Thermal Structure Analysis And Optimum Design Of PCB

In the actual work, the electronic equipments always work in a temperature environment with dramatic change, and some devices will be heated to a high temperature, due to temperature change,temperature gradient, the connection of heterogeneous materials and the existence of constraints, it will produce thermal stress and thermal deformation, these stresses and deformations can sometimes become the key factors in the destruction of electronic equipments, so it is very necessary to do the thermal control design for electronic equipments. The verification of thermal control scheme can be realized by thermal test and computer simulation. The former one is expensive and time consuming,while the latter one is more convenient and more popular. However, due to the complexity of the structure of the devices in recent years, on the one hand, there are still many problems in the simplify of the simulation conditions, on the other hand, how to optimize the model reasonably and effectively is an important problem that bothers the researchers.Therefore, it is significant to study how to establish a reasonable and efficient thermal structure analysis model of the electronic equipment and realize the effective optimization design.This paper firstly introduces the method and process of thermal structure simulation analysis of the ANSYS and UG NX software, and the analysis method of the common thermal stress problems of PCB, including the bending thermal stress analysis of PCB and the stress analysis of PCB of which the bottom surface is constraint, and summarizes the main experiment methods of the stress and deformation measurement of PCB.Then modeling methods of the thread connection are discussed, including the basic method and principle of the simplification of the model of thread connection structure, the load of pretightening force, and analysis on the contact setting of the thread connection structure.Using ANSYS software to do the thermal structure analysis of screw connection with different modeling methods and of PCB with different connection ways, such as splicing,welding, screw connection and bolt connection, and the influence factors of several typical connection models are studied.Finally introduce the response surface method and pre-deformation theory knowledge of PCB, using the response surface method to do the experiment design, with the minimum Z-direction deformation of the PCB in a satellite-borne active phased-array antenna as the response target, using the ANSYS software to do the thermal structure analysis, study on the effect of PCB's positioning point non coplanar on the response target, and find out the best positioning point non coplanar scheme, which provide a new idea for the thermal structure optimization design of PCB in practical engineering.