Stephen T. Trickey

Bio: Stephen T. Trickey is an academic researcher from United States Naval Research Laboratory. The author has contributed to research in topics: Attractor & Fiber Bragg grating. The author has an hindex of 8, co-authored 27 publications receiving 322 citations. Previous affiliations of Stephen T. Trickey include Duke University.

Bragg grating-based fibre optic sensors in structural health monitoring.

Abstract: This work first considers a review of the dominant current methods for fibre Bragg grating wavelength interrogation. These methods include WDM interferometry, tunable filter (both Fabry–Perot and acousto-optic) demultiplexing, CCD/prism technique and a newer hybrid method utilizing Fabry–Perot and interferometric techniques. Two applications using these techniques are described: hull loads monitoring on an allcomposite fast patrol boat and bolt pre-load loss monitoring in a composite beam in conjunction with a state-space modelling data analysis technique.

Structural Health Monitoring Through Chaotic Interrogation

Abstract: The field of vibration based structural health monitoring involves extracting a ‘feature’ which robustly quantifies damage induced changes to the structure in the presence of ambient variation, that is, changes in ambient temperature, varying moisture levels, etc In this paper, we present an attractor-based feature derived from the field of nonlinear time-series analysis Emphasis is placed on the use of chaos for the purposes of system interrogation The structure is excited with the output of a chaotic oscillator providing a deterministic (low-dimensional) input Use is made of the Kaplan–Yorke conjecture in order to ‘tune’ the Lyapunov exponents of the driving signal so that varying degrees of damage in the structure will alter the state space properties of the response attractor The average local attractor variance ratio (ALAVR) is suggested as one possible means of quantifying the state space changes Finite element results are presented for a thin aluminum cantilever beam subject to increasing damage, as specified by weld line separation, at the clamped end Comparisons of the ALAVR to two modal features are evaluated through the use of a performance metric

The stability of limit–cycle oscillations in a nonlinear aeroelastic system

Abstract: The effects of a freeplay structural nonlinearity on an aeroelastic system are studied experimentally. Particular attention is paid to the stability of a periodic nonlinear aeroelastic response, kn...

Bottlenecking phenomenon near a saddle-node remnant in a Duffing oscillator

Abstract: The bottlenecking phenomenon near a saddle-node remnant or ghost is discussed for an electronic circuit modeling Duffing's equation. Numerical simulation and a useful experimental perturbation method, stochastic interrogation, are used to confirm the analytic inverse square root scaling law associated with saddle-node bifurcations.

Strain Measurements from FBGs Embedded in Rotating Composite Propeller Blades

Abstract: Fiber optic sensors are routinely touted as being perfect for embedding in composite materials to create smart materials. In spite of this, there are few published reports where fiber sensors were embedded in a commercially manufactured composite structure and interrogated during the normal operation of that structure. This report describes our efforts to embed arrays of fiber Bragg grating (FBG) sensors in composite propeller blades and record the dynamic strains experienced by those blades during water tunnel testing. The results show large changes in strain that depend on the location of the blade in an unsteady flow field and how those strains vary with distance along the midchord of the blade.

An introduction to structural health monitoring

Abstract: This introduction begins with a brief history of SHM technology development. Recent research has begun to recognise that a productive approach to the Structural Health Monitoring (SHM) problem is to regard it as one of statistical pattern recognition (SPR); a paradigm addressing the problem in such a way is described in detail herein as it forms the basis for the organisation of this book. In the process of providing the historical overview and summarising the SPR paradigm, the subsequent chapters in this book are cited in an effort to show how they fit into this overview of SHM. In the conclusions are stated a number of technical challenges that the authors believe must be addressed if SHM is to gain wider acceptance.

A review of structural health monitoring literature 1996-2001

Abstract: Staff members at Los Alamos National Laboratory (LANL) produced a summary of the structural health monitoring literature in 1995. This presentation will summarize the outcome of an updated review covering the years 1996 2001. The updated review follows the LANL statistical pattern recognition paradigm for SHM, which addresses four topics: 1. Operational Evaluation; 2. Data Acquisition and Cleansing; 3. Feature Extraction; and 4. Statistical Modeling for Feature Discrimination. The literature has been reviewed based on how a particular study addresses these four topics. A significant observation from this review is that although there are many more SHM studies being reported, the investigators, in general, have not yet fully embraced the well-developed tools from statistical pattern recognition. As such, the discrimination procedures employed are often lacking the appropriate rigor necessary for this technology to evolve beyond demonstration problems carried out in laboratory setting.

Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications.

Abstract: In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques.

Fiber optic sensors for structural health monitoring of air platforms.

Abstract: Aircraft operators are faced with increasing requirements to extend the service life of air platforms beyond their designed life cycles, resulting in heavy maintenance and inspection burdens as well as economic pressure. Structural health monitoring (SHM) based on advanced sensor technology is potentially a cost-effective approach to meet operational requirements, and to reduce maintenance costs. Fiber optic sensor technology is being developed to provide existing and future aircrafts with SHM capability due to its unique superior characteristics. This review paper covers the aerospace SHM requirements and an overview of the fiber optic sensor technologies. In particular, fiber Bragg grating (FBG) sensor technology is evaluated as the most promising tool for load monitoring and damage detection, the two critical SHM aspects of air platforms. At last, recommendations on the implementation and integration of FBG sensors into an SHM system are provided.

Vibration-based methods for structural and machinery fault diagnosis based on nonlinear dynamics tools

Abstract: This study explains and demonstrates the utilisation of different nonlinear-dynamics-based procedures for the purposes of structural health monitoring as well as for monitoring of robot joints.