Thin plate structure accumulated damage effect evaluation method based on modal frequency
By using a thin plate structure evaluation method based on modal frequency, combined with finite element simulation and neural network algorithm, the accuracy problem of damage effect evaluation of thin plate structures under multiple explosion loads was solved, and efficient and accurate damage effect evaluation of thin plate structures was achieved.
Patent Information
- Application Number
- CN202510705846.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-29
- Publication Date
- 2025-09-26
AI Technical Summary
The existing damage effect evaluation method for thin plate structures under multiple explosion loads based on the maximum plastic deformation value of the geometric center has accuracy deviations, and the traditional method requires complex modal tests, resulting in a cumbersome evaluation process.
A cumulative damage effect evaluation method for thin plate structures based on modal frequency is adopted. The vibration responses of the thin plate structure in the undeformed and cumulatively deformed states are measured by hitting the thin plate structure with a hammer, and autospectral analysis is performed. Combined with finite element simulation and neural network algorithm, an evaluation model for the first-order modal frequency and residual bearing capacity of the thin plate structure is established.
It achieves accurate evaluation of the cumulative damage effect of thin plate structures, avoids the deviation of traditional methods, improves evaluation efficiency, and simplifies the modal frequency extraction process.
Smart Images
Figure CN120706140A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of explosion damage, relates to cumulative damage of thin plate structures, and specifically relates to a method for evaluating cumulative damage effects of thin plate structures based on modal frequency. Background Art
[0002] Thin plates are important structural components in weaponry. Explosive loads cause them to deform plastically, and their residual load-bearing capacity after deformation is a crucial parameter for evaluating the degree of functional loss in equipment. Currently, the evaluation of damage effects on thin plate structures is primarily based on the maximum plastic deformation at the plate's geometric center. However, when evaluating the cumulative damage effects of multiple explosive loads, the cumulative effects of different impacts can lead to deformation patterns where the plastic deformation at the plate's geometric center remains constant but other regions exhibit varying plastic deformations. Consequently, the cumulative damage effect evaluation method based on the maximum plastic deformation amplitude at the plate's geometric center exhibits a bias.
[0003] In the journal article "Rapid Assessment Method for Explosion Damage of Reinforced Concrete Columns Based on Measured Frequency" (Shi Yanchao et al., Journal of Building Structures, 2020-03-09), a damage evaluation method for reinforced concrete column components based on measured frequency was proposed. However, this method only considers the single deformation effect of steel-concrete components. At the same time, this method requires complex modal tests to obtain the measured frequency of the structure, and the evaluation process is complicated. Summary of the Invention
[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a method for evaluating the cumulative damage effect of thin plate structures based on modal frequency, so as to solve the technical problem that the accuracy of the evaluation method in the existing technology needs to be further improved.
[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:
[0006] A method for evaluating cumulative damage effects of thin plate structures based on modal frequencies comprises the following steps:
[0007] Step 1: When the thin plate structure is in an undeformed state, use a hammer to strike the thin plate structure to measure the vibration response w0 of the thin plate structure in the undeformed state, perform autospectral analysis on the vibration response w0 of the thin plate structure in the undeformed state, and select the frequency corresponding to the first resonance peak in the vibration response autospectral curve as the first-order modal frequency f0 of the thin plate structure in the undeformed state.
[0008] Step 2: When the thin plate structure is in a state of cumulative deformation, the thin plate structure is struck with a force hammer to measure the vibration response w1 of the thin plate structure in the state of cumulative deformation. An autospectral analysis is performed on the vibration response w1 of the thin plate structure in the state of cumulative deformation, and the frequency corresponding to the first resonance peak in the vibration response autospectral curve is selected as the first-order modal frequency f1 of the thin plate structure in the state of cumulative deformation.
[0009] Step 3: Input the geometric parameters of the thin plate structure in the undeformed state, the first-order modal frequency f0 of the thin plate structure in the undeformed state, and the first-order modal frequency f1 of the thin plate structure in the cumulative deformation state into the cumulative damage effect evaluation model P to determine the residual bearing capacity P of the thin plate structure in the cumulative deformation state. m .
