CN114323723B - A method for controllable loading of structural surfaces based on flexible gaskets and rigid bases - Google Patents

Abstract

The invention discloses a controllable loading method of a structure surface based on a flexible gasket and a rigid base, which relates to the technical field of mechanical experiments and the field of structure design. The method determines the front surface of a loading tool according to the geometric characteristic parameters of the surface of the loaded structure According to the geometric feature parameters of the front surface of the loading tool and the target load distribution parameters of the surface of the loaded structure, the geometric feature parameters of the three-dimensional structure of the loaded tool are determined based on the method of numerical simulation; according to the geometric feature parameters of the three-dimensional structure Make a loading tool, fit the front surface of the loading tool to the surface of the loaded structure, connect the rear surface of the loading tool to the actuator, and convert the linear displacement of the rigid base into a controllable distributed surface load that meets the requirements of the target load distribution parameters , the method can adapt to more complex three-dimensional surfaces, and has low cost, high flexibility and reliability.

Description

A method for controllable loading of structural surfaces based on flexible gaskets and rigid bases

technical field

The invention relates to the technical field of mechanical experiments and the field of structural design, in particular to a controllable loading method of a structural surface based on a flexible gasket and a rigid base.

Background technique

Surface loading technology is a commonly used technology in structural mechanics experiments. It is a technology of applying surface loads to the entire surface of the structure. During the application of surface loading technology, it is necessary to control both the magnitude of the applied load and the distribution of the load applied to the surface. , which is more difficult to control than the single-point loading technique that only applies a load to one force point.

The structure based on the flexible gasket-rigid base provides an idea for surface loading. Using this structure, a displacement load is applied to the rigid base through an actuator, and then the displacement load is converted into a surface load through the flexible gasket and applied to the surface. structured surface. However, at present, there is a big defect: for plane loading, the use of this structure can only achieve uniform load loading; for surface loading, the loading distribution depends on the geometric characteristics of the surface structure, which cannot be designed for specific needs, and Uniform load loading cannot be achieved.

SUMMARY OF THE INVENTION

In view of the above-mentioned problems and technical requirements, the inventor proposes a controllable loading method for the structural surface based on a flexible gasket and a rigid base. The technical solution of the present invention is as follows:

A method for controllable loading of a structural surface based on a flexible gasket and a rigid base, the method comprising:

The geometric characteristic parameters of the front surface of the loading tool are determined according to the geometric characteristic parameters of the surface of the loaded structure. The loading tool includes a flexible gasket and a rigid base. The front surface of the flexible gasket serves as the front surface of the loading tool, and the rear surface of the flexible gasket The surface is attached to the front surface of the rigid base, and the rear surface of the rigid base serves as the rear surface of the loading tool;

According to the geometric characteristic parameters of the front surface of the loading tool and the target load distribution parameters of the surface of the loaded structure, the geometric characteristic parameters of the three-dimensional structure of the loaded tool are determined based on the method of numerical simulation;

According to the geometric characteristic parameters of the three-dimensional structure, the loading tool is made, the front surface of the loading tool is attached to the surface of the loaded structure, the rear surface of the loading tool is connected to the actuator, and the actuator is controlled to be applied perpendicular to the center of the surface of the loaded structure. The linear displacement of the cut plane, transmitted through the loading tool, is applied to the surface of the loaded structure according to the target load distribution parameters.

Its further technical scheme is, the method also includes:

According to the target load distribution parameters on the surface of the loaded structure, determine the material of the flexible gasket used;

Then, when the loading tooling is manufactured according to the geometric characteristic parameters of the three-dimensional structure, the corresponding manufacturing material is used to manufacture the flexible gasket.

Its further technical solution is to determine the material of the flexible gasket to be used according to the target load distribution parameters of the surface of the loaded structure, including:

Determine the maximum load P _max according to the target load distribution parameters of the surface of the loaded structure;

The material whose Young's modulus is E=P _max /ε _max is selected as the material for making the flexible gasket, and ε _max is the maximum strain.

