A decreasing type transient variable load loading device and test method

Abstract

The application discloses a kind of decreasing type transient variable load loading device and test method, it is related to loading test simulation technical field.The application includes: first sliding mechanism, first slider is configured with linear sliding along first direction;Second sliding mechanism, second slider is configured with linear sliding along second direction;Constant load force mechanism is used to output constant load parallel with first direction, and load acts on the first slider;The first direction is vertically arranged with the second direction, the first slider is connected with the second slider by inclined connecting rod, the second slider is connected with the product to be measured on the side away from the first slider, the distance between the hinge point of the connecting rod and the first slider and the hinge point of the connecting rod and the second slider in second direction is less than the length of the connecting rod;Overcome the shortcomings of existing variable load loading system structure, small loading range, slow response, realize the purpose of instantaneous decrease of load.

Description

Technical Field

[0001] This invention relates to the field of loading test simulation technology, specifically, to a decreasing instantaneous variable load loading device and test method. Background Technology

[0002] In the aerospace field, simulating the actual load conditions of a product during operation through loading tests is a common verification method. Depending on the actual usage of the product, this can be divided into constant load loading and variable load loading. Constant load loading is more common, and the test system used for it is relatively simple, generally achieved using a tension / compression loader or a constant pressure cylinder. However, constant loads do not exist in actual operating conditions; they are usually used for equivalence and simplification because variable load loading is difficult to achieve. Variable load loading better reflects the actual operating conditions of the product.

[0003] Variable load loading is further divided into incremental loading and decremental loading. The difference lies in whether the load gradually increases or decreases as the product operates. Decremental loading is more commonly used. Variable load loading can be achieved through wind tunnel testing or motor systems. In wind tunnel testing, the load changes more closely resemble actual operating conditions, better assessing the product's working characteristics. However, wind tunnel testing is costly and inefficient, hindering product design and verification. Motor systems, on the other hand, require large motors to apply high loads, resulting in complex testing systems, slow response times, and difficulty meeting millisecond-level load change requirements. Even motors with fast response times have limited load capacities, limiting their application range.

[0004] In summary, existing loading test systems lack a simple structure, a large loading range, and a fast response to load changes. To meet the actual testing needs of common products, there is an urgent need for a decreasing instantaneous variable load loading system. Summary of the Invention

[0005] The purpose of this invention is to provide a decreasing instantaneous variable load loading device and test method, which overcomes the shortcomings of existing variable load loading systems such as complex structure, small loading range and slow response, and achieves the purpose of instantaneous decreasing load change.

[0006] To achieve the above objectives, the present invention employs the following technical means:

[0007] A decreasing instantaneous variable load loading device, comprising:

[0008] The first sliding mechanism is configured with a first slider that slides linearly along a first direction;

[0009] The second sliding mechanism is configured with a second slider that slides linearly along a second direction;

[0010] A constant load applying mechanism is used to output a constant load parallel to the first direction, and the load is applied to the first slider;

[0011] The first direction is perpendicular to the second direction. The first slider and the second slider are connected by an inclined connecting rod. The side of the second slider away from the first slider is connected to the product to be tested. The distance between the hinge point of the connecting rod and the first slider and the hinge point of the connecting rod and the second slider in the second direction is less than the length of the connecting rod.

[0012] In this process, a constant load is applied to the first slider using a constant load application mechanism. This constant load is sequentially transmitted to the product under test through the first slider, a connecting rod, and the second slider. After the product under test receives the constant load, the test begins by actuating the product, pushing the second slider towards the first slider. The movement of the second slider, in turn, drives the first slider to move along a first direction via the connecting rod. During this movement, the angle between the connecting rod and the product's direction of motion changes. Assuming the length of the connecting rod is greater than the distance between the first and second sliders in the second direction, even with a constant load output by the constant load application mechanism, the load on the product decreases as the movement progresses.

[0013] Furthermore, the first sliding mechanism includes a first slide rail extending along a first direction, the first slider is slidably disposed within the first slide rail, and the load output end of the constant load applying mechanism is connected to the first slider via a first support rod.

