@article{banks_bekele-maxwell_bociu_noorman_guidoboni_2017, title={SENSITIVITY ANALYSIS IN PORO-ELASTIC AND PORO-VISCO-ELASTIC MODELS WITH RESPECT TO BOUNDARY DATA}, volume={75}, ISSN={["1552-4485"]}, DOI={10.1090/qam/1475}, abstractNote={In this article we consider poro-elastic and poro-visco-elastic models inspired by problems in medicine and biology, and we perform sensitivity analysis on the solutions of these fluid-solid mixture problems with respect to the imposed boundary data, which are the main drivers of the system. Moreover, we compare the results obtained in the elastic case vs. visco-elastic case, as it is known that structural viscosity of biological tissues decreases with age and disease. Sensitivity analysis is the first step towards optimization and control problems associated with these models, which is our ultimate goal.}, number={4}, journal={QUARTERLY OF APPLIED MATHEMATICS}, author={Banks, H. T. and Bekele-Maxwell, K. and Bociu, L. and Noorman, M. and Guidoboni, G.}, year={2017}, month={Dec}, pages={697–735} }
 @article{saadat_buckner_noori_2007, title={Structural system identification and damage detection using the intelligent parameter varying technique: An experimental study}, volume={6}, ISSN={["1741-3168"]}, DOI={10.1177/1475921707081980}, abstractNote={ The unique capabilities of the intelligent parameter varying (IPV) technique for structural system identification and damage detection have been previously documented via comparative simulations. An intelligent parameter varying (IPV) approach for non-linear system identification of base excited structures. International Journal of Non-Linear Mechanics, 39(6), 993—1004; Saadat, S., Noori, M.N., Buckner, G.D., Furukawa, T.D. and Suzuki, Y. (2004). Structural health monitoring and damage detection using an intelligent parameter varying (IPV) technique. International Journal of Non-Linear Mechanics, 39(10), 1687—1697). These simulations demonstrate the effectiveness of IPV in detecting the existence and location of damage in base excited structures, and conclude that accuracy is not compromised by the introduction of realistic structural nonlinearities and ground excitation characteristics. This study presents an experimental verification of the IPV technique for structural system identification and damage detection. A scaled three-story, base-excited structure is designed and fabricated for these experiments. The structure is excited using a displacement-controlled shake table, and damage is introduced by triggering the release of cross-bracing tendons, i.e., inducing sudden changes in the restoring forces. Experimental results using harmonic and recorded earthquake excitation data clearly demonstrate the effectiveness of this IPV technique. }, number={3}, journal={STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL}, author={Saadat, Soheil and Buckner, Gregory D. and Noori, Mohammad N.}, year={2007}, month={Sep}, pages={231–243} }
 @article{furukawa_ito_izawa_noori_2005, title={System identification of base-isolated building using seismic response data}, volume={131}, DOI={10.1061/(ASCE)0733-9399(2005)131:3(268)}, abstractNote={Due to the complex nature of the excitation, and the inherent dynamics characteristics of restoring force of the base isolation systems, the response of base-isolated structures subject to strong earthquakes often experiences excursion into the inelastic range. Therefore, in designing base-isolated structures, the nonlinear hysteretic restoring force model of the base isolation system is frequently used to predict structural response and to evaluate structural safety. In this paper, the prediction error method system identification technique is used in conjunction with nonlinear state-space models for identification of a base-isolated structure. Using a variety of nonlinear restoring force models and bidirectional recorded seismic responses, several identification runs are conducted to evaluate the accuracy of the selected models. Several nonlinear restoring force models are utilized for the base-isolation system, including a multiple shear spring (MSS) model. Among all models used, results indicate that the trilinear hysteretic MSS model closely matches the actual hysteretic restoring force profile and time histories obtained directly from the observed data.}, number={3}, journal={Journal of Engineering Mechanics}, author={Furukawa, T. and Ito, M. and Izawa, K. and Noori, M. N.}, year={2005}, pages={268–275} }
