scholarly journals Identification of elasticity modulus by vibratory analysis (Application to a natural composite: Aleppo pine wood)

2018 ◽  
Vol 149 ◽  
pp. 01045
Author(s):  
Abdelhakim DAOUI ◽  
Abdellatif ZERIZER
Keyword(s):  
Elasticity Modulus ◽  
Natural Frequencies ◽  
Aleppo Pine ◽  
Modal Parameter ◽  
Pine Wood ◽  
Vibratory Analysis ◽  
Analysis Application ◽  
Materials Used ◽  
Experimental Values ◽  
Natural Composite

In this paper, we present a method for the determination of the elasticity modulus in the vibratory domain of materials. This approach is based on research and interpretation of the spectrum of natural frequencies resulting from natural vibrations based on the theory of elastic beams. The tests consist of classical tests of longitudinal vibrations of natural composite beams (Aleppo pine wood), long enough to observe some natural frequencies. This identification method showed a good correlation between the theoretical and experimental values, notably the evaluation of the modal parameter for the case of the resonant frequencies and the identification of the modulus of elasticity of the materials used.

Calculations used for assessment of rapid maxillary expansion

ORL ro ◽  
2016 ◽  
Vol 1 (1) ◽  
pp. 24-26
Author(s):  
Ruxandra Bartok ◽  
Bogdan Dimitriu Dimitriu ◽  
Constantin Vârlan ◽  
Radu Stanciu ◽  
Georgiana Moldoveanu ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Elasticity Modulus ◽  
Rapid Maxillary Expansion ◽  
Laboratory Animals ◽  
Maxillary Expansion ◽  
Literature Reference ◽  
Bone Changes ◽  
Upper Jaw ◽  
Materials Used

Rapid maxillary expansion is defined as the release of medio-palatine suture using an orthopedic forces. The role of this procedure is to expand  the upper jaw in order to achieve the  broadening of the upper arch. This study was initiated to quantify the effects of disjunction and post- treatment bone changes, after an adequate contention which lasted for three weeks. This study  is  carried on laboratory animals (common breed rabbit) to determine tensile strength and the elasticity modulus of  biological materials  used in orthdodontics. The results of the study are consistent with those reported in the literature reference.  

Materials for bullet core

2020 ◽  
Vol 2020 (10) ◽  
pp. 8-21
Author(s):  
A. G. Kolmakov ◽  
◽  
I. O. Bannykh ◽  
V. I. Antipov ◽  
L. V. Vinogradov ◽  
...  
Keyword(s):  
High Speed ◽  
Bending Strength ◽  
Low Alloy Steels ◽  
Hard Alloys ◽  
Small Arms ◽  
Alloy Steels ◽  
Materials Used ◽  
Basic Ideas ◽  
New Generation ◽  
Natural Composite

he basic ideas about the process of introducing cores into protective barriers and the most common core patterns and their location in conventional and sub-caliber small arms bullets are discussed. The materials used for manufacture of cores are analyzed. It is concluded that for mass bullets of increased armor penetration the most rational choice can be considered the use of high-carbon low-alloy steels of a new generation with a natural composite structure and hardness of up to 70 HRC. For specialized armor-piercing bullets, cores made from promising economically-alloyed high-speed steels characterized by a high complex of «hardness—bending strength» are better alternative than ones made of hard alloys or tungsten alloys.

A Study on a Vibratory Model of a Human Body

1987 ◽  
Vol 109 (2) ◽  
pp. 148-153 ◽  
Author(s):  
S. P. Nigam ◽  
M. Malik
Keyword(s):  
Human Body ◽  
Natural Frequencies ◽  
Degree Of Freedom ◽  
Male Body ◽  
Mass System ◽  
Modeling Procedure ◽  
Experimental Values

This paper is concerned with the modeling of the human body as a spring mass system. Based on certain assumptions, an analysis for evaluating the mass and stiffness values of the model is developed. As an illustration of the modeling procedure, a 15-degree-of-freedom model of a male body is considered. The computed natural frequencies of the model are found to be within the range of available experimental values.

Modeling and simulation of the dynamic behavior of the macaw palm fruit-rachilla system

SIMULATION ◽  
2021 ◽  
pp. 003754972110437
Author(s):  
Mariana Ribeiro Pereira ◽  
Fábio Lúcio Santos ◽  
Nara Silveira Velloso ◽  
Flora Maria de Melo Villar ◽  
Mateus Resende Rodrigues
Keyword(s):  
Dynamic Behavior ◽  
Elasticity Modulus ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Palm Tree ◽  
Specific Mass ◽  
Palm Fruit ◽  
Modes Of Vibration ◽  
Macaw Palm ◽  
Three Dimensional Models

The macaw palm ( Acrocomia aculeata) is a palm tree native to tropical forests that stand out due to its great potential for oil production. This study was developed with the objective of constructing a high-fidelity model of the macaw palm fruit-rachilla system for the purpose of simulating its dynamic behavior when subjected to mechanical vibrations. The finite element method was used to determine the natural frequencies and modes of vibration of the system. The three-dimensional models of the fruit-rachilla systems were elaborated using CAD3D Fusion 360 software. The modal properties of the fruit-rachilla systems were obtained based on the models developed by varying the elasticity modulus values of the system. The parameters of greatest influence in the estimation of natural frequencies are the elasticity modulus, especially that of the fruit-rachilla joint, and the specific mass. The models that take into account the three-dimensional strains along the rachilla are the least sensitive to variations in the mechanical properties (elasticity modulus and specific mass) and are shown to be more representative of the actual physical system.

scholarly journals Experimental and Finite Element Studies on Free Vibration of Skew Plates

