Equipment transportation vibration fatigue evaluation method and system considering structural nonlinearity, storage medium and terminal

Abstract

The invention discloses an equipment transportation vibration fatigue evaluation method and system considering structural nonlinearity, a storage medium and a terminal, and belongs to the field of equipment transportation vibration fatigue analysis, and the method mainly comprises the steps: carrying out the quick calculation of key point response through a modal synthesis method condensation model, and determining a fatigue danger structure; equipment vibration load spectrums of multiple transportation modes are determined according to a vibration test control strategy with valley control or response limit values; establishing an equation of external load and dangerous section stress by considering structural nonlinearity; accumulative damage is obtained through a three-interval method and a maximum envelope method, and whether the equipment design state meets various transportation vibration environment requirements or not is evaluated. According to the method, the problems of equipment load spectrum analysis and stress amplitude and cumulative damage calculation of a nonlinear fatigue dangerous structure in various transportation environments are solved, the cumulative damage of the fatigue dangerous structure of the equipment can be quickly obtained, and the adaptability of the equipment in various transportation vibration environments can be evaluated.

Description

Technical Field

[0001] The present invention relates to the field of equipment transportation vibration fatigue analysis, and in particular to an equipment transportation vibration fatigue assessment method, system, storage medium and terminal taking into account structural nonlinearity. Background Art

[0002] With the continuous improvement of the actual combat requirements of weapons and equipment, the equipment should be able to meet multiple modes of transportation such as road transportation, field transportation, rail transportation, air transportation and water transportation at the same time. In the context of the continuous increase in the weight and size of weapons and equipment, the complex and long-term vibration environment brought by various modes of transportation may cause resonance and structural fatigue problems, which may further lead to safety problems such as failure of connection structures and loss of constraints on components. At the same time, there are many other design constraints in the weak links of the structure of weapons and equipment, and there are design contradictions with the fatigue strength of the structure. For example, in order to meet the requirements of low flight aerodynamic resistance, the windward structural dimensions of the structures such as the slider and the fixing button of the flight product should be as small as possible; in order to realize the launch unlocking function, and under the design constraints of low launch overload and impact, the fracture load of the connection structure should be as small as possible. The above requirements have greatly limited the transportation vibration fatigue life of the weak links of the structure.

[0003] At present, the stress of the weak links of the structure can be obtained through structural dynamics simulation and used for life assessment. However, due to the complexity of the transport vibration load spectrum and the difficulty in modeling the transfer characteristics of the connection structure, structural dynamics simulation often cannot take into account the nonlinear effects of the structure, and the accuracy of obtaining fatigue life is limited and the iterative calculation efficiency is low. On the other hand, under the constraints of the heavy weight and long size of the equipment, it is often necessary to use multiple vibrations to carry out transport vibration tests. The test is difficult to implement and the cycle is long, and it is impossible to effectively carry out the design and evaluation of the equipment's transport environment adaptability in the early design stage. Summary of the invention

[0004] The purpose of the present invention is to overcome the technical problems existing in the prior art and to provide a method, system, storage medium and terminal for equipment transportation vibration fatigue assessment taking into account structural nonlinearity, which solves the problems of equipment load spectrum analysis, stress amplitude and cumulative damage calculation of nonlinear fatigue hazardous structures under various transportation environments, and can quickly obtain the cumulative damage of equipment fatigue hazardous structures and evaluate the adaptability of equipment in various transportation vibration environments.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] In a first aspect, a method for evaluating equipment transportation vibration fatigue considering structural nonlinearity is provided, comprising the following steps:

[0007] S1. Establish the finite element model of the equipment, perform model reduction through modal synthesis method, calculate the key point response and determine the fatigue risk structure;

[0008] S2. Calculate the equipment mode and determine the first-order frequency and the highest frequency of the main mode;

[0009] S3. Determine the transport vibration conditions of various transport modes and determine the equipment vibration load spectrum according to the vibration test control strategy with valley control or response limit;

[0010] S4. Consider the influence of structural nonlinearity, conduct stress analysis on fatigue-hazardous structures, and establish equations between external loads and stress of hazardous sections;

[0011] S5. Calculate the damage of the equipment under the vibration load spectrum of different transportation modes one by one, and evaluate the adaptability of the equipment to the transportation vibration environment based on the cumulative damage.

