A fail-safe topology optimization design method under dynamic loads

Abstract

The present invention provides a method for failure-safe topology optimization design under dynamic load, comprising: step 1, defining the design domain and design parameters of the structure; step 2, performing transient dynamic analysis on the structure; step 3, calculating the equivalent static load of the dynamic load; step 4: performing failure-safe topology optimization design on the model under equivalent static load; minimizing the maximum flexibility of the structure under local failure as the optimization goal; and using the moving asymptote method to iteratively optimize the design variable unit density until the inner loop failure-safe topology optimization process is completed; step 5: judging whether the outer loop convergence condition is met based on the updated design variables after the failure-safe topology optimization. The present invention fully considers the possible local failure of the structure during the design process, thereby improving the performance of the structure under local failure conditions; converting the dynamic load under the original working condition into a static load through the equivalent static load method, effectively improving the computational efficiency of the optimization process.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical engineering, and in particular to a failure-safe topology optimization design method under dynamic load. Background Art

[0002] Optimization design methods include size optimization, shape optimization, and topology optimization. Topology optimization can change the material distribution within the design domain according to the constraints and objective function to obtain the optimal distribution of materials under the working conditions, while achieving weight reduction and performance optimization of the structure. Common topology optimization methods include homogenization method, variable density method, and progressive optimization method. At present, topology optimization is mostly used for structural optimization under static loads.

[0003] For transport equipment structures, there are many dynamic load conditions such as impact and vibration. Under these conditions, the structure is prone to local failure, seriously affecting its performance. Due to the complexity of the load conditions, the equivalent static load method is a method that converts the dynamic load on the structure into an equivalent static load. The equivalent static load obtained by this method can cause the structure to produce the same displacement as the original dynamic load, thereby simplifying the problem solution.

[0004] Fail-safe topology optimization builds on the foundation of topology optimization design by incorporating possible local failure scenarios into the design, thereby ensuring that the structure can still maintain performance even in the event of local failure, thus achieving a safe and redundant design. Fail-safe topology optimization builds on the foundation of topology optimization design by incorporating possible local failure scenarios into the design, thereby ensuring that the structure can still maintain performance even in the event of local failure, thus achieving a safe and redundant design.

[0005] The invention patent with publication number CN201610807923 discloses a dynamic response topology optimization method of the equivalent static load method based on an improved bidirectional progressive method. The improved bidirectional progressive method is applied to the equivalent static load method, which improves the optimization calculation efficiency and simplifies the optimization process. However, the safety redundancy of the optimized structure is small. If the structure fails locally under the action of dynamic loads, the structural safety will be challenged. The invention patent with publication number CN202410168312 discloses a dynamic topology optimization method for multiphase material structures based on the equivalent static load method. The equivalent static load method is used to replace the time variable with a static variable, and the dynamic topology optimization problem of the multiphase material structure is converted into a static topology optimization model of the multiphase material structure under multiple working conditions, which effectively improves the calculation efficiency. The optimized structure has better dynamic performance. However, the optimized structure still has the problem of small safety redundancy.

[0006] Utility model patent publication number CN202323032059 discloses a fail-safe design for an offshore wind turbine jacket. By defining a failure zone within the design domain and analyzing the dynamic performance of the optimized structure before and after failure in the failure zone, as well as the static performance of the optimized structure, the authors determined an optimized structure for the wind turbine jacket with fail-safe design. This structure maintains good stability even in the presence of partial damage. However, this structural design primarily optimizes the arrangement of connecting rods and does not utilize topology optimization methods, leaving room for improvement.

[0007] Compared with structures subjected to static loads, structures subjected to dynamic loads are more likely to experience local failure. Therefore, it is necessary to consider failure-safe design in the optimization of structures subjected to dynamic loads to ensure their performance in the event of local failure to prevent greater losses and provide more safety redundancy. Summary of the Invention

[0008] The content of the present invention is to fully consider the possible local failure of the structure under the dynamic load condition of the structure, improve the performance of the structure when local failure occurs under dynamic load, and achieve lightweight structure of the carrier equipment.