[0010] The present invention also has the following technical features:
[0011] In step 3, the method for constructing the cumulative damage effect evaluation model P includes the following steps:
[0012] Step 301 : establishing a finite element simulation model of the thin plate structure based on the geometric parameters of the thin plate structure in an undeformed state, the material parameters of the thin plate structure, and boundary constraints.
[0013] Step 302 : Based on the finite element simulation model of the thin plate structure, a modal analysis is performed on the thin plate structure in an undeformed state to obtain the first-order modal frequency f0 of the thin plate structure, and the simulation model is verified based on the first-order modal frequency f0 of the thin plate structure obtained from the test results.
[0014] Step 303 : Based on the finite element simulation model of the thin plate structure, a cumulative damage effect simulation is performed on the thin plate structure to obtain different cumulative deformation states of the thin plate structure.
[0015] Step 304: Based on the thin plate structure finite element simulation model, perform modal analysis on the kth cumulative deformation state to obtain the first-order modal frequency f under the cumulative deformation state. k1 .
[0016] Step 305: Based on the finite element simulation model of the thin plate structure, quasi-static pressure loading is performed on the thin plate structure in the kth cumulative deformation state until the thin plate structure is destroyed. The pressure P of the thin plate structure at the moment of destruction is defined as km It is the residual bearing capacity of the thin plate structure under the accumulated deformation state.
[0017] Step 306: Simulate the thin plate structure in different cumulative deformation states to establish the first-order modal frequency f under k deformation conditions. k1 and the remaining bearing capacity P km Dataset.
[0018] Step 307: The geometric parameters of the thin plate structure in the undeformed state, the undeformed first-order modal frequency f0 and the first-order modal frequency f of the kth cumulative deformation state are used. k1 As input, the residual bearing capacity of the thin plate structure P km As the output, the neural network algorithm is used for model training, and a cumulative damage effect evaluation model P based on the first-order modal frequency and residual bearing capacity of the thin plate structure is established.
[0019] In steps 304 to 307, k≥50.
[0020] In step three, the thin plate structure includes a rectangular thin plate and a circular thin plate; the geometric parameters of the rectangular thin plate in the undeformed state include length L, width W and thickness H; the geometric parameters of the circular thin plate in the undeformed state include diameter D and thickness H.
[0021] Compared with the prior art, the present invention has the following technical effects:
[0022] (I) In view of the fact that thin plate structures may produce the same plastic deformation characteristics at the geometric center of the thin plate structure under different impact loads, the present invention proposes a cumulative damage effect evaluation method based on the frequency change of the thin plate structure. This method accurately evaluates the damage effect of the thin plate structure by accumulating the change characteristics of the modal frequency before and after deformation. Different from the traditional evaluation method based on the maximum plastic deformation amplitude at the geometric center, the evaluation method proposed by the present invention can significantly improve the accuracy of the evaluation of the cumulative damage effect of the thin plate structure.
[0023] (II) The present invention proposes a method for evaluating the cumulative damage effect of thin plate structures based on frequency changes. By performing autospectral analysis on the responses of characteristic points of thin plate structures and constructing a damage effect evaluation model based on simulation, it can avoid extracting modal frequencies through complex modal tests and improve the efficiency of evaluating the cumulative damage effect of thin plate structures. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 It is a schematic diagram of the simulation model of the circular thin plate structure.
[0025] Figure 2 It is the mode shape of the circular thin plate structure in the undeformed state.
[0026] Figure 3 It is the modal vibration shape of the circular thin plate structure under a certain deformation state.
[0027] Figure 4 It is a schematic diagram of the quasi-static simulation destruction moment of a circular thin plate structure.
[0028] Figure 5 It is based on the training curve of the neural network algorithm model.
[0029] Figure 6 It is a validation curve based on the neural network algorithm model.
[0030] Figure 7 It is a schematic diagram of the vibration response test of the circular thin plate structure in the undeformed state.
[0031] Figure 8 It is the vibration response autospectral analysis curve of the circular thin plate structure in the undeformed state.
[0032] Figure 9 It is a schematic diagram of the vibration response test of a circular thin plate structure under a certain cumulative deformation state.
[0033] Figure 10 It is the autospectral analysis curve of the vibration response of the circular thin plate structure under a certain cumulative deformation state.
