scholarly journals Constitutive Model of Isotropic Magneto-Sensitive Rubber with Amplitude, Frequency, Magnetic and Temperature Dependence under a Continuum Mechanics Basis

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 472 ◽  
Author(s):  
Bochao Wang ◽  
Leif Kari
Keyword(s):  
Constitutive Model ◽  
Continuum Mechanics ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Temperature Dependent ◽  
Nonlinear Constitutive Model ◽  
Measurement Results ◽  
Standard Linear Solid ◽  
Standard Linear ◽  
Main Components

A three-dimensional nonlinear constitutive model of the amplitude, frequency, magnetic and temperature dependent mechanical property of isotropic magneto-sensitive (MS) rubber is developed. The main components of MS rubber are an elastomer matrix and magnetizable particles. When a magnetic field is applied, the modulus of MS rubber increases, which is known as the magnetic dependence of MS rubber. In addition to the magnetic dependence, there are frequency, amplitude and temperature dependencies of the dynamic modulus of MS rubber. A continuum mechanical framework-based constitutive model consisting of a fractional standard linear solid (SLS) element, an elastoplastic element and a magnetic stress term of MS rubber is developed to depict the mechanical behavior of MS rubber. The novelty is that the amplitude, frequency, magnetic and temperature dependent mechancial properties of MS rubber are integrated into a whole constitutive model under the continuum mechanics frame. Comparison between the simulation and measurement results shows that the fitting effect of the developed model is very good. Therefore, the constitutive model proposed enables the prediction of the mechanical properties of MS rubber under various operating conditions with a high accuracy, which will drive MS rubber’s application in engineering problems, especially in the area of MS rubber-based anti-vibration devices.

LED-Based 3-DMD Volumetric 3D Display

2014 ◽  
Vol 596 ◽  
pp. 442-445
Author(s):  
Chang Long Jing ◽  
Qi Bin Feng ◽  
Ying Song Zhang ◽  
Guang Lei Yang ◽  
Zhi Gang Song ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
High Speed ◽  
Three Dimensional ◽  
Human Vision ◽  
3D Display ◽  
Video Projector ◽  
High Speed Video ◽  
University Of Technology ◽  
Measurement Results ◽  
Main Components

A solid-state volumetric true 3D display developed by Hefei University of Technology consists of two main components: a high-speed video projector and a stack of liquid crystal shutters. The shutters are based on polymer stabilized cholesteric texture material, presenting different states that can be switched by different voltage. The high-speed video projector includes LED-based light source and tree-chip digital micro-mirror devices modulating RGB lights. A sequence of slices of three-dimensional images are projected into the liquid crystal shutters locating at the proper depth, forming a true 3D image depending on the human vision persistence. The prototype is developed. The measurement results show that the screen brightness can reach 149 nit and no flickers can be perceived.

Three-dimensional nonlinear constitutive model for composites

2016 ◽  
Vol 142 ◽  
pp. 78-86 ◽  
Author(s):  
Ulrich Mandel ◽  
Robin Taubert ◽  
Roland Hinterhölzl
Keyword(s):  
Constitutive Model ◽  
Three Dimensional ◽  
Nonlinear Constitutive Model

Efficient 3-D viscoelastic modeling with application to near‐surface land seismic data

Geophysics ◽  
1998 ◽  
Vol 63 (2) ◽  
pp. 601-612 ◽  
Author(s):  
Tong Xu ◽  
George A. McMechan
Keyword(s):  
Seismic Data ◽  
Three Dimensional ◽  
Elastic Response ◽  
Computational Time ◽  
Near Surface ◽  
Thrust Zone ◽  
Standard Linear Solid ◽  
Standard Linear ◽  
Time Formulation ◽  
Viscoelastic Modeling

Three‐dimensional viscoelastic modeling is implemented by reparameterizing the viscoelastic wave equation for a standard linear solid. The formulation uses weighting factors corresponding to relaxation frequencies and composite memory variables. This novel 3-D formulation requires less computer memory than the traditional relaxation time formulation because one set of relaxation frequencies can be used for all mechanisms for all parts of a model, and only three sets of composite memory variables are needed rather than the seven used in the standard implementation, giving a net reduction of 40% in the total required memory. Computational time is also reduced approximately 25% because of reduced input/output (I/O). The algorithm is applied to 3-D modeling of the viscoelastic response of the near‐surface structure beneath a 3-D reflection survey in the Ouachita frontal thrust zone of southeast Oklahoma. Comparison of the 3-D field data with both viscoelastic and elastic response clearly demonstrates the importance of inclusion of viscoelasticity when accurate amplitude fitting is desired. Observed amplitude and traveltime variations can be explained by shallow velocity and Q distributions obtained independently by 3-D tomography.

scholarly journals A General Temperature-Dependent Stress–Strain Constitutive Model for Polymer-Bonded Composite Materials

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1393
Author(s):  
Xiaochang Duan ◽  
Hongwei Yuan ◽  
Wei Tang ◽  
Jingjing He ◽  
Xuefei Guan
Keyword(s):  
Composite Materials ◽  
Constitutive Model ◽  
Model Parameters ◽  
Temperature Dependent ◽  
Stress Strain ◽  
Proposed Model ◽  
Single Temperature ◽  
Testing Data ◽  
Bonded Composite ◽  
Tension And Compression

