieving the aforementioned one object includes a pair of fixing arms and at least one adjusting unit. Both ends of the test piece are respectively fixed by a pair of fixing arms. The adjusting unit is disposed between the pair of fixing arms and is respectively connected to the pair of fixing arms in the assembled state. The length of the adjusting unit along the length direction of the test piece is adjustable. Among them, by adjusting the length of the adjusting unit, a movement tendency of the pair of fixing arms to separate from each other can be generated, so as to apply a preload to the test piece through the fixing arms.

Description

Technical Field

[0001] The present invention relates to an impact test system, and more particularly to a test piece fixing device in the impact test system. Background Art

[0002] One of the most severe working loads on an aero-engine fan blade is the impact load of birds and flocks of different masses inhaled by the engine. When a bird hits the blade, the blade is in a high-speed rotating state and has a large centrifugal force. Therefore, the load on the blade is the superposition of the bird strike load and the centrifugal force load. Further, the centrifugal force received by each point on the rotating blade is different. With and without the superposition effect of the centrifugal force, the deformation and failure characteristics of the blade during bird strike will be quite different, because the blade not only has different stress states but also different stiffnesses in the rotating state. Therefore, it is not accurate enough to use the bird strike test of a stationary fan blade to replace the bird strike test of a rotating fan blade.

[0003] However, the bird strike test of a rotating fan blade is not only extremely costly but also the test equipment is very scarce. Therefore, it is unrealistic to conduct such a test in the initial stage of blade design. However, because the bird strike load is very critical for the design of the fan blade, it must be considered in the initial stage of blade design.

[0004] Therefore, there is an urgent need for a test device that can apply a preload (equivalent to the centrifugal force) to the test piece and simultaneously conduct a soft body impact (equivalent to bird strike) test. Summary of the Invention

[0005] An object of the present invention is to provide a test piece fixing device that can fix the test piece and apply a preload to the test piece during an impact test.

[0006] Another object of the present invention is to provide an impact test system that uses the aforementioned test piece fixing device to fix the test piece.

[0007] The test piece fixing device for achieving the aforementioned one object is used to fix the test piece for an impact test, and includes:

[0008] A pair of fixing arms, with both ends of the test piece fixed by the pair of fixing arms respectively; and

[0009] At least one adjusting unit, disposed between the pair of fixing arms and respectively connected to the pair of fixing arms in the assembled state, and the length of the adjusting unit along the length direction of the test piece is adjustable;

[0010] Wherein, by adjusting the length of the adjusting unit, the pair of fixing arms has a tendency to move apart from each other, so as to apply a preload to the test piece through the fixing arms.

[0011] In one or more embodiments, each of the fixed arms includes a first arm and a second arm, and both ends of the test piece are clamped and fixed by the first arm and the second arm respectively;

[0012] Wherein, the first arm and the second arm are connected by a fastener, and the fastener is operated to adjust the distance between the first arm and the second arm, and clamp and fix the end of the test piece.

[0013] In one or more embodiments, an anti-slip unit is provided between the test piece and the first arm and / or the second arm.

[0014] In one or more embodiments, the adjusting unit includes:

[0015] A first screw rod, having a first thread portion at one end;

[0016] A second screw rod, having a second thread portion at one end; and

[0017] A connecting sleeve, threadedly connected to the first thread portion and the second thread portion respectively,

[0018] Wherein, the first thread portion and the second thread portion have different helix directions, and the connecting sleeve is rotated to make the first screw rod and the second screw rod extend out of or retract into the connecting sleeve respectively.

[0019] In one or more embodiments, an operating portion is provided on the connecting sleeve.

[0020] In one or more embodiments, the other end of the first screw rod has a first connecting block, the other end of the second screw rod has a second connecting block, and the adjusting unit abuts between the pair of fixed arms through the first connecting block and the second connecting block.

[0021] In one or more embodiments, universal joints are respectively provided between the first screw rod and the first connecting block, and between the second screw rod and the second connecting block.

[0022] In one or more embodiments, there are two adjusting units, which are respectively arranged between the two ends of the pair of fixed arms, and the test piece is fixed between the two adjusting units.

[0023] In one or more embodiments, connecting units are respectively provided at both ends of each fixed arm.

