MEMS passive strain recorders/counters

本提案的目标是开发小型2 MEMS峰值应变记录仪和应变周期计数器。用户可以将MEMS设备粘附在结构上，一周或一年后回来，并拍摄照片，记录结构所经历的峰值应变和循环次数。这是一个被动的，纯微机械系统。**大多数应变计是基于电阻的：它们很小(**通常应变值很小（1微应变= 1 ppm）；对于长度为1厘米的量规，测量10个微应变需要检测0.1微米的变化。使用无源MEMS系统可以测量如此小的变化，不需要电源。MEMS锁存系统用于永久存储峰值应变值。MEMS设备包含相当于条形码的微尺度，记录的应变可以使用智能手机光学读取。事实上，现代智能手机相机可以在微观尺度上进行测量。关键是基于傅里叶的技术，它可以健壮地检测亚微米尺度的位移。****小型，廉价和被动的记录仪表打开了一个全新的可能性：无处不在的监测机械结构。正如许多消费品都带有一次性无源RFID标签一样，许多机械部件也可以贴上MEMS应变记录贴片。飞机部件，汽车部件，风力涡轮机，假肢，建筑物，任何机械部件都可以应用MEMS贴片，然后进行监测以测量峰值负载。这个结构是否超载了？这个结构是否超过了安全极限？实现这一潜力的关键是使用MEMS使应变记录仪小型化和无源化

The goal of this proposal is to develop small 2 MEMS peak strain recorders and strain cycle counters. A user can adhere the MEMS device to a structure, and come back a week or a year later, and take a photograph that records the peak strain and number of cycles experienced by the structure. This is a passive, purely micro-mechanical system.**Most strain gages are resistance based: they are small (**Typically strain values are small (1 micro strain = 1 ppm); for a gage length of 1 cm, measuring 10 micro strain would require detecting 0.1 micron changes. Measuring such small changes is possible using a passive MEMS system, no power source required. A MEMS latching system is used to permanently store peak strain values. The MEMS device contains the micro-scale equivalent of a bar code and the recorded strain can be read optically using a smartphone. Modern smartphone cameras can in fact measure at the micro-scale. The key to this is Fourier based techniques that can robustly detect sub-micron scale displacements. ****Small, inexpensive and passive recording gages open up an entirely new possibility: the ubiquitous monitoring of mechanical structures. Just as many consumer goods come with disposable passive RFID tags, many mechanical components could be tagged with a MEMS strain recording patch. Aircraft components, automobile parts, wind turbines, artificial limbs, buildings, any mechanical part could have a MEMS patch applied and then be monitored to measure peak loads. Has the structure been overloaded? Has this structure exceed its safe limit? Key to this potential is making the strain recorders small and passive using MEMS.**