scholarly journals Effect of Process Orientation on the Mechanical Behavior and Piezoelectricity of Electroactive Paper

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 204
Author(s):  
Sean Yoon ◽  
Jung Woong Kim ◽  
Hyun Chan Kim ◽  
Jaehwan Kim
Keyword(s):  
Mechanical Behavior ◽  
Process Orientation ◽  
Linear Elastic ◽  
Strong Shear ◽  
Performance Deterioration ◽  
Alignment Angle ◽  
Anisotropic Elastic ◽  
Stretching Ratio ◽  
Orientation Dependency ◽  
Piezoelectric Charge

This paper reports the effect of process orientation on the mechanical behavior and piezoelectricity of electroactive paper (EAPap) made from natural cotton pulp. EAPap is fabricated by a casting and wet drawing of cellulose film after dissolving cotton with LiCl and DMAc solvent. During the fabrication, permanent wrinkles, a possible factor for performance deterioration, were found in the films. Finite element method was introduced to identify the formation mechanism behind the wrinkles. The simulation results show that the wrinkles were caused by buckling and are inevitable under any conditions. The tensile and piezoelectric tests show that the orientation dependency of the stretched EAPap gives the anisotropic characteristics on both mechanical and piezoelectric properties. In this research, the anisotropic elastic moduli and Poisson’s ratios are reported. The piezoelectric charge constant of EAPap in the linear elastic is calculated. The piezoelectric charge constants of EAPap are associated with the alignment angle in the order of 45° > 0° > 90° due to the strong shear effect. The higher stretching ratio gives the higher piezoelectricity due to the alignment of the molecular chains and the microstructure in EAPap. The highest piezoelectric charge constant is found to be 12 pC/N at a stretching ratio of 1.6 and aligning angle of 45°.

Mechanical response of double-stranded DNA to dynamic excitation

2021 ◽  
pp. 107754632110458
Author(s):  
Hamze Mousavi ◽  
Moein Mirzaei ◽  
Samira Jalilvand
Keyword(s):  
Mechanical Behavior ◽  
Mechanical Response ◽  
Actual Condition ◽  
Dimensional System ◽  
One Dimensional ◽  
Linear Elastic ◽  
Dynamic Excitation ◽  
Double Stranded Dna ◽  
Elastic Forces ◽  
Mass Spring

The present work investigates the vibrational properties of a DNA-like structure by means of a harmonic Hamiltonian and the Green’s function formalism. The DNA sequence is considered as a quasi one-dimensional system in which the mass-spring pairs are randomly distributed inside each crystalline unit. The sizes of the units inside the system are increased, in a step-by-step approach, so that the actual condition of the DNA could be modeled more accurately. The linear-elastic forces mimicking the bonds between the pairs are initially considered constant along the entire length of the system. In the next step, these forces are randomly shuffled so as to take into account the inherent randomness of the DNA. The results reveal that increasing the number of mass-spring pairs in the crystalline structure decreases the influence of randomness on the mechanical behavior of the structure. This also holds true for systems with larger crystalline units. The obtained results can be used to investigate the mechanical behavior of similar macro-systems.

Small Scale Contact Conditions for the Linear-Elastic Interface Crack

1988 ◽  
Vol 55 (4) ◽  
pp. 814-817 ◽  
Author(s):  
Peter M. Anderson
Keyword(s):  
Interface Crack ◽  
Growth Parameter ◽  
Small Scale ◽  
Elastic Materials ◽  
Small Scale Yielding ◽  
Contact Conditions ◽  
Linear Elastic ◽  
Elastic Interface ◽  
Scale Yielding ◽  
Anisotropic Elastic

Conditions are discussed for which the contact zone at the tip of a two-dimensional interface crack between anisotropic elastic materials is small. For such “small scale contact” conditions combined with small scale yielding conditions, a stress concentration vector uniquely characterizes the near tip field, and may be used as a crack growth parameter. Representative calculations for an interface crack on a representative Cu grain boundary show small contact conditions to prevail, except possibly under large shearing loads.

scholarly journals Mechanical behavior of ballasted railway track stabilized with polyurethane: A finite element analysis

2018 ◽  
Vol 251 ◽  
pp. 04056 ◽  
Author(s):  
Zelimkhan Khakiev ◽  
Alexander Kruglikov ◽  
Georgy Lazorenko ◽  
Anton Kasprzhitskii ◽  
Yakov Ermolov ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanical Behavior ◽  
Finite Element Simulation ◽  
Elasticity Modulus ◽  
Railway Track ◽  
Binding Agent ◽  
Element Analysis ◽  
Linear Elastic ◽  
Element Simulation

Analysis of mechanical behavior of ballast shoulder of railway track reinforced by polyurethane binding agent has been performed by the method of finite-element simulation Limitation of the model of linear-elastic properties of geocomposite has been displayed. Dependence of elasticity modulus of geocomposite on deformation value has been suggested. Influence of penetration depth of polyurethane binding agent on behavior of railway track construction under different train loads has been studied.

scholarly journals Anisotropic linear elastic parameter estimation using error in the constitutive equation functional

