**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**20

# Search results for: smart structure

##### 20 Active Control Improvement of Smart Cantilever Beam by Piezoelectric Materials and On-Line Differential Artificial Neural Networks

**Authors:**
P. Karimi,
A. H. Khedmati Bazkiaei

**Abstract:**

**Keywords:**
Smart material,
on-line differential artificial neural
network,
active control,
finite element method.

##### 19 Non-Linear Load-Deflection Response of Shape Memory Alloys-Reinforced Composite Cylindrical Shells under Uniform Radial Load

**Authors:**
Behrang Tavousi Tehrani,
Mohammad-Zaman Kabir

**Abstract:**

Shape memory alloys (SMA) are often implemented in smart structures as the active components. Their ability to recover large displacements has been used in many applications, including structural stability/response enhancement and active structural acoustic control. SMA wires or fibers can be embedded with composite cylinders to increase their critical buckling load, improve their load-deflection behavior, and reduce the radial deflections under various thermo-mechanical loadings. This paper presents a semi-analytical investigation on the non-linear load-deflection response of SMA-reinforced composite circular cylindrical shells. The cylinder shells are under uniform external pressure load. Based on first-order shear deformation* shell theory (FSDT),* the equilibrium equations of the structure are derived. One-dimensional simplified Brinson’s model is used for determining the SMA recovery force due to its simplicity and accuracy. Airy stress function and Galerkin technique are used to obtain non-linear load-deflection curves. The results are verified by comparing them with those in the literature. Several parametric studies are conducted in order to investigate the effect of SMA volume fraction, SMA pre-strain value, and SMA activation temperature on the response of the structure. It is shown that suitable usage of SMA wires results in a considerable enhancement in the load-deflection response of the shell due to the generation of the SMA tensile recovery force.

**Keywords:**
Airy stress function,
cylindrical shell,
Galerkin technique,
load-deflection curve,
recovery stress,
shape memory alloy.

##### 18 Implementation of State-Space and Super-Element Techniques for the Modeling and Control of Smart Structures with Damping Characteristics

**Authors:**
Nader Ghareeb,
R¨udiger Schmidt

**Abstract:**

**Keywords:**
Finite element analysis,
super-element,
state-space
model.

##### 17 Limit State of Heterogeneous Smart Structures under Unknown Cyclic Loading

**Authors:**
M. Chen,
S-Q. Zhang,
X. Wang,
D. Tate

**Abstract:**

This paper presents a numerical solution, namely limit and shakedown analysis, to predict the safety state of smart structures made of heterogeneous materials under unknown cyclic loadings, for instance, the flexure hinge in the micro-positioning stage driven by piezoelectric actuator. In combination of homogenization theory and finite-element method (FEM), the safety evaluation problem is converted to a large-scale nonlinear optimization programming for an acceptable bounded loading as the design reference. Furthermore, a general numerical scheme integrated with the FEM and interior-point-algorithm based optimization tool is developed, which makes the practical application possible.

**Keywords:**
Limit state,
shakedown analysis,
homogenization,
heterogeneous structure.

##### 16 Simulation of Piezoelectric Laminated Smart Structure under Strong Electric Field

**Authors:**
Shun-Qi Zhang,
Shu-Yang Zhang,
Min Chen

**Abstract:**

**Keywords:**
Smart structures,
piezolamintes,
material nonlinearity,
geometric nonlinearity,
strong electric field.

##### 15 Hybrid Stainless Steel Girder for Bridge Construction

**Authors:**
Tetsuya Yabuki,
Yasunori Arizumi,
Tetsuhiro Shimozato,
Samy Guezouli,
Hiroaki Matsusita,
Masayuki Tai

**Abstract:**

The main object of this paper is to present the research results of the development of a hybrid stainless steel girder system for bridge construction undertaken at University of Ryukyu. In order to prevent the corrosion damage and reduce the fabrication costs, a hybrid stainless steel girder in bridge construction is developed, the stainless steel girder of which is stiffened and braced by structural carbon steel materials. It is verified analytically and experimentally that the ultimate strength of the hybrid stainless steel girder is equal to or greater than that of conventional carbon steel girder. The benefit of the life-cycle cost of the hybrid stainless steel girder is also shown.

**Keywords:**
Smart structure,
hybrid stainless steel members,
ultimate strength,
steel bridge,
corrosion prevention.

##### 14 Active Control of Multiferroic Composite Shells Using 1-3 Piezoelectric Composites

**Authors:**
S. C. Kattimani

**Abstract:**

**Keywords:**
Active constrained layer damping,
doubly curved shells,
magneto-electro-elastic,
multiferroic composite,
smart structures.

