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循环计数器。用户可以将MEMS器件粘附到结构上，并在一周或一年后回来，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、纯粹的微机械系统。 大多数应变计都是基于电阻的：它们很小（ 通常应变值很小（1微应变= 1 ppm）;对于1 cm的标距长度，测量10微应变将需要检测0.1微米的变化。使用无源MEMS系统可以测量这种微小的变化，不需要电源。MEMS锁存系统用于永久存储峰值应变值。 MEMS器件包含相当于条形码的微尺度，并且可以使用智能手机光学读取记录的应变。现代智能手机摄像头实际上可以在微观尺度上进行测量。其中的关键是基于傅立叶的技术，可以鲁棒地检测亚微米级的位移。 小型、廉价和无源的记录仪开辟了一个全新的可能性：机械结构的无处不在的监测。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使用MEMS应变记录贴片进行标记。 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。结构是否超载？这座建筑物是否超过了安全极限？实现这一潜力的关键是使用MEMS使应变记录仪变得小型和无源。

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.