Impact response spectrum time domain conversion method, computer readable storage medium and program product

Abstract

The invention discloses an impact response spectrum time domain conversion method, a computer readable storage medium and a program product, and relates to the field of mechanical environment design of aircrafts, and the method comprises the steps: carrying out the time domain conversion of a reference impact response spectrum, obtaining a basic waveform y0, defining the whole waveform duration time of the basic waveform y0 as t0, and enabling the basic waveform y0 to adopt a sine wave xsin as a fundamental wave, the waveform delay time of the fundamental wave relative to the zero moment is tdi; a manual intervention waveform y '0 adopts an attenuation sine wave xexp as a fundamental wave; when t is smaller than or equal to t0, t is controlled to be equal to tdi, a manual intervention waveform y '0 is obtained, and the specified impact action time of the manual intervention waveform y' 0 is defined as t '0; 0 lt; the manual intervention waveforms y '0 and t' 0lt within the time interval t < = t '0; and combining the basic waveforms y0 in the time interval t < = t0 to obtain a target time domain waveform y. Defects of a traditional method can be effectively avoided, the accurate prediction requirement of an aircraft impact environment is met, and the effectiveness of an aircraft impact assessment test is supported.

Description

Technical Field

[0001] The present invention relates to the field of mechanical environment design of aircraft, and in particular to a time domain conversion method of impact response spectrum based on energy distribution, a computer-readable storage medium and a program product. Background Art

[0002] The shock environment is one of the most severe mechanical environments for crystal oscillators and optical devices on aircraft, and is also the main cause of failure of key instruments and equipment on aircraft. At present, in the product design stage, the shock response spectrum test based on the frequency domain method is usually used to assess the shock resistance of the product. The shock response spectrum is a series of envelopes of the maximum value of the forced vibration amplitude of a single-degree-of-freedom system in the frequency range. It is an artificially created harsh test condition that far exceeds the actual shock level. Since there is a "one-to-many" phenomenon between the response spectrum curve and the time domain shock signal, the timing of the shock signal after time domain conversion is not consistent with the timing of the actual signal. This difference in energy distribution may induce different failure modes and is the main cause of under-testing or over-testing. Therefore, when formulating the shock test conditions of the product, not only the frequency characteristics of the shock test conditions should be considered, but also its time domain characteristics. Only by considering the time-frequency characteristics of the test conditions at the same time can the rationality of the shock test conditions be guaranteed.

[0003] At present, in the time domain conversion process of the shock response spectrum, the wavelet synthesis method is generally used to obtain a time domain signal of a certain duration and intensity. The fundamental wave forms mainly include sine wave, attenuated sine wave, Hanning window wave, rectangular wave, etc. The attenuated sine fundamental wave is generally used as the fundamental wave function of the time domain signal with attenuation characteristics, and this time domain signal is used as the boundary input condition for the shock test assessment. However, the above method is used to transform the shock response spectrum in the time domain, and there are the following problems: there is a "one-to-many" phenomenon in the time domain quasi-transformation process of the shock response spectrum, that is, a shock response spectrum curve can theoretically derive countless time domain processes through the inverse transformation algorithm, which leads to the time domain boundary conditions used in a certain independent shock test being completely different from the expected test boundary conditions, and it is impossible to effectively assess the product.

[0004] In view of the above problems and needs, the development of a time-domain inverse transformation method of the shock response spectrum based on energy distribution has become a key technical challenge for the refined inverse transformation of the shock response spectrum and the effective assessment of the impact problems of aircraft. Summary of the invention

[0005] The technical problem solved by the present application is: to overcome the deficiencies of the prior art and to provide a time-domain conversion method for an impact response spectrum based on energy distribution. The time-domain conversion method for an impact response spectrum based on energy distribution can effectively avoid the deficiencies of traditional methods, meet the requirements for accurate prediction of the aircraft impact environment, and support the effectiveness of aircraft impact assessment tests.

