Method for calculating random vibration transmissibility of airborne electronic equipment

Abstract

The invention provides a method for calculating the random vibration transmissibility of airborne electronic equipment, and the method comprises the steps: obtaining the instantaneous acceleration of the airborne electronic equipment in a time domain when the airborne electronic equipment vibrates, and determining the distribution condition of the instantaneous acceleration according to the value of the instantaneous acceleration; constructing a first calculation formula for calculating random vibration fatigue accumulated damage # imgabs0 # according to the distribution condition of the instantaneous acceleration and a Miner equivalent damage criterion; based on a Miner linear damage accumulation criterion, constructing a second calculation formula for calculating sinusoidal vibration fatigue damage # imgabs1 #; constructing a third calculation formula for calculating the input acceleration # imgabs2 according to the first calculation formula and the second calculation formula; the Miles theory and a third calculation formula are substituted into the Steinberg sinusoidal vibration transmissibility calculation model, and the transmissibility # imgabs3 # of random vibration is obtained through calculation. Through the calculation method, the vibration acceleration response condition of the airborne electronic equipment can be accurately calculated.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical vibration calculation, and in particular to a method for calculating the random vibration transmissibility of airborne electronic equipment. Background Art

[0002] With the development of electronic technology, electronic equipment has been more and more widely used in the aviation field. As an integral part of the aircraft, airborne electronic equipment will inevitably be subjected to vibration loads during operation. Electronic equipment mainly consists of two parts: electronic components and structural components. Since the materials of each component have a certain elasticity, elastic deformation will occur during the vibration process, so the vibration response of each component shows a strong coupling. The degree of coupling directly affects the magnitude of the vibration response value, which can be expressed by the transmissibility.

[0003] The current transmissibility calculation model is the sinusoidal vibration transmissibility calculation model proposed by Steinberg, as shown in the following formula: .

[0004] Where: Q is the transmissibility; A is the structural coefficient (1.0 for beam structure, 0.5 for plug-in PCB or peripheral supported PCB, 0.25 for small electronic baseboard or electronic chassis structure); is the natural frequency (Hz); Enter the acceleration in G (dimensionless) for sinusoidal vibration.

[0005] However, for airborne electronic equipment installed on aircraft, random vibration excitation is more common, so it is necessary to propose a transmissibility calculation model under random vibration excitation. Summary of the invention

[0006] In view of this, an embodiment of the present specification proposes a method for calculating the random vibration transmissibility of airborne electronic equipment, so as to achieve the purpose of effectively calculating the transmissibility of airborne electronic equipment installed in an aircraft under random vibration excitation.

[0007] The embodiments of this specification provide the following technical solutions: A method for calculating the random vibration transmissibility of airborne electronic equipment, comprising: Obtain the instantaneous acceleration in the time domain when the airborne electronic equipment vibrates, and determine the distribution of the instantaneous acceleration according to the value of the instantaneous acceleration; According to the distribution of instantaneous acceleration and Miner equivalent damage criterion, a random vibration fatigue cumulative damage calculation method is constructed. The first calculation formula of Based on Miner's linear damage accumulation criterion, a method for calculating sinusoidal vibration fatigue damage is constructed. The second calculation formula of The input acceleration is calculated based on the first calculation formula and the second calculation formula. The third calculation formula of Substitute Miles theory and the third calculation formula into the Steinberg sinusoidal vibration transmissibility calculation model to calculate the transmissibility of random vibration. .

[0008] Further, the distribution of the instantaneous acceleration is determined according to the value of the instantaneous acceleration, including: The distribution of instantaneous acceleration satisfies the normal distribution, and the value of instantaneous acceleration is within ±5 Within the range.

[0009] Furthermore, according to the distribution of instantaneous acceleration and Miner equivalent damage criterion, a method for calculating the cumulative damage of random vibration fatigue is constructed. The first calculation formula includes: According to the normal distribution of instantaneous acceleration, the random vibration fatigue cumulative damage is obtained ,in, is the acceleration, is the standard deviation.

[0010] Furthermore, based on Miner's linear damage accumulation criterion, a method for calculating sinusoidal vibration fatigue damage is constructed. The second calculation formula includes: Sinusoidal vibration fatigue damage ,in, is the input acceleration, is the transmission rate.

[0011] Further, the input acceleration is calculated according to the first calculation formula and the second calculation formula. The third calculation formula includes: Random vibration fatigue cumulative damage Fatigue damage with sinusoidal vibration If they are equal, then the acceleration ,in, is the root mean square acceleration of 1 standard deviation, is the transmission rate.

[0012] Furthermore, the Miles theory and the third calculation formula are introduced into the Steinberg sinusoidal vibration transmissibility calculation model to calculate the transmissibility of random vibration. ,include: According to Miles theory, the root mean square acceleration of 1 standard deviation , The input frequency is the resonant frequency PSD , is the natural frequency; Determine the structural coefficient based on the structure of the airborne electronic equipment ; The third calculation formula and Miles theory formula Substitute it into the Steinberg sinusoidal vibration transmissibility calculation model, and the transmissibility is ,in, is the structural coefficient.

