Design Optimization of a Curved Actuator with Piezoelectric Fibers

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1971-1975 ◽  
Author(s):  
Cheol Kim ◽  
Dong Yeub Lee
Keyword(s):  
Fiber Composite ◽  
Matrix Material ◽  
Three Dimensional ◽  
Linear Elastic ◽  
The Matrix ◽  
Dimensional Finite Element ◽  
Structural Responses ◽  
Piezoelectric Fiber Composite ◽  
Three Dimensional Finite Element ◽  
Piezoelectric Fiber

Piezoelectric Fiber Composite with Interdigitated Electrodes (PFCIDE) was previously introduced as an alternative to monolithic wafers with conventional electrodes for applications of structural actuation. This paper is an investigation into the performance improvement of piezoelectric fiber composite actuators by optimizing the stacking sequence and changing the matrix material. This paper presents the numerical optimization of a piezoelectric fiber/piezoelectric matrix composite actuator with IDE (PFPMIDE). Various concepts from different backgrounds, including three-dimensional linear elastic and dielectric theories, have been incorporated into the present linear piezoelectric model. To see the structural responses of the actuator integrated with the PFPMIDE, three dimensional finite element formulations were derived. Numerical analyses show larger center displacement of the curved actuator with the PFPMIDE due to optimization of the piezoelectric fiber angles. This paper presents the concept of a curved actuator that occurs naturally via thermal residual stress during the curing process, as well as the optimization of the maximum curved actuator displacement, which is accomplished using the Davidon-Fletcher-Powell (DFP) method.

Design Optimization of a Piezoelectric Fiber Actuator With a Natural Curvature

2002 ◽  
Author(s):  
Cheol Kim ◽  
Dong-Yeub Lee
Keyword(s):  
Fiber Composite ◽  
Matrix Material ◽  
Three Dimensional ◽  
Linear Elastic ◽  
The Matrix ◽  
Dimensional Finite Element ◽  
Structural Responses ◽  
Piezoelectric Fiber Composite ◽  
Three Dimensional Finite Element ◽  
Piezoelectric Fiber

Piezoelectric Fiber Composite with Interdigitated Electrodes (PFCIDE) was previously introduced as an alternative to monolithic wafers with conventional electrodes for applications of structural actuation. This paper is an investigation into the performance improvement of piezoelectric fiber composite actuators by optimizing the stacking sequence and changing the matrix material. This paper presents the numerical optimization of a piezoelectric fiber/piezoelectric matrix composite actuator with IDE (PFPMIDE). Various concepts from different backgrounds, including three-dimensional linear elastic and dielectric theories, have been incorporated into the present linear piezoelectric model. To see the structural responses of the actuator integrated with the PFPMIDE, three-dimensional finite element formulations were derived. Numerical analysis shows larger center displacement of the curved actuator with the PFPMIDE due to optimization of the piezoelectric fiber angles. This paper presents the concept of a curved actuator that occurs naturally via thermal residual stress during the curing process, as well as the optimization of the maximum curved actuator displacement, which is accomplished using the Davidon-Fletcher-Powell (DFP) method.

Assessing delamination initiation of angle-ply laminates from fiber and matrix properties

2018 ◽  
Vol 32 (12) ◽  
pp. 1601-1621 ◽  
Author(s):  
Jia-Jie Gu ◽  
Zheng-Ming Huang
Keyword(s):  
Three Dimensional ◽  
Free Edge ◽  
The Matrix ◽  
Dimensional Finite Element ◽  
Bridging Model ◽  
Element Approach ◽  
True Stresses ◽  
Stress Concentration Factors ◽  
Original Strength ◽  
Three Dimensional Finite Element

As a laminate is essentially bonded together from laminae by the matrix, any delamination of it must be initiated from a matrix failure. This article predicts the initiation of a laminate delamination through analyzing the matrix failure. A three-dimensional finite element approach is used to calculate the stress field of an angle-plied laminate under a uniaxial tension. The stresses in each lamina of the laminate are averaged with respect to the lamina thickness to eliminate a weak singularity near a free edge. Homogenized stresses in the matrix are then obtained through bridging model, which are further converted into true values by virtue of stress concentration factors of the matrix in the composite. Influence of any interface crack between the fiber and the matrix on the true stresses has been taken into account. A criterion for detecting the delamination initiation is proposed, which only involves the true stresses and the original strength data of the matrix. To assess the efficiency, comparisons between the predictions and available experiment data are made for a number of angle-plied laminates. Reasonable correlation has been found.

Development of a PZT Fiber/Piezo-Polymer Composite Actuator With Interdigitated Electrodes

2001 ◽  
Author(s):  
Cheol Kim ◽  
Kun-Hyung Koo
Keyword(s):  
Composite Plate ◽  
Effective Properties ◽  
Fiber Composite ◽  
Matrix Material ◽  
Three Dimensional ◽  
Fiber Composites ◽  
Numerical Analyses ◽  
Interdigitated Electrodes ◽  
Composite Actuator ◽  
Piezoelectric Fiber

Abstract Piezoelectric Fiber Composites with Interdigitated Electrodes (PFCIDE) were previously introduced as an alternative to monolithic wafers with conventional electrodes for applications of structural actuation. This paper is an investigation into the performance improvement of piezoelectric fiber composite actuators by changing the matrix material. This paper presents a modified micro-electromechanical model and numerical analyses of piezoelectric fiber/piezopolymer matrix composite actuator with interdigitated electrodes (PFPMIDE). Various concepts from different backgrounds including three-dimensional linear elastic and dielectric theories have been incorporated into the present linear piezoelectric model. The rule of mixture and the modified method to calculate effective properties of fiber composites were extended to apply to the PFPMIDE model. The new model was validated comparing with available experimental data and other analytical results. To see the structural responses of a composite plate integrated with the PFPMIDE, three-dimensional finite element formulations were derived. Numerical analyses show that the shape of the graphite/epoxy composite plate with the PFPMIDE may be controlled by judicious choice of voltages, piezoelectric fiber angles, and elastic tailoring of the composite plate.