[0012] In some embodiments, step S1 specifically includes:

[0013] By dividing the equipment into substructures, the finite element models of the substructures are established respectively, and the mass matrix M of the substructure in its local coordinate system is extracted. b , the damping matrix C b and the stiffness matrix K b , the structural dynamics equations of the constituent substructures are:

[0014]

[0015] According to the modal synthesis method, the substructure is condensed by solving the assumed modal set to obtain the dynamic equation of the mixed coordinate system:

[0016]

[0017] Where X p Represents mixed coordinates. According to the number of a certain substructure, the coordinate transformation relationship in another substructure and the displacement coordination condition of the connection interface, the dynamic equation of the mixed coordinate system is secondary condensed to obtain the independent modal coordinate dynamic equation with lower degrees of freedom:

[0018]

[0019] Where X q Represents independent modal coordinates, and selects a typical transport vibration power spectrum or frequency spectrum as the input force F of the system q Perform vibration response analysis, calculate key point responses based on the transformation relationship between physical coordinates and independent modal coordinates, obtain stress cloud diagrams under physical coordinates, select stress concentration areas based on the residual strength coefficient of metal materials and the TsaiH coefficient of non-metallic materials, and determine fatigue-hazardous structures, where the TsaiH coefficient is a strength verification value obtained based on the Tsai-Hill strength theory.

[0020] In some embodiments, step S2 specifically includes:

[0021] Solve the eigenvalues ​​and eigenvectors of the equipment's independent modal coordinate dynamics equations to obtain the overall modal frequency and vibration shape; determine the main modal first-order frequency f1 according to the lowest modal frequency with a modal effective mass ratio of more than 10%; calculate the cumulative modal effective mass ratio in order from low to high modal frequencies, and when the highest-order frequency with a cumulative modal effective mass ratio of more than 90% is determined as the main modal highest frequency f m .

[0022] In some embodiments, step S3 specifically includes:

[0023] According to the transportation mode and transportation mileage requirements, the measured data shall be used as the transportation vibration conditions in priority; if the measured data are not available, the transportation vibration conditions can be determined according to GJB150.16A;

[0024] According to the vibration test control strategy with valley control and response limit in the transport vibration test, the frequency band of the equipment vibration load spectrum is obtained.

[0025] Preferably, the transportation modes include road transportation, field transportation, railway transportation, air transportation and water transportation.

[0026] Preferably, the vibration load spectrum is in [f1,f m ] frequency band is +6dB of vibration test condition; in [f m ,2f m ] frequency band is 0dB of vibration test condition, at 2f m The above frequency band is 0.

[0027] In some embodiments, the equation of the external load and the critical section stress σ in step S4 is as follows:

[0028] σ=σ1+σ2

[0029]

[0030] Where d1 represents the maximum structural gap caused by tolerance, s represents the minimum dangerous cross-sectional area, F represents axial force, M represents bending moment, σ1 and σ2 represent the normal stress of the dangerous cross-sectional area caused by axial force and bending moment, Δx and Δy represent the displacement in the direction of axial force and bending moment, F0 represents the equivalent axial force caused by the installation preload, and K s is the stress concentration factor, b1, c1, a2, b2, c2 are fitting parameters.

[0031] In some embodiments, step S5 specifically includes:

[0032] Calculate the damage caused by broadband random vibration by three-interval method;

[0033] Determine the damage of sine swept / fixed frequency vibration by the maximum envelope method;

[0034] Calculate the cumulative damage and evaluate the equipment's adaptability to the transport vibration environment. If the cumulative damage does not exceed 0.1, the fatigue hazardous structure is judged to meet the requirements of the transport vibration environment.

[0035] In the second aspect, a vibration fatigue assessment system for equipment transportation considering structural nonlinearity is provided, comprising:

[0036] The fatigue hazardous structure determination module is used to establish the finite element model of the equipment, perform model reduction through the modal synthesis method, calculate the key point response and determine the fatigue hazardous structure;

[0037] Modal calculation module, used to calculate the equipment mode and determine the first-order frequency and the highest frequency of the main mode;

[0038] Equipment vibration load spectrum determination module, used to determine the transport vibration conditions of various transport modes, and determine the equipment vibration load spectrum according to the vibration test control strategy with valley control or response limit;

[0039] The stress analysis module is used to consider the nonlinear effects of the structure, perform stress analysis on fatigue-hazardous structures, and establish equations for external loads and stresses of hazardous sections;

[0040] The equipment transportation vibration environment adaptability analysis module is used to calculate the damage of equipment under the vibration load spectrum of different transportation modes one by one, and evaluate the equipment's transportation vibration environment adaptability based on the cumulative damage.

[0041] In a third aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, any one of the equipment transportation vibration fatigue assessment methods is implemented.

