MULTISCALE COMPUTATIONAL EVALUATION OF ELASTO-VISCOPLASTIC DEFORMATION BEHAVIOR OF AMORPHOUS POLYMER CONTAINING MICROSCOPIC HETEROGENEITY DURING UNIAXIAL TENSILE TEST

2010 ◽  
Vol 02 (03n04) ◽  
pp. 235-255 ◽  
Author(s):  
MAKOTO UCHIDA ◽  
NAOYA TADA
Keyword(s):  
Finite Element ◽  
Deformation Behavior ◽  
Volume Fraction ◽  
Amorphous Polymer ◽  
Element Model ◽  
Strength Distribution ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Viscoplastic Deformation ◽  
Heterogeneous Microstructures

The two-scale elasto-viscoplastic deformation behavior of amorphous polymer was investigated using the large deformation finite element homogenization method. In order to enable a large time increment for the simulation step in the plastic deformation stage, the tangent modulus method is introduced into the nonaffine molecular chain network theory, which is used to represent the deformation behavior of pure amorphous polymer. Two kinds of heterogeneous microstructures were prepared in this investigation. One was the void model, which contains uniformly or randomly distributed voids, and the other was the heterogeneous strength (HS) model, which contains a distribution of initial shear strength. In the macroscopic scale, initiation and propagation processes of necking during uniaxial tension were considered. The macroscopic nominal stress–strain relation was strongly characterized by the volume fraction and distribution of voids for the void model and by the width of the strength distribution for the HS model. Non-uniform deformation behaviors in microscopic and macroscopic scales are closely related to each other for amorphous polymers because continuous stretching and hardening in the localized zone of the microstructure brings about an increase in macroscopic deformation resistance. Furthermore, computational results obtained from the homogenization model are compared to those obtained from the full-scale finite element model, and the effect of the scale difference between microscopic and macroscopic fields is discussed.

scholarly journals Finite Element Analysis and Experimental Characterisation of SMC Composite Car Hood Specimens under Complex Loadings

2018 ◽  
Vol 2 (3) ◽  
pp. 53
Author(s):  
Josh Kelly ◽  
Edward Cyr ◽  
Mohsen Mohammadi
Keyword(s):  
Finite Element ◽  
Composite Materials ◽  
Finite Element Model ◽  
Volume Fraction ◽  
Failure Strain ◽  
Fibre Volume Fraction ◽  
Element Model ◽  
Experimental Results ◽  
Uniaxial Tensile ◽  
Structural Applications

Composite materials have recently been of particular interest to the automotive industry due to their high strength-to-weight ratio and versatility. Among the different composite materials used in mass-produced vehicles are sheet moulded compound (SMC) composites, which consist of random fibres, making them inexpensive candidates for non-structural applications in future vehicles. In this work, SMC composite materials were prepared with varying fibre orientations and volume fractions (25% and 45%) and subjected to a series of uniaxial tensile and flexural bending tests at a strain rate of 3 × 10−3 s−1. Tensile strength as well as failure strain increased with the increasing fibre volume fraction for the uniaxial tests. Flexural strength was found to also increase with increasing fibre percentage; however, failure displacement was found to decrease. The two material directions studied—longitudinal and transverse—showed superior strength and failure strain/displacement in the transverse direction. The experimental results were then used to create a finite element model to describe the deformation behaviour of SMC composites. Tensile results were first used to create and calibrate the model; then, the model was validated with flexural experimental results. The finite element model closely predicted both SMC volume fraction samples, predicting the failure force and displacement with less than 3.5% error in the lower volume fraction tests, and 6.6% error in the higher volume fraction tests.

Analysis on Oil Extraction Progressing Cavity Pump Three-Dimensional Finite Element Model

2014 ◽  
Vol 644-650 ◽  
pp. 670-673
Author(s):  
Guo You Han ◽  
Ming Qi Wang ◽  
Yu Hou ◽  
Qiang Li
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Fluid Pressure ◽  
Three Dimensional ◽  
Element Model ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Analysis Model ◽  
Element Analysis

The finite element analysis of PCP involves three nonlinear of geometry, material and contact, and the load of PCP is diversity, leading to it difficult to establish the finite element model and calculate by finite method. This article takes GLB120-27 as an example, to establish 3D solid model of PCP by using SolidWorks; to determine M-R model constant of stator rubber by using the data of uniaxial tensile test: to separate the seal band from the stator chamber by using Boolean operation and set up contact pairs, to achieve the correct simulation of stator chamber fluid pressure; to correctly simulate the interference fit between stator and rotor through setting correlation parameters; to establish 3D finite element analysis model and verify the correctness by using the experiment data of hydraulic characteristics of PCP.

