CAVITATION INSTABILITY IN RUBBER

Rubber materials and structures can fracture because tensile deformation and growth of small pre-existing voids become unstable, leading to failure localization and crack propagation. Thus, it is important to predict the onset of static instability of the growing voids. We consider two typical cases of interest: the instability of 3D voids under the remote hydrostatic tension in the bulk and the instability of 2D voids under the remote biaxial tension in the membrane. For the purpose of analysis, we use constitutive models of natural and styrene-butadiene rubbers with the failure description enforced by energy limiters. The limiters provide the saturation value for the strain energy which indicates the maximum energy that can be stored and dissipated by an infinitesimal material volume. We find that the unstable growth of a 3D bulk void can start when the remote hydrostatic tension reaches the value of ~2 ÷ 3 MPa and the unstable growth of a 2D membrane void can start when the remote biaxial tension reaches the value of ~50 ÷ 60 MPa.

Download Full-text

On Cavitation in Rubberlike Materials

Journal of Applied Mechanics ◽

10.1115/1.4032377 ◽

2016 ◽

Vol 83 (4) ◽

Cited By ~ 11

Author(s):

Yoav Lev ◽

Konstantin Y. Volokh

Keyword(s):

Present Note ◽

Constitutive Models ◽

Material Model ◽

Constitutive Laws ◽

Constitutive Law ◽

Cavity Expansion ◽

Hydrostatic Tension ◽

Hyperelastic Models ◽

Rubberlike Materials ◽

Energy Limiters

Microscopic voids can irreversibly grow into the macroscopic ones under hydrostatic tension. To explain this phenomenon, it was suggested in the literature to use the asymptotic value of the hydrostatic tension in the plateau yieldlike region on the stress–stretch curve obtained for the neo-Hookean model. Such an explanation has two limitations: (a) it relies on analysis of only one material model and (b) the hyperelasticity theory is used for the explanation of the failure phenomenon. In view of the mentioned limitations, the objective of the present note is twofold. First, we simulate the cavity expansion in rubber by using various experimentally calibrated hyperelastic models in order to check whether the stress–stretch curves have the plateau yieldlike regions independently of the constitutive law. Second, we repeat simulations via these same models enhanced with a failure description. We find (and that was not reported in the literature) that the process of cavity expansion simulated via hyperelastic constitutive models exhibiting stiffening, due to unfolding of long molecules, is completely stable and there are no plateau yieldlike regions on the stress–stretch curves associated with cavitation. In addition, we find that the instability in the form of yielding observed in experiments does appear in all simulations when the constitutive laws incorporate failure description with energy limiters.

Download Full-text

Characterization of Hyperelastic (Rubber) Material Using Uniaxial and Biaxial Tension Tests

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.570.1 ◽

2012 ◽

Vol 570 ◽

pp. 1-7

Author(s):

Yawar Jamil Adeel ◽

Ahsan Irshad Muhammad ◽

Azmat Zeeshan

Keyword(s):

Shear Test ◽

Biaxial Tension ◽

Constitutive Models ◽

Hyperelastic Material ◽

Strain Response ◽

Stress Strain ◽

Rubber Material ◽

Tension Tests ◽

Planar Shear

Hyperelastic material simulation is necessary for proper testing of products functionality in cases where prototype testing is expensive or not possible. Hyperelastic material is nonlinear and more than one stress-strain response of the material is required for its characterization. The study was focused on prediction of hyperelastic behavior of rubber neglecting the viscoelastic and creep effects in rubber. To obtain the stress strain response of rubber, uniaxial and biaxial tension tests were performed. The data obtained from these tests was utilized to find the coefficients of Mooney-Rivlin, Odgen and Arruda Boyce models. Verification of the behavior as predicted by the fitted models was carried out by comparing the experimental data of a planar shear test with its simulation using the same constitutive models.

Download Full-text

Cavitation in inhomogeneous soft solids

Soft Matter ◽

10.1039/c8sm01464g ◽

2018 ◽

Vol 14 (39) ◽

pp. 7979-7986 ◽

Cited By ~ 4

Author(s):

Jingtian Kang ◽

Changguo Wang ◽

Huifeng Tan

Keyword(s):

Homogeneous Case ◽

Hydrostatic Tension ◽

Soft Solids ◽

Cavitation Instability

When a large hydrostatic tension is applied to an inhomogeneous soft solid, cavitation instability can be induced in a way that is different from the homogeneous case.

