A MEMS-based stiffness/energy sensor for structural health prognostics

由于各种原因，包括健康诊断和健康预测，需要对结构的机械状态进行监测。由于(i)传感器技术和（ii）传感器密度的限制，确定损伤发生和增长的位置和性质的任务变得困难；这可以在现实的结构中实现。目前的机械传感器技术主要集中在测量变形或污渍，因此对基于变形的故障预测模型很有用。在这项研究中，我们建议开发一种新型的基于mems的、自给自足的传感器，它将直接在原位测量宿主结构中的瞬时局部应变、应力、刚度和能量密度。具体来说，我们提出：(a)为一种全新的刚度/能量传感器提供基本原理的概念验证；(b)演示基本原理的MEMS实现；(c)通过将其安装在结构板的外部来演示其在损伤/退化建模中的应用。预计这项研究将展示并提供全自动传感器的第一个工作版本，该传感器将提供结构局部刚度和应变能密度变化的实时、原位测量。结合本研究中开发的损伤模型，该传感器将首次提供在复杂结构中执行实时健康预测的真正机会，在其整个生命周期中经历复杂的动态载荷。

The mechanical state of structures need to be monitored for a variety of reasons, including health diagnostics and health prognostics. The task of identifying the location and nature of damage initiation and growth is made difficult by limitations of (i) sensor technologies and (ii) sensor densities; that can be achieved in realistic structures. Current technologies for mechanical sensors mostly focus on measuring deformations or stains, and are thus useful for deformation-based failure prediction models. In this study we propose to develop a novel class of MEMS-based, self-sufficient sensors that will make direct in-situ measurements of instantaneous local strain, stress, stiffness and energy density in the host structure. Specifically, we have proposed to: (a) provide proof-of-concept of the basic principles for a novel and completely new stiffness/energy sensor; (b) demonstrate a MEMS implementation of the underlying principles; and (c) demonstrate its application for damage/degradation modeling by mounting it externally to structural coupons. It is anticipated that this study will demonstrate and deliver the first working version of a fully autonomous sensor that will provide real-time, in-situ measurements of the changes in a structure's local stiffness and strain energy density. In conjunction with the damage models to be developed during this study, this sensor will provide the first real opportunity to perform real-time health prognostics in complex structures, experiencing complex dynamic loading throughout their life-cycle.