scholarly journals Numerical Modeling and Experimental Characterization of Elastomeric Pads Bonded in a Conical Spring under Multiaxial Loads and Pre-Compression

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Debora Francisco Lalo ◽  
Marcelo Greco ◽  
Matias Meroniuc
Keyword(s):  
Finite Element ◽  
Test Data ◽  
Complex Geometry ◽  
Experimental Tests ◽  
Element Model ◽  
Initial Guess ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Multiaxial Loading ◽  
Fitting Procedure

Elastomeric components are widely used in the engineering field since their mechanical properties can vary according to a specific condition, enabling their applications under large deformations and multiaxial loading. In this context, the present study seeks to investigate the main challenges involved in the finite element hyperelasticity simulation of rubber-like material components under different cases of multiaxial loading and precompression. The complex geometry of a conical rubber spring was chosen to deal with several deformation modes; this component is in the suspension system placed between the frame and the axle for railway vehicles. The framework of this study provides the correlation between axial and radial stiffness under precompression obtained by experimental tests in prototypes and virtual modeling obtained through a curve fitting procedure. Since the material approaches incompressibility, different shape functions were adopted to describe the fields of pressure and displacements according to the finite element hybrid formulation. The material parameters were accurately adjusted through an optimization algorithm implemented in Python program language which calibrates the finite element model according to the prototype test data. However, as an initial guess, the proper constitutive model and its parameters were first defined based only on the uniaxial tensile test data, since this test is easy to perform and well understood. The validation of the simulation results in comparison with the experimental data demonstrated that care should be given when the same component is subjected to different multiaxial loading cases.

Pseudo 3D RVE Based Finite Element Simulation on White Matter

2012 ◽  
Author(s):  
Yi Pan ◽  
Vivak Patel ◽  
Assimina A. Pelegri ◽  
David I. Shreiber
Keyword(s):  
Finite Element ◽  
White Matter ◽  
Spinal Cord Injuries ◽  
Axonal Injury ◽  
Mechanical Strain ◽  
Element Model ◽  
Tissue Level ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Brain White Matter

Axonal injury represents a critical target for traumatic brain and spinal cord injuries prevention and treatment. Finite element head models are often used to predict brain injury caused by mechanical loading exerted on the head. Many studies have been attempted to understand injury mechanisms and to define mechanical parameters of axonal injury. Mechanical strain has been identified as the proximal cause of axonal injury. Since the microstructure of the brain white matter is locally oriented, the stress and strain fields are highly axon orientation dependent. The accuracy of the finite element simulations depends not only on correct determination of the material properties but also on precise depiction of the tissues’ microstructure (microscopic level). We applied a finite element method and a mircomechanics approach to simulate the kinematics of axon, which was developed according to experimental data, and found that the degree of coupling between the axons and surrounding cells within the tissue will affect the behavior of the tissue. In this study, the finite element model and the kinematic axonal model are applied to the Representative Volume Element (RVE) of central nervous system (CNS) white matter to investigate the tissue level mechanical behavior. The uniaxial tensile test on the white matter tissue will be presented as an example using the RVE.

scholarly journals Microstructural Modeling and Strengthening Mechanism of TiB/Ti-6Al-4V Discontinuously-Reinforced Titanium Matrix Composite

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 827 ◽  
Author(s):  
Shuai Zhao ◽  
Yangjian Xu ◽  
Changliang Pan ◽  
Lihua Liang ◽  
Xiaogui Wang
Keyword(s):  
Finite Element ◽  
Matrix Composite ◽  
Distribution Density ◽  
Volume Fraction ◽  
Element Model ◽  
Titanium Matrix ◽  
Titanium Matrix Composite ◽  
Finite Element Software ◽  
Multiple User ◽  
Thiessen Polygon

A novel modeling method was proposed to provide an improved representation of the actual microstructure of TiB/Ti-6Al-4V discontinuously-reinforced titanium matrix composite (DRTMC). Based on the Thiessen polygon structure, the representative volume element (RVE) containing the complex microstructures of the DRTMC was first generated. Thereafter, by using multiple user-defined subroutines in the commercial finite element software ABAQUS, the application of asymmetric mesh periodic boundary conditions on the RVE was realized, and the equivalent elastic modulus of the DRTMC was determined according to the homogenization method. Through error analyses on the experimental and calculated results regarding the equivalent elastic parameters of the DRTMC, the rationality of generating the DRTMC finite element model by using the present method was validated. Finally, simulations based on four types of network-like models revealed that the present simplifications to the particle shape of the reinforcement phase had less of an influence on the overall composite strength. Moreover, the present study demonstrates that the DRTMC enhancement is mainly attributed to the matrix strengthening, rather than the load-transferring mechanism. The strengthening influences of the distribution forms of the reinforcement phases, including their distribution density and orientation, were studied further. It was found that both the higher distribution density and limited distribution orientation of the particles would increase the probability of overlapping and merging between particles, and; therefore, higher strength could be yielded when the volume fraction of the reinforcement phase reached a certain threshold. Owing to the versatility of the developed methods and programs, this work can provide a useful reference for the characterization of the mechanical properties of other composites types.

