The Experts below are selected from a list of 1893 Experts worldwide ranked by ideXlab platform

M B Rubin - One of the best experts on this subject based on the ideXlab platform.

  • an anisotropic discrete fibre model based on a Generalised Strain invariant with application to soft biological tissues
    International Journal of Engineering Science, 2012
    Co-Authors: Cormac Flynn, M B Rubin
    Abstract:

    Abstract This paper presents a discrete fibre model for soft biological tissues, which is based on a Generalised Strain invariant. Non-linear Strain energy functions of this Generalised invariant model the non-linear response of the soft tissue. Six fibre bundles are orientated such that they pass through opposing vertices of a regular icosahedron. The fibre bundles are weighted in order to characterise the anisotropic nature inherent in most soft tissues. A significant advantage of the Generalised Strain approach is that the fibre bundle weights are pure measures of the anisotropy of the simulated soft tissue. It is shown that the weights can be used to define an approximate continuous orientation distribution function of the fibres within the tissue. The proposed model accurately simulated uniaxial tensile loading of pig skin (Error 16.6%), biaxial stretching of rabbit skin (Error 12.0%), simple shear of septal myocardium (Error 13.4%), and the equibiaxial loading of fresh and fixed aortic valve cusps (Error 1.9% and 0.9%, respectively). The predicted fibre orientations are in general agreement with measurements in the literature.

Cormac Flynn - One of the best experts on this subject based on the ideXlab platform.

  • an anisotropic discrete fibre model based on a Generalised Strain invariant with application to soft biological tissues
    International Journal of Engineering Science, 2012
    Co-Authors: Cormac Flynn, M B Rubin
    Abstract:

    Abstract This paper presents a discrete fibre model for soft biological tissues, which is based on a Generalised Strain invariant. Non-linear Strain energy functions of this Generalised invariant model the non-linear response of the soft tissue. Six fibre bundles are orientated such that they pass through opposing vertices of a regular icosahedron. The fibre bundles are weighted in order to characterise the anisotropic nature inherent in most soft tissues. A significant advantage of the Generalised Strain approach is that the fibre bundle weights are pure measures of the anisotropy of the simulated soft tissue. It is shown that the weights can be used to define an approximate continuous orientation distribution function of the fibres within the tissue. The proposed model accurately simulated uniaxial tensile loading of pig skin (Error 16.6%), biaxial stretching of rabbit skin (Error 12.0%), simple shear of septal myocardium (Error 13.4%), and the equibiaxial loading of fresh and fixed aortic valve cusps (Error 1.9% and 0.9%, respectively). The predicted fibre orientations are in general agreement with measurements in the literature.

Thomas Nagel - One of the best experts on this subject based on the ideXlab platform.

  • control of tension compression asymmetry in ogden hyperelasticity with application to soft tissue modelling
    Journal of The Mechanical Behavior of Biomedical Materials, 2016
    Co-Authors: Kevin M. Moerman, Thomas Nagel, Ciaran Simms
    Abstract:

    This paper discusses tension-compression asymmetry properties of Ogden hyperelastic formulations. It is shown that if all negative or all positive Ogden coefficients are used, tension-compression asymmetry occurs the degree of which cannot be separately controlled from the degree of non-linearity. A simple hybrid form is therefore proposed providing separate control over the tension-compression asymmetry. It is demonstrated how this form relates to a newly introduced Generalised Strain tensor class which encompasses both the tension-compression asymmetric Seth-Hill Strain class and the tension-compression symmetric Bažant Strain class. If the control parameter is set to q=0.5 a tension-compression symmetric form involving Bažant Strains is obtained with the property Ψ(λ1,λ2,λ3)=Ψ(1λ1,1λ2,1λ3). The symmetric form may be desirable for the definition of ground matrix contributions in soft tissue modelling allowing all deviation from the symmetry to stem solely from fibrous reinforcement. Such an application is also presented demonstrating the use of the proposed formulation in the modelling of the non-linear elastic and transversely isotropic behaviour of skeletal muscle tissue in compression (the model implementation and fitting procedure have been made freely available). The presented hyperelastic formulations may aid researchers in independently controlling the degree of tension-compression asymmetry from the degree of non-linearity, and in the case of anisotropic materials may assist in determining the role played by, either the ground matrix, or the fibrous reinforcing structures, in generating asymmetry.