 @article{hou_hera_noori_2004, title={A stochastic model for localized disturbances and its applications}, volume={19}, ISSN={["0266-8920"]}, DOI={10.1016/j.probengmech.2004.02.004}, abstractNote={A stochastic model for local disturbances, particularly for a temporal harmonic with random modulations in amplitude and/or phase, is proposed in this paper. Results for the second moment responses of a linear single-degree-of-freedom system to this type of stochastic loading demonstrate a significant change in response characteristics due to a small uncertainty. A local phenomenon may last much longer and resonance may be smeared to a broad range. Integrated with wavelet transform, the proposed approach may be used to model a random process with non-stationary frequency content. Especially, it can be effectively used for Monte Carlo simulation to generate large size of samples that have similar characteristics in time and frequency domains as a pre-selected mother sample has. The technique has a great potential for the case where uncertainty study is warranted but the available samples are limited.}, number={3}, journal={PROBABILISTIC ENGINEERING MECHANICS}, author={Hou, ZK and Hera, A and Noori, M}, year={2004}, month={Jul}, pages={211–218} }
 @article{saadat_buckner_furukawa_noori_2004, title={An intelligent parameter varying (IPV) approach for non-linear system identification of base excited structures}, volume={39}, ISSN={["0020-7462"]}, DOI={10.1016/S0020-7462(03)00091-X}, abstractNote={Health monitoring and damage detection strategies for base-excited structures typically rely on accurate models of the system dynamics. Restoring forces in these structures can exhibit highly non-linear characteristics, thus accurate non-linear system identification is critical. Parametric system identification approaches are commonly used, but require a priori knowledge of restoring force characteristics. Non-parametric approaches do not require this a priori information, but they typically lack direct associations between the model and the system dynamics, providing limited utility for health monitoring and damage detection. In this paper a novel system identification approach, the intelligent parameter varying (IPV) method, is used to identify constitutive non-linearities in structures subject to seismic excitations. IPV overcomes the limitations of traditional parametric and non-parametric approaches, while preserving the unique benefits of each. It uses embedded radial basis function networks to estimate the constitutive characteristics of inelastic and hysteretic restoring forces in a multi-degree-of-freedom structure. Simulation results are compared to those of a traditional parametric approach, the prediction error method. These results demonstrate the effectiveness of IPV in identifying highly non-linear restoring forces, without a priori information, while preserving a direct association with the structural dynamics.}, number={6}, journal={INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS}, author={Saadat, S and Buckner, GD and Furukawa, T and Noori, MN}, year={2004}, month={Aug}, pages={993–1004} }
 @article{li_suzuki_noori_2004, title={Identification of hysteretic systems with slip using bootstrap filter}, volume={18}, ISSN={["0888-3270"]}, DOI={10.1016/j.ymssp.2003.08.001}, abstractNote={Hysteretic models with slip are frequently used to predict the non-linear behaviour of many structural systems, for example wood buildings and reinforced concrete structures. A model, called SL model, which can describe the pinching of most practical hysteresis loops perfectly was proposed by Baber and Noori. This model is characterised by control parameters that have to be identified from observed experimental data. A method of estimating the parameters of SL model on the basis of input–output data based on Bayesian state estimation and bootstrap filter is suggested in this paper, which has the great advantages of being able to handle any functional non-linearity and system and measurement noise of any distribution. A numerical simulation shows its suitability and effective for the system even in the case of very severe material non-linearity.}, number={4}, journal={MECHANICAL SYSTEMS AND SIGNAL PROCESSING}, author={Li, SJ and Suzuki, Y and Noori, M}, year={2004}, month={Jul}, pages={781–795} }
 @article{li_suzuki_noori_2004, title={Improvement of parameter estimation for non-linear hysteretic systems with slip by a fast Bayesian bootstrap filter}, volume={39}, ISSN={["1878-5638"]}, DOI={10.1016/j.ijnonlinmec.2004.02.005}, abstractNote={Modeling and identification of non-linear hysteretic systems are widely encountered in the structural dynamics field, especially for the hysteresis with slip. A model, called SL model, which can describe the pinching of most practical hysteresis loops perfectly was proposed by Baber and Noori (J. Eng. Mech. 111 (1985) 1010). A method of estimating the parameters of SL model on the basis of input–output data based on bootstrap filter was proposed by the writers. Bootstrap filter is a filtering method based on Bayesian state estimation and Monte Carlo method, which has the great advantage of being able to handle any functional non-linearity and system and/or measurement noise of any distribution. The standard bootstrap filter, however, is not time efficient, i.e., it is very time consuming and is not suitable for real-time applications. In this paper, previous work by the writers is extended to do the parameter estimation of SL model by a fast Bayesian bootstrap filtering technique. Simulation results are presented to demonstrate the performance of the algorithm.}, number={9}, journal={INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS}, author={Li, SJ and Suzuki, Y and Noori, M}, year={2004}, month={Nov}, pages={1435–1445} }
