Norris Stubbs

Bio: Norris Stubbs is an academic researcher from Texas A&M University. The author has contributed to research in topics: Modal & Modal analysis. The author has an hindex of 24, co-authored 64 publications receiving 2803 citations. Previous affiliations of Norris Stubbs include Youngsan University.

Field Verification of a Nondestructive Damage Localization and Severity Estimation Algorithm

Abstract: An experiment to field-test an existing methodology for nondestructive damage localization in bridges is described. he-damage and post-damage modal data are extracted from a 1300 A span bridge located in New Mexico. The data are fed into the damage detection algorithm and the damage localized. Results of the analysis indicate that the methodology accurately localizes the damage.

Damage Localization in Structures Without Baseline Modal Parameters

Abstract: A methodology to localize and estimate the severity of damage in structures for which only postdamage modal parameters are available for a few vibrational modes is presented. First, a theory of damage localization and severity estimation that utilizes only changes in mode shapes of the structures is outlined. Next, a system identification method that combines the experimental modal data and the modal parameters of a finite element model of the structure under investigation is developed to yield estimates of the baseline (i.e., predamage) modal parameters for the structure. Finally, the feasibility and practicality of the complete damage detection algorithm are demonstrated by localizing and sizing damage in a continuous beam for which only postdamage modal parameters for a single vibrational mode is available.

Damage identification and health monitoring of structural and mechanical systems from changes in their vibration characteristics: A literature review

Abstract: This report contains a review of the technical literature concerning the detection, location, and characterization of structural damage via techniques that examine changes in measured structural vibration response. The report first categorizes the methods according to required measured data and analysis technique. The analysis categories include changes in modal frequencies, changes in measured mode shapes (and their derivatives), and changes in measured flexibility coefficients. Methods that use property (stiffness, mass, damping) matrix updating, detection of nonlinear response, and damage detection via neural networks are also summarized. The applications of the various methods to different types of engineering problems are categorized by type of structure and are summarized. The types of structures include beams, trusses, plates, shells, bridges, offshore platforms, other large civil structures, aerospace structures, and composite structures. The report describes the development of the damage-identification methods and applications and summarizes the current state-of-the-art of the technology. The critical issues for future research in the area of damage identification are also discussed.

A summary review of vibration-based damage identification methods

Abstract: This paper provides an overview of methods to detect, locate, and characterize damage in structural and mechanical systems by examining changes in measured vibration response. Research in vibration-based damage identification has been rapidly expanding over the last few years. The basic idea behind this technology is that modal parameters (notably frequencies, mode shapes, and modal damping) are functions of the physical properties of the structure (mass, damping, and stiffness). Therefore, changes in the physical properties will cause detectable changes in the modal properties. The motivation for the development of this technology is presented. The methods are categorized according to various criteria such as the level of damage detection provided, model-based versus non-model-based methods, and linear versus nonlinear methods. The methods are also described in general terms including difficulties associated with their implementation and their fidelity. Past, current, and future-planned applications of this technology to actual engineering systems are summarized. The paper concludes with a discussion of critical issues for future research in the area of vibration-based damage identification.

Disasters by Design: A Reassessment of Natural Hazards in the United States

Abstract: Disasters by Design provides an alternative and sustainable way to view, study, and manage hazards in the United States that would result in disaster-resilient communities, higher environmental quality, inter- and intragenerational equity, economic sustainability, and improved quality of life. This volume provides an overview of what is known about natural hazards, disasters, recovery, and mitigation, how research findings have been translated into policies and programs; and a sustainable hazard mitigation research agenda. Also provided is an examination of past disaster losses and hazards management over the past 20 years, including factors--demographic, climate, social--that influence loss. This volume summarizes and sets the stage for the more detailed books in the series.

Structural control: past, present, and future

Abstract: This tutorial/survey paper: (1) provides a concise point of departure for researchers and practitioners alike wishing to assess the current state of the art in the control and monitoring of civil engineering structures; and (2) provides a link between structural control and other fields of control theory, pointing out both differences and similarities, and points out where future research and application efforts are likely to prove fruitful. The paper consists of the following sections: section 1 is an introduction; section 2 deals with passive energy dissipation; section 3 deals with active control; section 4 deals with hybrid and semiactive control systems; section 5 discusses sensors for structural control; section 6 deals with smart material systems; section 7 deals with health monitoring and damage detection; and section 8 deals with research needs. An extensive list of references is provided in the references section.

Vibration-based Damage Identification Methods: A Review and Comparative Study:

Abstract: A comprehensive review on modal parameter-based damage identification methods for beam- or plate-type structures is presented, and the damage identification algorithms in terms of signal processing...