2014 ◽  
Vol 19 (2) ◽  
pp. 365-377 ◽  
Author(s):  
C.V. Srinivasa ◽  
Y.J. Suresh ◽  
W.P. Prema Kumar
Keyword(s):  
Finite Element ◽  
Aspect Ratio ◽  
Free Vibration ◽  
Composite Laminates ◽  
Natural Frequencies ◽  
Experimental Studies ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Skew Angle ◽  
Experimental Values

Abstract The present paper deals with the experimental studies carried out on free vibration of isotropic and laminated composite skew plates. The natural frequencies were also determined using QUAD8 finite element of MSC/NASTRAN and a comparison was made between the experimental values and the finite element solution. The effects of the skew angle and aspect ratio on the natural frequencies of isotropic skew plates were studied. The effects of the skew angle, aspect ratio, fiber orientation angle and laminate sequence (keeping the number of layers constant) on the natural frequencies of antisymmetric composite laminates were also studied. The experimental values of natural frequencies are in good agreement with the FE solutions. The natural frequencies are found to increase with an increase in the skew angle. The variation of natural frequencies with the aspect ratio is small and negligible both for isotropic and laminated composite skew plates.

In-Plane Flexural Vibrations of Circular Rings

1969 ◽  
Vol 36 (3) ◽  
pp. 620-625 ◽  
Author(s):  
S. S. Rao ◽  
V. Sundararajan
Keyword(s):  
Natural Frequencies ◽  
Classical Equation ◽  
Circular Ring ◽  
Classical Formula ◽  
Free Ring ◽  
Circular Arcs ◽  
End Conditions ◽  
Circular Rings ◽  
Experimental Values ◽  
Fixed End

An equation of motion governing the free, in-plane vibrations of a circular ring is developed to include the effects of shear deformation and rotatory inertia. This equation is solved to find the natural frequencies of vibration of free rings and stiffened rings and the results compared with those given by a classical formula. The frequencies for a free ring are found to compare well with the experimental values of Kuhl [5]. Natural frequencies of circular arcs are calculated from the classical equation with hinged and fixed end conditions and the results compared with the approximate values given by Den Hartog [8, 9].

Evaluation of Mechanical Properties of Composite Materials Used in Dentistry Varying the Inorganic Composition

2015 ◽  
Vol 820 ◽  
pp. 320-324
Author(s):  
T.C.F. Melo-Silva ◽  
C.L. Melo-Silva ◽  
C.F. Carvalho ◽  
A.B. Teixeira ◽  
J.F.C. Lins ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Thermal Activation ◽  
Elasticity Modulus ◽  
Excitation Pulse ◽  
Composite Resins ◽  
Acoustic Excitation ◽  
Ceramic Filler ◽  
Inorganic Particles ◽  
Inorganic Composition ◽  
Materials Used

The aim of this study was to determine the hardness and the elasticity modulus of the two composite resins base of BISGMA with different inorganic particles: a nanoparticulated with a ceramic withload, (Filtek Z350XT-3M) with and without thermal activation and a microhybrid with no ceramic load (Opallis-FGM). The samples were prepared and subjected to the tests of Vickers hardness (Shimadzu HMV) and acoustic excitation pulse (Sonelastic ®). The samples were divided into three groups: G1-Filtek Z350 XT; G2-Filtek Z350XT MO (subject to further polymerization microwave) and G3-Opallis. The results showed that the hardness of G2 was significantly higher than the groups G1 and G3. The elastic modulus was higher than the G2 to G1 and G3. One can conclude that the resins filled with inorganic ceramic filler showed higher hardness and elastic modulus. The thermal activation increased the hardness and the elasticity modulus of the resin with ceramic load.

Research on the Natural Frequency Solving Method of the Simply Supported Beam Bridge with Cracks

2013 ◽  
Vol 437 ◽  
pp. 51-55
Author(s):  
Ping Yi Sun ◽  
Yan Hua Wang ◽  
Han Bing Liu ◽  
Guo Jin Tan
Keyword(s):  
Natural Frequency ◽  
Natural Frequencies ◽  
Beam Model ◽  
Euler Beam ◽  
Simply Supported Beam ◽  
Simply Supported ◽  
Solution Methods ◽  
Element Approach ◽  
Experimental Values ◽  
Beam Bridge

Two kinds of natural frequency solution methods for the simply supported beam bridge with cracks are presented respectively based on the Bernoulli-Euler beam model and the finite element approach. Multiple groups of crack damages are supposed on the experimental simply supported steel I-beam, and the natural frequencies of the experimental beam are measured in all the crack cases. By comparing the calculated natural frequencies respectively obtained by the above two methods with the experimental values, the characteristics of the two kinds of natural frequency solving methods are evaluated.

scholarly journals Modal Characterization of Sandwich Skew Plates

2021 ◽  
Vol 15 (3) ◽  
pp. 143-153
Author(s):  
Dhotre Pavan Kumar ◽  
Chikkol V. Srinivasa
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Edge Condition ◽  
Skew Angle ◽  
Composite Sandwich ◽  
Fiber Orientation Angle ◽  
Experimental Values ◽  
Element Free

Abstract The current work focuses on the experimental and finite element free vibration studies of laminated composite sandwich skew plates. The comparison was made between the experimental values obtained by the Fast Fourier transform (FFT) analyzer and a finite element solution obtained from CQUAD8 finite element of The MacNeal-Schwendler Corporation (MSC) / NASA STRucture Analysis (NASTRAN) software. The influence of parameters such as aspect ratio (AR) (a/b), skew angle (α), edge condition, laminate stacking sequence, and fiber orientation angle (θ°) on the natural frequencies of sandwich skew plates was studied. The values obtained by both the finite element and experiment approaches are in good agreement. The natural frequencies increase with an increase in the skew angle for all given ARs.

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