A single / multi-pulse impact load equivalent test method

Abstract

The present invention relates to the field of impact load technology, and specifically to a single / multi-pulse impact load equivalent test method. The purpose of the present invention is to provide an impact load test method that can simulate different impact pulse widths under actual impact loads through existing impact load test methods, that is, to provide a single / multi-pulse impact load equivalent test method, including establishing a physical analysis model, constructing a model vibration equation and calculating a displacement response function, calculating displacement response results, constructing a linear regression model, optimizing and improving the model, nonlinearly restoring and simplifying the model, and completing an equivalent test. The single / multi-pulse impact load equivalent test method provided by the present invention can equivalently simulate the dynamic impact environment between different impact load parameters, and has wide applicability and low cost.

Description

Technical Field

[0001] The invention relates to the technical field of impact loads, in particular to a single / multi-pulse impact load equivalent test method. Background Art

[0002] The impulse pulse width generated during the field launch process can reach more than ten milliseconds, and the high impact peak environment generated by the electromagnetic gun is more complex, and it also reflects the impact of multiple pulses on the basis of the long pulse width. Real-time live testing in the actual environment is the most direct and reliable test method for evaluating systems and devices, but considering the complex operation process and high cost of field tests, how to simulate real-life impact loads through conventional low-cost impact load test methods in laboratory environments is a problem that needs to be solved urgently.

[0003] The existing impact load test methods in laboratory environments include drop hammer collision test method, Machete hammer test method, Hopkinson rod impact test method and air cannon test method. The drop hammer collision test method and Machete hammer test method have low impact peak values, and it is difficult to simulate impact loads with high impact peak values ​​under actual impact loads. The Hopkinson rod impact test method is the most commonly used impact load test method in laboratory environments. It is simple to operate, cost-controlled, and the impact peak value can reach hundreds of thousands to hundreds of thousands, but its impact pulse width is short, usually not exceeding hundreds of microseconds, and it is difficult to simulate impact loads with long pulse widths under actual impact loads. The air cannon test method has a high impact peak value, and the impact pulse width can also reach the millisecond level, but its test cost is relatively high and the process is relatively complicated. For this reason, it is urgently needed to provide an impact load test method that can simulate actual impact loads under different impact pulse width conditions, so as to simulate actual impact loads through existing low-cost impact load test methods. Summary of the invention

[0004] In order to solve the problem that the existing impact load test method cannot simulate the actual impact load under different impact pulse width conditions at a low cost, the present invention provides a single / multi-pulse impact load equivalent test method.

[0005] The present invention is achieved by adopting the following technical solutions:

[0006] A single / multi-pulse impact load equivalent test method comprises the following steps:

[0007] (1) Establishing a physical analysis model under impact load, wherein the physical analysis model is an acceleration sensor device packaging structure;

[0008] (2) According to the measured acceleration data of the impact load test under the actual impact environment, it is determined that the form of the external inertial impact load of the physical analysis model in step (1) is a half-sine form;

[0009] (3) Under the external inertial impact load determined in step (2), perform force analysis on each structure in the physical analysis model and establish a vibration equation for the physical analysis model;

[0010] (4) Calculating the displacement response function of each structure in the physical analysis model according to the vibration equation of the physical analysis model established in step (3);

[0011] (5) Define the multi-pulse impact load form by the impact peak P , impulse pulse width T , interval time △ and number of pulses N Four load parameters are composed; in view of the form of multi-pulse impact load, the cumulative strain energy of elastic strain energy of each structure in the physical analysis model over time is selected as the equivalent factor;

[0012] (6) According to the multi-pulse impact load form defined in step (5), combined with the impact load realization range in the laboratory's existing test methods, different impact peak values ​​are P , impulse pulse width T , interval time △ and number of pulses N The load parameters of the set multi-pulse impact load are brought into the displacement response function in step (4) to calculate the displacement response results of each structure in the physical analysis model;

[0013] (7) According to the displacement response results of each structure in the physical analysis model calculated in step (6), the equivalent factors under each load parameter are calculated respectively, and the functional relationship between each load parameter and the equivalent factor is fitted. Among them, the fitting trends of the impact pulse width and interval time with the equivalent factor in the long pulse width (≥5,000µs) and short pulse width range (≤100µs) are quite different. Therefore, the functional relationship between the fitted load parameters and the equivalent factor is divided into two categories, namely, the functional relationship between each load parameter and the equivalent factor under the long pulse width and the functional relationship between each load parameter and the equivalent factor under the short pulse width;