2016 ◽  
Vol 472 (2192) ◽  
pp. 20160213 ◽  
Author(s):  
Shyamal Guchhait ◽  
Biswanath Banerjee
Keyword(s):  
Constitutive Equation ◽  
Elastic Parameter ◽  
Linear Elastic ◽  
Explicit Material ◽  
New Strategy ◽  
Minimization Procedure ◽  
Parameter Identification Problems ◽  
Anisotropic Elastic ◽  
Necessary Constraints ◽  
Constitutive Tensor

A modified error in the constitutive equation-based approach for identification of heterogeneous and linear anisotropic elastic parameters involving static measurements is proposed and explored. Following an alternating minimization procedure associated with the underlying optimization problem, the new strategy results in an explicit material parameter update formula for general anisotropic material. This immediately allows us to derive the necessary constraints on measured data and thus restrictions on physical experimentation to achieve the desired reconstruction. We consider a few common materials to derive such conditions. Then, we exploit the invariant relationships of the anisotropic constitutive tensor to propose an identification procedure for space-dependent material orientations. Finally, we assess the numerical efficacy of the developed tools against a few parameter identification problems of engineering interest.

On the existence of type-6 transonic states in linear elastic media of cubic symmetry

1987 ◽  
Vol 411 (1840) ◽  
pp. 251-263 ◽  
Keyword(s):  
Wave Propagation ◽  
Surface Wave ◽  
Elastic Solid ◽  
Mechanics Of Solids ◽  
Elastic Media ◽  
Slowness Surface ◽  
Cubic Symmetry ◽  
Linear Elastic ◽  
Surface Wave Propagation ◽  
Anisotropic Elastic

Crucial to the understanding of surface-wave propagation in an anisotropic elastic solid is the notion of transonic states, which are defined by sets of parallel tangents to a centred section of the slowness surface. This study points out the previously unrecognized fact that first transonic states of type 6 (tangency at three distinct points on the outer slowness branch S 1 ) indeed exist and are the rule, rather than the exception, in so-called C 3 cubic media (satisfying the inequalities c 12 + c 44 > c 11 - c 44 > 0); simple numerical analysis is used to predict orientations of slowness sections in which type-6 states occur for 21 of the 25 C 3 cubic media studied previously by Chadwick & Smith (In Mechanics of solids , pp. 47-100 (1982)). Limiting waves and the composite exceptional limiting wave associated with such type-6 states are discussed.

Mechanical Behavior of Fracture Filled with Variable Medium

2012 ◽  
Vol 472-475 ◽  
pp. 2203-2206
Author(s):  
Jin Gang Chen ◽  
Na Chen ◽  
Jun Li Yang
Keyword(s):  
Mechanical Behavior ◽  
Laboratory Experiments ◽  
Behavior Model ◽  
Flow State ◽  
Linear Elastic ◽  
Ideal Plastic ◽  
Strain Data ◽  
Variable Medium ◽  
Normal Compression ◽  
The Ideal

Filled fracture is a fracture in which sands or other materials occupy some void spaces. This study uses well-controlled laboratory experiments to investigate mechanical behavior of fracture filled with variable medium by means of normal compression and lateral restraint. A large number of stress-strain data are obtained. The mechanical behavior of filled fracture with variable medium can be divided into three phases: rheological phase, compaction phase and linear elastic phase. At the beginning of the experiment, the filled fracture is in the ideal plastic flow state. The overall strength of filled fracture increase with finite deformation and normal stress increasing, and show linear elastic characters. Based on the experiment results and characteristics, the mechanical behavior model of fracture filled with variable medium is constructed, and also its mechanism is analyzed.

scholarly journals ANÁLISE DO COMPORTAMENTO MECÂNICO DE MACIÇOS ROCHOSOS CONTENDO DESCONTINUIDADES ATRAVÉS DO MÉTODO DAS DIFERENÇAS FINITAS VIA IMPLEMENTAÇÃO COMPUTACIONAL [ Analysis of the mechanical behavior of rocky mass with discontinuities through the finite differences method via computational implementation ]

2018 ◽  
Vol 15 (1) ◽  
Author(s):  
Luma Alvarenga Carvalho de Vasconcelos ◽  
Pedro Guilherme Cipriano Silva ◽  
Pedro Ivo Amaro Alves
Keyword(s):  
Rock Mass ◽  
Mechanical Behavior ◽  
Numerical Solutions ◽  
Compressive Force ◽  
Shear Stiffness ◽  
Relative Displacement ◽  
Shear Stresses ◽  
Linear Elastic ◽  
Finite Differences Method ◽  
Fortran 90