Three-Dimensional Analyses of Single Rivet-Row Lap Joints — Part II: Elastic-Plastic Response

1999 ◽  
Author(s):  
K. Iyer ◽  
C. A. Rubin ◽  
G. T. Hahn
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Lap Joints ◽  
Finite Element Analyses ◽  
Lap Joint ◽  
Stress Concentrations ◽  
Elastic Plastic ◽  
Linear Elastic ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Abstract Three-dimensional finite element analyses of an elastic-plastic, single rivet-row, aluminum lap joint are presented and compared with previous results for linear elastic models. The calculations treat non-countersunk aluminum and steel rivets, 3 different configurations of countersunk rivets as well as two values of the friction coefficient. The compliance of the connection, rivet tilt, the stresses in the panels, peak plastic strains and the contact pressures and slip amplitudes at the rivet-panel and panel-panel interfaces are evaluated. The transverse, axial, and shear stress distributions and the stress concentrations generated in four different rivets are derived from the linear elastic models and related to the rivet geometry. Laboratory measurements of the lap joint compliance and local out-of-plane displacements that support the reliability of the finite element analyses are presented.

Optimized and Robust Design of Tires Based on Numerical Simulation

2013 ◽  
Vol 41 (1) ◽  
pp. 21-39
Author(s):  
Michael Kaliske ◽  
Aleksandra Serafinska ◽  
Christoph Zopf
Keyword(s):  
Three Dimensional ◽  
Numerical Approach ◽  
Data Uncertainty ◽  
Tire Model ◽  
Design Data ◽  
Dimensional Finite Element ◽  
Structural Responses ◽  
Steady State Rolling ◽  
Quality Design ◽  
Three Dimensional Finite Element

ABSTRACT: This publication presents a numerical approach for analyzing tires based on multiobjective optimization, with particular consideration of uncertainties. Within the optimization, which uses evolutionary algorithms, the evaluation of a three-dimensional, finite element tire model at steady-state rolling is performed. To obtain a reliable and high-quality design, data uncertainty caused, e.g., by variation in production conditions of the tire components, as well as incomplete information concerning loading, have to be considered. Among several design goals, this study looked at durability as an example. An improvement is achieved by the consideration of two objective functions: one focusing on reducing wear, and the other on providing resistance to fatigue. In addition, the proposed optimization measures robustness implicitly. A tire model is regarded as robust when large variations of the uncertain influencing factors mentioned, e.g., loading or material properties, lead to only minor variations in uncertain structural responses, e.g., strains, stresses, or contact pressures. To improve the numerical efficiency of the proposed design approach, a response-surface approximation, based on artificial neural networks, is applied.

Contact stress variations near the insulated rail joints

2002 ◽  
Vol 216 (4) ◽  
pp. 265-273 ◽  
Author(s):  
Y. C. Chen ◽  
J. H. Kuang
Keyword(s):  
Contact Stress ◽  
Three Dimensional ◽  
Hertzian Contact ◽  
Stress Distributions ◽  
Linear Elastic ◽  
Contact Points ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Stress Variations ◽  
Contact Stress Distribution

The effect of an insulated rail joint (IRJ) on the contact stress variation near wheel-rail contact zones was simulated by employing three-dimensional finite element models. Three linear elastic IRJ materials, i.e. epoxy-fibreglass, polytetrafluoroethylene (PTFE) and Nylon-66, were investigated. Contact elements were used to simulate the interaction between the wheel and rail contact points. Numerical results showed that the presence of IRJ might significantly affect the wheel-rail contact stress distributions. Results also indicated that the traditional Hertzian contact theory is no longer available to predict the contact stress distribution around the rail joints.

Effect of the Residual Stresses at the Stem–Cement Interface on the Mechanical Behaviour of Cemented Hip Femoral Prosthesis

2015 ◽  
Vol 17 ◽  
pp. 54-63 ◽  
Author(s):  
M.M. Bouziane ◽  
A. Moulgada ◽  
N. Djebbara ◽  
A. Sahli ◽  
Bel Abbès Bachir Bouiadjra ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Exothermic Reaction ◽  
Three Dimensional ◽  
Thermal Shrinkage ◽  
Shear Stresses ◽  
Cement Interface ◽  
Linear Elastic ◽  
Dimensional Finite Element ◽  
Von Mises ◽  
Three Dimensional Finite Element

In orthopaedic surgery and particularly in the total hip arthroplasty, the stem fixation is performed in general using a surgical cement which consists essentially of polymer polymethyl-methacrylate (PMMA). During polymerisation of PMMA, residual stresses caused by volumetric and thermal shrinkage (exothermic reaction) are generated in the bulk cement. In this study, the three-dimensional finite element method is used to analyze the distribution stresses in the bone cement. Linear elastic analysis is adapted; von Mises, normal and shear stresses are the criterions that are of concern. The results showed that the inclusion of the residual stresses at the interface stem–cement increase the von Mises and the normal stresses in the different sides of the cement compared to the case without residual stresses.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

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