Vibration of Thick Circular Plate--Determination of Elastic Properties Through the Resonant Behaviour

1983 ◽  
Vol 7 (2) ◽  
pp. 58-64
Author(s):  
P. Priolo ◽  
C. Sitzia
Keyword(s):  
Finite Elements ◽  
Elastic Properties ◽  
Thick Plate ◽  
Plate Theory ◽  
Resonant Condition ◽  
High Frequencies ◽  
Thick Circular Plate ◽  
Properties Of Materials ◽  
Points Of View

The authors examine, from two complementary points of view, the main problem deriving from the necessity of deducing elastic properties of materials by considering the resonant condition of transversely vibrating discs, that is the determination of the efficiency at high frequencies of finite elements formulated with the assumptions of the thick plate theory. The first approach consists, having standardized the basic relations for various thick annular semi-analytical finite elements, in testing convergence and correspondence to known analytical solutions. The second consists in the experimental evaluation of the influence of thickness in deducing the Young’s modulus of a series of polycarbonate resin discs at frequencies corresponding to modes with up to eight nodal circles.

Nanomechanical Characterization of Cement-Based Materials

2015 ◽  
pp. 41-55
Author(s):  
Salim Barbhuiya
Keyword(s):  
Mechanical Properties ◽  
Data Analysis ◽  
Sample Preparation ◽  
Elastic Properties ◽  
Nanomechanical Properties ◽  
Cement Based Materials ◽  
Properties Of Materials ◽  
Preparation Techniques

Nanoindentation technique is used to assess the mechanical properties of materials at nano-level. A very small tip (usually diamond) produces indents at the surface of the material to be tested. A load vs. deflection curve is generated and is used to study the elastic properties of materials. Generally, it is used for obtaining the hardness and Young's modulus of materials at nano-meter scale. Currently, the method to evaluate the mechanical properties by nanoindentation is restricted to homogeneous materials. Cement-based materials are heterogeneous in nature. Therefore, nanoindentation study of cement-based materials is critical and requires several important steps, which need to be performed accurately. This chapter provides a review of the theory of nanoindentation, instruments being used for nanoindentation, sample preparation techniques, indentation strategy, and determination of nanomechanical properties and data analysis for cement-based materials.

scholarly journals Moment and Stress Analysis Solutions of Clamped Rectangular Thick Plate

2020 ◽  
Vol 5 (4) ◽  
pp. 531-534 ◽  
Author(s):  
O. M. Ibearugbulem ◽  
Festus Chukwudi Onyeka
Keyword(s):  
Thick Plate ◽  
Plate Theory ◽  
Analytic Solutions ◽  
Numerical Comparison ◽  
Theory Analysis ◽  
Third Order ◽  
Total Potential ◽  
Out Of Plane ◽  
Plane Displacement

The bending solutions of rectangular thick plate with all four edges clamped (CCCC) were investigated in this study. The basic governing equations used for analysis are based on third-order shear deformation plate theory analysis under uniformly distributed load. Using a formulated total potential energy equation, the three coupled general governing differential equations for the determination of the out of plane displacement and shear deformations rotation along the direction of x and y coordinates were obtained. These equations as obtained are solved simultaneously after minimization to determine the coefficients of displacements of the plate and other the mentioned functions. By solving these equations, the analytic solutions of rectangular thick plate with all four edges clamped were derived. From the formulated expression, the formula for calculation of the maximum deflection, moment, stress and in-plane displacements were deduced. The proposed method obviates the need of shear correction factors, which is associated with Mindlin’s theory (FSDT) for the solution to the problem. Moreover, numerical comparison shows the correctness and accuracy of the results.

scholarly journals Overview on Determination of Elastic and Damping Properties of Different Materials using Impulse Excitation Technique

