A Finite Element Approach for Study of Wave Attenuation Characteristics of Epoxy Polymer Composite

2018 ◽  
Author(s):  
Shank S. Kulkarni ◽  
Alireza Tabarraei ◽  
Pratik P. Ghag
Keyword(s):  
Finite Element ◽  
Polymer Composite ◽  
Polymer Matrix ◽  
Wave Attenuation ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Element Model ◽  
Loading Frequency ◽  
Macroscopic Properties ◽  
Attenuation Characteristics

The properties of the inclusions, viz. size, shape, and distribution significantly affect macroscopic properties of a polymer composite. Finite element (FE) modeling provides a viable approach for investigating the effects of the inclusions on the macroscopic properties of the polymer composite. In this paper, finite element method is used to investigate ultrasonic wave propagation in polymer matrix composite with a dispersed phase of inclusions. The finite element models are made up of three phases; viz. the polymer matrix, inclusions (micro constituent), and interphase zones between the inclusions and the polymer matrix. The analysis is performed on a three dimensional finite element model and the attenuation characteristics of ultrasonic longitudinal waves in the matrix are evaluated. The attenuation in polymer composite is investigated by changing the size, volume fraction of inclusions, and addition of interphase layer. The effect of loading frequency of the wave on the attenuation characteristics is also studied by varying the frequency in the range of 1–4 MHz. Results of the test revealed that higher volume fraction of inclusions gave higher attenuation in the polymer composite as compared to the lower volume fraction model. Smaller size of inclusions are preferred over larger size as they give higher wave attenuation. It was found that the attenuation characteristics of the polymer composite are better at higher frequencies as compared to lower frequencies. It is also concluded that the interphase later plays a significant role in the attenuation characteristics of the composite.

Evaluation of Stress Wave Attenuation in a Polymer Matrix Composite Using Finite Element Analysis Technique

2016 ◽  
Author(s):  
Shrikant Nargund
Keyword(s):  
Finite Element ◽  
Polymer Matrix ◽  
Wave Attenuation ◽  
Volume Fraction ◽  
Material Model ◽  
Adhesion Properties ◽  
Interphase Region ◽  
Spherical Inclusions ◽  
Attenuation Characteristics ◽  
Inclusion Matrix

The dynamic behavior of polymer composites is significantly affected by the properties of their micro constituents including shape and size of inclusions and inclusions/matrix adhesion properties. Wave propagation through such a composite is a complex phenomenon as it includes random scattering, absorption and transmittance of the incident wave and is dependent upon factors such as the properties, size and placement of the inclusions inside the matrix. Finite element modeling provides a viable approach for investigating the effects of micro constituent structure on the dynamic behavior of polymer composites. In this paper, we investigate the stress wave attenuation characteristics of a particulate polymer matrix composite using Finite Element (FE) analysis approach. The wave attenuation of ultrasonic sinusoidal waves of frequency ranging from 1 MHz to 4 MHz is evaluated for different FE models. The spherical inclusions are randomly distributed inside the polymer matrix with a certain minimum distance apart from each other. Inclusion-Matrix adhesion properties are studied by modeling a small region at the interface of inclusions and matrix known as interphase region. The interphase region is modeled explicitly using the cohesive zone modeling approach to study how the properties of this region will affect the wave attenuation characteristics of the polymer composite. Cohesive zone models are governed by traction separation law which helps in the measurement of the inclusion-matrix bonding strength and also allow the study of de-bonding at the interface in the critically stressed region produced due application of load. Thus the FE models consist of three phases; polymer matrix, particulate inclusions and the interphase region. Various three dimensional FE models are created using 3D tetrahedral/hexahedral elements by varying the radius of the spherical inclusions and by varying volume fraction of the inclusions. The analyses are performed using a general purpose finite element software LS-Dyna. A rate dependent viscoelastic material model with four terms in prony series expansion is used for modeling the polymer matrix. A linear elastic isotropic material model is used for modeling the inclusions. The wave attenuation is measured as reduction in the amplitude of the wave as it passes through the composite. A comparison of results for various models is done to check for general trend of attenuation coefficient as a function of size of inclusions, volume fraction of inclusions, frequency of loading and interphase region properties. Results show that volume fraction and load frequency have a maximum effect on the wave attenuation coefficient. Interphase region stiffness and interface de-bonding also plays an important role in attenuation characteristics of the polymer composite.