[0013] Furthermore, the structural coefficient is determined according to the fixed structure of the airborne electronic equipment. ,include: If the fixed structure of the airborne electronic equipment is a beam structure, the structural coefficient ; If the fixed structure of the airborne electronic equipment is an inserted PCB or a peripherally supported PCB, the structural coefficient ; If the fixed structure of the airborne electronic equipment is a small electronic base plate or electronic chassis structure, the structural coefficient .

[0014] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above technical solutions adopted in the embodiments of this specification include at least: The method for calculating the random vibration transmissibility of the embodiment of the present invention can accurately calculate the vibration acceleration response of a product in engineering, and can also be used to correct the setting of the damping value in vibration simulation to improve the simulation accuracy. It has been verified by engineering experiments that it has high accuracy and can be applied to the calculation of random vibration transmissibility of various airborne electronic equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 is a flow chart of a method for calculating random vibration transmissibility according to an embodiment of the present invention; Figure 2 It is a schematic diagram of the time domain distribution of random vibration; Figure 3 The response curve of the airborne electronic equipment installed on the first aircraft for random vibration; Figure 4 The response curve of the airborne electronic equipment installed on the second aircraft is random vibration. DETAILED DESCRIPTION

[0017] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0018] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0019] like Figure 1 As shown, a method for calculating the random vibration transmissibility of an airborne electronic device comprises: S101: Obtain the instantaneous acceleration of the airborne electronic equipment in the time domain when it vibrates, and determine the distribution of the instantaneous acceleration according to the value of the instantaneous acceleration, and the value of the instantaneous acceleration is within ±5 within the interval; S102: Based on the distribution of instantaneous acceleration and Miner equivalent damage criterion, a method for calculating the cumulative damage of random vibration fatigue is constructed. The first calculation formula of S103: Based on Miner's linear damage accumulation criterion, a method for calculating sinusoidal vibration fatigue damage is constructed The second calculation formula of S104: Constructing and calculating input acceleration according to the first calculation formula and the second calculation formula The third calculation formula: S105: Substitute Miles theory and the third calculation formula into the Steinberg sinusoidal vibration transmissibility calculation model to calculate the transmissibility of random vibration .

[0020] Specifically, the instantaneous acceleration distribution of random vibration in the time domain conforms to the normal distribution, as shown in the attached figure. Figure 2 The time during which the instantaneous acceleration is within the full range of ±5σ levels during the entire random vibration process is 100%.

[0021] According to Miner's equivalent damage theory, the cumulative damage of random vibration fatigue is as follows: ,in, = *2.

[0022] For sinusoidal vibration fatigue damage , the calculation formula is as follows: ,in, is the input acceleration, is the transmission rate.

[0023] make , so we get: ,in is the 1δ random vibration acceleration response.

[0024] The Miles equation is also used to calculate the root mean square acceleration (RMS) of a structure's response to random vibration: ; The above formula (Miles theory formula and ) is substituted into the Steinberg sinusoidal vibration transmissibility calculation model (the Steinberg sinusoidal vibration transmissibility calculation model is a model used to estimate the vibration transfer characteristics of a structure in sinusoidal vibration), and the calculation model of the random vibration transmissibility of airborne electronic equipment can be obtained as follows: ; It has been verified that the accuracy of the model can meet the engineering needs.

[0025] Random vibration tests are carried out in different application scenarios to verify the correctness of the transmissibility calculation model of airborne electronic equipment.

[0026] The first application scenario: A random vibration test was conducted on an electronic device installed on an aircraft. The monitoring curve of the acceleration sensor on the device is as follows: Figure 3 shown.

[0027] like Figure 3 As shown, after calculation based on the measured values, the transmission rate Q of the response curve 1 at the frequency position of 1425Hz is 79.89.

[0028] The natural frequency , random vibration input acceleration PSD value P, structural coefficient A are brought into the airborne electronic equipment transmission rate calculation model, where the natural frequency =1425Hz, random vibration input acceleration PSD value P=0.1g2 / Hz, structural coefficient A=0.5.

[0029] Substituting the above variables into the airborne electronic equipment transmission rate calculation model, the transmission rate Q=76.58 can be obtained.

[0030] Comparing the measured value of the transmissibility Q with the transmissibility Q calculated by the airborne electronic equipment transmissibility calculation model, the calculation error is 4.14%.

[0031] Second application scenario: A random vibration test was conducted on an electronic device installed on a propeller aircraft. The monitoring curve of the acceleration sensor on the device is as follows: Figure 4 shown.

[0032] like Figure 4 As shown, according to the measured value calculation, the amplified Q of response curve 2 at 100Hz is 7.33 times.