2018 ◽  
Vol 3 (3) ◽  
pp. 35-41 ◽  
Author(s):  
Inês Pereira
Keyword(s):  
Shear Modulus ◽  
Elastic Properties ◽  
Damping Properties ◽  
Analysis And Design ◽  
Dynamic Technique ◽  
Impulse Excitation ◽  
Different Types ◽  
Properties Of Materials ◽  
Dynamic Elastic Properties

Knowledge of elastic and damping properties of materials is very relevant for the analysis and design of components, as they are relevant parameters in the performance of structural materials. The impulse excitation technique is a renowned dynamic technique for measuring dynamic elastic properties as Young´s modulus, shear modulus and Poisson’s ratio, as well as damping properties. This paper provides a review on the applicability of the impulse excitation technique in the analysis of elastic and damping properties of different types of materials.

scholarly journals A parametric prediction of the Young’s modulus of polymers enhanced with ΜWCNTs

2018 ◽  
Vol 233 ◽  
pp. 00025
Author(s):  
P.V. Polydoropoulou ◽  
K.I. Tserpes ◽  
Sp.G. Pantelakis ◽  
Ch.V. Katsiropoulos
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Experimental Results ◽  
Scale Model ◽  
Fe Model ◽  
Multi Scale ◽  
Unit Cells ◽  
Random Dispersion

In this work a multi-scale model simulating the effect of the dispersion, the waviness as well as the agglomerations of MWCNTs on the Young’s modulus of a polymer enhanced with 0.4% MWCNTs (v/v) has been developed. Representative Unit Cells (RUCs) have been employed for the determination of the homogenized elastic properties of the MWCNT/polymer. The elastic properties computed by the RUCs were assigned to the Finite Element (FE) model of a tension specimen which was used to predict the Young’s modulus of the enhanced material. Furthermore, a comparison with experimental results obtained by tensile testing according to ASTM 638 has been made. The results show a remarkable decrease of the Young’s modulus for the polymer enhanced with aligned MWCNTs due to the increase of the CNT agglomerations. On the other hand, slight differences on the Young’s modulus have been observed for the material enhanced with randomly-oriented MWCNTs by the increase of the MWCNTs agglomerations, which might be attributed to the low concentration of the MWCNTs into the polymer. Moreover, the increase of the MWCNTs waviness led to a significant decrease of the Young’s modulus of the polymer enhanced with aligned MWCNTs. The experimental results in terms of the Young’s modulus are predicted well by assuming a random dispersion of MWCNTs into the polymer.

scholarly journals Enhancement of a New Methodology Based on the Impulse Excitation Technique for the Nondestructive Determination of Local Material Properties in Composite Laminates

2020 ◽  
Vol 11 (1) ◽  
pp. 101
Author(s):  
Carlo Boursier Niutta
Keyword(s):  
Resonant Frequency ◽  
Elastic Properties ◽  
Composite Laminates ◽  
Concentrated Mass ◽  
Modal Shape ◽  
Nondestructive Determination ◽  
Material Orientation ◽  
Impulse Excitation ◽  
Clamping System

A new approach for the nondestructive determination of the elastic properties of composite laminates is presented. The approach represents an improvement of a recently published experimental methodology based on the Impulse Excitation Technique, which allows nondestructively assessing local elastic properties of composite laminates by isolating a region of interest through a proper clamping system. Different measures of the first resonant frequency are obtained by rotating the clamping system with respect to the material orientation. Here, in order to increase the robustness of the inverse problem, which determines the elastic properties from the measured resonant frequencies, information related to the modal shape is retained by considering the effect of an additional concentrated mass on the first resonant frequency. According to the modal shape and the position of the mass, different values of the first resonant frequency are obtained. Here, two positions of the additional mass, i.e., two values of the resonant frequency in addition to the unloaded frequency value, are considered for each material orientation. A Rayleigh–Ritz formulation based on higher order theory is adopted to compute the first resonant frequency of the clamped plate with concentrated mass. The elastic properties are finally determined through an optimization problem that minimizes the discrepancy on the frequency reference values. The proposed approach is validated on several materials taken from the literature. Finally, advantages and possible limitations are discussed.

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