[0014] (8) The functional relationship between each load parameter and the equivalent factor under the short pulse width and the functional relationship between each load parameter and the equivalent factor under the long pulse width obtained by fitting in step (7) are respectively transformed into variables to obtain a multiple linear regression model between each load parameter and the equivalent factor under the short pulse width and a multiple linear regression model between each load parameter and the equivalent factor under the long pulse width;

[0015] (9) Perform regression calculations on the two multiple linear regression models constructed in step (8) respectively, complete the multiple linear regression hypothesis test, and then optimize and improve the corresponding models according to the hypothesis test results;

[0016] (10) performing nonlinear reduction on the optimized and improved multiple linear regression model corresponding to step (9), and obtaining a multiple nonlinear regression model under short pulse width and a multiple nonlinear regression model under long pulse width, both of which are composed of constant terms and variable terms;

[0017] (11) analyzing the proportion of cumulative strain energy corresponding to each variable term in the multiple nonlinear regression model under short pulse width and the multiple nonlinear regression model under long pulse width in step (10), and eliminating the low-proportion terms to simplify them;

[0018] (12) The simplified multiple nonlinear regression model under short pulse width and the multiple nonlinear regression model under long pulse width in step (11) are respectively determined as the single / multi-pulse impact equivalent model under short pulse width and the single / multi-pulse impact equivalent model under long pulse width. When equivalent, the load parameters under short pulse width in the actual impact load are substituted into the multiple nonlinear regression model under short pulse width, and the corresponding cumulative strain energy is calculated. Then, the calculated cumulative strain energy is substituted into the single / multi-pulse impact equivalent model under long pulse width, and the remaining load parameters are inversely calculated according to any three known load parameters in the laboratory's existing test methods. Finally, the residual load parameters are calculated by The laboratory's existing experimental methods realize the equivalent test of actual impact loads according to the inverse residual load parameters and known load parameters; or the load parameters under the long pulse width in the actual impact load are brought into the multiple nonlinear regression model under the long pulse width, and the corresponding cumulative strain energy is calculated. Then the calculated cumulative strain energy is brought into the single / multi-pulse impact equivalent model under the short pulse width, and the residual load parameters are inversely calculated according to any three known load parameters in the laboratory's existing experimental methods. Finally, the equivalent test of actual impact loads is realized through the laboratory's existing experimental methods according to the inverse residual load parameters and known load parameters.

[0019] Principle description: The equivalent test method described above is mainly realized through the equivalent model established therein. The dynamic response process of different parameters is fully considered during the establishment of the equivalent model. The equivalent criterion between long pulse width and short pulse width is established from the perspective of cumulative strain energy, which provides theoretical guidance for the selection of parameters in the impact load required for the dynamic impact environment.

[0020] The beneficial effects of the present invention are as follows: the single / multi-pulse impact load equivalent test method provided by the present invention can equivalently simulate impact load tests with different parameters, has wide applicability and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0023] Figure 1 The figure is an overall flow chart of the method of the present invention. DETAILED DESCRIPTION

[0024] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0025] In the description, it should be noted that the terms "first" and "second" are only used for descriptive purposes and should not be understood as indicating or implying relative importance. It should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0026] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0027] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0028] like Figure 1 As shown, a single / multi-pulse impact load equivalent test method includes the following steps:

[0029] (1) Establishing a physical analysis model under impact load, wherein the physical analysis model is a simplified model of a piezoelectric acceleration sensor device packaging structure (it is well known to those skilled in the art that a piezoelectric acceleration sensor device packaging structure is mainly composed of a beam-mass block, a glass substrate, a patch adhesive, a potting adhesive, and a tube shell); in this embodiment, the physical analysis model is a model of a piezoelectric acceleration sensor device packaging structure simplified into a three-degree-of-freedom nonlinear second-order series-parallel oscillation system;

[0030] (2) According to the measured acceleration data of the impact load test in a real impact environment (the real impact environment in this embodiment is an outdoor live-fire shooting test environment), it is determined that the form of the external inertial impact load of the physical analysis model in step (1) is a half-sine form;

[0031] (3) Under the external inertial impact load determined in step (2), perform force analysis on each structure in the physical analysis model and establish a vibration equation for the physical analysis model;

[0032] (4) Calculating the displacement response function of each structure in the physical analysis model according to the vibration equation of the physical analysis model established in step (3);

[0033] (5) Define the multi-pulse impact load form by the impact peak P , impulse pulse width T , interval time △ and number of pulses N Four load parameters are composed; for the form of multi-pulse impact load, by calculating the external force work, kinetic energy and elastic deformation energy of each structure in the physical analysis model, it is found that the kinetic energy accounts for a very small proportion, and the external force work is mainly converted into elastic deformation energy. At the same time, considering the effect of the impact peak value and the impact pulse width on the structure, the cumulative strain energy of elastic strain energy over time is selected as the equivalent factor, so as to construct the impact load equivalent model later;