 @article{saadat_noori_buckner_furukawa_suzuki_2004, title={Structural health monitoring and damage detection using an intelligent parameter varying (IPV) technique}, volume={39}, ISSN={["1878-5638"]}, DOI={10.1016/j.ijnonlinmec.2004.03.001}, abstractNote={Most structural health monitoring and damage detection strategies utilize dynamic response information to identify the existence, location, and magnitude of damage. Traditional model-based techniques seek to identify parametric changes in a linear dynamic model, while non-model-based techniques focus on changes in the temporal and frequency characteristics of the system response. Because restoring forces in base-excited structures can exhibit highly non-linear characteristics, non-linear model-based approaches may be better suited for reliable health monitoring and damage detection. This paper presents the application of a novel intelligent parameter varying (IPV) modeling and system identification technique, developed by the authors, to detect damage in base-excited structures. This IPV technique overcomes specific limitations of traditional model-based and non-model-based approaches, as demonstrated through comparative simulations with wavelet analysis methods. These simulations confirm the effectiveness of the IPV technique, and show that performance is not compromised by the introduction of realistic structural non-linearities and ground excitation characteristics.}, number={10}, journal={INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS}, author={Saadat, S and Noori, MN and Buckner, GD and Furukawa, TD and Suzuki, Y}, year={2004}, month={Dec}, pages={1687–1697} }
 @article{ramasubramanian_noori_lee_2003, title={Evolution of mechatronics into a graduate degree program in the United States: The NC State University master of science program with mechatronics concentration}, volume={19}, number={4}, journal={International Journal of Engineering Education}, author={Ramasubramanian, M. K. and Noori, M. N. and Lee, G. K.}, year={2003}, pages={519–524} }
 @article{khechfe_noori_hou_kelly_ahmadi_2002, title={An experimental study on the seismic response of base-isolated secondary systems}, volume={124}, ISSN={["0094-9930"]}, DOI={10.1115/1.1445795}, abstractNote={The paper provides an experimental study on the feasibility of base isolation for seismic protection of nonstructural secondary system such as sensitive instrumentation, computer equipment, communication network, HVAC facilities, and power transmission systems housed in nonisolated primary structures. Damages to these secondary systems may result in significant social chaos and costly economic loss. A one-sixth-scaled three-story building model with a single-degree-of-freedom secondary system placed on its third floor is employed in this study. The secondary system is base-isolated by a laminated rubber bearing (LRB) base isolation system from the supporting floor. The ground motion input is simulated by a shaking table which generates three different types of signal including sweeping harmonic sinusoidal, the S00E component of the 1940 E1 Centro earthquake, and the simulated white noise. The experimental results demonstrate significant reduction in both displacement and acceleration responses of the secondary system by using the base isolation. Effects of parameters of the base isolation such as damping ratio and mass on its performance are also investigated. This study provides a valuable guideline for future work in this area and also verifies some previous analytical work by the authors (Hou et al., 2001). Secondary systems in a structure can be divided into two categories: structural and nonstructural. A thorough review of these types of systems and their response behavior under seismic loading has been presented by (Chen and Soong, 1988). In this paper, only nonstructural secondary systems are the subject of the study. These systems include sensitive instrumentation, computer equipment, communication network, HVAC facilities, and power transmission system that reside within a primary structure system. The huge investment made, the mission, and the critical role played by secondary systems in modern day warrant an effective protection strategy against earthquake-induced vibrations. Studies on employing base isolation techniques to protect primary structures have shown the ability of such techniques to limit dynamic response of structures in seismic disturbance (Kelley, 1986; and Ahmadi, 1988); this paper proposes the adoption of a base isolation mechanism for seismic protection of secondary systems and presents the experimental results achieved with this strategy in a scaled-down system designed without primary structural isolation. This study provides a valuable guideline for future work in this area and also verifies some previous analytical work by the authors (Ghantous, 1991; and Samaha, 1992).}, number={1}, journal={JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME}, author={Khechfe, H and Noori, M and Hou, Z and Kelly, JM and Ahmadi, G}, year={2002}, month={Feb}, pages={81–88} }