[0009] The present invention discloses a method for optimizing a design of a fail-safe topology under dynamic load, which comprises the following steps:

[0010] Step 1, define the design domain and design parameters of the structure;

[0011] Step 2, perform transient dynamic analysis on the structure;

[0012] Step 3: Calculate the equivalent static load of the dynamic load based on the control equation;

[0013] Step 4: Perform failure-safe topology optimization design on the model under equivalent static load;

[0014] The following steps are involved:

[0015] Step 41, designing a fail-safe topology optimization model;

[0016] Step 42, using a damage group method to divide the cantilever beam into local failure conditions;

[0017] Step 43, taking minimizing the maximum flexibility of the structure under local failure as the optimization goal;

[0018] Step 44, obtaining the sensitivity of the optimization target, and using the moving asymptote method to iteratively optimize the design variable unit density until the inner loop fail-safe topology optimization process is completed;

[0019] Step 5: Determine whether the outer loop convergence condition is met based on the updated design variables after fail-safe topology optimization.

[0020] Furthermore, in step 1, the structure is a cantilever beam, one end of the cantilever beam is fixed, and a dynamic load is applied to the midpoint of the other end. During the design process, the boundary of the end applied with the dynamic load is set as a failure-free area.

[0021] Furthermore, in step 2, a transient dynamic analysis is performed on the structure, and the governing dynamic equation is:

[0022]

[0023] x represents the design variable unit density; M(x) represents the structural mass matrix, C(x) represents the structural damping matrix, K(x) represents the structural stiffness matrix, and the three matrices are related to the unit density and change with the change of unit density. F(t) represents the dynamic load on the structure, and u represents the displacement. represents acceleration, Indicates speed.

[0024] Furthermore, in step 3, the equivalent static load of the dynamic load is:

[0025]

[0026] Where K(x) is the stiffness matrix of the structure, is the displacement at moment i under dynamic load;

[0027] Take the displacement calculation at n moments to obtain n sets of equivalent static loads, and then take the average of the obtained n sets of data to obtain the final set of equivalent static loads:

[0028]

[0029] F eq is the final equivalent static load;

[0030] The obtained equivalent static load is applied to the original model for subsequent topology optimization design.

[0031] Furthermore, in step 41, the optimization model is described as:

[0032] Findx=[x1,x2,...,x N ]

[0033] min f=max c i (x)i=1…m

[0034] stV / V0≤v0

[0035] xmin ≤x≤1

[0036] Ku=F eq

[0037] Where x represents the design variable unit density; N represents the number of units; f represents the objective function: the maximum flexibility of the structure under local failure conditions, c i (x) represents the flexibility of the structure under the i-th local failure scenario, m represents the number of local failure scenarios, v0 represents the optimized volume fraction constraint, and the ratio of the final optimized structure volume to the volume before optimization should be less than this value; x min represents the minimum unit density; K is the stiffness matrix of the structure; F eq is the equivalent static load.

[0038] Furthermore, in step 42, the definition of the local failure scenario is:

[0039]

[0040] E i represents the elastic modulus of unit i, E min represents the elastic modulus of the failure zone, ρ i represents the pseudo density of element i, p represents the material interpolation penalty factor, N represents the design domain, F represents the local failure region, and E0 represents the material elastic modulus;

[0041] For the units in the failure area, the damage group method is used to divide the local failure conditions of the cantilever beam, and the square damage is spread across the entire design domain, and the damage areas do not overlap with each other. On this basis, more possible damage is considered and the damage is translated diagonally. The horizontal and vertical translation distances are L / 2, where L is the preset size of the local failure, and the local damage beyond the damage domain is removed.

[0042] Furthermore, in step 43, the maximum compliance under local failure conditions is minimized as the optimization objective:

[0043] min:f=max c(x)

[0044] f represents the objective function, i.e., the maximum flexibility of the structure under local failure conditions, and c(x) represents the structural flexibility. Using the KS function in the aggregation function, the optimization objective function is transformed into:

[0045]

[0046] Where γ is the regularization parameter, and γ is selected f0 is the same order of magnitude of flexibility, c i (x) is the flexibility of the structure under the i-th local failure scenario.