[0034] The specific contents of the present invention are further explained in detail below with reference to the embodiments. DETAILED DESCRIPTION
[0035] It should be noted that, unless otherwise specified, all devices, models, software and algorithms in the present invention adopt devices, models, software and algorithms known in the prior art.
[0036] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made on the basis of the technical solution of this application fall within the protection scope of the present invention.
[0037] Example:
[0038] This embodiment provides a method for evaluating cumulative damage effects of thin plate structures based on modal frequencies, the method comprising the following steps:
[0039] Step 1: When the thin plate structure is in an undeformed state, use a hammer to strike the thin plate structure, measure the vibration response w0 of the thin plate structure in the undeformed state through a sensor, perform autospectral analysis on the vibration response w0 of the thin plate structure in the undeformed state, and select the frequency corresponding to the first resonance peak in the vibration response autospectral curve as the first-order modal frequency f0 of the thin plate structure in the undeformed state.
[0040] Step 2: When the thin plate structure is in a state of cumulative deformation, the thin plate structure is struck with a force hammer, and the vibration response w1 of the thin plate structure in the state of cumulative deformation is measured by a sensor. An autospectral analysis is performed on the vibration response w1 of the thin plate structure in the state of cumulative deformation, and the frequency corresponding to the first resonance peak in the vibration response autospectral curve is selected as the first-order modal frequency f1 of the thin plate structure in the state of cumulative deformation.
[0041] Step 3: Input the geometric parameters of the thin plate structure in the undeformed state, the first-order modal frequency f0 of the thin plate structure in the undeformed state, and the first-order modal frequency f1 of the thin plate structure in the cumulative deformation state into the cumulative damage effect evaluation model P to determine the residual bearing capacity P of the thin plate structure in the cumulative deformation state. m .
[0042] In this embodiment, the sensor is a sensor commonly used in the art for measuring vibration response.
[0043] Step 3: Input the geometric parameters of the thin plate structure in the undeformed state, the first-order modal frequency f0 of the thin plate structure in the undeformed state, and the first-order modal frequency f1 of the thin plate structure in the cumulative deformation state into the cumulative damage effect evaluation model P to determine the residual bearing capacity P of the thin plate structure in the cumulative deformation state. m .
[0044] In step three, the thin plate structure includes a rectangular thin plate and a circular thin plate; the geometric parameters of the rectangular thin plate in the undeformed state include length L, width W and thickness H; the geometric parameters of the circular thin plate in the undeformed state include diameter D and thickness H.
[0045] In step 3, the method for constructing the cumulative damage effect evaluation model P includes the following steps:
[0046] Step 301 : establishing a finite element simulation model of the thin plate structure based on the geometric parameters of the thin plate structure in an undeformed state, the material parameters of the thin plate structure, and boundary constraints.
[0047] Step 302 : Based on the finite element simulation model of the thin plate structure, a modal analysis is performed on the thin plate structure in an undeformed state to obtain the first-order modal frequency f0 of the thin plate structure, and the simulation model is verified based on the first-order modal frequency f0 of the thin plate structure obtained from the test results.
[0048] Step 303 : Based on the finite element simulation model of the thin plate structure, a cumulative damage effect simulation is performed on the thin plate structure to obtain different cumulative deformation states of the thin plate structure.
[0049] Step 304: Based on the thin plate structure finite element simulation model, perform modal analysis on the kth cumulative deformation state to obtain the first-order modal frequency f under the cumulative deformation state. k1 .
[0050] Step 305: Based on the finite element simulation model of the thin plate structure, quasi-static pressure loading is performed on the thin plate structure in the kth cumulative deformation state until the thin plate structure is destroyed. The pressure P of the thin plate structure at the moment of destruction is defined as km It is the residual bearing capacity of the thin plate structure under the accumulated deformation state.
[0051] Step 306: Simulate the thin plate structure in different cumulative deformation states to establish the first-order modal frequency f under k deformation conditions. k1 and the remaining bearing capacity P km Dataset.
[0052] Step 307: The geometric parameters of the thin plate structure in the undeformed state, the undeformed first-order modal frequency f0 and the first-order modal frequency f of the kth cumulative deformation state are used. k1 As input, the residual bearing capacity of the thin plate structure P km As the output, the neural network algorithm is used for model training, and a cumulative damage effect evaluation model P based on the first-order modal frequency and residual bearing capacity of the thin plate structure is established.