This study develops a general temperature-dependent stress–strain constitutive model for polymer-bonded composite materials, allowing for the prediction of deformation behaviors under tension and compression in the testing temperature range. Laboratory testing of the material specimens in uniaxial tension and compression at multiple temperatures ranging from −40 ∘C to 75 ∘C is performed. The testing data reveal that the stress–strain response can be divided into two general regimes, namely, a short elastic part followed by the plastic part; therefore, the Ramberg–Osgood relationship is proposed to build the stress–strain constitutive model at a single temperature. By correlating the model parameters with the corresponding temperature using a response surface, a general temperature-dependent stress–strain constitutive model is established. The effectiveness and accuracy of the proposed model are validated using several independent sets of testing data and third-party data. The performance of the proposed model is compared with an existing reference model. The validation and comparison results show that the proposed model has a lower number of parameters and yields smaller relative errors. The proposed constitutive model is further implemented as a user material routine in a finite element package. A simple structural example using the developed user material is presented and its accuracy is verified.

scholarly journals Stable and Efficient Modeling of Anelastic Attenuation in Seismic Wave Propagation

2012 ◽  
Vol 12 (1) ◽  
pp. 193-225 ◽  
Author(s):  
N. Anders Petersson ◽  
Björn Sjögreen
Keyword(s):  
Wave Equation ◽  
Finite Difference ◽  
Half Space ◽  
Material Model ◽  
Second Order ◽  
Finite Difference Approximation ◽  
Difference Approximation ◽  
Space Problem ◽  
Standard Linear Solid ◽  
Standard Linear

AbstractWe develop a stable finite difference approximation of the three-dimensional viscoelastic wave equation. The material model is a super-imposition of N standard linear solid mechanisms, which commonly is used in seismology to model a material with constant quality factor Q. The proposed scheme discretizes the governing equations in second order displacement formulation using 3N memory variables, making it significantly more memory efficient than the commonly used first order velocity-stress formulation. The new scheme is a generalization of our energy conserving finite difference scheme for the elastic wave equation in second order formulation [SIAM J. Numer. Anal., 45 (2007), pp. 1902-1936]. Our main result is a proof that the proposed discretization is energy stable, even in the case of variable material properties. The proof relies on the summation-by-parts property of the discretization. The new scheme is implemented with grid refinement with hanging nodes on the interface. Numerical experiments verify the accuracy and stability of the new scheme. Semi-analytical solutions for a half-space problem and the LOH.3 layer over half-space problem are used to demonstrate how the number of viscoelastic mechanisms and the grid resolution influence the accuracy. We find that three standard linear solid mechanisms usually are sufficient to make the modeling error smaller than the discretization error.

scholarly journals Alternative derivation of the higher-order constitutive model for six-parameter elastic shells

2021 ◽  
Vol 72 (2) ◽  
Author(s):  
Mircea Bîrsan
Keyword(s):  
Energy Density ◽  
Constitutive Model ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Shell Theory ◽  
Constitutive Relations ◽  
Three Dimensional ◽  
Classical Shell Theory ◽  
Three Dimensional Elasticity ◽  
General Method

AbstractIn this paper, we present a general method to derive the explicit constitutive relations for isotropic elastic 6-parameter shells made from a Cosserat material. The dimensional reduction procedure extends the methods of the classical shell theory to the case of Cosserat shells. Starting from the three-dimensional Cosserat parent model, we perform the integration over the thickness and obtain a consistent shell model of order $$ O(h^5) $$ O ( h 5 ) with respect to the shell thickness h. We derive the explicit form of the strain energy density for 6-parameter (Cosserat) shells, in which the constitutive coefficients are expressed in terms of the three-dimensional elasticity constants and depend on the initial curvature of the shell. The obtained form of the shell strain energy density is compared with other previous variants from the literature, and the advantages of our constitutive model are discussed.

scholarly journals A nonlinear strain-rate dependent constitutive model for uncured rubber materials under large deformation

2020 ◽  
Vol 37 ◽  
pp. 118-125
Author(s):  
Weihua Zhou ◽  
Changqing Fang ◽  
Huifeng Tan ◽  
Huiyu Sun
Keyword(s):  
Constitutive Model ◽  
Large Deformation ◽  
Mechanical Response ◽  
Uniaxial Tensile ◽  
Hysteresis Phenomenon ◽  
Mechanical Behaviors ◽  
Nonlinear Constitutive Model ◽  
Rate Dependent ◽  
Parallel Networks ◽  
Non Gaussian

Abstract Uncured rubber possesses remarkable hyperelastic and viscoelastic properties while it undergoes large deformation; therefore, it has wide application prospects and attracts great research interests from academia and industry. In this paper, a nonlinear constitutive model with two parallel networks is developed to describe the mechanical response of uncured rubber. The constitutive model is incorporated with the Eying model to describe the hysteresis phenomenon and viscous flow criterion, and the hyperelastic properties under large deformation are captured by a non-Gaussian chain molecular network model. Based on the model, the mechanical behaviors of hyperelasticity, viscoelasticity and hysteresis under different strain rates are investigated. Furthermore, the constitutive model is employed to estimate uniaxial tensile, cyclic loading–unloading and multistep tensile relaxation mechanical behaviors of uncured rubber, and the prediction results show good agreement with the test data. The nonlinear mechanical constitutive model provides an efficient method for predicting the mechanical response of uncured rubber materials.

Sign in / Sign up

Export Citation Format

Share Document