[0047] Furthermore, in step 44, the sensitivity of the objective function is:

[0048]

[0049] in,

[0050] The moving asymptote method is used to iteratively optimize the design variable unit density, and the failure-safe topology optimization design is performed on the model with equivalent static load. The local failure scenario defined in step 41 is applied to the structure to obtain the flexibility sensitivity information under each failure scenario. The sensitivity of the optimization objective function is thus obtained, and the failure-safe topology optimization design of the structure is realized, which enhances the redundancy of the structure so that it can still maintain a certain stiffness in the case of local failure.

[0051] Furthermore, in step 44, after optimization, it is determined whether the updated design variables meet the convergence condition. In this case, the convergence condition is that the change in flexibility before and after structural optimization is less than 0.1%. The updated element density is applied to the original structure to obtain a new optimized structure, and the flexibility of the structure is recalculated. The flexibility of the structure is as follows:

[0052] c(x)=U T K(x)U

[0053] Where U is the displacement, K(x) is the structural stiffness matrix, which is related to the element density;

[0054] The structural flexibility at the unit density after the topology optimization update is compared with the structural flexibility at the unit density before the topology optimization update. If the change in flexibility between the optimized structure and the unoptimized structure is less than 0.1%, the inner loop fail-safe topology optimization process is terminated.

[0055] Furthermore, in step 5, based on the updated design variable unit density, it is determined whether the optimization meets the outer loop convergence condition. Here, the convergence condition is that the flexibility change between the structure when constructing the equivalent static load and the structure after optimization under the equivalent static load is less than 0.1%. The updated unit density in step 4 is applied to the original structure to obtain the optimized new structure, and the dynamic analysis of the structure is performed again. If the flexibility change between the optimized structure and the structure when constructing the equivalent static load is greater than 0.1%, then return to step 2, re-perform the dynamic analysis based on the updated structure, construct a new equivalent static load, and perform the failure-safe topology optimization design in step 4 under the new equivalent static load; if the flexibility change between the optimized structure and the structure when constructing the equivalent static load before optimization is less than 0.1%, then the outer loop failure-safe topology optimization process under dynamic and static loads is terminated, and the result obtained is the optimal dynamic load failure-safe topology optimization result.

[0056] The beneficial effects achieved by the present invention are:

[0057] This invention improves the performance of structures under dynamic load conditions. It fully considers the potential for localized failures during the design process, improving their performance in these conditions. By converting the dynamic loads under the original conditions into static loads using the equivalent static load method, the optimization process is effectively improved in terms of computational efficiency. The optimized structure according to this invention exhibits strong stiffness under dynamic loads, maintaining performance even in the event of localized failures, with minimal stiffness loss and high safety redundancy. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 is a flow chart of the fail-safe topology optimization design method under dynamic load implemented in the present invention;

[0059] Figure 2 The geometric parameters, boundary conditions and design domain division of the structure in the embodiment of the present invention;

[0060] Figure 3 It is a demonstration of local failure structure;

[0061] Figure 4 is the distribution of local failure areas of the structure in the embodiment of the present invention;

[0062] Figure 5 Design for topology optimization under dynamic loads;

[0063] Figure 6 The topology optimization design for dynamic load failure safety with damage size L = 0.005m;

[0064] Figure 7 This is the optimization result of the cantilever beam of the present invention with a preset local damage size of 0.02m. DETAILED DESCRIPTION

[0065] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as the description proceeds. However, these embodiments are merely exemplary and do not constitute any limitation to the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the technical solutions of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, and such modifications and replacements fall within the scope of protection of the present invention.

[0066] like Figure 1 As shown, the present invention provides a topology optimization design method that considers fail-safety under dynamic loads. This method rationally plans the distribution of materials within the design domain based on possible local failures within the design domain, taking into account the constraints set in the optimization problem. This achieves a safe and redundant design of the structure, improving its dynamic performance and structural performance under local failure conditions.