Strength Evaluation of Polymer Composite Spur Gear by Finite Element Analysis

2008 ◽  
Author(s):  
Mohammad Robiul Hossan ◽  
Zhong Hu
Keyword(s):  
Finite Element ◽  
Polymer Composite ◽  
Volume Fraction ◽  
Gear Tooth ◽  
Axial Stress ◽  
High Stress ◽  
Element Model ◽  
Simulation Method ◽  
Spur Gear ◽  
Element Analysis

Modern advanced polymer composite materials have opened a new level of noiseless, lubricant free, high resilience and precision gearing in power and motion transmission. The proper understanding and evaluation of gear strength and performance is an important prerequisite for any reliable application. In this paper, a 20% short glass fiber reinforced nylon66 spur gear fabricated by injection molding has been carefully investigated. A three-dimensional finite element model was used to simulate the multi-axial stress-strain behaviors of a gear tooth under the dynamic load for a complete working cycle with a special geometry, operating condition, fiber orientation and volume fraction. The strength of composite gears has been compared with isotropic un-reinforced nylon66 and steel gears. The tooth root region of a gear which usually experiences high stress and potential to failure has been carefully investigated. This computer simulation method can be used as a useful tool for evaluating strength and predicting failure of the polymer composite gears.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

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.

scholarly journals Comparison of Tooth- and Bone-Borne Appliances on the Stress Distributions and Displacement Patterns in the Facial Skeleton in Surgically Assisted Rapid Maxillary Expansion—A Finite Element Analysis (FEA) Study

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1152
Author(s):  
Rafał Nowak ◽  
Anna Olejnik ◽  
Hanna Gerber ◽  
Roman Frątczak ◽  
Ewa Zawiślak
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Rapid Maxillary Expansion ◽  
Stress Distributions ◽  
Maxillary Expansion ◽  
Facial Skeleton ◽  
Element Analysis ◽  
Maxillary Constriction

The aim of this study was to compare the reduced stresses according to Huber’s hypothesis and the displacement pattern in the region of the facial skeleton using a tooth- or bone-borne appliance in surgically assisted rapid maxillary expansion (SARME). In the current literature, the lack of updated reports about biomechanical effects in bone-borne appliances used in SARME is noticeable. Finite element analysis (FEA) was used for this study. Six facial skeleton models were created, five with various variants of osteotomy and one without osteotomy. Two different appliances for maxillary expansion were used for each model. The three-dimensional (3D) model of the facial skeleton was created on the basis of spiral computed tomography (CT) scans of a 32-year-old patient with maxillary constriction. The finite element model was built using ANSYS 15.0 software, in which the computations were carried out. Stress distributions and displacement values along the 3D axes were found for each osteotomy variant with the expansion of the tooth- and the bone-borne devices at a level of 0.5 mm. The investigation showed that in the case of a full osteotomy of the maxilla, as described by Bell and Epker in 1976, the method of fixing the appliance for maxillary expansion had no impact on the distribution of the reduced stresses according to Huber’s hypothesis in the facial skeleton. In the case of the bone-borne appliance, the load on the teeth, which may lead to periodontal and orthodontic complications, was eliminated. In the case of a full osteotomy of the maxilla, displacements in the buccolingual direction for all the variables of the bone-borne appliance were slightly bigger than for the tooth-borne appliance.

Reduction of Free-Edge Stress Concentration

1985 ◽  
Vol 52 (4) ◽  
pp. 801-805 ◽  
Author(s):  
P. R. Heyliger ◽  
J. N. Reddy
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Free Edge ◽  
Shear Stresses ◽  
Normal Stresses ◽  
Interlaminar Shear ◽  
Three Dimensional Elasticity

A quasi-three dimensional elasticity formulation and associated finite element model for the stress analysis of symmetric laminates with free-edge cap reinforcement are described. Numerical results are presented to show the effect of the reinforcement on the reduction of free-edge stresses. It is observed that the interlaminar normal stresses are reduced considerably more than the interlaminar shear stresses due to the free-edge reinforcement.

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