Its further technical solution is to determine the geometric characteristic parameters of the three-dimensional structure of the loaded tooling based on the method of numerical simulation, including:

According to the geometric characteristic parameters of the front surface of the loading tool and the target load distribution parameters of the surface of the loaded structure, the thickness distribution parameters of the flexible gasket are determined based on the method of numerical simulation;

Determine the geometric characteristic parameters of the rear surface of the flexible gasket according to the geometric characteristic parameters of the front surface of the loading tool and the thickness distribution parameters of the flexible gasket;

The geometric characteristic parameters of the front surface of the rigid base are determined according to the geometric characteristic parameters of the rear surface of the flexible gasket, and the geometric characteristic parameters of the rear surface of the rigid base are determined according to the structural requirements of the actuator.

Its further technical solution is to determine the thickness distribution parameters of the flexible gasket based on the method of numerical simulation, including:

Determine the thickness distribution law of the flexible gasket according to the target load distribution parameters on the surface of the loaded structure;

The initial thickness distribution parameters are determined according to the thickness distribution law, and the finite element model of the flexible gasket is established based on the geometric characteristic parameters and thickness distribution parameters of the front surface of the flexible gasket;

Carry out numerical simulation on the finite element model of the flexible gasket, and iteratively adjust the thickness distribution parameters to correct the finite element model, until the numerical simulation results of the load distribution parameters of the front surface of the flexible gasket are determined by using the finite element model and the target load distribution parameters are in the same range. Within the error range, the thickness distribution parameters of the flexible gasket are obtained.

Its further technical solution is to perform numerical simulation on the finite element model of the flexible gasket, including:

A displacement constraint is applied to the front surface of the finite element model of the flexible gasket, and a uniform displacement load is applied to the rear surface of the finite element model of the flexible gasket to conduct numerical simulations.

Its further technical solution is to determine the thickness distribution law of the flexible gasket according to the target load distribution parameter of the surface of the loaded structure, including:

If the target load distribution parameter on the surface of the loaded structure indicates that the load on the surface of the loaded structure is uniformly distributed, the thickness distribution law of the flexible gasket is determined as the thickness continuously decreases from the center of the flexible gasket to the periphery.

Its further technical solution is to iteratively adjust the thickness distribution parameters to correct the finite element model, including:

Calculate the stress deviation between the center point and the edge of the numerical simulation results of the load distribution parameters of the front surface of the flexible gasket η = (σ _m -σ _o )/σ _o , σ _m is the numerical simulation result of the center point, σ _o is Numerical simulation results at the edge;

If η≤| _ηmax |, it is determined that the numerical simulation result of the load distribution parameter of the front surface of the flexible gasket and the target load distribution parameter are within the error range, and _ηmax is the stress deviation threshold;

If η>|η _max |, the thickness of the center point of the flexible gasket is adjusted based on the stress deviation η as B _n+1 =B _n /(1+η), where B _n is the flexible gasket in the current thickness distribution parameters The thickness of the center point of the flexible gasket is maintained; the thickness at the edge of the flexible gasket is consistent with the current thickness distribution parameters, and the adjusted thickness distribution parameters are obtained by spline curve fitting according to the adjusted thickness B _n+1 of the center point.

Its further technical solution is to iteratively adjust the thickness distribution parameters to correct the finite element model, including: calculating the difference between the numerical simulation result σ′ _k and the target load distribution parameter σ _k at any kth calibration point on the front surface of the flexible gasket. The stress deviation η _k =(σ′ _k -σ _k )/σ _k ; if the stress deviation at all calibration points does not exceed the stress deviation threshold η _max , determine the value of the load distribution parameter of the front surface of the flexible gasket The simulation results and the target load distribution parameters are within the error range; if the stress deviation at at least one calibration point exceeds the stress deviation threshold η _max , the thickness at the calibration point where the stress deviation exceeds the stress deviation threshold η _max is adjusted to B _{i, n+1} =B _i,n /(1+η _i ), keep the thickness at other calibration points consistent with the current thickness distribution parameters, and use spline curve fitting to obtain the adjusted thickness distribution parameters according to the adjusted thickness ; where η _i is the stress deviation at any ith calibration point that exceeds the stress deviation threshold η _max , and B _i,n is the thickness at the ith calibration point in the current thickness distribution parameters.