[0067] The method comprises the following steps:

[0068] Step 1: Define the design domain and design parameters of the structure;

[0069] Figure 2 This is an embodiment of the present invention. In this embodiment, the design domain of the structure is a cantilever beam with a length of 0.18m and a width of 0.06m. The left end of the cantilever beam is fixed, and a dynamic load is applied to the midpoint of the right end. The load size is Since a load is applied to the right boundary, the right boundary is set as a non-failure domain during the design process, as shown in the blue area in the figure. That is, the right boundary area will not fail in the fail-safe topology optimization.

[0070] Step 2: If Figure 1 As shown, the optimization design begins. Enter the outer loop to perform structural dynamic analysis and establish equivalent static loads. Perform transient dynamic analysis on the structure, and the dynamic control equation is as follows:

[0071]

[0072] x represents the design variable unit density; M(x) represents the structural mass matrix, C(x) represents the structural damping matrix, K(x) represents the structural stiffness matrix, and the three matrices are related to the unit density and change with the change of unit density. F(t) represents the dynamic load on the structure, and u represents the displacement. represents acceleration, Indicates speed.

[0073] Step 3: According to the control equation, the displacement at the i-th moment under dynamic load can be obtained Based on this displacement, the equivalent static load of the dynamic load can be calculated as:

[0074]

[0075] Where K(x) is the stiffness matrix of the structure, which is related to the element density.

[0076] It can be seen that in order to optimize the dynamic performance of the structure during the whole process, the displacement at n moments can be calculated to obtain n sets of equivalent static loads, and then the average of the obtained n sets of data is taken to obtain the final set of equivalent static loads.

[0077]

[0078] The obtained equivalent static load is applied to the original model for subsequent topology optimization design, and the structure is transformed from the original optimization problem under dynamic load to a static problem.

[0079] Step 4: Use equivalent static loads to replace the dynamic loads of the original structure, and perform failure-safe topology optimization design on the model with equivalent static loads.

[0080] The optimization goal is to minimize the maximum flexibility of the structure under local failure conditions and achieve a fail-safe optimal design of the structure. The specific steps include:

[0081] Step 41, designing a fail-safe topology optimization model;

[0082] The optimization problem is described as:

[0083] Findx=[x1,x2,...,x N ]

[0084] min f = maxc i (x)i=1…m

[0085] stV / V0≤v0

[0086] x min ≤x≤1

[0087] Ku=F eq

[0088] x represents the design variable unit density; N represents the number of units; f represents the objective function: the maximum flexibility of the structure under local failure conditions, c i (x) represents the flexibility of the structure under the i-th local failure scenario, m represents the number of local failure scenarios, v0 represents the optimized volume fraction constraint, and the ratio of the final optimized structure volume to the volume before optimization should be less than this value; x min represents the minimum unit density; K is the stiffness matrix of the structure; F eq is the equivalent static load.

[0089] Step 42, it is necessary to define each local failure scenario and introduce it into the optimization design;

[0090] To achieve fail-safe topology optimization design, it is first necessary to define each local failure scenario and introduce it into the optimization design. The definition of the local failure scenario is as follows:

[0091]

[0092] E i represents the elastic modulus of unit i, E min represents the elastic modulus of the failure region, ρ i represents the pseudo density of element i, p represents the material interpolation penalty factor, N represents the design domain, F represents the local failure region, and E0 represents the material elastic modulus.

[0093] It can be seen from the formula that for the elements outside the failure area in the design domain, their elastic modulus is related to the element density; for the elements in the failure area, their elastic modulus will be equal to E min In finite element analysis, the failure area will appear as a state where no material exists, and local failure occurs in the area resulting in material loss, such as Figure 3 shown.

[0094] In the embodiment, the preset size of local failure is L, which represents the square damage with a side length of L considered in the optimization design process. Here, the damage group method is used to divide the local failure of the cantilever beam. First, the square damage is spread across the entire design domain, and the damage areas do not overlap with each other. On this basis, considering more possible damage, the damage is translated diagonally, with a horizontal and vertical translation distance of L / 2, and the local damage outside the damage domain is removed. The damage division diagram is shown as follows: Figure 4 shown.

