The equation

is a possible dimensionless version of a model for the configuration of a very long strut resting on a nonlinear elastic foundation with axial loading P. By seeking to establish the existence of homoclinic orbits connecting the zero equilibrium of (*), now regarded as defining a four dimensional dynamical system, to itself one is pursuing the so-called ‘dynamical phase-space analogy’ for the spatial configuration suggested by the form of the equation. The existence of homoclinic solutions is then interpreted as indicating the presence of spatially localized buckling of the deformed strut.

The diffraction of a plane sound wave in a fluid by an adjacent elastic solid containing a surface flaw is analysed using ray techniques. By solving the eikonal equation with suitable boundary data, the pattern of the rays leaving the boundary and propagating into the fluid and solid respectively is established, with the corresponding amplitudes being furnished by the appropriate system of transport equations. For the acoustic and elastic cylindrical bulk waves that emanate from the flaw itself, the amplitude directivities cannot be found from this ray analysis alone.

In this paper we consider the numerical analysis of a parabolic variational inequality arising from a deep quench limit of a model for phase separation in a binary mixture due to Cahn and Hilliard. Stability, convergence and error bounds for a finite element approximation are proven. Numerical simulations in one and two space dimensions are presented.

In this paper we investigate the mathematical model of the equilibrium of a finite volume in ℝn (n = 1,2, 3) of a two-phase continuous medium, under the assumption that each pure phase is an isotropic elastic solid. The main results in this paper are:

(i) the existence and uniqueness of a solution of this mathematical model;

(ii) a discussion of the stress-strain law associated with the free energy of this two-phase continuous medium, which is multiple-valued due to the non-smoothness of the Gibbs potential (complementary energy);

(iii) a description of the structure of solutions in plane strain.