A further technical solution is that the rear surface of the loading tool and the actuator are detachably connected.

The beneficial technical effects of the present invention are:

The present application discloses a method for controllable loading of a structure surface based on a flexible gasket and a rigid base. The method designs a corresponding three-dimensional structure based on theoretical analysis and numerical simulation technology according to the geometric characteristic parameters of the surface of the loaded structure and the target load distribution parameters. The flexible gasket and rigid base of the structure convert the linear displacement of the rigid base into a controllable distributed surface load that meets the requirements of the target load distribution parameters. The existing technology of uniform loading of the surface, this method can realize the controllable distributed loading of the surface megapa-level load, can adapt to more complex three-dimensional surfaces, and has low cost, high flexibility and high reliability.

Description of drawings

FIG. 1 is a flow chart of a method for controllable loading of a structured surface in one embodiment.

Figure 2 is a schematic diagram of the assembly of the flexible gasket, the rigid base and the surface of the loaded structure and the actuator.

FIG. 3 is a flow chart of the steps of determining geometric characteristic parameters of the three-dimensional structure of the loaded tool in one embodiment.

FIG. 4 is a flow chart of obtaining the thickness distribution parameters of the flexible gasket in one embodiment.

Figure 5 is a schematic diagram of the thickness and stress of the finite element model of the flexible gasket loaded with uniform load.

Figure 6 is a schematic diagram of the thickness and stress of a finite element model of a flexible gasket loaded with gradient loads.

(a) in FIG. 7 is a schematic structural diagram of using the method of the present application to realize uniformly distributed load loading on a plane loaded structure, and (b) in FIG. 7 is a method of the present application to realize the realization of the plane loaded structure Schematic diagram of the structure of gradient distributed load loading.

(a) in FIG. 8 is a schematic structural diagram of using the method of the present application to realize uniformly distributed load loading on the loaded structure of the convex surface, and (b) in FIG. 8 is the realization of the loaded structure of the convex surface by using the method of the present application. Schematic diagram of the structure of gradient distributed load loading.

Fig. 9(a) is a schematic structural diagram of using the method of the present application to achieve uniformly distributed load loading on a concave loaded structure, and Fig. 9 (b) is a method of the present application to achieve gradients for the concave loaded structure Structural diagram of distributed load loading.

Detailed ways

The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

The present application discloses a method for controllable loading of a structural surface based on a flexible gasket and a rigid base. The method includes the following steps, please refer to the flowchart shown in FIG. 1 :

Step 102: Determine the geometric feature parameters of the front surface of the loading tool according to the geometric feature parameters of the surface of the loaded structure.

In the present application, as shown in FIG. 2 , the surface 200 of the loaded structure is a plane or a curved surface or other more complex three-dimensional surface. And when the surface of the loaded structure is a curved surface, the surface of the loaded structure is a convex surface with any curvature or a concave surface with any curvature. FIG. 2 is a schematic diagram taking as an example that the surface 200 of the loaded structure is convex.

As shown in FIG. 2 , the loading tool includes a flexible gasket 210 and a rigid base 220. The front surface 211 of the flexible gasket 210 is used as the front surface of the entire loading tool to fit with the surface 200 of the loaded structure. For example, the two fit together. The rear surface 212 of the flexible gasket 210 is attached to the front surface 221 of the rigid base 220 . For the sake of clarity, FIG. 2 shows the flexible gasket 210 and the rigid base 220 separated. The rear surface 222 of the rigid base 220 serves as the rear surface of the entire loading tool. The flexible gasket 210 is made of a flexible material and can be deformed by force, while the rigid base 220 is made of a rigid material and can be considered to not be deformed by force within an error range.