[0014] The second sliding mechanism includes a second slide rail extending along a second direction, and the second slider is slidably disposed within the second slide rail. The product to be tested is connected to the second slider via a connecting rod.

[0015] Furthermore, the first slider and / or the second slider includes a pair of limiting blocks connected by a coupling, the two limiting blocks being respectively disposed within the first slide rail or the second slide rail, the first support rod being hinged to a coupling, the two ends of the connecting rod being hinged to a coupling of the first slider and a coupling of the second slider respectively, the connecting rod including a second support rod parallel to the second direction, one end of the second support rod being hinged to a coupling of the second slider, and the other end of the second support rod being connected to the product under test through a tension / compression sensor and an adapter.

[0016] Furthermore, the limiting block includes a slider frame and a cover plate, the cover plate being fastened to the slider frame;

[0017] When the limiting block is located inside the first slide rail, the cover plate is positioned towards the non-force-bearing side of the first slide rail. When the limiting block is located inside the second slide rail, the cover plate is positioned towards the non-force-bearing side of the second slide rail. A plurality of ball bearings are slidably embedded on the surface of the cover plate.

[0018] The outer edge of the slider frame is provided with a sliding groove, and a plurality of rollers are slidably installed in the sliding groove. The side of the slider frame facing the force side is provided with an open channel for the column of the roller to extend out and abut against the force side of the first slide rail or the second slide rail.

[0019] In this way, the ball bearings reduce the friction between the first and second sliders and the sidewalls of the first and second slide rails. Furthermore, the rollers not only allow the first and second sliders to bear greater loads, but also allow the rollers to circulate along the surrounding grooves during movement, further reducing the friction between the force-bearing sides of the first and second sliders and the first and second slide rails. This reduces external interference with the testing process.

[0020] Furthermore, the constant load application mechanism includes a cylinder and a load compensation mechanism. The piston end of the cylinder extends out as a load output end and is connected to the first slider. The load compensation mechanism is located inside the cylinder and includes a spring, a buffer tube, or a buffer block made of honeycomb aluminum material.

[0021] When the load compensation mechanism is a spring, it is sleeved on the piston rod and located on the side opposite to the air chamber. Its two ends abut against the inner wall of the cylinder and the side wall of the piston, respectively. After the load is applied, the spring returns to its original length.

[0022] When the load compensation mechanism is a buffer tube or a buffer block made of honeycomb aluminum material, it is located in the air chamber of the cylinder, with both ends abutting against the piston side wall and the cylinder inner wall respectively. After the load is applied, the two ends of the buffer tube or the buffer block made of honeycomb aluminum material are exactly in contact with the piston and the cylinder inner wall.

[0023] Thus, the load compensation mechanism here is used to adjust the effect of the increased output load caused by the reduction of the air chamber and the increase of the internal air pressure due to the piston movement of the cylinder, so as to ensure that a constant load can be output when the cylinder is used as the load output mechanism.

[0024] In addition, a decreasing instantaneous variable load loading test method uses the aforementioned decreasing instantaneous variable load loading device as the load loading system;

[0025] The initial load is determined by determining the length L of the connecting rod, the initial distance B between the first and second sliders in the second direction, and the output load F of the constant load applying mechanism.

[0026] P 0 :

[0027] ;

[0028] After the initial load output is completed, the product under test (DUT) begins operation, pushing the second slider towards the first slider along the second direction. When the DUT has moved a distance of U, the distance between the first and second sliders in the second direction becomes (BU), and the load is output in real time. P for:

[0029] ;

[0030] A load reduction test that increases with stroke can be implemented.

[0031] Furthermore, by adjusting the ratio between the length L of the connecting rod and the initial distance B between the first slider and the second slider, the slope and range of the load reduction curve can be controlled.

[0032] Furthermore, the two connecting nodes of an actuating part of the product under test are connected to two different sets of second sliders, and equipped with independent first sliding mechanisms and constant load applying mechanisms. The two constant load applying mechanisms apply the same output load, and the total load Z satisfies:

[0033] ;

[0034] in, , B1 is the initial distance between the first slider and the second slider in the second direction in the first system, L1 is the length of the connecting rod in the first system, B2 is the initial distance between the first slider and the second slider in the second direction in the second system, L2 is the length of the connecting rod in the second system, and U is the moving distance of the product to be tested.