 @article{saadat_salichs_noori_hou_davoodi_bar-on_suzuki_masuda_2002, title={An overview of vibration and seismic applications of NiTi shape memory alloy}, volume={11}, ISSN={["0964-1726"]}, DOI={10.1088/0964-1726/11/2/305}, abstractNote={Shape memory alloys (SMAs) exhibit peculiar thermomechanical, thermoelectrical and thermochemical behaviors under mechanical, thermal, electrical and chemical conditions. Examples of these materials are Cu-based SMAs, NiTi SMAs, ferrous SMAs, shape memory ceramics and shape memory polymers. NiTi SMAs in particular, have unique thermomechanical behaviors such as shape memory effect and pseudoelasticity, which have made them attractive candidates for structural vibration control applications. Numerous studies have been conducted in modeling and applications of NiTi SMAs in structural vibration control. Several active, passive and hybrid energy absorption and vibration isolation devices have been developed utilizing NiTi SMAs. In this paper we present an overview of NiTi behaviors, modeling and applications as well as their limitations for structural vibration control and seismic isolation.}, number={2}, journal={SMART MATERIALS & STRUCTURES}, author={Saadat, S and Salichs, J and Noori, M and Hou, Z and Davoodi, H and Bar-On, I and Suzuki, Y and Masuda, A}, year={2002}, month={Apr}, pages={218–229} }
 @article{vestroni_noori_2002, title={Hysteresis in mechanical systems - modeling and dynamic response}, volume={37}, ISSN={["0020-7462"]}, DOI={10.1016/S0020-7462(02)00059-8}, abstractNote={Hysteretic behaviour characterizes elements of a wide class of mechanical systems: the dependence of their restoring force on the deformation history has a great influence on the dynamic response. For this reason, an increasing interest has been registered in the study of typical phenomena of nonlinear dynamics, also because hysteresis belongs to the class of strong nonlinearities. The paper is devoted to the analysis of the modification of the response of two degrees-of-freedom chain systems due to the characteristics of the restoring force of a hysteretic element; attention is given to its dissipation characteristic, comparing the cases of full and reduced hysteresis. With increasing excitation amplitude, the strong hysteretic nonlinearity modifies the nonlinear frequencies and in turn their ratio, easily leading to internal resonance conditions. For a system close to a 3:1 resonance condition, the modification of the frequency response curves (frcs) for increasing excitation intensity is illustrated and compared with the response of similar systems not in internal resonance. The general trend of the phenomena is slightly qualitatively influenced by the dissipation property, whereas the quantitative differences are notable. The only evident difference is the presence of a frequency range of coexisting solutions in the case of reduced hysteresis. In both cases, after a bifurcation a novel mode arises around the first resonance, with similar frequency and different shape. The case of reduced hysteresis makes it possible to better investigate the evolution of nonlinear modes of a system, close to the Hamiltonian system embedded by the actual dissipative one. The occurrence of this novel mode, peculiar of systems with strong nonlinearities, is responsible of a substantial transfer of energy between the two modes in internal resonance conditions. Finally, an example of quasiperiodic oscillations is presented to show one of the other possible scenarios which arise even in the presence of significant dissipation.}, number={8}, journal={INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS}, author={Vestroni, F and Noori, M}, year={2002}, month={Dec}, pages={1261–1262} }
