A structural model of the left ventricle is presented. It is a cylindricalthick-walled model composed of muscle fibre models and coronaryvessel models. The ventricular wall is divided in ten layers to accountfor the transmural variation of myofibre and coronary vessel orientation.These structures give the global performance of the ventricular modeldepending on their own behaviour and on the way they...

The free vibrations of circular cylindrical shells partiallyloaded by a distributed mass and rested on an elastic bed are studied in this paper. Both the mass-load and the elastic bed are assumed to be applied on limited arcs and with arbitrary distributions in circumferential direction,while they are considered to be uniformly distributed in longitudinaldirection on the entire shell length. Therefore,...

Thiw work is concerned with the formulation of constituent interactions and corresponding balance relations in classical mixture theory as based on a model for the (classical) constituent structure of such a mixture.

An approximate analytical procedure is presented to estimate theresponse spectrum of an oscillator with elastic impacts under a Gaussian whitenoise excitation. The proposed approach is based on a perturbation analysis ofthe problem and on the use of the stochastic averaging principle. The basicidea is to replace the initial system by a more regular system obtained byapproximating the nonlinear restoring...

A high resolution essentially non-oscillatory (ENO) numerical scheme is applied to a new model of heat propagation in crystals for an accurate reconstruction of second sound waves. A splitting of the governing equations allows to approximate the differential terms and the forcing term by means of the ENO scheme and a Runge--Kutta third order scheme, respectively. Results obtained on data relative...

We consider continuous media in which contact edge forces are present. Introducing thenotion of quasi-balanced contact force distribution, we are able to prove the conjectures by Noll andVirga [1] concerning the representation of contact edge forces. We generalize the Hamel--Nolltheorem on the Cauchy postulate. Then we adapt the celebrated tetrahedron construction of Cauchy in orderto obtain a representation...

The three basic functionals of potential energy, complementary energy and Hellinger–Prange–Reissner are usedto obtain a rational derivation of Reissner–Mindlinplate models, starting from the three-dimensional theory.We show that the models so obtained are instances of the same plate theory; nevertheless, due to the different constitutive relations governing their response, they mimic the three-dimensional...

The unsteady laminar incompressible boundary layer flow of an electricallyconducting fluid in the stagnation region of two-dimensional and axisymmetricbodies with an applied magnetic field has been studied. The boundary layerequations which are parabolic partial differential equations with threeindependent variables have been reduced to a system of ordinary differential equations by using suitable...

The dynamic impact problem for the Timoshenko beam against a rigid frictionless obstacle is studied. The unknown reaction is modeled as a positive measure with support contained in the contact set and acting on the centroid of the beam in the vertical direction. Three independent invariant quantities of energy type for the free beam are derived. These quantities turn out to be useful in the description...

A fluid-dynamic model of two non-coalescing liquid drops of the same liquid, pressed against one another in the presence of thermocapillary convection, is proposed to correlate experimental results on the deformation of the drop surfaces, on the pressure distribution and on the thickness of the air film between the drops. The two-point boundary value problem for the Gauss–Laplace hydrostaticequation,...

As an outcome of our hypercomplex unitary description [9] of some peculiaraspects of the Kepler problem (regularization, prequantization of theKepler manifold), we show how both the differential time transformationadopted by Levi-Civita for the regularization of the plane problem, and thequaternionic transformation which prequantizes the Kepler manifold, derivefrom the same quaternionic definition...

This paper presents a technique that allows the direct linearidentification of frequency response functions from the computation ofa weighted integral transform. This transform allows toemphasize the influence of the poles and zeros of the frequencyresponse functions its formation is based on the Cauchy--Weierstrass theorem. It isthen shown that this transform is directly linked to a complex wavelettransform...

Mixed boundary value problems of solid mechanics are treated by numericalsolutions of Boundary Integral Equations (BIE) in time domain with theBoundary Element Method (BEM) thus reducing the spatial problem dimensionby one. Viscoelastic constitutive behaviour is implemented by means of aLaplace transform technique based on an elastic--viscoelasticcorrespondence principle. The concept of fractional...

A performance of direct and inverse integral transforms withkernels, depending on the division or product of arguments isconsidered for the study of linear viscoelastic behaviour ofsolid materials. An approach based on digital filteringlogarithmically sampled relaxation measurement data is developedfor carrying out the transforms. Examples of performingHeaviside-Carson sine transform and an inherently...

The problem of realtime measurement, control and parameter identificationyields to numerical problems as processors with finite word length areused. The nature of these problems is caused in the mapping character of thez-transform which is normally applied. New transformmethods are introduced which have the feature of reduced sensitivityagainst inaccuracies of coefficients.

In this paper generalized variational principles in thesense of the Laplace transform for viscoelastic problems arederived. Then mathematical theory of viscoelasticity ingeneralized Hardy spaces and in weighted anisotropic Sobolevspaces and spectral theory of corresponding non-selfadjointoperators is elaborated. Finally the Laplace transform--FEMfor numerical analysis of time-dependent problems of...

In this paper, it is demonstrated how a direct stiffness method for wavepropagation in multilayered saturated poroelastic media, based on integraltransform techniques, can be modified to account for a small amount of gasin the pores. Unsaturated media with small gas fractions can be treatedusing Smeulders‘ extension of Biot‘s poroelastic theory. The effect of thepresence of gas bubbles on the fluid...