[0034] (6) According to the multi-pulse impact load form defined in step (5), combined with the impact load realization range in the laboratory's existing test methods, different impact peak values ​​are P , impulse pulse width T , interval time △ and number of pulses N The load parameters of the set multi-pulse impact load are brought into the displacement response function in step (4) to calculate the displacement response results of each structure in the physical analysis model;

[0035] (7) According to the displacement response results of each structure in the physical analysis model calculated in step (6), the equivalent factors under each load parameter are calculated respectively, and the functional relationship between each load parameter and the equivalent factor is fitted. Specifically, under short pulse width, the impact pulse width corresponds to a quadratic function, and the interval time is an inverse function. Under long pulse width, the impact pulse width corresponds to an inverse function, and the interval time is a cubic function. The fitting trends of the impact pulse width and the interval time with the equivalent factor in the long pulse width (≥5,000µs) and short pulse width range (≤100µs) are quite different. Therefore, the functional relationship between the fitted load parameters and the equivalent factor is divided into two categories, namely, the functional relationship between the load parameters and the equivalent factor under long pulse width and the functional relationship between the load parameters and the equivalent factor under short pulse width;

[0036] (8) The functional relationship between each load parameter and the equivalent factor under the short pulse width and the functional relationship between each load parameter and the equivalent factor under the long pulse width obtained by fitting in step (7) are respectively transformed into variables to obtain a multiple linear regression model between each load parameter and the equivalent factor under the short pulse width and a multiple linear regression model between each load parameter and the equivalent factor under the long pulse width;

[0037] (9) Regression calculations are performed on the two multiple linear regression models constructed in step (8) respectively, and multiple linear regression hypothesis tests are completed (regression hypothesis tests are common knowledge for those skilled in the art, i.e., regression hypothesis tests include independence tests, linear relationship tests, equal variance tests, multicollinearity tests, outlier tests, normal distribution tests, etc.), and then the corresponding models are optimized and improved according to the hypothesis test results;

[0038] (10) The optimized and improved multiple linear regression model corresponding to step (9) is subjected to nonlinear reduction to obtain a multiple nonlinear regression model under short pulse width and a multiple nonlinear regression model under long pulse width. In this embodiment, the multiple nonlinear regression model under short pulse width is composed of a constant term (a constant term is -7.901e-4 ) and 13 variables (the 13 variables are 8.324e-5P, 1.155e-6P 2 , 1.242e-5T, -3.373e-7T 2 ,-4.239e-2 / △,-4.818e-5N,- 5.163e-6N 2 , -8.906e-8TP 2 , 9.898e-10T 2 P 2 , -3.278e-6TN, 8.934e-7TN 2 , 7.439e-8T 2 N、- 9.362e-9T 2 N 2 ), the multiple nonlinear regression model under long pulse width consists of a constant term (a constant term is 3.510e- 6 ) and 10 variables (the 10 variables are 1.893e-6P, 4.679e-8P 2 , -0.407 / T, 3.978e-9△, -3.136e- 11△ 2 、1.404e-13△ 3 , 1.778e-6N, -1.737e-6N 2 , 0.386N / T, -3.989e-10△N 2 ) is composed as follows

[0039] ①

[0040] and:

[0041] ②

[0042] Among them, Σ E ss is the accumulated strain energy under short pulse width, Σ E sl is the accumulated strain energy under long pulse width, P is the impact peak value, N is the number of pulses, T is the impulse pulse width, △ is the interval time;

[0043] (11) Analyze the proportion of cumulative strain energy corresponding to each variable term in the multiple nonlinear regression model under short pulse width and the multiple nonlinear regression model under long pulse width in step (10), remove the low-proportion terms to simplify them, and the simplified multiple nonlinear regression model under short pulse width and the multiple nonlinear regression model under long pulse width are as follows:

[0044] ③

[0045] and:

[0046] ④

[0047] (12) The simplified multiple nonlinear regression model under short pulse width and the multiple nonlinear regression model under long pulse width in step (11) are respectively determined as the single / multi-pulse impact equivalent model under short pulse width and the single / multi-pulse impact equivalent model under long pulse width. When equivalent, the load parameters under the field live-fire shooting test environment are substituted into formula ④ to calculate the cumulative strain energy. Then, the calculated cumulative strain energy is substituted into formula ③, and the remaining load parameters are inversely calculated according to any three known load parameters in the Hopkinson bar impact test method. Finally, the equivalent test of the actual impact load is realized through the Hopkinson bar impact test method according to the inverse residual load parameters and the known load parameters.