[0042] In a fourth aspect, an electronic device is provided, comprising a memory and a processor, wherein the memory stores computer instructions executable on the processor, and wherein the processor executes any one of the equipment transport vibration fatigue assessment methods when executing the computer instructions.

[0043] It should be further explained that the technical features corresponding to the above options can be combined or replaced with each other to form a new technical solution if there is no conflict.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] (1) The present invention uses the modal synthesis method to condense the model to quickly calculate the key point response and determine the fatigue dangerous structure; determine the equipment vibration load spectrum of various transportation modes according to the vibration test control strategy with valley control or response limit; consider the structural nonlinearity to establish the equation of external load and dangerous section stress; obtain the cumulative damage through the three-interval method and the maximum envelope method, and evaluate whether the equipment design state meets the requirements of various transportation vibration environments. It solves the problems of equipment load spectrum analysis, stress amplitude and cumulative damage calculation of nonlinear fatigue dangerous structures under various transportation environments, and can quickly obtain the cumulative damage of equipment fatigue dangerous structures and evaluate the adaptability of equipment in various transportation vibration environments.

[0046] (2) In some examples, in terms of fatigue hazardous structure identification, compared with finite element method, the present invention improves the efficiency of fatigue hazardous structure identification by performing model reduction through modal synthesis method; and can achieve rapid iteration by replacing substructure models, which has strong application value in the iterative design process at the scheme stage.

[0047] (3) In some examples, in terms of fatigue calculation of dangerous structures, compared with existing fatigue calculation methods, the present invention fully considers the influence of structural nonlinearity on the stress of dangerous sections, improves the calculation accuracy of equivalent cyclic stress and cumulative damage, and ultimately improves the accuracy of equipment transportation vibration fatigue assessment.

[0048] (4) In some examples, in terms of transport vibration fatigue assessment, compared with existing transport vibration fatigue assessment methods, the present invention can comprehensively assess the cumulative damage of various transport modes and vibration types and equipment transport vibration fatigue, and has a wider range of application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is an overall flow chart of a method for evaluating equipment transportation vibration fatigue taking into account structural nonlinearity, shown in an embodiment of the present invention;

[0050] Figure 2 A flow chart of a method for evaluating equipment transportation vibration fatigue taking into account structural nonlinearity, shown in an embodiment of the present invention;

[0051] Figure 3 A schematic diagram of equipment substructure division shown in an embodiment of the present invention;

[0052] Figure 4 A schematic diagram of a fatigue hazard structure shown in an embodiment of the present invention;

[0053] Figure 5 The air transport vibration conditions and vibration load spectrum shown in the embodiment of the present invention;

[0054] Figure 6 The stress concentration factor simulation result shown in the embodiment of the present invention;

[0055] Figure 7 The bending moment and bending normal stress fitting curve shown in the embodiment of the present invention;

[0056] Figure 8 A typical material SN curve shown for an embodiment of the present invention. DETAILED DESCRIPTION

[0057] The technical solution of the present invention is clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the accompanying drawings can be arranged and designed in various configurations. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0058] It should be noted that the defects existing in the solutions in the above-mentioned prior art are the results obtained by the inventor after practice and careful research. Therefore, the discovery process of the above-mentioned problems and the solutions proposed in the embodiments of the present application for the above-mentioned problems below should all be the contributions made by the inventor to the present application in the process of invention and creation, and should not be understood as technical contents known to technical personnel in this field.

[0059] In view of the technical problems pointed out in the background technology, the embodiments provided by the present invention are as follows:

[0060] Example 1

[0061] Reference Figure 1 In an exemplary embodiment, a method for evaluating equipment transportation vibration fatigue considering structural nonlinearity is provided, comprising the following steps:

[0062] S1. Establish the finite element model of the equipment, perform model reduction through modal synthesis method, calculate the key point response and determine the fatigue risk structure;

[0063] S2. Calculate the equipment mode and determine the first-order frequency and the highest frequency of the main mode;

[0064] S3. Determine the transport vibration conditions of various transport modes and determine the equipment vibration load spectrum according to the vibration test control strategy with valley control or response limit;

[0065] S4. Consider the influence of structural nonlinearity, conduct stress analysis on fatigue-hazardous structures, and establish equations between external loads and stress of hazardous sections;

[0066] S5. Calculate the damage of the equipment under the vibration load spectrum of different transportation modes one by one, and evaluate the adaptability of the equipment to the transportation vibration environment based on the cumulative damage.