[0095] Step 43, taking minimizing the maximum flexibility of the structure under local failure as the optimization goal;

[0096] From the description of the local failure scenario, it can be seen that the structure has multiple local failure conditions. In the embodiment, the optimization goal is to minimize the maximum flexibility of the structure under local failure conditions, which can be expressed as:

[0097] min:f=max c i (x)i=1…m

[0098] The objective function f is a discrete function, which is difficult to optimize directly. It needs to be converted into a continuous function to achieve subsequent optimization. The aggregation function is an important tool in structural optimization. It can be used to approximate the max function. It has the characteristics of being differentiable and is very suitable for the transformation of the objective function here. Here, the KS function in the aggregation function is used, and the objective function will be converted into:

[0099]

[0100] Where γ is the regularization parameter, and its value determines the degree of approximation between the approximate function and the maximum value in the original data set. The larger the value, the greater the peak weight of the function. However, too large a value will lead to oscillation of the optimization iteration process. The recommended value here is Where f0 is the same order of magnitude of flexibility.

[0101] Step 44, obtaining the sensitivity of the optimization target, and using the moving asymptote method to iteratively optimize the design variable unit density until the inner loop fail-safe topology optimization process is completed;

[0102] For the objective function, its sensitivity is:

[0103]

[0104] After calculating the sensitivity information, the moving asymptote method is used to optimize the design variable unit density iteratively to achieve Figure 1 In the optimization cycle process in the inner loop, the failure-safe topology optimization design is performed on the model with equivalent static load. The local failure scenarios defined in step 41 are applied to the structure to obtain the flexibility sensitivity information under each failure scenario. The sensitivity of the optimization objective function is thus obtained, and the failure-safe topology optimization design of the structure is realized, which enhances the redundancy of the structure so that it can still maintain a certain stiffness in the case of local failure.

[0105] After achieving the optimized design, determine whether the updated design variables meet the convergence conditions. In this case, the convergence condition is that the change in flexibility before and after structural optimization is less than 0.1%. Apply the updated element density to the original structure to obtain the optimized new structure, and recalculate the flexibility of the structure. The flexibility of the structure is as follows:

[0106] c(x)=U T K(x)U

[0107] Where U is the displacement and K(x) is the structural stiffness matrix, which is related to the element density. The structural flexibility at the element density after the topology optimization update is compared with the structural flexibility at the element density before the topology optimization update. If the change in flexibility between the optimized structure and the pre-optimization structure is less than 0.1%, the inner loop fail-safe topology optimization process is terminated.

[0108] Step 5: After achieving the fail-safe topology optimization, the design variable unit density updated in the inner loop is obtained, thereby obtaining the structural optimization design under the equivalent static load, and realizing an outer loop.

[0109] Based on the updated design variable unit density, determine whether the optimization meets the outer loop convergence condition. Here, the convergence condition is that the flexibility change between the structure when constructing the equivalent static load and the structure after optimization under the equivalent static load is less than 0.1%. Apply the updated unit density in step 4 to the original structure to obtain the optimized new structure, and re-perform the dynamic analysis of the structure. If the flexibility change between the optimized structure and the structure when constructing the equivalent static load is greater than 0.1%, return to step 2, re-perform the dynamic analysis based on the updated structure, construct a new equivalent static load, and perform the failure-safe topology optimization design in step 4 under the new equivalent static load. If the flexibility change between the optimized structure and the structure before the optimization when constructing the equivalent static load is less than 0.1%, the outer loop failure-safe topology optimization process under dynamic and static loads is terminated, and the result obtained is the optimal dynamic load failure-safe topology optimization result.

[0110] Figure 5 The dynamic load topology optimization design results are given. Figure 6 、 Figure 7 The dynamic load failure safety topology optimization design results obtained according to the above steps are given and explained below.

