FPCWAY

Analysis of Vibration Characteristics of FPCBs Under Random Vibration_1_Introduction

1.Introduction

    In recent years, with the rapid development of science and technology, flexible structures represented by flexible circuit boards have gradually emerged in the chip industry, biomedical healthcare, and related interconnected fields, achieving significant progress [1-13]. The high elasticity and toughness of flexible structures give them unique advantages in monitoring special environments such as biological soft tissues and curved structural components, which has promoted the rise of this industry. The advantages of flexible structures effectively compensate for the defects of traditional monitoring sensors that are too rigid. Traditional monitoring sensors, due to their hard substrate material characteristics, are increasingly unable to adapt to current complex usage environments [14-17]. Therefore, combining flexible structures with circuitry can effectively improve the elasticity of sensor structures, allowing them to overcome harsh limitations of usage environments. Especially in recent years, the gradual development of micro-nano processing technology and flexible material preparation technology has brought hope to the preparation of flexible circuit boards .

    Flexible Printed Circuits (FPCs) use flexible insulating substrates. As flexible printed circuit boards are applied more widely, electronic products using flexible circuit boards are imposing higher requirements on structural safety, especially regarding dynamic environments. However, current research on the dynamics of flexible circuit boards is insufficient, and most studies focus on external environmental excitations, lacking analysis of the structure's own dynamic characteristics. Therefore, to further understand the dynamic characteristics of flexible circuit boards and clarify the design criteria for flexible circuit boards, it is necessary to start from the study of the dynamic characteristics of flexible structures themselves and analyze the mechanical representation of flexible circuit board structures in actual high dynamic characteristic environments.

    Modal shape, as a typical dynamic characteristic of a structure, can explain the specific vibration situation of the structure in a specific environment. Therefore, this paper takes the calculation and analysis of modal shape characteristics of flexible circuit boards as the entry point. Based on understanding the structure of flexible circuit boards and related technologies such as random vibration, the theory of modal analysis is briefly introduced. After explaining the real modal analysis method and the complex modal analysis method, the COMSOL Multiphysics finite element simulation technology is applied to simulate and calculate flexible circuit boards attached with electronic components. The modal shapes of the structure are summarized, and according to different random vibration PSD spectrum inputs, corresponding stress and strain nephograms are calculated and drawn to analyze the random vibration characteristics of the flexible circuit board.