The geometric characteristic parameters of the surface of the loaded structure include the plane size and shape and the three-dimensional relief of the surface of the loaded structure. When the geometric feature parameters of the front surface of the loading tool are determined according to the geometric feature parameters of the surface of the loaded structure, the front surface realized by determining the geometric feature parameters of the front surface of the loading tool is fully fitted with the surface of the loaded structure, so that the loading The front surface of the tool and the surface of the loaded structure can achieve full fit without loading.

Step 104 , according to the geometric feature parameters of the front surface of the loading tool and the target load distribution parameters of the surface of the loaded structure, determine the geometric feature parameters of the three-dimensional structure of the loaded tool based on a numerical simulation method.

The target load distribution parameter of the surface of the loaded structure indicates the load at each position where the surface of the loaded structure needs to be loaded, regardless of the surface topography of the loaded structure, the uniform distribution at each position of the surface of the loaded structure Or non-uniform distribution, non-uniform distribution is distributed according to the predetermined gradient change law.

The geometric feature parameters of the three-dimensional structure loaded with the tooling include not only the geometric feature parameters of each surface, but also the thickness parameters of the solid. As mentioned above, the loading tool includes the flexible gasket 210 and the rigid base 220. Since the rigid base 220 hardly deforms, it can be considered that the linear displacement applied to the rear surface of the rigid base 220 will form a uniform distribution on the front surface. to the displacement to achieve the required load transmission. Since the flexible gasket 210 will be deformed by force, the co-directional displacement applied to the rear surface of the flexible gasket 210 will change at the front surface due to the deformation of the flexible gasket 210, so that the load on the front surface will change. Therefore, the key point of this step is to determine the geometric characteristic parameters of the three-dimensional structure of the flexible gasket 210 .

Further, considering that different flexible materials have different resistance to deformation, in one embodiment, the material for making the flexible gasket 210 also needs to be determined. In this embodiment, the material of the flexible gasket used is determined according to the target load distribution parameters of the surface of the loaded structure. Specifically: the maximum load P _max is determined according to the target load distribution parameter of the surface of the loaded structure. A material whose Young's modulus is E=P _max /ε _max is selected as the material for making the flexible gasket 210 , and ε _max is a preset value for the maximum strain. For example, ε _max = 20% and P _max = 1 MPa, then the Young's modulus E = 5 MPa can be determined. In this case, ordinary rubber can be selected as the manufacturing material of the flexible gasket 210 .

The method for determining the geometric feature parameters of the three-dimensional structure of the loaded tooling includes the following steps, please refer to the flowchart shown in Figure 3:

Step 302 , according to the geometric characteristic parameters of the front surface of the loading tool and the target load distribution parameters of the surface of the loaded structure, determine the thickness distribution parameters of the flexible gasket 210 based on the method of numerical simulation. This step includes the following steps, please refer to Figure 4:

Step 402: Determine the thickness distribution law of the flexible gasket according to the target load distribution parameter of the surface of the loaded structure. The thickness distribution law of the flexible gasket indicates the thickness variation at each position of the flexible gasket, and the thickness of the flexible gasket is flexible. The distance between the front and rear surfaces of the shim in the direction perpendicular to the tangent plane at the center of the surface of the loaded structure. It mainly includes the following two situations:

(1) If the target load distribution parameter of the surface of the loaded structure indicates that the load on the surface of the loaded structure is uniformly distributed, then the thickness distribution rule of the flexible gasket is determined as the thickness continuously decreases from the center of the flexible gasket to the periphery.

(2) If the target load distribution parameter of the surface of the loaded structure indicates that the load on the surface of the loaded structure is distributed according to a predetermined gradient change law, then the flexible gasket is determined according to the predetermined gradient change law of the load and the curvature of the surface of the loaded structure. The thickness distribution law can be obtained by fitting the existing software through theoretical analysis or numerical simulation.