[0067] Specifically, the implementation process of step S1 is as follows:

[0068] By dividing the equipment into substructures, the finite element models of the substructures are established respectively, and the mass matrix M of the substructure in its local coordinate system is extracted. b , the damping matrix C b and the stiffness matrix K b , the structural dynamics equations of the constituent substructures are:

[0069]

[0070] According to the modal synthesis method, the substructure is condensed by solving the assumed modal set to obtain the dynamic equation of the mixed coordinate system:

[0071]

[0072] Where X p Represents mixed coordinates. According to the number of a certain substructure, the coordinate transformation relationship in another substructure and the displacement coordination condition of the connection interface, the dynamic equation of the mixed coordinate system is secondary condensed to obtain the independent modal coordinate dynamic equation with lower degrees of freedom:

[0073]

[0074] Where X q Represents independent modal coordinates, and selects a typical transport vibration power spectrum or frequency spectrum as the input force F of the system q Perform vibration response analysis, calculate key point responses based on the transformation relationship between physical coordinates and independent modal coordinates, obtain stress cloud maps under physical coordinates, select stress concentration areas based on the residual strength coefficient of metal materials and the TsaiH coefficient of non-metallic materials, and determine fatigue-hazardous structures. Among them, the TsaiH coefficient is a strength verification value obtained based on the Tsai-Hill strength theory. The Tsai-Hill strength theory is based on the Von-Mises deformation energy yield criterion, which links the destruction of unidirectional composite materials with the tensile and compressive strength of the material in the longitudinal, transverse and thickness directions of the fibers, as well as the shear strength between layers and within the surface, to form a strength theory formula. The calculation of this coefficient is a prior art and will not be described in detail here.

[0075] The implementation process of step S2 is as follows:

[0076] Solve the eigenvalues ​​and eigenvectors of the equipment's independent modal coordinate dynamics equations to obtain the overall modal frequency and vibration shape; determine the main modal first-order frequency f1 according to the lowest modal frequency with a modal effective mass ratio of more than 10%; calculate the cumulative modal effective mass ratio in order from low to high modal frequencies, and when the highest-order frequency with a cumulative modal effective mass ratio of more than 90% is determined as the main modal highest frequency f m .

[0077] The implementation process of step S3 is as follows:

[0078] According to the requirements of transportation mode and transportation mileage, measured data shall be used as transportation vibration conditions in priority. When measured data are not available, the transportation vibration conditions can be determined according to the national vibration test standard GJB150.16A (Part 16: Vibration Test for Laboratory Environmental Test Methods for Military Equipment). The vibration conditions for road transportation and field transportation refer to Appendix A2.2.2~A2.2.4; the vibration conditions for railway transportation refer to Appendix A2.2.9; the vibration conditions for air transportation refer to Appendix A2.2.5~A2.2.7; and the vibration conditions for water transportation refer to Appendix A2.2.8.

[0079] According to the vibration test control strategy with valley control and response limit used in the transport vibration test, it can be determined that the equipment m ] frequency band vibration response does not exceed the vibration condition +6dB; according to the modal superposition principle, it can be determined that the equipment in [f m ,2f m ] The vibration response of the frequency band is 0dB of the vibration condition, at 2f m The vibration response in the above frequency band is obviously attenuated, so the vibration response in this frequency band is ignored.

[0080] According to the vibration conditions and the above response characteristics, the frequency band can be obtained as [f1,2f m ]’s equipment vibration load spectrum.

[0081] The implementation process of step S4 is as follows:

[0082] Considering the influence of structural nonlinearity, the geometric model of fatigue dangerous structure is established according to the maximum structural gap d1 and the minimum dangerous cross-sectional area s caused by tolerance, and the maximum deformation d2 is determined according to the structural limit. Combining theoretical analysis and finite element method, the relationship between external loads under typical loads such as axial force F and bending moment M and dangerous cross-sectional stress σ is analyzed:

[0083] σ=σ1+σ2

[0084]

[0085] Among them, σ1 and σ2 represent the normal stress of the dangerous section caused by axial force and bending moment, Δx and Δy represent the displacement in the direction of axial force and bending moment, F0 is the equivalent axial force caused by the installation preload, K s is the stress concentration factor, b1, c1, a2, b2, c2 are fitting parameters.

[0086] The implementation process of step S5 is as follows:

[0087] The vibration load spectrum of the equipment can be divided into two types: broadband random vibration and sinusoidal swept frequency / fixed frequency vibration. The damage of the two types of load spectra can be calculated separately as follows.