[0006] The technical solution provided by this application is as follows:

[0007] A time-domain conversion method for shock response spectrum based on energy distribution, comprising:

[0008] Perform time-domain conversion on the reference shock response spectrum to obtain the basic waveform y0, and define the entire waveform duration of the basic waveform y0 as t0;

[0009] Calculate the basic waveform y0 within the range of 0 < t ≤ t0;

[0010] Calculate the specified shock action time 0 - t'0 of the defined artificial intervention waveform y'0, where t0 > t'0; calculate the artificial intervention waveform y'0 within the duration of 0 < t ≤ t'0;

[0011] Combine the artificial intervention waveform y'0 within the time interval of 0 < t ≤ t'0 and the basic waveform y0 within the time interval of t'0 < t ≤ t0 to obtain the target time-domain waveform y;

[0012] Among them, calculating the artificial intervention waveform y'0 within the duration of 0 < t ≤ t'0 includes:

[0013] The artificial intervention waveform y'0 includes m attenuation sine waves x exp as the fundamental wave, and the waveform delay time of the fundamental wave relative to the zero moment is t di ;

[0014] The artificial intervention waveform y'0 is obtained by the following formula:

[0015]

[0016] Among them, A i ’ is the waveform amplitude of the i-th fundamental wave, f i ’ is the waveform frequency of the i-th fundamental wave, N i ’ is the number of half-sine waves of the waveform of the i-th fundamental wave;

[0017] When calculating the artificial intervention waveform y'0, within the duration of 0 < t ≤ t'0, make t di ’ = (T max ’ - T i ’) / 2, where T i ’ is the duration of the i-th fundamental wave, i represents the i-th fundamental wave, i ∈ [1, m]; T max ’ is the maximum value among multiple T i ’ within the duration range of all fundamental waves; within the duration of t'0 < t ≤ t0, control t di of each time point t of the basic waveform y0 to be t; obtain the artificial intervention waveform y'0 within the range of 0 < t ≤ t0.

[0018] The total energy of the target time-domain waveform y within the entire waveform duration t0 is E = E'0 + λE0, where E'0 is the total energy within the time interval 0 < t ≤ t'0, and λE0 is the total energy within the time interval t'0 < t ≤ t0, and λ is the energy coefficient.

[0019] The energy proportion of the artificial intervention waveform y'0 in the target time-domain waveform is η = E'0 / E. By defining the value of η, the corresponding value of λ is determined.

[0020] It is stated that t0 > t'0.

[0021] The reference shock response spectrum is determined according to the test conditions.

[0022] The proportion ξ of the impact action time of the artificial intervention waveform y'0 in the entire waveform duration is ξ = t'0 / t0.

[0023] A computer-readable storage medium has a computer program / instructions stored thereon. When the computer program / instructions are executed by a processor, the steps of any of the above-mentioned methods are implemented.

[0024] A computer program product includes a computer program / instructions. When the computer program / instructions are executed by a processor, the steps of any of the above-mentioned methods are implemented.

[0025] The main content of the present invention is to construct a time-domain waveform according to the principle of energy distribution during the entire impact process, so as to simulate the differences in the time-domain signal distributions of different impact source characteristics on the object of action, and characterize the time-domain energy distribution characteristics of different impact sources. The target time-domain waveform is obtained by the method of combining the artificial intervention waveform and the basic waveform. The same set of fundamental wave functions and sampling rates are used in the synthesis process of the artificial intervention waveform and the basic waveform. The main feature of the artificial intervention waveform is that during the impact time history, a time-domain waveform within the specified impact action time is constructed, accumulating all the energy of the entire impact history, and the energy outside the specified impact action time is zero, which can be achieved by adjusting the waveform delay time relative to the zero moment. Its key role is that after spectral transformation, its shock response spectrum characteristics meet the target spectrum shape, which is the core element in the process of synthesizing the target time-domain waveform. The main role of the basic waveform is to provide the decay wave time history of the target waveform outside the specified impact action time during the entire impact time history. Its feature is that it has no influence on the target spectrum shape after spectral transformation, and only plays a role in allocating energy during the entire impact time history. The target time-domain waveform of the entire impact time history is composed of the artificial intervention wave within the specified impact action time and the basic wave outside the specified impact action time with a weight coefficient. By adjusting the weight coefficient, the energy distribution during the entire impact time history can be achieved.

