Study On Thermal Deformation Simulation Technology Of Planar Slotted Array Antenna

As a widely used antenna, the deformation of the planar slotted array antenna has a great influence on the electrical properties of the welding process which is one of the main factors affecting the accuracy of the antenna. In order to predict the deformation of the plate, the vacuum brazing process of the planar slotted array antenna is simulated in this paper to study the simulation technology of the thermal deformation. Specific contents are as follows:Firstly, the finite element analysis software ANSYS is used to analyze the thermal structure of the test model. And the effect of the grid partition precision and different modeling methods on the deformation field is obtained so as to find out the relatively reasonable accuracy of grid and modeling method(namely, the horizontal solder modeling method) and the application in the following research.On the basis of above, the finite element model of the planar slotted array antenna is established and the temperature field of the environment is loaded, then the transient temperature field of the model is obtained.By using the indirect coupling method, the transient nonlinear analysis of the structural field is carried out. The phase transformation process of the brazing alloy is simulated by the birthdeath element technique. The deformation field and the stress field of the plate are solved by using the temperature field load.After that, the new modeling method(horizontal solder modeling) presented in this paper is compared with the previous one(vertical solder modeling),fully illustrates the rationality of the horizontal solder modeling approach.Finally, the contact element is used to simulate the friction between the antenna and the fixture, which makes the simulation settings more close to the actual situation, and the calculation results are more accurate.Secondly, the theoretical formula of heat transfer coefficient is verified by using the experimental model in FloEFD software,and the relationship between the wind speed and the cooling time in forced convection is summarized.Further,the relationship between the wind speed and the heat transfer coefficient is concluded for the follow-up study.When simulating the brazing process of the Planar Slotted Array Antenna in the ANSYS software,the deformation fields of the Planar Slotted Array Antenna are calculated by using the formulas of the heat transfer coefficient in two kinds of cooling mode.Finally,according to the actual situation,it is shown that applying the formula of heat transfer coefficient is more close to the actual situation than that of the constant.Finally, in view of the main factors influencing the brazing deformation of the Planar Slotted Array Antenna(the thermal expansion coefficient, the melting point and the different cooling curves),the vacuum brazing process is simulated.The influence of each factor on the ultimate deformation field and the stress field is found, and then the guidance is provided for the engineering practice.