[0088] Among them, the damage caused by broadband random vibration is calculated by the three-interval method:

[0089] The maximum cyclic axial force and maximum cyclic bending moment are determined by the total root mean square value of the acceleration of the equipment vibration load spectrum, the fatigue dangerous structure bearing mass, and the maximum bending displacement; the stress amplitude σ of the root mean square stress is calculated based on the relationship between the external load and the dangerous section stress. a and the mean stress σ m ; Calculate the equivalent cyclic load σ of the root mean square stress according to the Goodman formula -1 :

[0090]

[0091] where σ b is the yield limit of the material.

[0092] Calculation of damage D caused by broadband random vibration based on the three-interval method and material SN curve i :

[0093]

[0094] in is the average vibration frequency, which can be generally calculated as Choose f for conservative calculations m ; T is the vibration time; 1σ -1 , 2σ -1 , 3σ -1 The number of cycles of the SN curve of the corresponding material under stress.

[0095] Determination of damage D of sine swept / fixed frequency vibration by maximum envelope method i :

[0096] The maximum cyclic axial force and maximum cyclic bending moment are determined by the maximum amplitude fatigue dangerous structure bearing mass and maximum bending displacement of the equipment vibration load spectrum; the stress amplitude σ under the maximum amplitude is calculated according to the relationship between the external load and the dangerous section stress a and the mean stress σ m ; Calculate the equivalent cyclic load σ at the maximum amplitude according to the Goodman formula -1 .

[0097] Calculate the damage D of sine sweep / fixed frequency vibration based on the material SN curve i :

[0098]

[0099] Finally, the cumulative damage D is calculated to evaluate the equipment's adaptability to the transportation vibration environment.

[0100] The cumulative damage can be calculated as follows:

[0101] D=ΣD i

[0102] Taking into account the influence of factors such as SN curve measurement error, vibration condition error, fatigue dispersion, etc., if the cumulative damage does not exceed 0.1, it is judged that the fatigue hazardous structure meets the transportation vibration environment requirements, that is, the equipment meets the vibration environment requirements of each mode of transportation.

[0103] Example 2

[0104] Reference Figure 2 , based on the inventive concept of Example 1, this example introduces the fatigue assessment method in detail according to specific equipment.

[0105] Step 1: Establish a finite element model of the equipment, reduce the model through modal synthesis method, calculate the key point response and determine the fatigue hazardous structure. Figure 3 A schematic diagram of the equipment substructure is given, and the dynamic equation of substructure 1 in its local coordinate system can be expressed as:

[0106]

[0107] According to the fixed interface modal synthesis method, the assumed modal set of substructure 1 consists of the main mode and the constraint mode. The solution method of the main mode and the constraint mode of substructure 1 is:

[0108]

[0109] Therefore, the assumed mode set of substructure 1 in its local coordinate system is:

[0110]

[0111] The dynamic equation of substructure 2 is:

[0112]

[0113] According to the same method, the hypothetical mode set of substructure 2 can be obtained as follows:

[0114]

[0115] The first coordinate transformation of the system's dynamic equation can condense the physical coordinates with higher degrees of freedom of the coupled system into hybrid coordinates with lower degrees of freedom, that is, the system's dynamic equation is:

[0116]

[0117] Introduce coordinate transformation relationship and interface displacement coordination condition:

[0118]

[0119] The dynamic equations expressed in independent modal coordinates with lower degrees of freedom are:

[0120]

[0121] Select the air transport vibration power spectrum as the input force F of the system q Perform vibration response analysis based on the transformation relationship between physical coordinates and modal coordinates:

[0122]

[0123] The vibration response at the corresponding position can be obtained.

[0124] The fatigue hazardous structure is identified through simulation as the connection structure of substructure 1 and substructure 2, see Figure 4 .

[0125] Step 2: Calculate the equipment mode and determine the first-order frequency and the highest frequency of the main mode.

[0126] Solve the eigenvalues ​​and eigenvectors of the equipment independent modal coordinate dynamics equation (9) to obtain the overall modal frequency and vibration shape. The first-order frequency f1 of the main modal is determined to be 15 Hz according to the lowest modal frequency with a modal effective mass ratio exceeding 10%; calculate the cumulative modal effective mass ratio in order from low to high modal frequencies, and when the highest-order frequency with a cumulative modal effective mass ratio exceeding 90% is determined as the highest frequency f of the main modal. m is 40Hz.

[0127] Step 3: Determine the transport vibration conditions of various transport modes, and determine the equipment vibration load spectrum based on the vibration test control strategy with valley control or response limit.