Step 404: Determine the initial thickness distribution parameter according to the thickness distribution law, and the thickness distribution law of the flexible gasket indicates the thickness of each position of the flexible gasket.

After the thickness distribution law is determined, the absolute value of the thickness also needs to be determined. Generally, after the thickness of the center of the flexible gasket 210 is determined, the thickness at other positions can be determined according to the thickness distribution law, thereby obtaining the thickness distribution parameters. The thickness of the center of the flexible gasket 210 can be determined according to the load required by the center of the surface of the loaded structure and the design value of the load applied by the actuator 230. Generally, the load applied by the actuator 230 is considered to be facing the rigid base 220. The center of the flexible gasket 210 and the center of the flexible gasket 210, and then act on the center of the surface of the loaded structure, and through the transmission of the loading tool, under the deformation of the flexible gasket 210, the load applied by the actuator 230 will be attenuated to a certain extent , when the thickness of the center of the flexible gasket 210 is different, the attenuation of the load is different. The design value of the load applied by the actuator 230 can be adjusted and known, and the load required at the center of the surface of the loaded structure can be determined by the target load distribution parameters of the surface of the loaded structure, thereby obtaining a flexible gasket 210 The thickness of the center. The specific method for obtaining the thickness can be obtained according to experience or numerical fitting.

After determining the initial thickness distribution parameters, a finite element model of the flexible gasket is established based on the geometric characteristic parameters and thickness distribution parameters of the front surface of the flexible gasket. During modeling, a finite element model is established and subsequent numerical simulations are performed according to the properties of the flexible gasket material determined by the above method.

Step 406 , perform numerical simulation on the finite element model of the flexible gasket. During the numerical simulation, a displacement constraint is imposed on the front surface of the finite element model of the flexible gasket, and a uniform displacement is imposed on the rear surface of the finite element model of the flexible gasket. The load is numerically simulated, and the numerical simulation result of the load distribution parameters of the front surface of the flexible gasket can be obtained by simulation.

Step 408 , if the error between the numerical simulation result of the load distribution parameter on the front surface of the flexible gasket and the target load distribution parameter exceeds the preset error range, then iteratively adjust the thickness distribution parameter to correct the finite element model and recalculate the value. simulation.

1. When the target load distribution parameter indicates uniform load distribution data on the surface of the loaded structure, iteratively adjust the thickness distribution parameter to correct the finite element model as follows:

(1) Calculate the stress deviation η=(σ _m −σ _o )/σ _o between the center point and the edge of the numerical simulation results of the load distribution parameters of the front surface of the flexible gasket. σ _m is the numerical simulation result of the center point of the front surface of the flexible gasket, and σ _o is the numerical simulation result of the edge of the front surface of the flexible gasket, and any edge can be taken. As shown in Figure 5.

(2) If η≤| _ηmax |, it is determined that the numerical simulation results of the load distribution parameters of the front surface of the flexible gasket and the target load distribution parameters are within the error range. η _max is the stress deviation threshold, which represents the maximum error of the uniform loading surface load allowed in the project, for example, it can be set to 2%.

(3) If η>|η _max |, adjust the thickness of the center point of the flexible gasket based on the stress deviation η as B _n+1 =B _n /(1+η), where B _n is the current thickness distribution parameter The thickness of the center point of the flexible gasket, that is, the distance between OA in Figure 5. Keep the thickness at the edge of the flexible gasket consistent with the current thickness distribution parameters, that is, keep A' and A" unchanged, and use spline curve fitting to obtain the adjusted thickness B _n+1 at the center point after adjustment. thickness distribution parameters.

2. When the target load distribution parameter indicates that the load on the surface of the loaded structure is distributed according to the predetermined gradient variation law, the specific method of iteratively adjusting the thickness distribution parameter to correct the finite element model is as follows:

(1) Calculate the stress deviation between the numerical simulation result σ′ _k at any k-th calibration point on the front surface of the flexible gasket and the target load distribution parameter σ _k of the calibration point η _k =(σ′ _k -σ _k )/σ _k . Several calibration points are pre-selected on the front surface of the flexible gasket, and for accuracy, multiple calibration points are generally selected evenly in different areas. Figure 6 assumes that there are a total of K calibration points.

