| Electronics are extensively used in daily life, including but not limited to avionics, computers, and handheld devices. During manufacturing, handling/shipping, and service life, electronic packages are prone to various mechanical loadings, i.e. vibration. Assessment of vibration-induced solder joint reliability of electronic packages is therefore a major concern in the industry. This dissertation aims to provide research methodologies for developing high-fidelity finite element (FE) models, validated with accurate measured data combined with simple analytical approaches, all to be used in high-cycle fatigue life assessments of electronic assemblies under vibration.;Performing finite element analysis (FEA) of a board-level package is difficult due to the complexity of the structure and the wide range of geometric scales of the various parts. For example, the printed circuit board (PCB) contains copper layers, woven fabrics, plated-through holes, and so forth. In addition to the modeling demands of such details, the mechanical behavior will be non-isotropic. Furthermore, due to manufacturing and assembly processes the installments of such complexities would be different which will cause differences in material properties of various test vehicles, including but not limited to stiffness and damping properties. Ignoring such diversities can cause unreliable stress computations and inaccurate fatigue-life predictions. To this instance, one goal of the current dissertation is to develop a novel methodology to build and tune FE models that faithfully simulate the dynamic characteristics of electronic assemblies and consider the diversities of different test pieces. These accurate models were consequently used to estimate stresses in critical locations within electronic assemblies.;A typical electronic package test vehicle mainly consists of three parts: PCB, component and solder joints. A few published papers that discuss analytical approaches to simulate dynamic characteristics of electronic packages, solder joint deflections, and vibration-induced stresses are available. For this purpose, the current work proposes an analytical solution to characterize the dynamics electronic assemblies under vibration. Consequently, this approach allows accurate estimation of the dynamic response and stresses for critical solder joints within an electronic test vehicle used for solder joint reliability studies. The results of this solution are in well-agreement with experimental data and accurately match the FE simulations. |
