PCB板热结构分析及优化设计

发布时间：2018-07-06 10:50

本文选题：PCB板 + 热结构分析　；参考：《西安电子科技大学》2015年硕士论文

【摘要】：电子设备在实际工作中经常会处在温度剧烈变化的环境中,也有些器件在工作过程中会被加热到很高的温度,由于温度变化、温度梯度、异质材料连接以及约束的存在,就会产生热应力和热变形,这些应力和变形有时甚至会成为器件破坏的决定性因素,因此对电子设备进行热控制设计很有必要。热控方案的验证可通过热试验和计算机仿真来实现,前者成本高而且耗时,后者则较为方便快捷,也受到越来越多的青睐。但由于近年来设备结构越来越复杂,一方面模型及仿真条件的简化处理仍然存在较多问题,另一方面如何对模型进行合理有效的优化设计也是困扰研究者的一个重要问题。因此,研究如何建立合理高效的电子设备热结构分析模型并实现有效的优化设计很有意义。本文首先介绍了ANSYS和UG NX软件热结构仿真分析的方法流程,以及PCB板常见热应力问题的分析方法,主要包括PCB板弯曲热应力分析和PCB板底面约束应力分析,同时总结了目前PCB板应力和变形的主要实验测量方法。接着讨论了螺纹连接的建模方法,主要包含螺纹连接结构模型简化处理的基本方法和原则,预紧力的加载,螺纹连接结构接触设置分析;并借助ANSYS软件对不同建模方式的螺钉连接模型及粘接、焊接、螺钉连接和螺栓连接等PCB板不同连接固定方式模型进行了热结构分析并对其中几种典型连接方式进行了影响因素研究,验证模型实际应用的有效性,为工程实际提供参考。最后介绍了响应曲面法和PCB板预变形的相关理论知识,采用响应曲面法进行试验设计,以某星载有源相控阵天线中PCB板的最小Z向变形为响应目标,借助ANSYS软件进行热结构分析,研究PCB板定位点不共面对上述响应目标的影响,并找出最佳的定位点不共面方案,为工程实际中PCB组件的热结构优化设计提供一个新思路。
[Abstract]:Electronic devices are often in an environment in which the temperature varies dramatically in practice, and some devices are heated to a very high temperature in the course of operation, because of the temperature change, temperature gradient, heterogeneity material connection and the existence of constraints. Thermal stress and deformation will be produced, which sometimes even become the decisive factor of device failure, so it is necessary to design the thermal control of electronic equipment. The verification of thermal control scheme can be realized by thermal test and computer simulation. The former is expensive and time-consuming, while the latter is more convenient and more popular. However, due to the increasing complexity of the equipment structure in recent years, on the one hand, there are still many problems in simplifying the model and simulation conditions. On the other hand, how to optimize the model reasonably and effectively is an important problem that puzzles the researchers. Therefore, it is significant to study how to establish a reasonable and efficient thermal structure analysis model of electronic equipment and to realize effective optimization design. This paper first introduces the method flow of thermal structure simulation analysis of ANSYS and UG NX software, and the analysis methods of common thermal stress problems of PCB board, including bending thermal stress analysis of PCB board and constraint stress analysis of PCB board bottom. At the same time, the main experimental measurement methods of PCB board stress and deformation are summarized. Then the modeling method of thread connection is discussed, including the basic method and principle of simplified processing of thread connection structure model, the loading of preload force and the analysis of contact setting of thread connection structure. And with the help of ANSYS software, the screw connection model, bonding and welding of different modeling methods are made. This paper analyzes the thermal structure of different PCB connection modes, such as screw connection and bolt connection, and studies the influencing factors of several typical connection modes. It verifies the validity of the practical application of the model and provides a reference for engineering practice. Finally, the theory of response surface method and PCB board pre-deformation is introduced. The experimental design is carried out by using the response surface method, and the minimum Z-direction distortion of PCB board in a star-carrying phased array antenna is taken as the response target. Based on the thermal structure analysis of ANSYS software, this paper studies the influence of PCB positioning points on the above response targets, and finds out the best location point noncoplanar scheme, which provides a new idea for the thermal structure optimization design of PCB components in engineering practice.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN41

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