(2) If the stress deviation at all calibration points does not exceed the stress deviation threshold η _max , it is determined that the numerical simulation results of the load distribution parameters of the front surface of the flexible gasket and the target load distribution parameters are within the error range. Similarly, η _max is the stress deviation threshold, which represents the maximum error of the uniform loading surface load allowed in the project, for example, it can be set to 2%.

(3) If the stress deviation at at least one calibration point exceeds the stress deviation threshold η _max , adjust the thickness at the calibration point where the stress deviation exceeds the stress deviation threshold η _max as B _i,n+1 =B _i,n / (1+η _i ), keep the thickness at other calibration points consistent with the current thickness distribution parameters, and use spline curve fitting to obtain the adjusted thickness distribution parameters according to the adjusted thickness; wherein, η _i is the excess stress deviation The stress deviation at any ith calibration point of the threshold η _max , B _i,n is the thickness at the ith calibration point in the current thickness distribution parameters. For example, in Fig. 6, assuming that only the η _i calculated at the ith calibration point exceeds η _max , and the stress deviations calculated at other calibration points are all smaller than η _max , then the thickness at the ith calibration point, that is, the adjustment The distance between O _i A _i in Fig. 6 _keeps the thickness _{O 1} A ₁ , O ₂ A ₂ . Adjusted thickness distribution parameters.

Step 410, if the error between the numerical simulation result of the load distribution parameter on the front surface of the flexible gasket and the target load distribution parameter is within the preset error range, then the iteration is ended, and the thickness distribution parameter of the flexible gasket is obtained .

Step 304: Determine the geometric feature parameters of the rear surface of the flexible gasket according to the geometric feature parameters of the front surface of the loading tool and the thickness distribution parameters of the flexible gasket.

Step 306: Determine the geometric feature parameters of the front surface of the rigid base according to the geometric feature parameters of the rear surface of the flexible gasket. The front surface constructed by the geometric feature parameters of the front surface of the rigid base fully fits the rear surface of the flexible gasket, so that the front surface of the rigid base and the rear surface of the flexible gasket can be fully fitted without loading. . The geometric characteristic parameters of the rear surface of the rigid base are determined according to the structural requirements of the actuator. Generally, the rear surface of the rigid base can be designed as a plane.

Step 106 , making a loading tool according to the geometric feature parameters of the three-dimensional structure. During manufacture, the flexible gasket 210 is manufactured according to the manufacturing material of the flexible gasket determined in the above steps.

After the loading tool is fabricated, the front surface of the loading tool is attached to the surface of the loaded structure, and the rear surface of the loading tool is connected to the actuator. In one embodiment, the front surface 211 of the flexible gasket 210 and the surface 200 of the loaded structure are fixedly connected, and the rear surface 212 of the flexible gasket 210 and the front surface 221 of the rigid base 220 are also fixedly connected to avoid During the loading process, there is a phenomenon that the contact surfaces slip with each other, such as bonding by glue. The rear surface of the loading tool, that is, the rear surface 222 of the rigid base 220 and the actuator 230 are detachably connected, so that the rigid base 220 or the actuator 230 can be easily replaced according to requirements while ensuring the tightness of the connection. , such as the common bolted connection.

After the installation is completed, the actuator 230 is controlled to apply a linear displacement perpendicular to the tangent plane at the center of the surface of the loaded structure, and the actuator 230 applies a corresponding load according to the design value. The linear position exerted by the actuator 230 forms a uniformly distributed co-directional displacement at each point of the front surface 221 of the rigid base 220, and is applied to the rear surface 212 of the flexible gasket 210, through the flexibility of the corresponding thickness distribution parameters. After the gasket 210 is transferred, it is converted into a required distributed load and applied to the surface of the loaded structure, that is, the load applied by the actuator 230 according to the design value is applied to the surface of the loaded structure according to the target load distribution parameters through the transmission of the loading tool. .