scholarly journals 3D-Finite element modeling of lead rubber bearing using high damping material

2019 ◽  
Vol 276 ◽  
pp. 01013
Author(s):  
Ahmad Basshofi Habieb ◽  
Tavio Tavio ◽  
Gabriele Milani ◽  
Usman Wijaya
Keyword(s):  
Finite Element ◽  
Shear Behaviour ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Fe Model ◽  
Rubber Material ◽  
Isolation System ◽  
Cyclic Shear ◽  
Rubber Bearing ◽  
Lead Rubber Bearing

Lead Rubber Bearing (LRB) has been widely applied for seismic protection of mid and high-rise buildings around the world. Its excellent energy dissipation becomes the most important aspect of this isolation system thanks to the plasticity and recovery behavior of the lead core. Aiming to develop a deeper knowledge on the behavior of LRB’s, a 3D detailed finite element (FE) modeling is performed in Abaqus FE software. Some important parameters involved in the model are plasticity of the lead core and hyper-elasticity and viscosity of the rubber material. The parameters for rubber material are derived from the results of experimental works in the laboratory, including uniaxial tensile test and relaxation test. The bearing model is then subjected to a cyclic shear-test under constant vertical load. The result of the 3D-FE model is then compared with the analytic-Abaqus model for LRB isolators, developed in the literature. Finally, both 3D-FE model and analytic model result in a good agreement on the shear behaviour of the presented LRB.

The Effects of Layer-by-Layer Thickness and Fiber Volume Fraction Variation on the Mechanical Performance of a Pressure Vessel

2018 ◽  
Author(s):  
Emre Özaslan ◽  
Ali Yetgin ◽  
Volkan Coşkun ◽  
Bülent Acar ◽  
Tarık Olğar
Keyword(s):  
Finite Element ◽  
Layer Thickness ◽  
Pressure Vessel ◽  
Fiber Volume Fraction ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Element Model ◽  
Layer By Layer ◽  
Fiber Volume ◽  
Filament Wound

Due to high stiffness/weight ratio, composite materials are widely used in aerospace applications such as motor case of rockets which can be regarded as a pressure vessel. The most commonly used method to manufacture the pressure vessels is the wet filament winding. However, the mechanical performance of a filament wound pressure vessel directly depends on the manufacturing process, manufacturing site environmental condition and material properties of matrix and fiber. The designed ideal pressure vessel may not be manufactured because of the mentioned issues. Therefore, manufacturing of filament wound composite structures are based on manufacturing experience and experiment. In this study, the effect of layer-by-layer thickness and fiber volume fraction variation due to manufacturing process on the mechanical performance was investigated for filament wound pressure vessel with unequal dome openings. First, the finite element model was created for designed thickness dimensions and constant material properties for all layers. Then, the model was updated. The updated finite element model considered the layer-by-layer thickness and fiber volume fraction variation. Effects of the thickness and fiber volume fraction on the stress distribution along the motor axial direction were shown. Also hydrostatic pressurization test was performed to verify finite element analysis in terms of fiber direction strain through the motor case outer surface. Important aspects of analyzing a filament wound pressure vessel were addressed for designers.

The Effects of Layer-by-Layer Thickness and Fiber Volume Fraction Variation on the Mechanical Performance of a Pressure Vessel

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Emre Özaslan ◽  
Ali Yetgin ◽  
Bülent Acar ◽  
Volkan Coşkun ◽  
Tarık Olğar
Keyword(s):  
Finite Element ◽  
Pressure Vessel ◽  
Material Properties ◽  
Fiber Volume Fraction ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Element Model ◽  
Layer By Layer ◽  
Fiber Volume ◽  
Filament Wound