[0035] The present invention has the following beneficial effects:

[0036] By using a connecting rod structure to change the direction of the cylinder's output load, and then by changing the geometric relationship during the movement of the connecting rod structure, the force changes. The rate of load change depends on the product's movement speed. The load on the product during operation is related to its movement state, making it more similar to actual working conditions. It is simple and reliable in structure, while also having a faster response speed and higher precision.

[0037] The first and second sliders are linearly rolling, and rolling friction on the force-bearing side is achieved through rollers. This allows them to withstand greater loads. Compared with traditional rolling bearings or linear bearings, they can bear greater loads for the same size and significantly reduce the inherent inertial mass of the loading system to adapt to different overall working conditions.

[0038] For different stroke and load variations, the length of the connecting rod between the first and second sliders and the initial distance between the first and second sliders can be adjusted. For more complex load variation curves, multiple systems can be combined and superimposed. Only the adapter between the product and the tension / compression sensor needs to be replaced. It has strong versatility and design flexibility, and is applicable to a wider range of applications. Attached Figure Description

[0039] Figure 1 A schematic diagram of the structure of this invention.

[0040] Figure 2 This is a schematic diagram of the structure of the first or second slider of the present invention.

[0041] Figure 3 for Figure 2 A cross-sectional structural diagram.

[0042] Figure 4 This is an exploded structural diagram of the limiting block of the present invention.

[0043] Figure 5 This is a schematic diagram of the assembly structure of the roller of the present invention.

[0044] Figure 6 This is a schematic diagram of the constant load application mechanism of the present invention, which uses a spring as a load compensation mechanism.

[0045] Figure 7 This is a load variation curve for a single loading system of the present invention.

[0046] Figure 8 This is a schematic diagram of the dual-system parallel structure of the present invention.

[0047] Figure 9 This is a surface diagram showing the load variation of the dual-loading system of the present invention.

[0048] Among them, 1-first slider, 2-second slider, 3-constant load application mechanism, 4-first slide rail, 5-first support rod, 6-connecting rod, 7-second slide rail, 8-coupling shaft, 9-second support rod, 10-tension and compression sensor, 11-adapter, 12-slider frame, 13-cover plate, 14-ball bearing, 15-slide groove, 16-roller, 17-cylinder, 18-load compensation mechanism, 19-air chamber. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0050] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0051] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0052] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0053] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0054] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0055] Please refer to Figure 1 As shown, a decreasing instantaneous variable load loading device includes:

[0056] The first sliding mechanism is configured with a first slider 1 that slides linearly along a first direction;

[0057] The second sliding mechanism is configured with a second slider 2 that slides linearly along a second direction;

[0058] The constant load force application mechanism 3 is used to output a constant load parallel to the first direction, and the load acts on the first slider 1;

[0059] The first direction is perpendicular to the second direction. The first slider 1 and the second slider 2 are connected by an inclined connecting rod 6. The side of the second slider 2 away from the first slider 1 is connected to the product to be tested. The distance between the hinge point of the connecting rod 6 and the first slider 1 and the hinge point of the connecting rod 6 and the second slider 2 in the second direction is less than the length of the connecting rod 6.

[0060] In this process, a constant load is applied to the first slider 1 using a constant load application mechanism 3. This constant load is sequentially transmitted to the product under test through the first slider 1, connecting rod 6, and second slider 2. When the product under test receives the constant load and the test begins, the product moves, pushing the second slider 2 towards the first slider 1. The movement of the second slider 2, in turn, drives the first slider 1 to move along a first direction via the connecting rod 6. During this movement, the angle between the connecting rod 6 and the product's direction of movement changes. As long as the length of the connecting rod 6 is greater than the distance between the first slider 1 and the second slider 2 in the second direction, even with a constant load output by the constant load application mechanism 3, the load on the product decreases as the movement progresses.

[0061] Furthermore, the first sliding mechanism includes a first slide rail 4 extending along a first direction, the first slider 1 is slidably disposed within the first slide rail 4, and the load output end of the constant load force application mechanism 3 is connected to the first slider 1 through a first support rod 5.