[0111] Figure 6 The optimization results of the cantilever beam with a preset local damage size of 0.005m are given by this method. The target volume fraction is 40% of the design domain. After finite element calculation, it can be obtained Figure 6 When the structure is damaged by a square with a side length of 0.005m as set in the optimization design, the maximum flexibility of the structure is 0.00829. Figure 5 The maximum flexibility of the structure is 0.0151. It can be seen that under dynamic load failure-safe topology optimization, the maximum flexibility value decreased by 45.1% when the structure suffered a square damage with a side length of 0.005m. The ability of the structure to resist failure was significantly improved. This comparison illustrates the importance of performing failure-safe topology optimization.

[0112] Figure 7 The optimization results of the cantilever beam with a preset local damage size of 0.02m are given by this method. The target volume fraction is Figure 2 40% of the design domain. After finite element calculation, we can get Figure 7 When the structure is damaged by a square with a side length of 0.02m as set in the optimization design, the maximum flexibility of the structure is 0.0117. Figure 5 The maximum flexibility of the structure is 0.112, Figure 6 The maximum structural flexibility is 0.184. Figure 7 When the structure is damaged by a square with a side length of 0.02m, its maximum flexibility is Figure 5 The structure decreased by 89.5% compared to Figure 6 The structural damage decreased by 93.6%. This shows that in the design process, different failure size settings will affect the results. In view of the local failure that may occur in actual working conditions, selecting the appropriate local damage size in the design will significantly improve the structure's ability to resist damage of the corresponding size and ensure the performance of the structure when local damage occurs.

[0113] The above are only specific steps of the present invention and do not constitute any limitation to the scope of protection of the present invention; any technical solutions formed by equivalent transformation or equivalent replacement fall within the scope of protection of the present invention; the parts not elaborated in detail in the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A method for optimizing the design of fail-safe topology under dynamic loads, characterized in that: The fail-safe topology optimization design method under dynamic load comprises the following steps: Step 1, define the design domain and design parameters of the structure; Step 2, perform transient dynamic analysis on the structure; Step 3: Calculate the equivalent static load of the dynamic load based on the control equation; Step 4: Perform failure-safe topology optimization design on the model under equivalent static load; The following steps are involved: Step 41, designing a fail-safe topology optimization model; Step 42, using a damage group method to divide the cantilever beam into local failure conditions; Step 43, taking minimizing the maximum flexibility of the structure under local failure as the optimization goal; Step 44, obtaining the sensitivity of the optimization target, and using the moving asymptote method to iteratively optimize the design variable unit density until the inner loop fail-safe topology optimization process is completed; Step 5: Determine whether the outer loop convergence condition is met based on the updated design variables after fail-safe topology optimization; In step 3, the equivalent static load of the dynamic load is: Where K(x) is the stiffness matrix of the structure, is the displacement at moment i under dynamic load; Take the displacement calculation at n moments to obtain n sets of equivalent static loads, and then take the average of the obtained n sets of data to obtain the final set of equivalent static loads: F eq is the final equivalent static load; Apply the obtained equivalent static load to the original model for subsequent topology optimization design; In step 41, the optimization model is described as: Find x=[x1,x2,...,x N ] min f=maxc i (x)i=1…m stV / V0≤v0 x min ≤x≤1 Ku=F eq Where x represents the design variable unit density; N represents the number of units; f represents the objective function: the maximum flexibility of the structure under local failure conditions, c i (x) represents the flexibility of the structure under the i-th local failure scenario, m represents the number of local failure scenarios, v0 represents the optimized volume fraction constraint, and the ratio of the final optimized structure volume to the volume before optimization should be less than this value; x min represents the minimum unit density; K is the stiffness matrix of the structure; F eq is the equivalent static load.

2. The fail-safe topology optimization design method under dynamic load according to claim 1, characterized in that: In step 1, the structure is a cantilever beam, one end of the cantilever beam is fixed, and a dynamic load is applied to the midpoint of the other end. During the design process, the boundary of the end applied with the dynamic load is set as a failure-free area.