##### 13 Modeling, Analysis and Control of a Smart Composite Structure

**Authors:**
Nader H. Ghareeb,
Mohamed S. Gaith,
Sayed M. Soleimani

**Abstract:**

In modern engineering, weight optimization has a priority during the design of structures. However, optimizing the weight can result in lower stiffness and less internal damping, causing the structure to become excessively prone to vibration. To overcome this problem, active or smart materials are implemented. The coupled electromechanical properties of smart materials, used in the form of piezoelectric ceramics in this work, make these materials well-suited for being implemented as distributed sensors and actuators to control the structural response. The smart structure proposed in this paper is composed of a cantilevered steel beam, an adhesive or bonding layer, and a piezoelectric actuator. The static deflection of the structure is derived as function of the piezoelectric voltage, and the outcome is compared to theoretical and experimental results from literature. The relation between the voltage and the piezoelectric moment at both ends of the actuator is also investigated and a reduced finite element model of the smart structure is created and verified. Finally, a linear controller is implemented and its ability to attenuate the vibration due to the first natural frequency is demonstrated.

**Keywords:**
Active linear control,
Lyapunov stability theorem,
piezoelectricity,
smart structure,
static deflection.

##### 12 Self-Sensing Concrete Nanocomposites for Smart Structures

**Authors:**
A. D'Alessandro,
F. Ubertini,
A. L. Materazzi

**Abstract:**

In the field of civil engineering, Structural Health Monitoring is a topic of growing interest. Effective monitoring instruments permit the control of the working conditions of structures and infrastructures, through the identification of behavioral anomalies due to incipient damages, especially in areas of high environmental hazards as earthquakes. While traditional sensors can be applied only in a limited number of points, providing a partial information for a structural diagnosis, novel transducers may allow a diffuse sensing. Thanks to the new tools and materials provided by nanotechnology, new types of multifunctional sensors are developing in the scientific panorama. In particular, cement-matrix composite materials capable of diagnosing their own state of strain and tension, could be originated by the addition of specific conductive nanofillers. Because of the nature of the material they are made of, these new cementitious nano-modified transducers can be inserted within the concrete elements, transforming the same structures in sets of widespread sensors. This paper is aimed at presenting the results of a research about a new self-sensing nanocomposite and about the implementation of smart sensors for Structural Health Monitoring. The developed nanocomposite has been obtained by inserting multi walled carbon nanotubes within a cementitious matrix. The insertion of such conductive carbon nanofillers provides the base material with piezoresistive characteristics and peculiar sensitivity to mechanical modifications. The self-sensing ability is achieved by correlating the variation of the external stress or strain with the variation of some electrical properties, such as the electrical resistance or conductivity. Through the measurement of such electrical characteristics, the performance and the working conditions of an element or a structure can be monitored. Among conductive carbon nanofillers, carbon nanotubes seem to be particularly promising for the realization of self-sensing cement-matrix materials. Some issues related to the nanofiller dispersion or to the influence of the nano-inclusions amount in the cement matrix need to be carefully investigated: the strain sensitivity of the resulting sensors is influenced by such factors. This work analyzes the dispersion of the carbon nanofillers, the physical properties of the fresh dough, the electrical properties of the hardened composites and the sensing properties of the realized sensors. The experimental campaign focuses specifically on their dynamic characterization and their applicability to the monitoring of full-scale elements. The results of the electromechanical tests with both slow varying and dynamic loads show that the developed nanocomposite sensors can be effectively used for the health monitoring of structures.

**Keywords:**
Carbon nanotubes,
self-sensing nanocomposites,
smart cement-matrix sensors,
structural health monitoring.

##### 11 Interval Type-2 Fuzzy Vibration Control of an ERF Embedded Smart Structure

**Authors:**
Chih-Jer Lin,
Chun-Ying Lee,
Ying Liu,
Chiang-Ho Cheng

**Abstract:**

The main objective of this article is to present the semi-active vibration control using an electro-rheological fluid embedded sandwich structure for a cantilever beam. ER fluid is a smart material, which cause the suspended particles polarize and connect each other to form chain. The stiffness and damping coefficients of the ER fluid can be changed in 10 micro seconds; therefore, ERF is suitable to become the material embedded in the tunable vibration absorber to become a smart absorber. For the ERF smart material embedded structure, the fuzzy control law depends on the experimental expert database and the proposed self-tuning strategy. The electric field is controlled by a CRIO embedded system to implement the real application. This study investigates the different performances using the Type-1 fuzzy and interval Type-2 fuzzy controllers. The Interval type-2 fuzzy control is used to improve the modeling uncertainties for this ERF embedded shock absorber. The self-tuning vibration controllers using Type-1 and Interval Type-2 fuzzy law are implemented to the shock absorber system. Based on the resulting performance, Internal Type-2 fuzzy is better than the traditional Type-1 fuzzy control for this vibration control system.

**Keywords:**
Electro-Rheological Fluid,
Semi-active vibration control,
shock absorber,
type 2 fuzzy control.

##### 10 Numerical Investigation of Poling Vector Angle on Adaptive Sandwich Plate Deflection

**Authors:**
Alireza Pouladkhan,
Mohammad Yavari Foroushani,
Ali Mortazavi

**Abstract:**

This paper presents a finite element model for a Sandwich Plate containing a piezoelectric core. A sandwich plate with a piezoelectric core is constructed using the shear mode of piezoelectric materials. The orientation of poling vector has a significant effect on deflection and stress induced in the piezo-actuated adaptive sandwich plate. In the present study, the influence of this factor for a clamped-clamped-free-free and simple-simple-free-free square sandwich plate is investigated using Finite Element Method. The study uses *ABAQUS* (*v.6.7*) software to derive the finite element model of the sandwich plate. By using this model, the study gives the influences of the poling vector angle on the response of the smart structure and determines the maximum transverse displacement and maximum stress induced.