 @article{masuda_noori_2002, title={Optimization of hysteretic characteristics of damping devices based on pseudoelastic shape memory alloys}, volume={37}, ISSN={["0020-7462"]}, DOI={10.1016/S0020-7462(02)00024-0}, abstractNote={In order to develop a fundamental understanding and the feasibility of SMA devices for passive vibration control, an undamped SDOF system with a pseudoelastic SMA restoring force is investigated to find the basic relationship between the shape of the hysteresis loop of SMA elements and their performance as a damping device. The dynamic characteristics of the device are evaluated by the steady-state response at the resonance point in order to focus on the damping effect. Dynamic analysis utilizing the equivalent linearization approach results in two major findings that, to the best of the authors' knowledge, have not yet been reported in the literature. These results which characterize the unique behavior of the SMA hysteresis include: (a) for a given excitation amplitude, the "scale" of the hysteresis loop, which is a measure of displacement and restoring force, needs to be adjusted so that the response sweeps the maximum loop but does not exceed it; (b) the ratio of the area confined within the hysteresis loop to the area of a corresponding envelope of triangular shape should be as large as possible. The results of this study would be quite useful not only as a guideline for the design of actual SMA devices, but also as a basis for the development of new autoadaptive materials in future.}, number={8}, journal={INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS}, author={Masuda, A and Noori, M}, year={2002}, month={Dec}, pages={1375–1386} }
 @article{mirza_bryan_noori_2001, title={Fiber-reinforced composite cylindrical vessel with lugs}, volume={53}, ISSN={["0263-8223"]}, DOI={10.1016/S0263-8223(00)00185-9}, abstractNote={The use of fiber-reinforced composites has steadily increased over the last few decades. Although the use of composites allows designers to optimize material usage, the analysis becomes fairly complex. The present work deals with the analysis of composite vessels subjected to concentrated moments applied at discrete lug positions. Finite element (FE) formulation has been used to study the stress variation in composite vessels with lug attachments. Stress indices have been developed for two different load conditions, namely, longitudinal and circumferential moments. Numerical data have been generated for rectangular lugs of varying sizes. Although the numerical results presented here include one case of relatively thick shell, they are particularly important for thin shells. Discussion related to rotations at the interface is not presented here.}, number={2}, journal={COMPOSITE STRUCTURES}, author={Mirza, S and Bryan, A and Noori, M}, year={2001}, month={Aug}, pages={143–151} }
 @article{saadat_noori_davoodi_hou_suzuki_masuda_2001, title={Using NiTiSMA tendons for vibration control of coastal structures}, volume={10}, ISSN={["1361-665X"]}, DOI={10.1088/0964-1726/10/4/313}, abstractNote={Hurricane damage inflicted upon coastal structures, particularly residential structures, results in millions of dollars in financial damage and loss of life each year. A major cause of this damage usually begins with roof uplifts of coastal structures; prevention of roof uplift helps mitigate damage to coastal structures by hurricanes. Development of more effective fastening mechanisms for the connections between the walls and the roofs of these structures will aid in damage reduction to coastal structures. Recent developments in the new field of auto-adaptive materials offer promising opportunities for developing radically new fastening mechanisms. One of the classes of materials in this category is shape memory alloys (SMAs). SMAs are very attractive for structural application because of their major constitutive behaviors such as pseudoelastic characteristics. The pseudoelastic behavior of NiTi SMAs is a unique hysteretic energy dissipation behavior which, combined with a very long fatigue life, makes NiTi a viable candidate for developing new fasteners. However, as a first step it is important to develop an in-depth understanding of NiTi behavior under dynamic loads. Research carried out in this area has been very limited in scope. Therefore, in this paper, eight different configurations of bracing systems, divided into two categories, are explored on a single degree of freedom (SDOF) structure to investigate the feasibility of developing devices for the mitigation of hurricane damage. These bracing devices basically utilize the hysteretic energy dissipation of NiTi resulting from its pseudoelastic characteristic. Since the main goal of this ongoing research is to develop a thorough understanding of the pseudoelastic and hysteretic behavior of SMAs under severe dynamic loading/excitation, a series of earthquake data has been considered as the source of excitation. Through this analysis both the damping and stiffening characteristics of NiTi wires and the effect of these dynamic characteristics on changing the dynamic response of the structure are studied. In the first category the NiTi wires are not pre-strained, while in the second category they are pre-strained. In each category, four different combinations of wire length and modeling of pseudoelastic behavior of NiTi wire are considered. A bilinear stress-strain model is used for representing the pseudoelastic behavior of NiTi tendons, capable of representing internal yield, internal recovery and trigger line concepts. This study establishes that hybrid tendons have the highest damping and stiffening effects on the structure. It is also concluded that, when the amplitude of excitation is small, tendons act as stiffening devices. Once the amplitude of the excitation is large enough to initiate stress-induced phase transformations, tendons act as energy absorption devices. These findings provide very useful information for the development of more effective fastening devices that can withstand severe dynamic loads, such as hurricane loadings.