[0024] An impact test system for achieving the aforesaid another object, which is used for the impact test of a flexible body, includes an impact object, an impact object launching device and a fixing device. The test piece is fixed by the fixing device, and the impact object launching device launches the impact object towards the test piece; it is characterized in that the fixing device is the aforesaid test piece fixing device.

[0025] The progressive effects of the present invention include one or a combination of the following:

[0026] 1) By applying a preload to the test piece to simulate the centrifugal force, the centrifugal force received by the blade under the rotating state can be simulated, so that the test piece always maintains a given prestress during the test process of being impacted by the flexible body, thereby achieving an effect equivalent to the blade bird strike test under the centrifugal force load.

[0027] 2) Since the test piece is fixed by the fixing arms on both sides and a preload is applied, even if the test piece deforms, that is, the fixing arms applying the preload are directly fixedly connected to the test piece, the direction of the preload applied by the fixing arms to the test piece can still be maintained in the length direction of the test piece, and no undesired bending moment will be applied, further improving the authenticity of the simulation of the centrifugal force received by the test piece in the actual working condition.

[0028] 3) By setting the universal joint, the bending of the fixing arm will not cause the deformation of the adjusting unit, thereby avoiding the inability to continue loading due to the jamming of the turnbuckle; at the same time, the screw rod will not restrict the rotation of the inertia constraint rod, thereby ensuring the inertia constraint effect during the impact process and the preload does not change during the impact process. Description of the Drawings

[0029] The above-mentioned and other features, properties and advantages of the present invention will become more obvious through the following description in conjunction with the drawings and embodiments, wherein:

[0030] Figure 1 Shows a three-dimensional schematic diagram of an embodiment of the present test piece fixing device;

[0031] Figure 2 Is a front schematic diagram of an embodiment of the test piece fixing device;

[0032] Figure 3 Is Figure 2 A cross-sectional schematic diagram along the A-A direction;

[0033] Figure 4 Shows a schematic diagram of an embodiment of the adjusting unit;

[0034] Figure 5 Shows a schematic diagram of an embodiment of the present impact test system. Detailed Embodiments

[0035] The following discloses various different embodiments or examples for implementing the described subject technical solutions. To simplify the disclosure, specific examples of each element and arrangement are described below. Of course, these are merely examples and do not limit the scope of protection of this application. For example, in the subsequent description in the specification, if a first feature is formed above or on a second feature, it may include an embodiment in which the first and second features are formed by direct connection, and may also include an embodiment in which additional features are formed between the first and second features, so that the first and second features may not be directly connected. Additionally, in these disclosures, reference numerals and / or letters may be repeated in different examples. This repetition is for brevity and clarity and does not itself indicate the relationship between the various embodiments and / or structures to be discussed. Further, when a first element is described as being connected or coupled to a second element, this description includes embodiments in which the first and second elements are directly connected or coupled to each other, and also includes embodiments in which one or more other intervening elements are added to indirectly connect or couple the first and second elements to each other.

[0036] It should be noted that, when used, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "positive", "negative", "clockwise" and "counterclockwise" in the following description are used only for convenience and do not imply any specific fixed direction. In fact, they are used to reflect the relative positions and / or directions between the various parts of an object.

[0037] It should be noted that these and subsequent other drawings are only examples and are not drawn under conditions of equal scale, and should not be used to limit the actual scope of protection required by the present invention. In addition, the transformation methods under different embodiments can be appropriately combined.

[0038] It should be noted that, as described later, the reference numerals in the drawings are in a different marking system from those in the background art, and there is no association between the reference numerals of the two.

[0039] To solve one or more problems existing in the prior art, one aspect of the present invention provides a test piece fixing device for fixing a test piece to conduct an impact test. As Figure 1 shows a perspective schematic diagram of the test piece fixing device in one embodiment, Figure 2 and is a front schematic diagram of the test piece fixing device in one embodiment.

[0040] Please refer to Figure 1 , the test piece fixing device includes a pair of fixing arms 1. The test piece 2 is fixed at both ends by the fixing arms 1 as shown in the figure. The test piece 2 is fixed between the two fixing arms 1, and the two fixing arms 1 respectively restrict the movement of the test piece relative to the two fixing arms 1.