**Keywords:**
Finite element method,
Sandwich plate,
Poling vector,
Piezoelectric materials,
Smart structure,
Electric enthalpy.

##### 9 Comparative Finite Element Simulation of Nonlinear Vibrations and Sensor Output Voltage of Smart Piezolaminated Structures

**Authors:**
Ruediger Schmidt,
Thang Duy Vu

**Abstract:**

Two geometrically nonlinear plate theories, based either on first- or third-order transverse shear deformation theory are used for finite element modeling and simulation of the transient response of smart structures incorporating piezoelectric layers. In particular the time histories of nonlinear vibrations and sensor voltage output of a thin beam with a piezoelectric patch bonded to the surface due to an applied step force are studied.

**Keywords:**
Nonlinear vibrations,
piezoelectric patches,
sensor voltage output,
smart structures.

##### 8 Controller Design for Euler-Bernoulli Smart Structures Using Robust Decentralized FOS via Reduced Order Modeling

**Authors:**
T.C. Manjunath,
B. Bandyopadhyay

**Abstract:**

**Keywords:**
Smart structure,
Euler-Bernoulli beam theory,
Fastoutput sampling feedback control,
Finite Element Method,
Statespace model,
Vibration control,
LMI,
Model order Reduction.

##### 7 Vibration Suppression of Timoshenko Beams with Embedded Piezoelectrics Using POF

**Authors:**
T. C. Manjunath,
B. Bandyopadhyay

**Abstract:**

**Keywords:**
Smart structure,
Timoshenko beam theory,
Periodic
output feedback control,
Finite Element Method,
State space model,
SISO,
Embedded sensors and actuators,
Vibration control.

##### 6 Modeling and FOS Feedback Based Control of SISO Intelligent Structures with Embedded Shear Sensors and Actuators

**Authors:**
T. C. Manjunath,
B. Bandyopadhyay

**Abstract:**

**Keywords:**
Smart structure,
Timoshenko beam theory,
Fast output sampling feedback control,
Finite Element Method,
State space model,
SISO,
Vibration control,
LMI

##### 5 Development of New Control Techniques for Vibration Isolation of Structures using Smart Materials

**Authors:**
Shubha P Bhat,
Krishnamurthy,
T.C.Manjunath,
C. Ardil

**Abstract:**

**Keywords:**
DOF,
Space structures,
Acceleration,
Excitation,
Smart structure,
Vibration,
Isolation,
Earthquakes.

##### 4 Control of Vibrations in Flexible Smart Structures using Fast Output Sampling Feedback Technique

**Authors:**
T.C. Manjunath,
B. Bandyopadhyay

**Abstract:**

**Keywords:**
Smart structure,
Finite element method,
State spacemodel,
Euler-Bernoulli theory,
SISO model,
Fast output sampling,
Vibration control,
LMI

##### 3 Multivariable Control of Smart Timoshenko Beam Structures Using POF Technique

**Authors:**
T.C. Manjunath,
B. Bandyopadhyay

**Abstract:**

**Keywords:**
Smart structure,
Timoshenko theory,
Euler-Bernoulli
theory,
Periodic output feedback control,
Finite Element Method,
State space model,
Vibration control,
Multivariable system,
Linear
Matrix Inequality

##### 2 Controller Design for Euler-Bernoulli Smart Structures Using Robust Decentralized POF via Reduced Order Modeling

**Authors:**
T.C. Manjunath,
B. Bandyopadhyay

**Abstract:**

**Keywords:**
Smart structure,
Euler-Bernoulli beam theory,
Periodic output feedback control,
Finite Element Method,
State space
model,
SISO,
Embedded sensors and actuators,
Vibration control,
Reduced order model

##### 1 Mathematical Modeling of SISO based Timoshenko Structures – A Case Study

**Authors:**
T.C. Manjunath,
Student Member,
B. Bandyopadhyay

**Abstract:**

This paper features the mathematical modeling of a single input single output based Timoshenko smart beam. Further, this mathematical model is used to design a multirate output feedback based discrete sliding mode controller using Bartoszewicz law to suppress the flexural vibrations. The first 2 dominant vibratory modes is retained. Here, an application of the discrete sliding mode control in smart systems is presented. The algorithm uses a fast output sampling based sliding mode control strategy that would avoid the use of switching in the control input and hence avoids chattering. This method does not need the measurement of the system states for feedback as it makes use of only the output samples for designing the controller. Thus, this methodology is more practical and easy to implement.

**Keywords:**
Smart structure,
Timoshenko beam theory,
Discretesliding mode control,
Bartoszewicz law,
Finite Element Method,
State space model,
Vibration control,
Mathematical model,
SISO.