Evaluation of very low bending radius of flexible circuits beyond the standard design rules
The Flexible Printed Circuits (FPC) used in high-end applications have some specific characteristics. It has a more complex build-up and must be compatible with repair processes. Moreover, they are used in harsh environment and long mission profile. Current FPC design are based on industrial standards, which propose design rules, such as minimum bending radius calculated from the maximum accepted copper elongation. This work is part of a large study focused on the development of a new generation of digital board solutions for electronic interconnection. In this paper, a finite element simulation study will be applied to FPC bending analysis beyond industrial standard limits. As a conclusion, we propose to consider the maximum copper strain and the bending shape for the minimum bending radius definition.
Experimental and numerical analyses of flexible PCBs under various loading conditions
This work will present case studiesof three types of Flexible Printable Circuits subjected to different loading conditions in order to evaluate their tecnologies regarding mechanical reliability. Typical causes of failure in electronic devices are associated with mechanical stress, moisture, heat from transportation and field use. Typically manufacturers carry out tests to evaluate the reliability of electronic components regarding these environmental loads. Common tools used for this evaluation, in early stages of design, are FEA (Finite Element Analysis) and experimental laboratory tests. In this work simulation models were generated aiming at developing tools for early stages of design, and mechanical tests were performed to assess actual reliability of parts and also to provide information to evaluate the simulation models. The different types of failure in the flexible printed embeded circuits, such as delamination, will be presented. Failures due to high shear stresses in flex- rigid joints will also be evaluated. Experimental tests and computational simulation will also be applied in order to perform these evaluations.
Commentary: Scholarship as a Way of Life—Character and Virtue in the Age of Big Humanities
From the Renaissance to the nineteenth century, most European scholars considered moral cultivation as the primary purpose of the humanities. The humanities were human not just because they concerned the products of the human mind but also because they transformed scholars and students into better human beings. During the late nineteenth and early twentieth centuries, the rise of Big Humanities questioned this moral purpose. However, Big Humanities also reemphasized the importance of epistemic virtues for scholarship. The language of epistemic virtues helped scholars create new communities of learning and scholarship. Within these communities, the language of virtues established common standards of collaboration and granted scholars a sense of purpose. Many of these scholars also continued to associate epistemic virtues with moral virtues.