[0041] The test piece fixing device further includes an adjusting unit 3, which is arranged between a pair of fixing arms 1 and is connected to the pair of fixing arms 1 respectively in the assembled state as shown in Figures 1 to 2 . Among them, the length of the adjusting unit 3 along the length direction a of the test piece 2 is adjustable. It can be understood that the way the adjusting unit 3 is connected to the pair of fixing arms 1 respectively includes, but is not limited to, in the assembled state as shown in Figures 1 to 2 , the two ends of the adjusting unit 3 are fixedly connected to the pair of fixing arms 1 respectively. Or, the two ends of the adjusting unit 3 are not fixedly connected to the pair of fixing arms 1, and by adjusting the length of the adjusting unit 3 along the length direction a, the two ends of the adjusting unit 3 are respectively abutted against the pair of fixing arms 1 to realize the connection of the adjusting unit 3 to the pair of fixing arms 1 respectively.

[0042] It can be understood that in the embodiment as shown in Figures 1 to 2 , the number of the adjusting units 3 in the test piece fixing device is a pair, and the number of the adjusting units 3 can also be adaptively adjusted according to the shape, size, etc. of the test piece. For example, in one embodiment, the number of the adjusting units 3 is only one, and in another embodiment, the number of the adjusting units 3 is three or more.

[0043] Among them, when adjusting the length of the adjusting unit 3, the adjusting unit 3 will extend along the length direction a. At this time, the adjusting unit 3 will press against the fixing arms 1 on both sides respectively, so that there is a tendency for the fixing arms 1 to move away from each other relatively. At this time, since the two ends of the test piece 2 are fixed by the fixing arms 1, when the fixing arms 1 have a tendency to move away from each other, tensile forces will be applied to the two ends of the test piece 2 respectively, and a preload will be applied to the test piece to simulate the centrifugal force suffered by the test piece 2 in the actual working condition. For example, in one embodiment, the test piece 2 is an engine blade or an engine blade simulation piece. Since the blade will be affected by centrifugal force in the rotating state of the actual working condition, by applying a preload to the test piece to simulate the centrifugal force, the centrifugal force suffered by the blade in the rotating state can be simulated, so that the test piece 2 can always maintain a given prestress during the test process of being impacted by the soft body, thus realizing the effect equivalent to the blade bird strike test under the centrifugal force load.

[0044] At the same time, in the impact test, the test piece 2 will deform along the impact direction under the impact of the impact object. At this time, since the test piece 2 is fixed by the fixing arms 1 on both sides and a preload is applied, so that even if the test piece 2 deforms, that is, the fixing arms applying the preload are directly fixedly connected to the test piece 2, the direction of the preload applied by the fixing arms 1 to the test piece 2 can still be maintained in the length direction a of the test piece 2, and no undesired bending moment will be applied. The boundary effect of the device is not obvious and no abnormal damage mode will be caused, further improving the authenticity of the simulation of the centrifugal force suffered by the test piece 2 in the actual working condition.

[0045] Although one embodiment of the test piece fixing device is as described above, in other embodiments of the test piece fixing device, the test piece fixing device can have more details in many aspects relative to the above embodiment, and at least a part of these details can have various variations. Some embodiments will be used below to illustrate at least a part of these details and variations.

[0046] Figure 3 For Figure 2 a schematic cross-sectional view along the A-A direction, please continue to refer to Figure 1 and Figure 3 , in one embodiment of the test piece fixing device, each fixing arm 1 includes a first arm 11 and a second arm 12, and the test piece 2 is as Figure 1 shown, with both ends clamped by the first arm 11 and the second arm 12 respectively. Specifically, the first arm 11 and the second arm 12 are connected by a fastener 13, and by operating the fastener 13, the distance between the first arm 11 and the second arm 12 can be adjusted, so as to clamp and fix the end of the test piece 2. For example, in one embodiment, the fastener 13 is a bolt, and by tightening the bolt, the first arm 11 and the second arm 12 can clamp and fix the test piece 2.

[0047] In some other embodiments different from the illustrated ones, there can also be many suitable deformations or variations in the connection manner between the test piece 2 and the fixing arm 1. For example, in one embodiment, each fixing arm 1 can also include only one arm body, and the end parts of the test piece 2 are respectively fixedly connected to the arm body through fasteners. In another embodiment, the first arm 11 and the second arm 12 can be connected by snap connection, and the test piece 2 is clamped and fixed between the snap-connected first arm 11 and second arm 12.