Kevin M. Moerman - One of the best experts on this subject based on the ideXlab platform.

  • control of tension compression asymmetry in ogden hyperelasticity with application to soft tissue modelling
    Journal of The Mechanical Behavior of Biomedical Materials, 2016
    Co-Authors: Kevin M. Moerman, Thomas Nagel, Ciaran Simms
    Abstract:

    This paper discusses tension-compression asymmetry properties of Ogden hyperelastic formulations. It is shown that if all negative or all positive Ogden coefficients are used, tension-compression asymmetry occurs the degree of which cannot be separately controlled from the degree of non-linearity. A simple hybrid form is therefore proposed providing separate control over the tension-compression asymmetry. It is demonstrated how this form relates to a newly introduced Generalised Strain tensor class which encompasses both the tension-compression asymmetric Seth-Hill Strain class and the tension-compression symmetric Bažant Strain class. If the control parameter is set to q=0.5 a tension-compression symmetric form involving Bažant Strains is obtained with the property Ψ(λ1,λ2,λ3)=Ψ(1λ1,1λ2,1λ3). The symmetric form may be desirable for the definition of ground matrix contributions in soft tissue modelling allowing all deviation from the symmetry to stem solely from fibrous reinforcement. Such an application is also presented demonstrating the use of the proposed formulation in the modelling of the non-linear elastic and transversely isotropic behaviour of skeletal muscle tissue in compression (the model implementation and fitting procedure have been made freely available). The presented hyperelastic formulations may aid researchers in independently controlling the degree of tension-compression asymmetry from the degree of non-linearity, and in the case of anisotropic materials may assist in determining the role played by, either the ground matrix, or the fibrous reinforcing structures, in generating asymmetry.

Garau M - One of the best experts on this subject based on the ideXlab platform.

  • Alternating Strain Regimes for Failure Propagation in Flexural Systems
    'Oxford University Press (OUP)', 2019
    Co-Authors: Garau M, Mj Nieves, Is Jones
    Abstract:

    We consider both analytical and numerical studies of a steady-state fracture process inside a discrete mass-beam structure, composed of periodically placed masses connected by Euler–Bernoulli beams. A fault inside the structure is assumed to propagate with a constant speed and this occurs as a result of the action of a remote sinusoidal, mechanical load. The established regime of fracture corresponds to the case of an alternating Generalised Strain regime. The model is reduced to a Wiener–Hopf equation and its solution is presented. We determine the minimum feeding wave energy required for the steady-state fracture process to occur. In addition, we identify the dynamic features of the structure during the steady-state fracture regime. A transient analysis of this problem is also presented, where the existence of steady-state fracture regimes, revealed by the analytical model, are verified and the associated transient features of this process are discussed

  • Alternating Strain regimes for failure propagation in flexural systems
    2019
    Co-Authors: Garau M, Nieves M. J., Jones I. S.
    Abstract:

    We consider both analytical and numerical studies of a steady-state fracture process inside a discrete mass-beam structure, composed of periodically placed masses connected by Euler-Bernoulli beams. A fault inside the structure is assumed to propagate with a constant speed and this occurs as a result of the action of a remote sinusoidal, mechanical load. The established regime of fracture corresponds to the case of an alternating Generalised Strain regime. The model is reduced to a Wiener-Hopf equation and its solution is presented. We determine the minimum feeding wave energy required for the steady-state fracture process to occur. In addition, we identify the dynamic features of the structure during the steady-state fracture regime. A transient analysis of this problem is also presented, where the existence of steady-state fracture regimes, revealed by the analytical model, are verified and the associated transient features of this process are discussed.Comment: 37 pages, 13 figure