Disclosure of Invention
The invention overcomes the defects of long time consumption and high cost of the existing airplane lightning stroke area division test, and provides a simulation calculation method for obtaining the airplane lightning stroke area division through software simulation.
The invention provides a lightning zoning method, which comprises the following steps:
constructing an airplane and a discharge cloud layer model, and taking a pitch angle, a yaw angle and a roll angle which are all zero as reference simulation models;
combining SAE-ARP-5414A standard partition theory, the method is obtained through repeated simulation analysis: on the basis of the 1-zone division of the charge distribution, about 35% of the maximum charge density induced by the surface of the airplane is taken as a threshold value, and the area exceeding the threshold value is determined as a lightning zone 1 zone;
respectively acquiring the surface charge distribution conditions of the airplane at different angles under different pitch angles, yaw angles and roll angles;
and counting to obtain the thunder and lightning division conditions of each region of the airplane according to the distribution conditions of the surface charges of the airplane at different angles.
Specifically, the constructing of the aircraft and the discharge cloud layer model specifically includes:
the nearest distance between the cloud layer and the airplane in the airplane and the discharge cloud layer model is 60m, and the voltage between the cloud layers is set to be 150 ten thousand volts.
Specifically, the aircraft and the discharge cloud model in the discharge cloud model are two copper plates with the potential difference of 150 ten thousand volts, and the aircraft model is an aluminum model.
Specifically, the acquiring the surface charge distribution of the aircraft at different angles under different pitch angles, yaw angles and roll angles includes:
and acquiring the surface charge distribution conditions of the airplane at different angles by using Ansys Q3D software under different pitch angles, yaw angles and roll angles.
Specifically, according to the distribution situation of the surface charges of the airplane at different angles, the lightning division situation of each area of the airplane is obtained through statistics, and the method specifically comprises the following steps:
comparing SAE-ARP-5414A standard partition theory, about 35% of the maximum charge density of the airplane surface induction is a threshold value, and an area exceeding the threshold value is determined as a lightning partition 1 area;
and obtaining the lightning division conditions of the 1A areas of all parts of the airplane in the typical posture.
Specifically, respectively under different pitch angle, yaw angle and roll angle, acquire aircraft surface charge distribution under the different angles, specifically include:
changing the rolling angle of the airplane, and simulating to obtain the surface charge distribution conditions of the wingtips and the horizontal tails.
Specifically, respectively under different pitch angle, yaw angle and roll angle, acquire aircraft surface charge distribution under the different angles, specifically include:
and changing the rolling angle of the airplane, and simulating to obtain the surface charge distribution condition of the vertical tail.
Specifically, respectively under different pitch angle, yaw angle and roll angle, acquire aircraft surface charge distribution under the different angles, specifically include:
changing the pitching angle of the airplane, and simulating to obtain the surface charge distribution conditions of the nose and the tail.
In conclusion, the invention provides an effective method for obtaining simulation analysis of the airplane lightning partition 1 (including the 1A partition and the 1B partition) through software simulation calculation, compared with a lightning partition test, the method has the advantages of obvious advantages, high speed, low cost and low manpower consumption, the airplane lightning partition 1 is quickly divided through software, the airplane lightning protection capability can be pre-evaluated in a scheme stage in advance, the lightning protection design is carried out on the whole airplane according to the lightning partition result, and the problems of blind design and design lag caused by long test period of the lightning partition after the design are solved.
Detailed Description
The Ansys Q3D software can give the distribution of the induced charge on the surface of the airframe shortly before lightning strikes the aircraft using a quasi-static method. The lightning voltage is different from several million volts to several hundred million volts, the voltage between layers of clouds in simulation changes, the charge distribution on the surface of the airplane also changes, but under different conditions, the charge distribution trend is the same, the initial lightning strike attachment area is determined by referring to the definition of the initial lightning strike attachment area in SAE-ARP-5414A and combining the induced charge distribution condition, and then the area 1 of each lightning strike area is divided.
The major implementation steps of lightning stroke area division by using Ansys Q3D software comprise: repairing an airplane model (the original structure model of the airplane does not meet the electrical continuity requirement of simulation software), establishing a simulation model (constructing a physical model simulating the airplane and a discharge cloud layer), calculating and dividing a lightning stroke region (obtaining the induced charge distribution of each part of the airplane by a quasi-static calculation method, and determining the position which exceeds the maximum value of the induced charge density by 35 percent as an initial lightning adhesion 1 region).
The method comprises three main contents of simulation modeling, threshold value calibration, simulation setting and calculation analysis for the division of the airplane lightning region 1 through software.
a) Simulation modeling
Constructing a physical model for simulating the airplane and the discharge cloud layer, wherein the shortest distance between the cloud layer and the airplane in the model is 60m, and the minimum distance meets the requirements specified in SAE ARP 5416: the test should simulate a discharge that is 50m away from the nearest aircraft surface. The inter-cloud voltage was set to 150 kilovolts.
Two copper plates with the potential difference of 150 ten thousand volts are used for simulating the charged cloud layer in the model, the material of the airplane model is aluminum, and three angles for determining the airplane attitude in a three-dimensional rectangular coordinate system are as follows: pitch angle, yaw angle, and roll angle. The attitude coordinate system of the pitch angle, the yaw angle and the roll angle of the plane in the simulation is shown in figure 1.
b) Threshold calibration
Combining SAE-ARP-5414A standard partition theory, the method is obtained through repeated simulation analysis: the 1-zone division based on the charge distribution is characterized in that about 35% of the maximum charge density induced by the aircraft surface is used as a threshold value, and the area exceeding the threshold value is determined as a lightning zone 1 zone.
c) Simulation setup
In the simulation, one of the pitch angle, the yaw angle and the roll angle is changed respectively and is changed once every 30 degrees (due to the symmetry of the model, the range of pitch angle to be discussed is [ -90,90] degrees, the range of yaw angle to be discussed is [ -90,90] degrees, and the range of roll angle to be discussed is [ -90,90] degrees. A Q3D simulated reference engineering model with zero pitch, yaw and roll angles is shown in fig. 2.
d) Computational analysis
And analyzing the surface charge distribution condition of the airplane at different angles. The change of the rolling angle of the airplane mainly influences the size of lightning stroke zones of a wingtip, a horizontal tail and a vertical tail. When the roll angle is 90 degrees (same as minus 90 degrees), the region of the droop 1A reaches a maximum. When the roll angle is 0 degrees, namely the wingspan direction of the airplane is opposite to the charged cloud layer, the area 1A of the wingtip reaches the maximum. The change of the pitching angle of the airplane mainly influences the size of the lightning stroke subareas of the nose and the tail of the airplane. When the pitch angle is 0 degree, the area of the machine head 1A and the area of the machine tail 1B reach the maximum value. The airfoil tip charge distribution is shown in figure 3.