Singular Integral Equations. By N.I. Muskhelishvili. Translated fromthe 2nd Russian edition by J.R.M. Radok. Pp. 447. F1. 28.50. 1953. (Noordhoff, Groningen)

The review outlines modern trends in theoretical developments, novel designs and modern applications of sandwich structures. The most recent work published at the time of writing of this review is considered, older sources are listed only on as-needed basis. The review begins with the discussion on the analytical models and methods of analysis of sandwich structures as well as representative problems utilizing or comparing these models. Novel designs of sandwich structures is further elucidated concentrating on miscellaneous cores, introduction of nanotubes and smart materials in the elements of a sandwich structure as well as using functionally graded designs. Examples of problems experienced by developers and designers of sandwich structures, including typical damage, response under miscellaneous loads, environmental effects and fire are considered. Sample applications of sandwich structures included in the review concentrate on aerospace, civil and marine engineering, electronics and biomedical areas. Finally, the authors suggest a list of areas where they envision a pressing need in further research.

Review of current trends in research and applications of sandwich structures

A theoretical treatment of mode I crack problem is put forward for a functionally graded orthotropic strip. The internal crack and edge crack perpendicular to the boundaries are investigated, respectively. The elastic property of the material is assumed to vary continuously along the thickness direction. The principal directions of orthotropy are parallel and perpendicular to the boundaries of the strip. The singular integral equation for solving the problem and the corresponding asymptotic expression of the singular kernel are obtained. Three different loading conditions, namely crack surface pressure, fixed-grip loading and bending, are considered during the analysis. The influences of parameters such as the material constants and the geometry parameters on the stress intensity factors (SIFs) are studied.

Mode I crack problem for a functionally graded orthotropic strip

On the electrical boundary conditions on the crack surfaces in piezoelectric ceramics

A moving mode-III crack in functionally graded piezoelectric material: permeable problem

Electromechanical behaviour of a finite piezoelectric layer under a flat punch

Buckling and vibro-acoustic response of the clamped composite laminated plate in thermal environment

A finite element/finite difference scheme for the non-classical heat conduction and associated thermal stresses

Composite sandwich structures are extensively applied in automotive, marine, aircraft because of superior stiffness-to-weight ratios. These structures are invariably exposed to the thermal and noise environment in their service life especially as a component of the hypersonic aircraft. The paper is originally focused on the sound transmission loss (STL) of the sandwich panels constituted of orthotropic materials in thermal environment. Firstly, the governing equations are obtained by applying Hamilton's principle. Both the natural frequencies and corresponding mode functions are derived with thermal stresses taking into account. The formulation of STL is obtained by using the mode superposition method. Then the published experimental result and numerical simulation are demonstrated to validate the accuracy of the analytical solution. Finally, the influences of temperature, elevation angle and azimuth angle of incident sound on the STL of finite sandwich panels are investigated systematically. It is observed that natural frequencies of the panel decrease and peaks of the STL tend to drop and flow to the lower frequencies with the increment of the temperature. The STL decreases with the increment of the elevation angle.

Jingyong Han

Papers

Electromechanical behaviour of a finite piezoelectric layer under a flat punch

Buckling and vibro-acoustic response of the clamped composite laminated plate in thermal environment

A finite element/finite difference scheme for the non-classical heat conduction and associated thermal stresses

Sound transmission loss of composite and sandwich panels in thermal environment

A piecewise shear deformation theory for free vibration of composite and sandwich panels