Download Full-text

Experimental Investigations and Numerical Modeling of Incompressible Elastomers during Non-Homogeneous Deformations

Rubber Chemistry and Technology ◽

10.5254/1.3538501 ◽

1998 ◽

Vol 71 (4) ◽

pp. 730-749 ◽

Cited By ~ 20

Author(s):

P. A. Przybylo ◽

E. M. Arruda

Keyword(s):

Compression Test ◽

Tensile Deformation ◽

Constitutive Models ◽

Thin Disk ◽

Experimental Investigations ◽

Uniaxial Compression Test ◽

Principal Stretch ◽

Global Force ◽

Yeoh Model ◽

First Time

Abstract Three hyperelastic constitutive models, the Arruda and Boyce model, the Yeoh model, and the Ogden model, are used to simulate the response of vinyl elastomers in large, non-homogeneous deformation states. A single uniaxial compression test is used to characterize the elastomers to obtain model constants. Drucker stability is enforced by restriction of the coefficients for the Yeoh and Ogden models to produce physically feasible uniaxial results. The ability of the models to predict the global force versus deformation responses and deformed shapes for large deformation shear, tensile deformation of a long bar with fixed grips, and inflation of a thin disk is examined. The experiments used in this study are designed to provide known boundary conditions to eliminate ambiguity in the modeling. We demonstrate for the first time that each of these models may be sufficiently characterized via a simple, homogeneous compression test to allow accurate predictions of large, non-homogeneous deformations involving rotations of the principal stretch directions.

Download Full-text

The Study on Rubber’s Constitutive Model about Parameters Identification and the Effect of Fitting Error

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.503-504.1094 ◽

2012 ◽

Vol 503-504 ◽

pp. 1094-1099

Author(s):

Wen Tao Wang ◽

Wen Bin Shang Guan

Keyword(s):

Biaxial Tension ◽

Constitutive Models ◽

Least Square Method ◽

Least Square ◽

Test Material ◽

Model Parameters ◽

Element Analysis ◽

The Finite Element Analysis ◽

Hyper Elastic ◽

Fitting Accuracy

Fitting accuracy of hyper-elastic constitutive models of rubber and parameter identification of the models play important roles in the finite element analysis of rubber components. In this paper, to obtain stress-strain characteristics, uniaxial and planar as well as biaxial tension of a standard rubber sample are measured. Model parameters of three kinds of classic constitutive models are identified using least square method. Then, the fitting accuracy among different models is compared. The comparison shows that the fitting accuracy is getting higher when the test material strain is increased. Also, it can be concluded that Mooney-Rivlin model and Van der Waals model as well as third-order Ogden model have relatively stable fitting accuracy.

Download Full-text

On the Performance of Isotropic Hyperelastic Constitutive Models for Rubber-Like Materials: A State of the Art Review

Applied Mechanics Reviews ◽

10.1115/1.4050978 ◽

2021 ◽

Author(s):

Hüsnü Dal ◽

Kemal Açikgöz ◽

Yashar Badienia

Keyword(s):

Search Algorithm ◽

Biaxial Tension ◽

Pure Shear ◽

Constitutive Models ◽

Multi Objective Optimization ◽

Multi Objective ◽

Variable Weight ◽

Simultaneous Fitting ◽

Quality Of Fit

Abstract Besides the well-known landmark models for hyperelastic response of rubberlike materials, many new hyperelastic constitutive models heve emerged over the last decade. Despite many reviews on constitutive modelling or elastomers, it is still a challenging endeavor for engineers to decide for a constitutive model for the specific rubber compound and application. In this work, we have reviewed 44 hyperelastic constitutive models for elastomers and assessed their strength and weaknesses under uniaxial, pure shear, and (equi)biaxial deformations. To this end, we first present a novel parameter identification methodology based on various multi-objective optimization strategies for the selection of the best constitutive models from a given set of uniaxial tension, pure shear and (equi)biaxial tension experiments. We utilize a hybrid multi-objective optimization procedure using a genetic algorithm to generate multiple initial points for gradient based search algorithm, Fmincon utility in Matlab. The novelty of the approach is (i) simultaneous fitting with variable weight factors for uniaxial, equibiaxial, and pure shear data, and (ii) the sorting of the models based on an objective normalized quality of fit metric. For the models incapable of simultaneously fitting the three distinct deformation data, the validity range is assessed through a threshold value for the quality of fit measure. Accordingly, 44 hyperelastic models are sorted with respect to their simultaneous fitting performance to the experimental dataset of Treloar and Kawabata. Based on the number of material parameters, and their fitting performance to experimental data, a detailed discussion is carried out.

Download Full-text

ASSESSING THE MULTIAXIAL DEFORMATION RESPONSE OF UNIDIRECTIONAL NON-CRIMP FABRICS

10.12783/asc36/35914 ◽

2021 ◽

Author(s):

MEHDI GHAZIMORADI ◽

VALTER CARVELLI ◽

JOHN MONTESANO

Keyword(s):

Tensile Deformation ◽

Biaxial Tension ◽

Axial Loading ◽

Forming Process ◽

Plane Shear ◽

Deformation Response ◽

Tension Tests ◽

Macro Scale ◽

Induced Defects ◽

Deformation Modes

In this study, the mixed-mode deformation response of a unidirectional non- crimp fabric (UD-NCF) was investigated. Multiaxial in-plane shear-biaxial tension tests were performed using a new multi-branched fabric specimen on a custom multi-axial loading device. Tests were performed with various ratios of deformation along three loading directions to impose combined tension and shear deformation on the fabric specimens. The different loading cases revealed a strong inter-dependency between shear and tensile deformation modes. Observation and measurement of local deformations provided important quantitative and qualitative information to deeply understand the interaction of typical meso- and macro-scale deformations, which can be leveraged during the forming process of liquid composite molded components to reduce shear-induced defects such as wrinkling.

Download Full-text