[0053] In steps 304 to 307, k≥50.
[0054] Application examples:
[0055] This application example provides a method for evaluating the cumulative damage effect of a thin plate structure based on modal frequency based on the above embodiment.
[0056] refer to Figure 1 The schematic diagram of the thin plate structure is given. A circular thin plate structure is taken as an example for analysis. The diameter D of the circular thin plate structure is 288 mm, the thickness is 0.5 mm, the material is Q235 steel, and the boundary constraint condition is peripheral clamping.
[0057] First, the cumulative damage effect model P of the thin plate structure is constructed. Based on the LS-DYNA simulation software, the impact deformation simulation model of the circular thin plate structure is established. Figure 1 As shown in the figure, by simulating the impact deformation of the thin plate structure and performing modal analysis on the thin plate structure before and after deformation, the first-order modal frequency of the thin plate structure in the undeformed state is 61.447 Hz. Figure 2 This is the first-order modal vibration shape diagram of the thin plate structure in the undeformed state; and by performing a hammer impact test on the thin plate structure and performing autospectral analysis, it is found that the first-order modal frequency of the thin plate structure is 61.988Hz, verifying the reliability of the simulation model.
[0058] Then, based on the LS-DYNA simulation software, the cumulative deformation simulation analysis of the thin plate structure under different impact loads was carried out to obtain 65 groups of cumulative deformation states of the thin plate structure; modal analysis was performed on the 65 groups of deformation states of the thin plate structure to obtain the first-order modal frequencies f corresponding to the 65 groups of deformation states. k1 (k=1~65), Figure 3 is the modal vibration shape diagram of the thin plate structure under a certain deformation state; quasi-static loading simulation of the thin plate structure under 65 sets of deformation states is performed to obtain the residual bearing pressure P under 65 sets of deformation states km (k=1~65), Figure 4The quasi-static simulation damage effect diagram of the thin plate structure under a certain deformation state. Based on the above simulation results, the radius D of the circular thin plate structure, the thickness h of the thin plate, the first-order modal frequency f0 of the undeformed, the first-order modal frequency f of the kth cumulative deformation state, k1 As input, the residual bearing capacity of the thin plate structure P km For output, 65 sets of damage effect model data sets are constructed, of which 50 sets are used as damage effect model training sets and 15 sets are used as damage effect model verification and test sets. The data sets are trained and tested based on the neural network algorithm to obtain the cumulative damage effect model P of the circular thin plate structure. Figure 5 The corresponding curve of the damage effect model training set is given. Figure 6 The corresponding curves of the damage effect model validation test are given. The model fitting degree R of model training and validation reaches above 0.99, indicating the reliability of the damage effect model.
[0059] Finally, based on the cumulative damage effect model, the cumulative damage effect of the circular thin plate structure is analyzed. Figure 7 Schematic diagram of the vibration response measurement of the thin plate structure in the undeformed state. Figure 8 The vibration response autospectral curve is given. Figure 8 ZP1, ZP2 and ZP3 in the Figure 7 The three measuring points correspond to the three sensors arranged radially outward from the center of the circle. Figure 8 It can be seen that the first-order modal frequency of the circular thin plate structure in the undeformed state is 61.988 Hz; Figure 9 Schematic diagram of the vibration response measurement of a thin plate structure under a certain cumulative deformation state. Figure 10 The autospectral curve of the vibration response of the thin plate structure under the cumulative deformation state is given. Figure 10 ZP1, ZP2 and ZP3 in the Figure 9 The three measuring points correspond to the three sensors arranged radially outward from the center of the circle. Figure 10 The first-order modal frequency of the thin plate structure in this deformed state is 993.729 Hz. Substituting the following data into the cumulative damage effect model P: a diameter of 288 mm, a thickness of 0.5 mm, a first-order modal frequency of 61.988 Hz in the undeformed state, and a first-order modal frequency of 993.729 Hz in the cumulative deformation state, the residual bearing pressure of the thin plate structure in this deformed state is 3.54 MPa.