[0128] The typical transportation conditions of this equipment are road transportation and air transportation. For road transportation, the maximum envelope of the actual road transportation vibration power spectrum is selected as the road transportation vibration condition, and for air transportation, Appendix A2.2.5~A2.2.7 of GJB150.16A-2009 is selected as the air transportation vibration condition.

[0129] According to the vibration test control strategy with valley control and response limit used in the transport vibration test, it can be determined that the vibration response of the equipment in the [15,40]Hz frequency band does not exceed +6dB of the vibration condition; it can be determined that the vibration response of the equipment in the [40,80]Hz frequency band is 0dB of the vibration condition, and the vibration response in the frequency band above 80Hz is significantly attenuated, so the vibration response in this frequency band is ignored. Air transport vibration conditions and vibration load spectrum can be found in Figure 5 .

[0130] Step 4: Consider the influence of structural nonlinearity, conduct stress analysis on the fatigue-hazardous structure, and establish an equation for external load and stress of hazardous section.

[0131] Considering the influence of structural nonlinearity, the geometric model of fatigue dangerous structure is established according to the maximum structural gap d1 and the minimum dangerous cross-sectional area s caused by tolerance, and the maximum deformation d2 is determined according to the structural limit. Combining theoretical analysis and finite element method, the relationship between external loads under typical loads such as axial force F and bending moment M and dangerous cross-sectional stress σ is analyzed:

[0132] σ=σ1+σ2 (11)

[0133]

[0134] Among them, σ1 and σ2 represent the normal stress of the dangerous section caused by axial force and bending moment, Δx and Δy represent the displacement in the direction of axial force and bending moment, F0 is the equivalent axial force caused by the installation preload, K s is the stress concentration factor, b1, c1, a2, b2, c2 are fitting parameters.

[0135] By comparing the axial normal stress caused by the theoretical calculation and the finite element simulation, see Figure 6 , the stress concentration factor can be obtained as 1.2; by applying multiple bending moments and performing linear fitting and quadratic curve fitting by the least squares method, the bending normal stress fitting curve can be obtained, see Figure 7 .

[0136] Step 5: Calculate the damage D of the equipment under the vibration load spectrum of different transportation modes one by one i , evaluate the equipment’s adaptability to the transportation vibration environment based on the cumulative damage D.

[0137] The equipment is transported by road and air. The transport vibration of both modes is broadband random vibration. The three-interval method is used to calculate the damage caused by broadband random vibration. The maximum cyclic axial force and maximum cyclic bending moment are determined by the total root mean square value of the acceleration of the equipment vibration load spectrum, the fatigue dangerous structure bearing mass, and the maximum bending displacement; the stress amplitude σ of the root mean square stress is calculated based on the relationship between the external load and the dangerous section stress. a and the mean stress σ m ; Calculate the equivalent cyclic load σ of the root mean square stress according to the Goodman formula -1 :

[0138]

[0139] where σ b is the yield limit of the material.

[0140] Calculation of damage D caused by broadband random vibration based on the three-interval method and material SN curvei :

[0141]

[0142] in is the average vibration frequency, which can be generally calculated as Choose f for conservative calculations m ; T is the vibration time; 1σ -1 , 2σ -1 , 3σ -1 The number of cycles of the SN curve of the corresponding material under stress.

[0143] The road transport vibration and air transport vibration time are determined according to the road transport mileage and air transport take-off and landing times during the service life, and 40Hz is selected as the average vibration frequency based on conservative calculation. Figure 8 Given the SN curve of the material, the two transport vibration 1σ can be calculated -1 , 2σ -1 , 3σ -1 Table 1 gives the damage calculation results of the fatigue dangerous structure at the dangerous section.

[0144] Table 1 Results of dangerous structure transportation vibration fatigue analysis

[0145]

[0146]

[0147] Among them, the three-directional damage of road transport vibration is 0.0131, 0.0000 and 0.0045 respectively; the three-directional damage of air transport vibration is 0.0018, 0.0000 and 0.0000 respectively. The cumulative damage is 0.0194, which is less than 0.1. It is judged that the fatigue dangerous structure meets the requirements of the transportation vibration environment, that is, the equipment meets the vibration environment requirements of road transportation and air transportation during its service life.