[0026] In summary, this application at least includes the following beneficial technical effects:

[0027] In the waveform synthesis process, it is possible to specify the energy proportion of the specified impact action time in the entire impact time history.

[0028] It can more accurately restore the time domain history of the real impact environment and support the precise prediction of the aircraft impact environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the overall scheme of the shock spectrum time domain conversion method based on energy distribution.

[0030] Figure 2 Schematic diagram of a reference shock response spectrum example.

[0031] Figure 3 This is a schematic diagram of the basic waveform of the reference impulse response spectrum after time domain transformation.

[0032] Figure 4 Schematic diagram of the artificial intervention waveform (ξ=0.2) after the reference shock response spectrum is transformed in the time domain.

[0033] Figure 5 Schematic diagram of the comparison between the shock spectrum of the artificial intervention waveform and the reference spectrum.

[0034] Figure 6 Schematic diagram of the target time domain waveform (ξ=0.2, λ=0.93).

[0035] Figure 7 Schematic diagram of the comparison between the impact spectrum of the target time domain waveform and the reference spectrum. DETAILED DESCRIPTION

[0036] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0037] The present application embodiment discloses a method for time domain conversion of impulse response spectrum based on energy distribution, such as Figure 1 As shown, the following steps are included:

[0038] The reference shock response spectrum is determined according to the test conditions.

[0039] For the starting frequency f start , the termination frequency is f end , the inflection frequency is f infexion , the reference impulse response spectrum with a slope of m and an amplitude of s is converted into the time domain to obtain the basic waveform y0, and the entire waveform duration t0 and the quality factor Q of the basic waveform y0 are defined. The basic waveform y0 adopts the attenuated sine wave x expis the fundamental wave, and the waveform delay time of the fundamental wave relative to the zero moment is t di .

[0040] Sine wave x sin is obtained by the following formula: x sin (t) = A i sin(2πf i t)sin(2πf i t / N i )

[0041] The basic waveform y0 is obtained by the following formula:

[0042] where A i is the waveform amplitude of the i-th fundamental wave, f i is the waveform frequency of the i-th fundamental wave, N i is the number of half-sine waves of the waveform of the i-th fundamental wave;

[0043] When calculating the basic waveform y0, within the duration of 0 < t ≤ t0, make t di =(T max -T i ) / 2 to obtain the basic waveform y0 within the range of 0 < t ≤ t0;

[0044] where T i is the duration of the i-th fundamental wave, i represents the i-th fundamental wave, i ∈ [1, n]; T max is the maximum value of multiple Ts within the duration range of all fundamental waves i ;

[0045] Define the entire waveform duration of the artificial intervention waveform y'0 as t0. The artificial intervention waveform y'0 includes m fundamental waves using the attenuated sine wave x exp is the fundamental wave, and the waveform delay time of the fundamental wave relative to the zero moment is t di ;

[0046] The attenuated sine wave x exp is obtained by the following formula: x exp (t) = A i ’sin(2πf i ’t)exp(-2πf i ’t / N i ’)

[0047] The artificial intervention waveform y'0 is obtained by the following formula:

[0048]

[0049] where A i ’ is the waveform amplitude of the i-th fundamental wave, f i’ is the waveform frequency of the i-th fundamental wave, N i ’ is the number of half-sine waves of the waveform of the i-th fundamental wave;

[0050] Define the specified impact action time 0 - t'0 of the artificial intervention waveform y'0, where t0 > t'0;

[0051] When calculating the artificial intervention waveform y'0, within the duration 0 < t ≤ t'0, make t di ’ = (T max ’ - T i ’) / 2, where T i ’ is the duration of the i-th fundamental wave, i represents the i-th fundamental wave, i ∈ [1, m]; T max ’ is the maximum value among multiple T i ’ within the duration range of all fundamental waves; within the duration t'0 < t ≤ t0, control t at each time point t of the basic waveform y0 di = t; obtain the artificial intervention waveform y'0 within the range 0 < t ≤ t0;

[0052] The artificial intervention waveform y'0 within the time interval 0 < t ≤ t'0 and the basic waveform y0 within the time interval t'0 < t ≤ t0 are combined to obtain the target time-domain waveform y.

