印制电路板与集成电路组件的模态分析及振动可靠性研究

【作者】 程诗叙；

【导师】 敬守钊；

【作者基本信息】 电子科技大学 ， 电路与系统， 2005， 硕士

【摘要】 电子产品的振动可靠性问题是目前国内外航空航天界非常关心和研究的重点之一。据统计,在导致机载电子设备故障中,振动因数已经占到27%,而印制电路板组件(PCBA)又是振动问题的核心。在振动环境下,PCBA 对振动的敏感性已经影响到整板的性能和系统的稳定性。模态分析技术是获得结构动态特性的重要手段,它起源于80 年代初,经过20 多年发展,至今已趋成熟。它和有限元分析技术一起,已成为结构动力学中两大支柱。目前这一技术已发展成为解决工程中振动问题的重要手段,在机械、航空、航天和电子等工程领域被广泛应用。结构动态特性包括各阶固有频率、主振型、阻尼比等,我们根据结构动态特性就可以对结构进行优化设计、故障诊断、可靠性分析与估计。本文从电路系统的角度,摈弃电子和机械工程的学科界限,结合现代模态分析技术对某卫星信号处理电路组件出现的振动可靠性问题进行研究。首先研究了适用于PCBA 的有限元建模方法,据此建立了目标PCBA 的有限元分析模型,应用大型工程分析软件ANSYS 对它进行计算模态分析,得到的动态特性结果与最后的实验结果表明此建模方法是合理的。实验模态分析是精确获得结构动态特性的唯一方法,我们借助美国DP 公司的动态信号分析仪对目标PCBA 进行了实验模态分析,获得了包括固有频率、振型和阻尼等特性参数,为下一步的故障诊断、可靠性分析与估计、优化设计与结构动力修改打下基础。实验模态分析的同时研究了振动信号的分析与参数提取方法。根据前期获得结果,找到了目标PCBA 的薄弱环节,提出改进抗振性措施,对它进行基于灵敏度分析的动力修改,并用Protel 对电路板重新布板投产,模态分析表明,结果有很大改善,经第三次改进布板投产,抗振性得到较大提高,经严酷的扫频和随机振动实验,均一次通过,未出现改板前的各种故障,目前整机已通过验收并交付使用。我们以此为契机全面研究了PCBA 的一般动态特性,提出PCBA 的一些通用抗振设计原则,填补了国内空白,为电路设计师在前期PCB 布局布线设计中考虑电路的抗振性问题提供了依据,从而为全面提高电路系统振动可靠性打下坚实基础。本文的一些结论也可以植入EDA软件的设计规则检查中,其方法对EDA软件的开发也有一定的参考意义和价值。更多还原

【Abstract】 Vibration reliability of electronic equipment is one of the research emphasis inthe aerial electronics industry. According to statistic, vibration is more than 27% inthe factor resulting failure of electronic equipment, and printed circuit boardsassembly (PCBA) is the focus of vibration problem. In vibration environment, thePCBA is so sensitive to vibration that influence holistic equipmentModal analysis technology is the most important means to obtain structuredynamic properties. It come of early of 80 ages, and has maturated in the development20 years. Together with finite element (FE) analysis, they have become the twobackbones of structure dynamics. And they have been applied widely in mechanicalengineering, aviation and spaceflight and electronic industry. Dynamic propertiesinclude natural frequency, vibration model shape and damping ratio etc. Accordingwith these dynamic properties, we can process optimal design, troubleshooting,reliability analysis and estimate.From the point of circuit and system, discarding the boundary between electronicand mechanical, combining with modem modal analysis technology, a series ofresearch was processed to the vibration reliability problem of one digital processingPCBA installed in one satellite. Firstly, we researched FE modeling methods of thePCB, and, the FE modal of PCBA was set up. Subsequently, modal analysis wasprocessed to this FE modal applying ANSYS software. And it figured out its dynamicproperty parameter. By contrasting with the result of experiment modal analysis, itwas indicated that the FE modeling methods was reasonable. Experiment modalanalysis is the exclusive methods of obtaining the actual structure dynamic property.Recur to the dynamic signal analyzer of DP cop. of USA, We processed Experimentmodal analysis to the PCBA, and obtained its actual parameter of dynamic propertyincluding natural frequency, modal shape and damping ratio etc. these result wasgrounded for troubleshooting, optimal design, reliability analysis and dynamicimprovement. At the same time, the analysis of vibration signal and the methods ofpick-up parameter was researched.Based the result of modal analysis, the weakness of PCBA was found, andanti-vibration measure was put forwarded, this PCBA was processed dynamicmodification based in sensitive analysis. So, the PCBA was redesigned and fabricated.Result was very good. Its anti-vibration property was improved largely. And, it passed更多还原