[0048] In the above-mentioned equivalent test method, how to calculate the vibration equation of the physical analysis model, how to calculate the displacement response function and solve the displacement response result, calculate the equivalent factor and other calculations are all conventional algorithms known to those skilled in the art. The calculation results are different for specific situations, and since the calculation process is long, it is not elaborated in this application)

[0049] In order to verify the effectiveness of the equivalent test method established above, the cumulative strain energy under the single pulse impact load obtained in the field live-fire shooting test environment is compared with the measured cumulative strain energy corresponding to the three groups of equivalent impact loads obtained by the Hopkinson bar impact test method in the laboratory after the equivalent test, as shown in Table 1. It can be seen from Table 1 that the equivalent error of the cumulative strain energy of the impact load obtained by the equivalent test method is less than 10%.

[0050] Table 1 Single / multi-pulse impact equivalent test results

[0051]

[0052] The above is only a specific implementation of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions are given with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments, and they should all be covered by the protection scope of the claims.

Claims

1. A single / multi-pulse impact load equivalent test method, characterized in that: The steps include: (1) Establishing a physical analysis model under impact load, wherein the physical analysis model is an acceleration sensor device packaging structure; (2) According to the measured acceleration data of the impact load test under the actual impact environment, it is determined that the form of the external inertial impact load of the physical analysis model in step (1) is a half-sine form; (3) Under the external inertial impact load determined in step (2), perform force analysis on each structure in the physical analysis model and establish a vibration equation for the physical analysis model; (4) Calculating the displacement response function of each structure in the physical analysis model according to the vibration equation of the physical analysis model established in step (3); (5) Define the multi-pulse impact load form by the impact peak P , impulse pulse width T , interval time △ and number of pulses N Four load parameters are composed; in view of the form of multi-pulse impact load, the cumulative strain energy of elastic strain energy of each structure in the physical analysis model over time is selected as the equivalent factor; (6) According to the multi-pulse impact load form defined in step (5), combined with the impact load realization range in the laboratory's existing test methods, different impact peak values ​​P, impact pulse widths T, interval times △, and pulse numbers are set. N The load parameters of the set multi-pulse impact load are brought into the displacement response function in step (4) to calculate the displacement response results of each structure in the physical analysis model; (7) According to the displacement response results of each structure in the physical analysis model calculated in step (6), the equivalent factors under each load parameter are calculated respectively, and the functional relationship between each load parameter and the equivalent factor is fitted. Among them, the fitting trend of the impact pulse width and interval time with the equivalent factor in the long pulse width and short pulse width range is quite different. Therefore, the functional relationship between the fitted load parameters and the equivalent factor is divided into two categories, namely, the functional relationship between each load parameter and the equivalent factor under the long pulse width and the functional relationship between each load parameter and the equivalent factor under the short pulse width; (8) The functional relationship between each load parameter and the equivalent factor under the short pulse width and the functional relationship between each load parameter and the equivalent factor under the long pulse width obtained by fitting in step (7) are respectively transformed into variables to obtain a multiple linear regression model between each load parameter and the equivalent factor under the short pulse width and a multiple linear regression model between each load parameter and the equivalent factor under the long pulse width; (9) Perform regression calculations on the two multiple linear regression models constructed in step (8) respectively, complete the multiple linear regression hypothesis test, and then optimize and improve the corresponding models according to the hypothesis test results; (10) performing nonlinear reduction on the optimized and improved multiple linear regression model corresponding to step (9), and obtaining a multiple nonlinear regression model under short pulse width and a multiple nonlinear regression model under long pulse width, both of which are composed of constant terms and variable terms; (11) analyzing the proportion of cumulative strain energy corresponding to each variable term in the multiple nonlinear regression model under short pulse width and the multiple nonlinear regression model under long pulse width in step (10), and eliminating the low-proportion terms to simplify them; (12) The simplified multiple nonlinear regression model under short pulse width and the multiple nonlinear regression model under long pulse width in step (11) are respectively determined as the single / multi-pulse impact equivalent model under short pulse width and the single / multi-pulse impact equivalent model under long pulse width. When equivalent, the load parameters under short pulse width or the load parameters under long pulse width in the actual impact load are substituted into the corresponding model, and the corresponding cumulative strain energy is calculated. Then, the calculated cumulative strain energy is substituted into the single / multi-pulse impact equivalent model under long pulse width or the single / multi-pulse impact equivalent model under short pulse width, and the remaining load parameters are inversely calculated according to any three known load parameters in the laboratory's existing test methods. Finally, the equivalent test of the actual impact load is realized according to the inverse residual load parameters and the known load parameters through the laboratory's existing experimental methods.

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