3. The fail-safe topology optimization design method under dynamic load according to claim 1, characterized in that: In step 2, a transient dynamic analysis is performed on the structure, and the dynamic governing equation is: x represents the design variable unit density; M(x) represents the structural mass matrix, C(x) represents the structural damping matrix, K(x) represents the structural stiffness matrix, and the three matrices are related to the unit density and change with the change of unit density. F(t) represents the dynamic load on the structure, and u represents the displacement. represents acceleration, Indicates speed.

4. The fail-safe topology optimization design method under dynamic load according to claim 1, characterized in that: In step 42, the local failure scenario is defined as: E i represents the elastic modulus of unit i, E min represents the elastic modulus of the failure zone, ρ i represents the pseudo density of element i, p represents the material interpolation penalty factor, N represents the design domain, F represents the local failure region, and E0 represents the material elastic modulus; For the units in the failure area, the damage group method is used to divide the local failure conditions of the cantilever beam, and the square damage is spread across the entire design domain, and the damage areas do not overlap with each other. On this basis, more possible damage is considered and the damage is translated diagonally. The horizontal and vertical translation distances are L / 2, where L is the preset size of the local failure, and the local damage beyond the damage domain is removed.

5. The fail-safe topology optimization design method under dynamic load according to claim 1, characterized in that: In step 43, the optimization objective is to minimize the maximum compliance under local failure conditions: min:f=max c(x) f represents the objective function, i.e., the maximum flexibility of the structure under local failure conditions, and c(x) represents the structural flexibility. Using the KS function in the aggregation function, the optimization objective function is transformed into: Where γ is the regularization parameter, and γ is selected f0 is the same order of magnitude of flexibility, c i (x) is the flexibility of the structure under the i-th local failure scenario.

6. The fail-safe topology optimization design method under dynamic load according to claim 5, characterized in that: In step 44, the sensitivity of the objective function is: in, The moving asymptote method is used to iteratively optimize the design variable unit density, and the failure-safe topology optimization design is performed on the model with equivalent static load. The local failure scenario defined in step 41 is applied to the structure to obtain the flexibility sensitivity information under each failure scenario. The sensitivity of the optimization objective function is thus obtained, and the failure-safe topology optimization design of the structure is realized, which enhances the redundancy of the structure so that it can still maintain a certain stiffness in the case of local failure.

7. The fail-safe topology optimization design method under dynamic load according to claim 6, characterized in that: In step 44, after optimization, it is determined whether the updated design variables meet the convergence condition. In this case, the convergence condition is that the change in flexibility before and after structural optimization is less than 0.1%. The updated element density is applied to the original structure to obtain the optimized new structure, and the flexibility of the structure is recalculated. The flexibility of the structure is as follows: c(x)=U T K(x)U Where U is the displacement, K(x) is the structural stiffness matrix, which is related to the element density; The structural flexibility at the unit density after the topology optimization update is compared with the structural flexibility at the unit density before the topology optimization update. If the change in flexibility between the optimized structure and the unoptimized structure is less than 0.1%, the inner loop fail-safe topology optimization process is terminated.

8. The fail-safe topology optimization design method under dynamic load according to claim 1, characterized in that: In step 5, based on the updated design variable unit density, it is determined whether the optimization meets the outer loop convergence condition. Here, the convergence condition is that the flexibility change between the structure when constructing the equivalent static load and the structure after optimization under the equivalent static load is less than 0.1%. The updated unit density in step 4 is applied to the original structure to obtain the optimized new structure, and the dynamic analysis of the structure is performed again. If the flexibility change between the optimized structure and the structure when constructing the equivalent static load is greater than 0.1%, return to step 2, re-perform the dynamic analysis based on the updated structure, construct a new equivalent static load, and perform the failure-safe topology optimization design in step 4 under the new equivalent static load; if the flexibility change between the optimized structure and the structure when constructing the equivalent static load before optimization is less than 0.1%, the outer loop failure-safe topology optimization process under dynamic and static loads is terminated, and the result obtained is the optimal dynamic load failure-safe topology optimization result.

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