[0033] The natural frequency , random vibration input acceleration PSD value P, structural coefficient A are brought into the airborne electronic equipment transmission rate calculation model, where the natural frequency =100Hz, random vibration input acceleration PSD value P=0.03g2 / Hz, structural coefficient A=0.25.

[0034] Substituting the above variables into the airborne electronic equipment transmission rate calculation model, the transmission rate Q=6.68 can be obtained.

[0035] Comparing the measured value of the transmissibility Q with the transmissibility Q calculated by the airborne electronic equipment transmissibility calculation model, the calculation error is 2.6%.

[0036] In the above two application scenarios, the error between the measured value and the value calculated by the airborne electronic equipment transfer rate calculation model is less than 5%, which meets the allowable error in practical applications.

[0037] Beneficial effects of the embodiments of the present invention: The method for calculating the random vibration transmissibility of the embodiment of the present invention can accurately calculate the vibration acceleration response of the product in engineering, and can also be used to correct the setting of the damping value in the vibration simulation to improve the simulation accuracy. It has been verified by engineering experiments that it has high accuracy and can be applied to the calculation of the random vibration transmissibility of various airborne electronic equipment.

[0038] The above is only a specific embodiment of the present invention, and cannot be used to limit the scope of the invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the scope of protection of the patent of the present invention, should still fall within the scope of this patent. In addition, the technical features of the present invention can be freely combined with each other, with each other, and with each other.

Claims

1. A method for calculating the random vibration transmissibility of an airborne electronic device, characterized in that: include: Acquire the instantaneous acceleration in the time domain when the airborne electronic device vibrates, and determine the distribution of the instantaneous acceleration according to the value of the instantaneous acceleration; According to the distribution of instantaneous acceleration and Miner equivalent damage criterion, a method for calculating the cumulative damage of random vibration fatigue is constructed. The first calculation formula of Based on Miner's linear damage accumulation criterion, a method for calculating sinusoidal vibration fatigue damage is constructed. The second calculation formula of The input acceleration is calculated based on the first calculation formula and the second calculation formula. The third calculation formula of Substitute Miles theory and the third calculation formula into the Steinberg sinusoidal vibration transmissibility calculation model to calculate the transmissibility of random vibration: .

2. The method for calculating the random vibration transmissibility of an airborne electronic device according to claim 1, characterized in that: Determining the distribution of the instantaneous acceleration according to the value of the instantaneous acceleration includes: The distribution of the instantaneous acceleration satisfies the normal distribution, and the value of the instantaneous acceleration is within ±5 Within the range.

3. The method for calculating the random vibration transmissibility of an airborne electronic device according to claim 1, characterized in that: According to the distribution of instantaneous acceleration and Miner equivalent damage criterion, a method for calculating the cumulative damage of random vibration fatigue is constructed. The first calculation formula includes: According to the instantaneous acceleration of normal distribution, the random vibration fatigue cumulative damage is obtained ,in, is the acceleration, is the standard deviation.

4. The method for calculating the random vibration transmissibility of an airborne electronic device according to claim 1, characterized in that: Based on Miner's linear damage accumulation criterion, a method for calculating sinusoidal vibration fatigue damage is constructed. The second calculation formula includes: Sinusoidal vibration fatigue damage ,in, is the input acceleration, is the transmission rate.

5. The method for calculating the random vibration transmissibility of an airborne electronic device according to claim 1, characterized in that: The input acceleration is calculated based on the first calculation formula and the second calculation formula. The third calculation formula includes: Let the random vibration fatigue cumulative damage Fatigue damage with the sinusoidal vibration If they are equal, then the acceleration ,in, is the root mean square acceleration of 1 standard deviation, is the transmission rate.

6. The method for calculating the random vibration transmissibility of an airborne electronic device according to claim 1, characterized in that: Substitute the Miner equation and the third calculation formula into the Steinberg sinusoidal vibration transmissibility calculation model to calculate the transmissibility of random vibration: ,include: According to Miles theory, the root mean square acceleration of 1 standard deviation , The input frequency is the resonant frequency PSD , is the natural frequency; Determine the structural coefficient based on the structure of the airborne electronic equipment ; The third calculation formula and 1 standard deviation of the RMS acceleration Substitute it into the Steinberg sinusoidal vibration transmissibility calculation model, and the transmissibility is ,in, is the structural coefficient.

7. The method for calculating the random vibration transmissibility of an airborne electronic device according to claim 6, characterized in that: Determine the structural coefficient based on the fixed structure of the airborne electronic equipment ,include: If the fixed structure of the airborne electronic equipment is a beam structure, the structural coefficient ; If the fixed structure of the airborne electronic equipment is an inserted PCB or a peripherally supported PCB, the structural coefficient ; If the fixed structure of the airborne electronic equipment is a small electronic base plate or electronic chassis structure, the structural coefficient .

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