[0062] The second sliding mechanism includes a second slide rail 7 extending along a second direction, and the second slider 2 is slidably disposed within the second slide rail 7. The product to be tested is connected to the second slider 2 via a connecting rod.

[0063] Furthermore, please combine... Figure 2 and Figure 3As shown, the first slider 1 and / or the second slider 2 include a pair of limiting blocks connected by a connecting shaft 8. The two limiting blocks are respectively disposed in the first slide rail 4 or the second slide rail 7. The first support rod 5 is hinged to a connecting shaft 8. The two ends of the connecting rod 6 are respectively hinged to a connecting shaft 8 of the first slider 1 and a connecting shaft 8 of the second slider 2. The connecting rod includes a second support rod 9 parallel to the second direction. One end of the second support rod 9 is hinged to a connecting shaft 8 of the second slider 2. The other end of the second support rod 9 is connected to the product under test through a tension / compression sensor 10 and an adapter 11.

[0064] Furthermore, combining Figure 4 and Figure 5 As shown, the limiting block includes a slider frame 12 and a cover plate 13, and the cover plate 13 is fastened to the slider frame 12;

[0065] When the limiting block is located inside the first slide rail 4, the cover plate 13 is positioned towards the non-force-bearing side of the first slide rail 4. When the limiting block is located inside the second slide rail 7, the cover plate 13 is positioned towards the non-force-bearing side of the second slide rail 7. A plurality of balls 14 are slidably embedded on the surface of the cover plate 13.

[0066] Specifically, a two-dimensional orthogonal coordinate system is constructed using the aforementioned first and second directions, and a third direction is introduced to form a three-dimensional orthogonal coordinate system with the first and second directions. Therefore, the non-load-bearing side of the aforementioned first slide rail 4 is its sidewall in the third direction, and the non-load-bearing side of the aforementioned second slide rail 7 is its sidewall in the third direction.

[0067] The outer edge of the slider frame 12 is provided with a groove 15, and a plurality of rollers 16 are slidably installed in the groove 15. The side of the slider frame 12 facing the force side is provided with an open channel for the column of the roller 16 to extend out and abut against the force side of the first slide rail 4 or the second slide rail 7.

[0068] In this way, on the one hand, the arrangement of the ball bearings 14 reduces the friction between the first slider 1 and the second slider 2 and the sidewalls of the first slide rail 4 and the second slide rail 7. On the other hand, the arrangement of the rollers 16 not only allows the first slider 1 and the second slider 2 to bear a greater load, but also allows the rollers 16 to circulate along the surrounding grooves 15 during the movement of the first slider 1 and the second slider 2, further reducing the friction between the force-bearing sides of the first slider 1 and the second slider 2 and the first slide rail 4 and the second slide rail 7. This reduces external interference to the test process. Figure 5 V represents the direction of motion of either the first slider 1 or the second slider 2.

[0069] Furthermore, please combine... Figure 6As shown, the constant load force application mechanism 3 includes a cylinder 17 and a load compensation mechanism 18. The piston end of the cylinder 17 extends out as a load output end and is connected to the first slider 1. The load compensation mechanism 18 is located inside the cylinder 17 and includes a spring, a buffer tube, or a buffer block made of honeycomb aluminum material.

[0070] When the load compensation mechanism 18 is a spring, it is sleeved on the piston rod and located on the side opposite to the air chamber 19. Its two ends abut against the inner wall of the cylinder 17 and the side wall of the piston, respectively. After the load is applied, the spring is in its original length state.

[0071] When the load compensation mechanism 18 is a buffer tube or a buffer block made of honeycomb aluminum material, it is located in the air chamber 19 of the cylinder 17, with both ends abutting against the piston side wall and the inner wall of the cylinder 17 respectively. After the load is applied, the two ends of the buffer tube or the buffer block made of honeycomb aluminum material are exactly in contact with the piston and the inner wall of the cylinder 17.