[0060] It can be seen that the method for evaluating the cumulative damage effect of thin plate structures based on modal frequency proposed in the present invention is feasible. Based on the constructed cumulative damage effect model and combined with the modal frequencies of different deformation states, a rapid evaluation of the residual bearing capacity of the thin plate structure can be achieved. This method can avoid the evaluation deviation caused by the similar plastic deformation amplitude of the geometric center of the thin plate structure, and improve the accuracy of the cumulative damage effect evaluation of the thin plate structure.
Claims
1. A method for evaluating cumulative damage effects of thin plate structures based on modal frequency, characterized in that: The method comprises the following steps: Step 1: When the thin plate structure is in an undeformed state, the thin plate structure is struck with a hammer to measure the vibration response w0 of the thin plate structure in the undeformed state, and an autospectral analysis is performed on the vibration response w0 of the thin plate structure in the undeformed state. The frequency corresponding to the first resonance peak in the vibration response autospectral curve is selected as the first-order modal frequency f0 of the thin plate structure in the undeformed state; Step 2: When the thin plate structure is in a state of cumulative deformation, the thin plate structure is struck with a force hammer to measure the vibration response w1 of the thin plate structure in the state of cumulative deformation, and an autospectral analysis is performed on the vibration response w1 of the thin plate structure in the state of cumulative deformation. The frequency corresponding to the first resonance peak in the vibration response autospectral curve is selected as the first-order modal frequency f1 of the thin plate structure in the state of cumulative deformation; Step 3: Input the geometric parameters of the thin plate structure in the undeformed state, the first-order modal frequency f0 of the thin plate structure in the undeformed state, and the first-order modal frequency f1 of the thin plate structure in the cumulative deformation state into the cumulative damage effect evaluation model P to determine the residual bearing capacity P of the thin plate structure in the cumulative deformation state. m .
2. The method for evaluating cumulative damage effects of thin plate structures based on modal frequency according to claim 1, wherein: In step 3, the method for constructing the cumulative damage effect evaluation model P includes the following steps: Step 301: establishing a finite element simulation model of the thin plate structure based on the geometric parameters of the thin plate structure in an undeformed state, the material parameters of the thin plate structure, and boundary constraints; Step 302 , based on the finite element simulation model of the thin plate structure, a modal analysis is performed on the thin plate structure in an undeformed state to obtain the first-order modal frequency f0 of the thin plate structure, and the simulation model is verified based on the first-order modal frequency f0 of the thin plate structure obtained from the test results; Step 303: Based on the finite element simulation model of the thin plate structure, simulate the cumulative damage effect of the thin plate structure to obtain different cumulative deformation states of the thin plate structure; Step 304: Based on the thin plate structure finite element simulation model, perform modal analysis on the kth cumulative deformation state to obtain the first-order modal frequency f under the cumulative deformation state. k1 ; Step 305: Based on the finite element simulation model of the thin plate structure, quasi-static pressure loading is performed on the thin plate structure in the kth cumulative deformation state until the thin plate structure is destroyed. The pressure P of the thin plate structure at the moment of destruction is defined as km is the residual bearing capacity of the thin plate structure under the accumulated deformation state; Step 306: Simulate the thin plate structure in different cumulative deformation states to establish the first-order modal frequency f under k deformation conditions. k1 and the remaining bearing capacity P km Dataset; Step 307: The geometric parameters of the thin plate structure in the undeformed state, the undeformed first-order modal frequency f0 and the first-order modal frequency f of the kth cumulative deformation state are used. k1 As input, the residual bearing capacity of the thin plate structure P km As the output, the neural network algorithm is used for model training, and a cumulative damage effect evaluation model P based on the first-order modal frequency and residual bearing capacity of the thin plate structure is established.
3. The method for evaluating cumulative damage effects of thin plate structures based on modal frequency according to claim 2, wherein: In steps 304 to 307, k≥50.
4. The method for evaluating cumulative damage effects of thin plate structures based on modal frequency according to claim 1, wherein: In step three, the thin plate structure includes a rectangular thin plate and a circular thin plate; the geometric parameters of the rectangular thin plate in the undeformed state include length L, width W and thickness H; the geometric parameters of the circular thin plate in the undeformed state include diameter D and thickness H.