Using the method of the present application, controllable loading of various load distribution parameters of the loaded structures of various surface structures can be realized. For example, when the surface of the loaded structure is flat, the structure of the flexible gasket 210 and the rigid base 220 can be designed by using the method of the present application, as shown in (a) of FIG. 7 to achieve uniformly distributed load loading. Alternatively, the structure of the flexible gasket 210 and the rigid base 220 can be designed using the method of the present application as shown in (b) of FIG. 7 to achieve gradient distributed load loading.

For another example, when the surface of the loaded structure is convex, the structure of the flexible gasket 210 and the rigid base 220 can be designed by using the method of the present application, as shown in (a) of FIG. 8 to achieve uniformly distributed load loading. Alternatively, the structures of the flexible gasket 210 and the rigid base 220 can be designed using the method of the present application as shown in (b) of FIG. 8 to achieve gradient distributed load loading.

For another example, when the surface of the loaded structure is concave, the structure of the flexible gasket 210 and the rigid base 220 can be designed using the method of the present application, as shown in (a) in FIG. 9 to achieve uniformly distributed load loading. Alternatively, the structure of the flexible gasket 210 and the rigid base 220 can be designed using the method of the present application as shown in (b) of FIG. 9 to achieve gradient distributed load loading.

The above descriptions are only preferred embodiments of the present application, and the present invention is not limited to the above embodiments. It can be understood that other improvements and changes directly derived or thought of by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.

Claims (8)