[0072] Thus, the load compensation mechanism 18 here is used to adjust the effect of the increased output load caused by the reduction of the air chamber 19 and the increase of the internal air pressure due to the piston movement of the cylinder 17, so as to ensure that a constant load can be output when the cylinder 17 is used as the load output mechanism.

[0073] Furthermore, a decreasing instantaneous variable load loading test method uses the aforementioned decreasing instantaneous variable load loading device as the load loading system;

[0074] The initial load is determined by determining the length L of the connecting rod 6, the initial distance B between the first slider 1 and the second slider 2 in the second direction, and the output load F of the constant load applying mechanism 3. P 0 :

[0075] ;

[0076] After the initial load output is completed, the product under test begins to work, pushing the second slider 2 to move towards the first slider 1 along the second direction. When the product under test moves a distance U, the distance between the first slider 1 and the second slider 2 in the second direction becomes (BU), and the load is output in real time. P for:

[0077] ;

[0078] A load reduction test that increases with stroke can be implemented.

[0079] Specifically, the change in real-time applied load and function as the motion stroke U changes. Same, such as Figure 7 As shown. When U is in the range (0, U1),x The range is Due to the constraints of the actual structure, B will be significantly smaller than L, and the load will change mainly in the descending segment of the above function curve. Therefore, the load applied by this system is gradually reduced as the product moves.

[0080] By adjusting the ratio of the length L of the connecting rod 6 to the initial distance B between the first slider 1 and the second slider 2, the slope and range of the load reduction curve can be controlled, thereby applying a decreasing load to the product in various different states.

[0081] Furthermore, such as Figure 8 and Figure 9 As shown, the loading system in this embodiment can also be configured in parallel.

[0082] Specifically, the two connecting nodes of an actuating part of the product under test are connected to two different sets of second sliders 2 respectively, and are equipped with independent first sliding mechanisms and constant load applying mechanisms 3, and the two constant load applying mechanisms 3 apply the same output load.

[0083] Thus, the total load Z at this time satisfies:

[0084] ;

[0085] in, , B1 is the initial distance between the first slider 1 and the second slider 2 in the second direction in the first system, L1 is the length of the connecting rod 6 in the first system, B2 is the initial distance between the first slider 1 and the second slider 2 in the second system in the second direction, L2 is the length of the connecting rod 6 in the second system, and U is the moving distance of the product to be tested.

[0086] In this case, both systems are used for the same product and the same displacement U. Therefore, the following relationship can exist: U = B1 - L1 x =B2-L2 y ,but:

[0087] ;

[0088] Therefore, the dimensionless parameters of the two systems have a strict linear correspondence. And... x and y Through linear relationships: y = kx + b Mutual constraints, among which k = , b = .

[0089] Furthermore, according to the load surface, the total load Z can be considered as being at ( x , y Height function on a plane:

[0090] ;

[0091] Therefore, the actual total load variation path is and The line of intersection of two surfaces. For example... Figure 8 As shown, different load variation curves can be obtained by selecting different combinations of B1, B2, L1, and L2.

[0092] Thus, even if the parameters of the two systems are exactly the same, the total load Z=2 after the two systems are superimposed. P This directly doubles the load capacity. This allows the system to cover a wider load range and adapt to larger-scale testing needs.

[0093] Moreover, even if the F and U values ​​of the two systems are the same, by setting different geometric parameters for the two systems, namely different B values ​​and different L values, it is possible to construct complex load curves that cannot be achieved by a single system.