RESUMO: Neste trabalho é realizada uma análise computacional por meio da resolução de equações diferenciais para a modelagem de soluções analíticas e numéricas (MDF) do comportamento mecânico de um maciço rochoso contendo descontinuidades. Realizou-se simulações adotando um bloco composto por um material homogêneo, isotrópico e linear elástico sob atuação de uma força externa compressiva aplicada na sua extremidade livre e confinado entre duas descontinuidades rígidas, nas superfícies inferior e superior. A descontinuidade inferior apresenta rugosidade, caracterizada por um módulo de rigidez ao cisalhamento que conduz a uma distribuição de tensão cisalhante e a um deslocamento relativo entre o bloco e a base. Os resultados foram gerados através da compilação dos dados no programa computacional FORTRAN 90, e, com isso, pode-se verificar o deslocamento relativo entre o bloco e a descontinuidade, bem como as tensões atuantes em cada ponto previamente definido; e ainda realizar uma comparação entre as soluções analítica e numérica. Como principal contribuição do trabalho para a área da geotecnia, cita-se a possibilidade de uma análise de deslocamento de descontinuidades presentes em maciços rochosos mais próxima da realidade já que considera o meio como descontínuo. Além disso apresenta-se uma solução computacional de fácil implementação e entendimento.ABSTRACT: In this work a computational analysis is performed by solving differential equations for the modeling of numerical (MDF) and analytical solutions of the mechanical behavior of a rock mass with discontinuities. Simulations were carried out by adopting a block composed of a homogeneous, isotropic and linear elastic material under the action of an external compressive force applied at its free end and confined between two rigid discontinuities on the lower and upper surfaces. The lower discontinuity presents roughness characterized by a shear stiffness modulus leading to a shear stress distribution and a relative displacement between the block and the base. The results were generated through the compilation of the data in the FORTRAN 90 computer program, and with this, it is possible to verify the relative displacement between the block and the discontinuity, as well as the shear stresses acting at each previously defined point; and also perform a comparison between analytical and numerical solutions. The main contribution of the work to the area of geotechnics is the possibility of an analysis of discontinuity displacement present in rock mass closer to reality since it considers the environment as discontinuous. In addition, a computational solution is presented that is easy to implement and understand.

Simulation of the Mechanical Behavior of White Matter Using a Micromechanics Finite Element Method

2011 ◽  
Vol 1301 ◽  
Author(s):  
Yi Pan ◽  
Assimina A. Pelegri ◽  
David I. Shreiber
Keyword(s):  
White Matter ◽  
Mechanical Behavior ◽  
Scale Up ◽  
Constitutive Models ◽  
Local Fields ◽  
Scale Model ◽  
Linear Elastic ◽  
Surrounding Matrix ◽  
Axon Damage

ABSTRACTThe atypical mechanical behavior of white matter and its influence on the mechanical properties of brain tissue necessitate adoption of a mutli-scale model of white matter for accurate computational analysis. Herein, we present a micromechanical analysis coupled with finite elements into a biomechanical interacting model of white matter. A representation of the white matter of central nervous system is identified and its microstructure is generated. The geometric descriptions of the axon and the surrounding matrix are obtained from neurofilament immunohistochemistry images. Consecutively, linear elastic material constitutive models are applied to describe the behavior of axons and their surrounding matrix subjected to small deformations. This model facilitates determination of the tissue’s stress and strain fields, and enables an understanding of the effects of axon undulation on local fields. The fundamental nature of the model enables future scale-up for structural tissue analysis and predictions of axon damage at the microscale.

Measurement of the axial and circumferential mechanical properties of rat skin tissue at different anatomical locations

2015 ◽  
Vol 60 (2) ◽  
Author(s):  
Alireza Karimi ◽  
Maedeh Haghighatnama ◽  
Mahdi Navidbakhsh ◽  
Afsaneh Motevalli Haghi
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Mechanical Behavior ◽  
Clinical Decision Making ◽  
Mechanical Response ◽  
The Body ◽  
Skin Tissue ◽  
Linear Elastic ◽  
Biomechanical Models ◽  
Nonlinear Mechanical

AbstractSkin tissue is not only responsible for thermoregulation but also for protecting the human body from mechanical, bacterial, and viral insults. The mechanical properties of skin tissue may vary according to the anatomical locations in the body. However, the linear elastic and nonlinear hyperelastic mechanical properties of the skin in different anatomical regions and at different loading directions (axial and circumferential) so far have not been determined. In this study, the mechanical properties during tension of the rat abdomen and back were calculated at different loading directions using linear elastic and nonlinear hyperelastic material models. The skin samples were subjected to a series of tensile tests. The elastic modulus and maximum stress of the skin tissues were measured before the incidence of failure. The nonlinear mechanical behavior of the skin tissues was also computationally investigated through a constitutive equation. Hyperelastic strain energy density function was calibrated using the experimental data. The results revealed the anisotropic mechanical behavior of the abdomen and the isotropic mechanical response of the back skin. The highest elastic modulus was observed in the abdomen skin under the axial direction (10 MPa), while the lowest one was seen in the back skin under axial loading (5 MPa). The Mooney-Rivlin material model closely addressed the nonlinear mechanical behavior of the skin at different loading directions, which can be implemented in the future biomechanical models of skin tissue. The results might have implications not only for understanding of the isotropic and anisotropic mechanical behavior of skin tissue at different anatomical locations but also for providing more information for a diversity of disciplines, including dermatology, cosmetics industry, clinical decision making, and clinical intervention.

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