[0053] It is possible to concentrate all the energy of the entire waveform duration t0 within the specified impact action time interval 0 < t ≤ t'0 of the artificial intervention waveform to obtain the artificial intervention waveform y'0; the proportion ξ of the impact action time of the artificial intervention waveform y'0 in the entire waveform duration is ξ = t'0 / t0.

[0054] The target time-domain waveform y is composed of the artificial intervention waveform within the time interval 0 < t ≤ t'0 and the basic waveform within the time interval t'0 < t ≤ t0. The total energy of the target time-domain waveform y within the entire waveform duration t0 is E = E'0 + λE0, where E'0 is the total energy within the time interval 0 < t ≤ t'0. λE0 is the total energy within the time interval t'0 < t ≤ t0, and λ is the energy coefficient. The energy proportion η of the artificial intervention waveform in the target time-domain waveform is η = E'0 / E. By defining the value of η, the corresponding value of λ can be determined, thereby realizing the energy allocation of the basic waveform within the time interval t'0 < t ≤ t0. Through the above approach, it is possible to construct a target time-domain waveform with a certain energy proportion within the specified impact action time.

[0055] The following takes a reference shock response spectrum example to illustrate the technical approach of the present invention in detail.

[0056] The starting frequency f of the reference shock response spectrum start = 10Hz, and the inflection point frequency is f infexion= 100 Hz, the termination frequency is f end = 2000 Hz, the slope is m = 8, the amplitude is s = 20 g, as Figure 2 shown. Define the impact duration as t0 = 0.5 s, and the quality factor is taken as Q = 10. First, perform a time-domain conversion to obtain the basic waveform y0, as Figure 3 shown. Next, define the ratio of the impact action time in the entire waveform duration as ξ = 0.2, that is, all the energy of the impact process is concentrated in the time interval 0 < t ≤ 0.1 s. In the time interval 0.1 s < t ≤ 0.5 s, the waveform delay time t di satisfies t - t di = 0, and the energy in this time interval is zero. After performing a time-domain conversion, the artificially intervened waveform y'0 is obtained, as Figure 4 shown. The artificially intervened waveform y'0 undergoes an impact response spectrum transformation, as Figure 5 shown. It can be seen that the impact spectrum shape is in good agreement with the reference spectrum shape, proving that the waveform y'0 has good quality. Take the artificially intervened waveform in the time interval 0 < t ≤ 0.1 s and the basic waveform in the time interval 0.1 s < t ≤ 0.5 s for synthesis. Define the energy ratio of the artificially intervened waveform in the target time-domain waveform as η = 0.93, and the energy adjustment coefficient λ = 1.11 can be obtained, then the target time-domain waveform y is obtained, as Figure 6 shown. Perform an impact response spectrum transformation on the target time-domain waveform, as Figure 7 shown. It can be seen that the impact spectrum shape is in good agreement with the reference spectrum shape, proving that the waveform y has good quality. Through the above technical means, a target time-domain waveform with a waveform duration of 0.5 s, a specified impact action time ratio of 20%, and an energy ratio of 93% is constructed.

[0057] Therefore, based on the reference impact spectrum, through the way of combining the artificially intervened waveform and the basic waveform, by controlling the delay time t di in the artificially intervened waveform and adjusting the energy coefficient λ of the basic waveform, an impact spectrum time-domain conversion method based on energy distribution is established.

[0058] This embodiment also discloses a computer-readable storage medium, on which a computer program / instructions are stored. When the computer program / instructions are executed by a processor, the steps of any of the above-mentioned methods are implemented.

[0059] This embodiment also discloses a computer program product, including computer program / instructions. When the computer program / instructions are executed by a processor, the steps of any of the above-mentioned methods are implemented.

[0060] The content not detailedly described in the specification of this application belongs to the well-known technology of those skilled in the art.