[0048] Please continue to refer to Figure 1 , in one embodiment of the test piece fixing device, an anti-slip unit 14 is provided between the test piece 2 and the first arm 11 and / or the second arm 12. Specifically, in one embodiment, the anti-slip unit 14 can be a rubber pad, so as to increase the friction between the test piece 2 and the fixing device, prevent slipping, and at the same time reduce the clamping damage of the fixing device to the body of the test piece 2.

[0049] Such as Figure 4Shows a schematic diagram of an embodiment of the adjusting unit 3. Among them, the adjusting unit 3 includes a first screw 31, a second screw 32 and a connecting sleeve 30. One end of the first screw 31 has a first thread portion 31a, one end of the second screw 32 has a second thread portion 32a, and the inside of the connecting sleeve 30 has internal threads, so that the first thread portion 31a and the second thread portion 32a can be threadedly connected to the connecting sleeve 30 respectively, thereby connecting the first screw 31, the second screw 32 and the connecting sleeve 30 into a whole. Among them, the first thread portion 31a and the second thread portion 32a have different thread directions. When the connecting sleeve 30 is rotated, the first screw 31 and the second screw 32 can respectively extend out of or retract into the connecting sleeve 30. When the first screw 31 and the second screw 32 simultaneously extend out of the connecting sleeve 30, the length of the adjusting unit 3 in the length direction a increases, so as to apply a preload to the fixed arm 1. Through the adjusting unit 3 with a left-hand and right-hand screw structure, the length of the adjusting unit 3 can be accurately adjusted, so that the centrifugal force applied to the test piece 2 can be accurately simulated.

[0050] In some embodiments different from the illustrated ones, the structure of the adjusting unit 3 can have many suitable deformations or changes. For example, in one embodiment, the structure of the adjusting unit 3 can also be a spring rod, or a linkage mechanism or other structural forms that can realize the length change in the length direction.

[0051] In one embodiment of the test piece fixing device, an operating part 30a is further provided on the connecting sleeve 30, and the connecting sleeve 30 can be rotated by operating the operating part 30a. In one embodiment, the operating part 30a is a convex part structure as shown in the figure. In another embodiment, the operating part can also be a pattern or a handle provided on the outer peripheral side of the connecting sleeve 30.

[0052] Please continue to refer to Figure 1 , in one embodiment of the test piece fixing device, the other end of the first screw 31 has a first connecting block 33, the other end of the second screw 32 has a second connecting block 34, and the adjusting unit 3 abuts between a pair of fixed arms 1 through the first connecting block 33 and the second connecting block 34. By providing the first connecting block 33 and the second connecting block 34, the contact area between the adjusting unit and the pair of fixed arms 1 can be increased, so that the load transfer is more stable. For example, in one embodiment, by providing the first connecting block 33 and the second connecting block 34, the load can be simultaneously transferred to the first arm 11 and the second arm 12.

[0053] In an embodiment of the test piece fixing device, universal joints 35 are respectively arranged between the first screw 31 and the first connecting block 33, and between the second screw 32 and the second connecting block 34. In the impact test, the test piece 2 will deform along the impact direction under the impact of the impact object. At this time, the fixing arm 1 will also bend towards the impact direction under the drive of the test piece 2. At this time, by arranging the universal joint 35, the bending of the fixing arm 1 will not cause the deformation of the adjusting unit 3, thus avoiding the inability to continue loading due to the jamming of the turnbuckle; at the same time, the screw will not restrict the rotation of the inertial constraint rod, thus ensuring the inertial constraint effect during the impact process and the preload does not change during the impact process.

[0054] In an embodiment of the test piece fixing device, there are two adjusting units 3 as shown in the figure, which are respectively arranged between the two ends of a pair of fixing arms 1, and the test piece 2 is fixed between the two adjusting units 3.

[0055] In an embodiment of the test piece fixing device, connection units 4 are respectively arranged at both ends of each fixing arm 1. In the embodiment shown in the figure, the connection unit 4 can be a connecting rope, and in another embodiment, the connection unit 4 can also be a sling structure. The test piece fixing device realizes the suspension and fixing of the test piece 2 through the connection unit 4.