[0094] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for testing decreasing instantaneous variable loads, characterized in that, A decreasing instantaneous variable load loading device is used as the load loading system; The decreasing instantaneous variable load loading device includes: The first sliding mechanism is constructed with a first slider (1) that slides linearly along a first direction. The second sliding mechanism is constructed with a second slider (2) that slides linearly along the second direction. The constant load force application mechanism (3) is used to output a constant load parallel to the first direction, and the load is applied to the first slider (1). The first direction is perpendicular to the second direction. The first slider (1) and the second slider (2) are connected by an inclined connecting rod (6). The side of the second slider (2) away from the first slider (1) is connected to the product to be tested. The distance between the hinge points of the connecting rod (6) and the first slider (1) and the second slider (2) in the second direction is less than the length of the connecting rod (6). The initial load is determined by determining the length L of the connecting rod (6), the initial distance B between the first slider (1) and the second slider (2) in the second direction, and the output load F of the constant load applying mechanism (3). P 0 ; After the initial load output is completed, the product under test starts working, pushing the second slider (2) to move towards the first slider (1) along the second direction. When the product under test moves a distance of U, the distance between the first slider (1) and the second slider (2) in the second direction becomes (BU), and the real-time output load is obtained. P ; To achieve a load reduction test that increases with stroke; The constant load force application mechanism (3) includes a cylinder (17) and a load compensation mechanism (18). The piston end of the cylinder (17) extends out as a load output end and is connected to the first slider (1). The load compensation mechanism (18) is located inside the cylinder (17) and includes a spring, a buffer tube, or a buffer block made of honeycomb aluminum material. When the load compensation mechanism (18) is a spring, it is sleeved on the piston rod and located on the side opposite to the air chamber (19). Its two ends abut against the inner wall of the cylinder (17) and the side wall of the piston, respectively. After the load is applied, the spring is in its original length state. When the load compensation mechanism (18) is a buffer tube or a buffer block made of honeycomb aluminum material, it is located in the air chamber (19) of the cylinder (17), and its two ends abut against the piston side wall and the inner wall of the cylinder (17) respectively. After the load is applied, the two ends of the buffer tube or the buffer block made of honeycomb aluminum material are exactly in contact with the piston and the inner wall of the cylinder (17).

2. The method for a decreasing instantaneous variable load loading test according to claim 1, characterized in that, The first sliding mechanism includes a first slide rail (4) extending along a first direction, and the first slider (1) is slidably disposed in the first slide rail (4). The load output end of the constant load force application mechanism (3) is connected to the first slider (1) through a first support rod (5). The second sliding mechanism includes a second slide rail (7) extending along a second direction, and the second slider (2) is slidably disposed within the second slide rail (7). The product to be tested is connected to the second slider (2) via a connecting rod.

3. The method for a decreasing instantaneous variable load loading test according to claim 2, characterized in that, The first slider (1) and / or the second slider (2) include a pair of limiting blocks connected by a connecting shaft (8). The two limiting blocks are respectively disposed in the first slide rail (4) or the second slide rail (7). The first support rod (5) is hinged to a connecting shaft (8). The two ends of the connecting rod (6) are respectively hinged to a connecting shaft (8) of the first slider (1) and a connecting shaft (8) of the second slider (2). The connecting rod includes a second support rod (9) parallel to the second direction. One end of the second support rod (9) is hinged to a connecting shaft (8) of the second slider (2). The other end of the second support rod (9) is connected to the product to be tested through a tension / compression sensor (10) and an adapter (11).

4. The method for a decreasing instantaneous variable load loading test according to claim 3, characterized in that, The limiting block includes a slider frame (12) and a cover plate (13), and the cover plate (13) is fastened to the slider frame (12); When the limiting block is located inside the first slide rail (4), the cover plate (13) is positioned facing the non-force-bearing side of the first slide rail (4). When the limiting block is located inside the second slide rail (7), the cover plate (13) is positioned facing the non-force-bearing side of the second slide rail (7). A plurality of balls (14) are slidably embedded on the surface of the cover plate (13). The outer edge of the slider frame (12) is provided with a groove (15), and a plurality of rollers (16) are slidably installed in the groove (15). The slider frame (12) has an open channel on the side facing the force side, so that the column of the roller (16) extends out and abuts against the force side of the first slide rail (4) or the second slide rail (7).

5. The method for a decreasing instantaneous variable load loading test according to claim 1, characterized in that, The slope and range of the load reduction curve are controlled by adjusting the length L of the connecting rod (6) and the ratio of the initial distance B between the first slider (1) and the second slider (2).

6. A decreasing instantaneous variable load loading test method according to claim 1 or 5, characterized in that, The two connecting nodes of one actuating part of the product under test are connected to two different sets of second sliders (2), and are equipped with independent first sliding mechanisms and constant load applying mechanisms (3), and the two constant load applying mechanisms (3) apply the same output load.

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