[0061] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. A method for time domain conversion of an impulse response spectrum, characterized in that: Including: Performing a time-domain conversion on the reference shock response spectrum to obtain a base waveform y0, and defining the entire waveform duration of the base waveform y0 as t0; Calculating the base waveform y0 within the range of 0 < t ≤ t0; Calculating the specified shock action time 0 - t'0 for defining the artificial intervention waveform y'0, where t0 > t'0; calculating the artificial intervention waveform y'0 within the duration of 0 < t ≤ t'0; Combining the artificial intervention waveform y'0 within the time interval of 0 < t ≤ t'0 and the base waveform y0 within the time interval of t'0 < t ≤ t0 to obtain the target time-domain waveform y; Among them, calculating the artificial intervention waveform y'0 within the duration of 0 < t ≤ t'0 includes: The artificial intervention waveform y'0 consists of m decaying sinusoidal waves x exp is the fundamental wave, and the waveform delay time of the fundamental wave relative to the zero moment is t di ; The artificial intervention waveform y'0 is obtained by the following formula: Among them, A i ' is the waveform amplitude of the ith fundamental wave, f i ' is the waveform frequency of the i-th fundamental wave, N i ' is the number of half-sine waves of the waveform of the i-th fundamental wave; When calculating the artificially intervened waveform y'0, within the duration of 0 < t ≤ t'0, make t di ’ = (T max ’ - T i ’) / 2, where T i ’ is the duration of the i-th fundamental wave, i represents the i-th fundamental wave, and i ∈ [1, m]; T max ’ is the maximum value among multiple T i ’ within the duration range of all fundamental waves; within the duration of t'0 < t ≤ t0, control t di of each time point t of the basic waveform y0 to be t; obtain the artificially intervened waveform y'0 within the range of 0 < t ≤ t0.

2. The method for time-domain conversion of an impulse response spectrum according to claim 1, characterized in that: The total energy of the target time-domain waveform y within the entire waveform duration t0 is E = E0' + λE0, where E0' is the total energy within the time interval of 0 < t ≤ t'0, and λE0 is the total energy within the time interval of t'0 < t ≤ t0, where λ is the energy coefficient.

3. The method for time-domain conversion of impulse response spectrum according to claim 2, characterized in that: The energy proportion of the artificial intervention waveform y'0 in the target time-domain waveform is η = E0' / E. By defining the value of η, the corresponding value of λ is determined.

4. The method for time-domain conversion of impulse response spectrum according to claim 1, characterized in that: The t0 > t'0.

5. The method for time-domain conversion of impulse response spectrum according to claim 1, characterized in that: The reference shock response spectrum is determined according to the test conditions.

6. The method for time-domain conversion of impulse response spectrum according to claim 1, characterized in that: The proportion ξ of the shock action time of the artificial intervention waveform y'0 in the entire waveform duration is ξ = t'0 / t0.

7. The method for time-domain conversion of impulse response spectrum according to claim 1, characterized in that: Calculating the base waveform y0 within the range of 0 < t ≤ t0 includes: The basic waveform y0 consists of n sine waves x sin is the fundamental wave, and the waveform delay time of the fundamental wave relative to the zero moment is t di ; Sine wave x sin Obtained by the following formula: sin (t) = A i sin(2πf i t)sin(2πf i t / N i ) The basic waveform y0 is obtained by the following formula: Among them, A i is the waveform amplitude of the ith fundamental wave, f i is the waveform frequency of the ith fundamental wave, N i is the number of half-sine waves of the waveform of the ith fundamental wave; When calculating the basic waveform y0, within the duration of 0 < t ≤ t0, make t di =(T max -T i ) / 2 to obtain the basic waveform y0 within the range of 0 < t ≤ t0; Among them, T i is the duration of the ith fundamental wave, i represents the ith fundamental wave, i∈[1,n]; T max For multiple T within the range of all fundamental wave durations i The maximum value in .

8. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instructions are executed by a processor, the steps of the method according to any one of claims 1-7 are implemented.

9. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the method according to any one of claims 1-7 are implemented.

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