[0056] Another object of the present invention is to provide an impact test system. The test piece fixing device in one or more of the foregoing embodiments can be applied to an impact test system as shown in Figure 5 shown. The impact test system is used for the soft body impact test, and it further includes an impact object 5, an impact object launching device 6, and a test bench 7. Among them, the impact object launching device 6 can include an air storage tank 61, a valve 62, a gun barrel 63, and a shell stripper as shown in the figure. Pressure is applied to the impact object 5 through the impact object launching device 6 to launch the impact object 5 to form an impact on the test piece 2. The test piece fixing device in one or more of the foregoing embodiments is fixed in the test bench 7.

[0057] The progressive effects of the present invention include one or a combination of the following:

[0058] 1) By applying a preload to the test piece to simulate the centrifugal force, the centrifugal force received by the blade in the rotating state can be simulated, so that the test piece always maintains a given prestress during the test of being impacted by the soft body, thus achieving an equivalent effect to the blade bird strike test under the centrifugal force load.

[0059] 2) Since the test piece is fixed and preloaded through the fixed arms on both sides, so that even if the test piece deforms, that is, the fixed arms applying the preload are directly fixedly connected to the test piece, the direction of the preload applied by the fixed arms to the test piece can still be maintained in the length direction of the test piece, without applying an undesired bending moment, further improving the authenticity of simulating the centrifugal force received by the test piece in the actual working condition.

[0060] 3) By setting the universal joint, the bending of the fixed arm will not cause deformation of the adjusting unit, thus avoiding the inability to continue loading due to the jamming of the turnbuckle; at the same time, the screw rod will not restrict the rotation of the inertial constraint rod, thus ensuring the inertial constraint effect during the impact process and that the preload does not change during the impact process.

[0061] Although the present invention is disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modifications, equivalent changes and decorations made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A test piece fixing device for fixing a test piece to conduct an impact test, characterized in that, Comprising: A pair of fixed arms, with both ends of the test piece fixed by the pair of fixed arms respectively; And At least one adjusting unit, disposed between the pair of fixed arms and respectively connected to the pair of fixed arms in the assembled state, the length of the adjusting unit along the length direction of the test piece being adjustable; Wherein, adjusting the length of the adjusting unit can cause the pair of fixed arms to have a tendency to move apart from each other, so as to apply a preload to the test piece through the fixed arms; The adjusting unit comprises: A first screw rod, having a first thread portion at one end; A second screw rod, having a second thread portion at one end; and A connecting sleeve, threadedly connected to the first thread portion and the second thread portion respectively, Wherein, the first thread portion and the second thread portion have different thread directions, and rotating the connecting sleeve causes the first screw rod and the second screw rod to extend out of or retract into the connecting sleeve respectively; The other end of the first screw rod has a first connecting block, and the other end of the second screw rod has a second connecting block, and the adjusting unit abuts between the pair of fixed arms through the first connecting block and the second connecting block; Universal joints are respectively arranged between the first screw rod and the first connecting block, and between the second screw rod and the second connecting block.

2. The test piece fixing device according to claim 1, characterized in that, Each of the fixed arms includes a first arm and a second arm, and both ends of the test piece are clamped and fixed by the first arm and the second arm respectively; Wherein, the first arm and the second arm are connected by a fastener, and operating the fastener adjusts the distance between the first arm and the second arm and clamps and fixes the end of the test piece.

3. The test piece fixing device according to claim 2, characterized in that, An anti-slip unit is arranged between the test piece and the first arm and / or the second arm.

4. The test piece fixing device according to claim 1, characterized in that, An operating portion is arranged on the connecting sleeve.

5. The test piece fixing device according to claim 1, characterized in that, There are two adjusting units, respectively arranged between both ends of the pair of fixed arms, and the test piece is fixed between the two adjusting units.

6. The test piece fixing device according to claim 1, wherein, Connecting units are respectively arranged at both ends of each of the fixed arms.

7. An impact test system for soft body impact tests, comprising an impact object, an impact object launching device, and a fixing device. The test piece is fixed by the fixing device, and the impact object launching device launches the impact object towards the test piece; characterized in that, The fixing device is the test piece fixing device according to any one of claims 1 to 6.

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