Abstract Due to high stiffness/weight ratio, composite materials are widely used in aerospace applications such as motor case of rockets which can be regarded as a pressure vessel. The most commonly used method to manufacture pressure vessels is the wet filament winding. However, the mechanical performance of a filament wound pressure vessel directly depends on the manufacturing process, manufacturing site environmental condition, and material properties of matrix and fiber. The designed pressure vessel may not be manufactured because of the mentioned issues. Therefore, manufacturing of filament wound composite structures are based on manufacturing experience and experiment. In this study, effects of layer-by-layer thickness and fiber volume fraction variation due to manufacturing process on the mechanical performance were investigated for filament wound pressure vessel with unequal dome openings. First, the finite element model was created for designed thickness dimensions and constant material properties for all layers. Then, the model was updated. The updated finite element model considered the thickness of each layer separately and variation of fiber volume fraction between the layers. Effects of the thickness and fiber volume fraction on the stress distribution along the motor axial direction were shown. Also hydrostatic pressurization tests were performed to verify finite element analysis in terms of fiber direction strain through the motor case outer surface. Important aspects of analyzing a filament wound pressure vessel were addressed for designers.

scholarly journals Finite Element Simulation of the Thermo-mechanical Response of Graphene Reinforced Nanocomposites

2018 ◽  
Vol 188 ◽  
pp. 01016
Author(s):  
Androniki S. Tsiamaki ◽  
Nick K. Anifantis
Keyword(s):  
Finite Element ◽  
Mechanical Behavior ◽  
Mechanical Response ◽  
Volume Fraction ◽  
Matrix Material ◽  
Continuum Theory ◽  
Element Model ◽  
Multilayer Graphene ◽  
Temperature Changes ◽  
The Matrix

The research for new materials that can withstand extreme temperatures and present good mechanical behavior is of great importance. The interest is highly focused on the utilization of composites reinforced by nanomaterials. To cope with this goal the present work studies the mechanical response of graphene reinforced nanocomposite structures subjected to temperature changes. A computational finite element model has been developed that accounts for both the reinforcement and the matrix material phases. The model developed is based on both the continuum theory and the molecular mechanics theory, for the simulation of the three different material phases of the composite, respectively, i.e. the matrix, the intermediate transition phase and the reinforcement. Considering this model, the mechanical response of an appropriate representative volume element of the nanocomposite is simulated under various temperature changes. The study involves different types of reinforcement composed from either monolayer or multilayer graphene sheets. Apart from the investigation of the behavior of a nanocomposite with each particular type of the reinforcement, comparisons are also presented between them in order to reveal optimized material combinations. The principal parameters taken into consideration, which contribute also to the mechanical behavior of the nanocomposite, are its size, the sheet multiplicity as well as the volume fraction.

scholarly journals 4414 Collagen Dermal Replacement Scaffold Mechanobiology in Treatment of Difficult-to-Heal Wounds

2020 ◽  
Vol 4 (s1) ◽  
pp. 4-4
Author(s):  
David Oleh Sohutskay ◽  
Adrian Buganza Tepole ◽  
Sherry Voytik-Harbin
Keyword(s):  
Wound Healing ◽  
Finite Element ◽  
Finite Element Model ◽  
Animal Experiments ◽  
Element Model ◽  
Constitutive Law ◽  
Wound Contraction ◽  
Uniaxial Tensile ◽  
Scanning Electron Micrographs ◽  
Histological Image

OBJECTIVES/GOALS: Difficult-to-heal wounds of the skin are a common and costly medical problem. Dermal replacement strategies have emerged as a solution, but a challenge is identification of optimal scaffold parameters. We present a model for assessment of clinical potential of collagen scaffolds for wound healing. METHODS/STUDY POPULATION: In previous animal experiments, we evaluated dermal replacement scaffolds custom-fabricated from fibril-forming collagen oligomer with controlled fibril density (4, 20, 40mg/cm3) and spatial gradients in rat excisional wounds. Wound contraction and cellularization were monitored by gross and histological image analysis for comparison with model outcomes. We now parameterize the scaffold parameters for use in the mathematical model of wound healing with nonlinear curve fitting. A preliminary chemo-bio-mechanical finite element model including collagen, cells, and an inflammatory signal was adapted to simulate wound healing results. RESULTS/ANTICIPATED RESULTS: Collagen oligomer microstructure was quantified from scanning electron micrographs. A constitutive law for collagen mechanics was fit to experimental uniaxial tensile tests. We have conducted preliminary three-dimensional finite element model simulations to be validated against experimental wound contraction, recellularization, and collagen remodeling data collected from each experimental group. We show the effects of collagen density and stiffness on wound contraction by altering early wound mechanical properties. We anticipate future work to further improve the model of mechanotransduction, inflammation, and recellularization. DISCUSSION/SIGNIFICANCE OF IMPACT: This work represents the first step towards a computational model of wounds treated with collagen scaffold dermal replacements. In turn, the model will be used to explore cell-scaffold interactions for purposes of prediction and optimization of tissue regeneration outcomes.

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