Vibration suppression in cutting tools using collocated piezoelectric sensors/actuators with an adaptive control algorithm

The machining process is very important in many engineering applications. In high precision machining, surface finish is strongly correlated with vibrations and the dynamic interactions between the part and the cutting tool. Parameters affecting these vibrations and dynamic interactions, such as spindle speed, cut depth, feed rate, and the part's material properties can vary in real-time, resulting in unexpected or undesirable effects on the surface finish of the machining product. The focus of this research is the development of an improved machining process through the use of active vibration damping. The tool holder employs a high bandwidth piezoelectric actuator with an adaptive positive position feedback control algorithm for vibration and chatter suppression. In addition, instead of using external sensors, the proposed approach investigates the use of a collocated piezoelectric sensor for measuring the dynamic responses from machining processes. The performance of this method is evaluated by comparing the surface finishes obtained with active vibration control versus baseline uncontrolled cuts. Considerable improvement in surface finish (up to 50%) was observed for applications in modern day machining

Active-sensing platform for structural health monitoring: Development and deployment

Embedded sensing for structural health monitoring is a rapidly expanding field, propelled by algorithmic advances in structural health monitoring and the ever-shrinking size and cost of electronic hardware necessary for its implementation. Although commercial systems are available to perform the relevant tasks, they are usually bulky and/or expensive because of their high degree of general utility to a wider range of applications. As a result, multiple separate devices may be required in order to obtain the same results that could be obtained with a structural health monitoring–specific device. This work presents the development and deployment of a versatile, Wireless Active-Sensing Platform, designed for the particular needs of embedded sensing for multi-scale structural health monitoring. The Wireless Active-Sensing Platform combines a conventional data acquisition ability to record voltage output (e.g. from strain or acceleration transducers) with ultrasonic guided wave-based active-sensing, and a seamlessly integrated impedance measurement mode, enabling impedance-based structural health monitoring and piezoelectric sensor diagnostics to reduce the potential for false positives in damage identification. The motivation, capabilities, and hardware design for the Wireless Active-Sensing Platform are reviewed, and three deployment examples are presented, each demonstrating an important aspect of embedded sensing for structural health monitoring

Active-sensing platform for structural health monitoring: Development and deployment

Embedded sensing for structural health monitoring is a rapidly expanding field, propelled by algorithmic advances in structural health monitoring and the ever-shrinking size and cost of electronic hardware necessary for its implementation. Although commercial systems are available to perform the relevant tasks, they are usually bulky and/or expensive because of their high degree of general utility to a wider range of applications. As a result, multiple separate devices may be required in order to obtain the same results that could be obtained with a structural health monitoring–specific device. This work presents the development and deployment of a versatile, Wireless Active-Sensing Platform, designed for the particular needs of embedded sensing for multi-scale structural health monitoring. The Wireless Active-Sensing Platform combines a conventional data acquisition ability to record voltage output (e.g. from strain or acceleration transducers) with ultrasonic guided wave-based active-sensing, and a seamlessly integrated impedance measurement mode, enabling impedance-based structural health monitoring and piezoelectric sensor diagnostics to reduce the potential for false positives in damage identification. The motivation, capabilities, and hardware design for the Wireless Active-Sensing Platform are reviewed, and three deployment examples are presented, each demonstrating an important aspect of embedded sensing for structural health monitoring

Damage Identification of Wind Turbine Blades Using Piezoelectric Transducers

This paper presents the experimental results of active-sensing structural health monitoring (SHM) techniques, which utilize piezoelectric transducers as sensors and actuators, for determining the structural integrity of wind turbine blades. Specifically, Lamb wave propagations and frequency response functions at high frequency ranges are used to estimate the condition of wind turbine blades. For experiments, a 1 m section of a CX-100 blade is used. The goal of this study is to assess and compare the performance of each method in identifying incipient damage with a consideration given to field deployability. Overall, these methods yielded a sufficient damage detection capability to warrant further investigation. This paper also summarizes the SHM results of a full-scale fatigue test of a 9 m CX-100 blade using piezoelectric active sensors. This paper outlines considerations needed to design such SHM systems, experimental procedures and results, and additional issues that can be used as guidelines for future investigations

Development of polymer \u27chips\u27 used in medical diagnostics

In recent years, there has been growing interest in creating bio-inspired devices that feature artificial bilayer lipid membranes (BLM), or lipid bilayers. These membranes can be tailored to mimic the structure and transport properties of cellular walls and can be used to selectively transport ions and other species between aqueous volumes. One application of this research is the formation of a standardized BLM contained within a portable and disposable housing for use in medical diagnostics. This concept utilizes a flexible polymer \u27chip\u27 that has internal compartments for housing both an organic solvent and an aqueous solution, which contains phospholipid molecules, proteins, and specific analyte molecules. The formation of a BLM within the chip enables integration of the chip into an electronic reader to perform diagnostic measurements of the sample. A key element of the bilayer formation process requires a single aqueous volume to first be separated into multiple volumes such that it can then be reattached to form a bilayer at the interface. This process, called the regulated attachment method, relies on the geometry of the deformable \u27chip\u27 to separate and reattach the aqueous contents held inside by opening and closing an aperture that divides adjacent compartments through the application of mechanical force. The purpose of this research is to develop an optimized chip that provides a controllable method for initially separating the aqueous phase via dynamic excitation. This study focuses on two specific aspects: designing an efficient excitation method for separating the aqueous volume, and optimizing the geometry of the chip to decrease the required input energy and better target the location and duration of the separation. Finite Element (FE) models are used to optimize the chip geometry and to identify suitable excitation signals. A series of experimental studies are also presented to validate the FE models