[0148] Example 3

[0149] Based on the same inventive concept as that of Example 1, a system for evaluating equipment transportation vibration fatigue taking into account structural nonlinearity is provided, comprising:

[0150] The fatigue hazardous structure determination module is used to establish the finite element model of the equipment, perform model reduction through the modal synthesis method, calculate the key point response and determine the fatigue hazardous structure;

[0151] Modal calculation module, used to calculate the equipment mode and determine the first-order frequency and the highest frequency of the main mode;

[0152] Equipment vibration load spectrum determination module, used to determine the transport vibration conditions of various transport modes, and determine the equipment vibration load spectrum according to the vibration test control strategy with valley control or response limit;

[0153] The stress analysis module is used to consider the nonlinear effects of the structure, perform stress analysis on fatigue-hazardous structures, and establish equations for external loads and stresses of hazardous sections;

[0154] The equipment transportation vibration environment adaptability analysis module is used to calculate the damage of equipment under the vibration load spectrum of different transportation modes one by one, and evaluate the equipment's transportation vibration environment adaptability based on the cumulative damage.

[0155] It should be noted that each module of the system integrates the software and hardware corresponding to the functions of each step in the implementation method to achieve the same functions.

[0156] Example 4

[0157] Based on the same inventive concept as Example 1, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the equipment transportation vibration fatigue assessment method provided by the embodiment of the present invention is implemented. Based on such an understanding, the technical solution of this embodiment, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0158] Example 5

[0159] Based on the same inventive concept as Example 1, an electronic device is provided, including a memory and a processor, wherein the memory stores computer instructions that can be executed on the processor, and when the processor executes the equipment transportation vibration fatigue assessment method provided in the embodiment of the present invention, the computer instructions are executed.

[0160] The processor may be a single-core or multi-core central processing unit or a specific integrated circuit, or one or more integrated circuits configured to implement the present invention.

[0161] Embodiments of the subject matter and functional operations described in this specification may be implemented in: tangibly embodied computer software or firmware, computer hardware including the structures disclosed in this specification and their structural equivalents, or a combination of one or more of them. Embodiments of the subject matter described in this specification may be implemented as one or more computer programs, i.e., one or more modules of computer program instructions encoded on a tangible, non-transitory program carrier to be executed by a data processing device or to control the operation of the data processing device. Alternatively or additionally, the program instructions may be encoded on an artificially generated propagated signal, such as a machine-generated electrical, optical, or electromagnetic signal, which is generated to encode and transmit information to a suitable receiver device for execution by the data processing device.

[0162] The processes and logic flows described in this specification can be performed by one or more programmable computers executing one or more computer programs to perform corresponding functions by operating on input data and generating output. The processes and logic flows can also be performed by special purpose logic circuits, such as FPGAs (field programmable gate arrays) or ASICs (application-specific integrated circuits), and the apparatus can also be implemented as special purpose logic circuits.

[0163] Processors suitable for executing computer programs include, for example, general and / or special microprocessors, or any other type of central processing unit. Typically, the central processing unit will receive instructions and data from a read-only memory and / or a random access memory. The basic components of a computer include a central processing unit for implementing or executing instructions and one or more memory devices for storing instructions and data. Typically, the computer will also include one or more large-capacity storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks, or the computer will be operably coupled to this large-capacity storage device to receive data from it or to transmit data to it, or both. However, the computer does not necessarily have such a device. In addition, the computer can be embedded in another device, such as a mobile phone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a global positioning system (GPS) receiver, or a portable storage device such as a universal serial bus (USB) flash drive, just to name a few.

[0164] It should be understood that each box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a sequence different from that marked in the accompanying drawings. For example, two continuous boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs the specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0165] The above specific implementation methods are detailed descriptions of the present invention. It cannot be determined that the specific implementation methods of the present invention are limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions and substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for evaluating equipment transportation vibration fatigue considering structural nonlinearity, characterized in that: The following steps are involved: S1. Establish the finite element model of the equipment, perform model reduction through modal synthesis method, calculate the key point response and determine the fatigue risk structure; S2. Calculate the equipment mode and determine the first-order frequency and the highest frequency of the main mode; S3. Determine the transport vibration conditions of various transport modes and determine the equipment vibration load spectrum according to the vibration test control strategy with valley control or response limit; S4. Consider the influence of structural nonlinearity, conduct stress analysis on fatigue-hazardous structures, and establish equations between external loads and stress of hazardous sections; S5. Calculate the damage of the equipment under the vibration load spectrum of different transportation modes one by one, and evaluate the adaptability of the equipment to the transportation vibration environment based on the cumulative damage.