1. A method for controllable loading of a structural surface based on a flexible gasket and a rigid base, wherein the method comprises: The geometric characteristic parameters of the front surface of the loading tool are determined according to the geometric characteristic parameters of the surface of the loaded structure, the loading tool includes a flexible gasket and a rigid base, and the front surface of the flexible gasket serves as the front surface of the loading tool , the rear surface of the flexible gasket is attached to the front surface of the rigid base, and the rear surface of the rigid base serves as the rear surface of the loading tool; According to the geometric characteristic parameters of the front surface of the loading tool and the target load distribution parameters of the surface of the loaded structure, the numerical simulation-based method determines the geometric characteristic parameters of the three-dimensional structure of the loading tool, including: according to the loading The geometric characteristic parameters of the front surface of the tooling and the target load distribution parameters of the surface of the loaded structure, the thickness distribution parameters of the flexible gasket are determined based on the method of numerical simulation, and the geometric characteristic parameters of the front surface of the loading tooling are used. and the thickness distribution parameters of the flexible gasket to determine the geometric characteristic parameters of the rear surface of the flexible gasket, and determine the geometric characteristic parameters of the front surface of the rigid base according to the geometric characteristic parameters of the rear surface of the flexible gasket , and determine the geometric characteristic parameters of the rear surface of the rigid base according to the structural requirements of the actuator; wherein, the method based on numerical simulation determines the thickness distribution parameters of the flexible gasket, including according to the loaded structure The target load distribution parameters of the surface of the flexible gasket determine the thickness distribution law of the flexible gasket, determine the initial thickness distribution parameters according to the thickness distribution law, and based on the geometric characteristic parameters of the front surface of the flexible gasket and the thickness distribution parameters to establish a finite element model of the flexible gasket, perform numerical simulation on the finite element model of the flexible gasket, and iteratively adjust the thickness distribution parameters to correct the finite element model, until the finite element model is used to determine the When the numerical simulation result of the load distribution parameter of the front surface of the flexible gasket and the target load distribution parameter are within the error range, the thickness distribution parameter of the flexible gasket is obtained; The loading tool is manufactured according to the geometric characteristic parameters of the three-dimensional structure, the front surface of the loading tool is attached to the surface of the loaded structure, and the rear surface of the loading tool is connected to an actuator to control the loading tool. The actuator exerts a linear displacement perpendicular to the tangent plane at the center of the surface of the loaded structure, and the transmission through the loading tool is applied to the surface of the loaded structure according to the target load distribution parameter. 2. The method according to claim 1, wherein the method further comprises: Determine the material used for making the flexible gasket according to the target load distribution parameter of the surface of the loaded structure; Then, when the loading tool is manufactured according to the geometric characteristic parameters of the three-dimensional structure, the flexible gasket is manufactured by using the corresponding manufacturing material. 3. The method according to claim 2, wherein the determining the material of the flexible gasket to be used according to the target load distribution parameter of the surface of the loaded structure comprises: Determine the maximum load P _max according to the target load distribution parameter of the surface of the loaded structure; A material whose Young's modulus is E=P _max /ε _max is selected as the manufacturing material of the flexible gasket, and ε _max is the maximum strain. 4. The method according to claim 1, wherein the numerical simulation of the finite element model of the flexible gasket comprises: A displacement constraint is applied to the front surface of the finite element model of the flexible gasket, and a uniform displacement load is applied to the rear surface of the finite element model of the flexible gasket to perform numerical simulation. 5. The method according to claim 1, wherein the determining the thickness distribution law of the flexible gasket according to the target load distribution parameter of the surface of the loaded structure, comprising: If the target load distribution parameter on the surface of the loaded structure indicates that the load on the surface of the loaded structure is uniformly distributed, then the thickness distribution rule of the flexible gasket is determined as the thickness is continuous from the center of the flexible gasket to the periphery decrease. 6. The method of claim 5, wherein the iteratively adjusting the thickness distribution parameters to revise the finite element model comprises: Calculate the stress deviation between the center point and the edge of the numerical simulation result of the load distribution parameters of the front surface of the flexible gasket η=(σ _m -σ _o )/σ _o , σ _m is the numerical simulation result of the center point, σ _o is the numerical simulation result at the edge; If η≤| _ηmax |, determine that the numerical simulation result of the load distribution parameter of the front surface of the flexible gasket and the target load distribution parameter are within the error range, and _ηmax is the stress deviation threshold; If η>|η _max |, the thickness of the center point of the flexible gasket is adjusted based on the stress deviation η as B _n+1 =B _n /(1+η), where B _n is the current thickness distribution parameter The thickness of the center point of the flexible gasket; keep the thickness at the edge of the flexible gasket consistent with the current thickness distribution parameters, and use spline curve fitting to obtain the adjusted thickness according to the adjusted center point thickness B _n+1 Thickness distribution parameters. 7. The method according to claim 1, wherein the determining the thickness distribution law of the flexible gasket according to the target load distribution parameter of the surface of the loaded structure, comprising: If the target load distribution parameter of the surface of the loaded structure indicates that the load on the surface of the loaded structure is distributed according to a predetermined gradient change law, then the load is determined according to the predetermined gradient change law of the load and the curvature of the surface of the loaded structure. Describe the thickness distribution law of flexible gaskets. 8. The method of claim 7, wherein the iteratively adjusting the thickness distribution parameters to revise the finite element model comprises: Calculate the stress deviation η _k =(σ′ _k -σ _k )/σ _k between the numerical simulation result σ′ _k at any kth calibration point on the front surface of the flexible gasket and the target load distribution parameter σ _k ; If the stress deviations at all calibration points do not exceed the stress deviation threshold η _max , it is determined that the numerical simulation results of the load distribution parameters of the front surface of the flexible gasket and the target load distribution parameters are within the error range; If the stress deviation at at least one calibration point exceeds the stress deviation threshold η _max , adjust the thickness at the calibration point where the stress deviation exceeds the stress deviation threshold η _max as B _i,n+1 =B _i,n /(1+ η _i ), keep the thickness at other calibration points consistent with the current thickness distribution parameters, and use spline curve fitting to obtain the adjusted thickness distribution parameters according to the adjusted thickness; wherein, η _i is exceeding the stress deviation threshold η _max The stress deviation at any ith calibration point of , B _i,n is the thickness at the ith calibration point in the current thickness distribution parameters.

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