}, number={4}, journal={SMART MATERIALS AND STRUCTURES}, author={Saadat, S and Noori, M and Davoodi, H and Hou, Z and Suzuki, Y and Masuda, A}, year={2001}, month={Aug}, pages={695–704} }
 @article{salichs_hou_noori_2001, title={Vibration suppression of structures using passive shape memory alloy energy dissipation devices}, volume={12}, ISSN={["1045-389X"]}, DOI={10.1106/RGRQ-VJKM-QWCF-QQDE}, abstractNote={ The paper presents a preliminary study on feasibility using shape memory alloy (SMA) passive devices for vibration suppression of building structures. A one-story prototype-building model is used. The structure is subjected to a base excitation and is strengthened by SMA diagonal bracing wires. Constitutive behavior of SMA wires used in the study was experimentally characterized to properly model the SMA super- or pseudoelastic material properties and results were compared with the numerical simulation based on theoretical SMA constitutive models by Lexcellent and Bourbon ((1996). Thermodynamical model of cyclic behavior of Ti-Ni and Cu-Zn-Al shape memory alloys under isothermal undulated tensile tests. Mechanics of Materials, 24: 59-73) and Brinson ((1993). One-dimensional constitutive behavior of shape memory alloys: Thermomechanical derivation with non-constant material functions and redefined martensite internal variable. Journal of Intelligent Material Systems and Structures, 4: 229). The Single-degree-of-freedom structural system was also experimentally calibrated to determine the structural parameters. Both the experimentally calibrated structural model and SMA constitutive model were then employed in numerical simulation to predict dynamic response of the building structure with SMA bracing wires subjected to a base input and results showed a good agreement with experimental data. The results were also compared with both cases of conventional steel bracing wires and no bracing at all. The results showed that SMA passive devices maybe effectively used to suppress vibration by introducing additional stiffness to shift the system natural frequency away from the resonance and/or providing additional energy dissipation by its superelastic hysteresis. The SMA damping is adaptive and is especially attractive for the case when the loading is random in nature. When an unexpected excitation causes excessive vibration, more energy will be dissipated through larger SMA superelastic hysteretic loops and therefore, the vibration will eventually be mitigated. Numerical simulation also showed that the SMA device dissipated more energy than the viscous damping in the case studied. }, number={10}, journal={JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES}, author={Salichs, J and Hou, Z and Noori, M}, year={2001}, month={Oct}, pages={671–680} }
 @article{hou_noori_st. amand_2000, title={Wavelet-based approach for structural damage detection}, volume={126}, DOI={10.1061/(ASCE)0733-9399(2000)126:7(677)}, abstractNote={A wavelet-based approach is proposed for structural damage detection and health monitoring. Characteristics of representative vibration signals under the wavelet transformation are examined. The methodology is then applied to simulation data generated from a simple structural model subjected to a harmonic excitation. The model consists of multiple breakable springs, some of which may suffer irreversible damage when the response exceeds a threshold value or the number of cycles of motion is accumulated beyond their fatigue life. In cases of either abrupt or accumulative damages, occurrence of damage and the moment when it occurs can be clearly determined in the details of the wavelet decomposition of these data. Similar results are observed for the real acceleration data of the seismic response recorded on the roof of a building during the 1971 San Fernando earthquake. Effects of noise intensity and damage severity are investigated and presented by a detectability map. Results show the great promise of the wavelet approach for damage detection and structural health monitoring.}, number={7}, journal={Journal of Engineering Mechanics}, author={Hou, Z. and Noori, M. and St. Amand, R.}, year={2000}, pages={677–683} }