2. The equipment transportation vibration fatigue assessment method according to claim 1 is characterized in that: The step S1 specifically includes: By dividing the equipment into substructures, the finite element models of the substructures are established respectively, and the mass matrix M of the substructure in its local coordinate system is extracted. b , the damping matrix C b and the stiffness matrix K b , the structural dynamics equations of the constituent substructures are: According to the modal synthesis method, the substructure is condensed by solving the assumed modal set to obtain the dynamic equation of the mixed coordinate system: Where X p Represents mixed coordinates. According to the number of a certain substructure, the coordinate transformation relationship in another substructure and the displacement coordination condition of the connection interface, the dynamic equation of the mixed coordinate system is secondary condensed to obtain the independent modal coordinate dynamic equation with lower degrees of freedom: Where X q Represents independent modal coordinates, and selects a typical transport vibration power spectrum or frequency spectrum as the input force F of the system q Perform vibration response analysis, calculate key point responses based on the transformation relationship between physical coordinates and independent modal coordinates, obtain stress cloud diagrams under physical coordinates, select stress concentration areas based on the residual strength coefficient of metal materials and the TsaiH coefficient of non-metallic materials, and determine fatigue-hazardous structures, where the TsaiH coefficient is a strength verification value obtained based on the Tsai-Hill strength theory.

3. The equipment transportation vibration fatigue assessment method according to claim 2 is characterized in that: The step S2 specifically includes: Solve the eigenvalues ​​and eigenvectors of the equipment's independent modal coordinate dynamics equations to obtain the overall modal frequency and vibration shape; determine the main modal first-order frequency f1 according to the lowest modal frequency with a modal effective mass ratio of more than 10%; calculate the cumulative modal effective mass ratio in order from low to high modal frequencies, and when the highest-order frequency with a cumulative modal effective mass ratio of more than 90% is determined as the main modal highest frequency f m .

4. The equipment transportation vibration fatigue assessment method according to claim 1, characterized in that: The step S3 specifically includes: According to the transportation mode and transportation mileage requirements, the measured data shall be used as the transportation vibration conditions in priority; if the measured data are not available, the transportation vibration conditions can be determined according to GJB150.16A; According to the control strategy with valley control and response limit used in the transport vibration test, the equipment is obtained in [f1,2f m ] frequency band.

5. The equipment transportation vibration fatigue assessment method according to claim 4 is characterized in that: The vibration load spectrum is [f1,f m ] frequency band is +6dB of vibration test condition; in [f m ,2f m ] frequency band is 0dB of vibration test condition, at 2f m The above frequency band is 0.

6. The equipment transportation vibration fatigue assessment method according to claim 1, characterized in that: The equation of the external load and the dangerous section stress σ in step S4 is as follows: σ=σ1+σ2 Where d1 represents the maximum structural gap caused by tolerance, s represents the minimum dangerous cross-sectional area, F represents axial force, M represents bending moment, σ1 and σ2 represent the normal stress of the dangerous cross-sectional area caused by axial force and bending moment, Δx and Δy represent the displacement in the direction of axial force and bending moment, F0 represents the equivalent axial force caused by the installation preload, and K s is the stress concentration factor, b1, c1, a2, b2, c2 are fitting parameters.

7. The equipment transportation vibration fatigue assessment method according to claim 1, characterized in that: The step S5 specifically includes: Calculate the damage caused by broadband random vibration by three-interval method; Determine the damage of sine swept / fixed frequency vibration by the maximum envelope method; Calculate the cumulative damage and evaluate the equipment's adaptability to the transport vibration environment. If the cumulative damage does not exceed 0.1, the fatigue hazardous structure is judged to meet the requirements of the transport vibration environment.

8. An equipment transportation vibration fatigue assessment system considering structural nonlinearity, characterized in that: include: The fatigue hazardous structure determination module is used to establish the finite element model of the equipment, perform model reduction through the modal synthesis method, calculate the key point response and determine the fatigue hazardous structure; Modal calculation module, used to calculate the equipment mode and determine the first-order frequency and the highest frequency of the main mode; Equipment vibration load spectrum determination module, used to determine the transport vibration conditions of various transport modes, and determine the equipment vibration load spectrum according to the vibration test control strategy with valley control or response limit; The stress analysis module is used to consider the nonlinear effects of the structure, perform stress analysis on fatigue-hazardous structures, and establish equations for external loads and stresses of hazardous sections; The equipment transportation vibration environment adaptability analysis module is used to calculate the damage of equipment under the vibration load spectrum of different transportation modes one by one, and evaluate the equipment's transportation vibration environment adaptability based on the cumulative damage.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the equipment transportation vibration fatigue assessment method described in any one of claims 1 to 7 is implemented.

10. An electronic device comprising a memory and a processor, wherein the memory stores computer instructions that can be executed on the processor, wherein: When the processor runs the computer instructions, it executes the equipment transportation vibration fatigue assessment method described in any one of claims 1-7.

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