The research works published in this special issue were presented during the 19th DYMAT Technical Meeting concerning “Dynamic mechanical behaviour of polymers and composites” which was held the 1-3 December, 2010 at the University of Strasbourg, France. This topic is of considerable interest to researchers and engineers involved in transportation, defence applications, and material processing being concerned with a new generation of light materials. The 42 papers presented during the Technical Meeting in Strasbourg covered experimental, theoretical and numerical studies of the dynamic mechanical behaviour of these light materials. Different sessions were organised: Experimental, Modelling and Simulation, Experimental and Modelling. In each session, a wide range of polymer and composite materials were considered: glassy polymers, carbon fibre reinforced epoxy composites, polymeric foams, elastomers, ionomers, polymer-bonded explosives, biodegradable polymers (blended and unblended), 3D fabrics, glass fibre laminates. This special issue is mainly focused on the experimental contributions. A complete description of the material processes and the micro structural and conventional mechanical properties are also provided in each paper. This special issue also covers a wide range of composite applications: the first paper presents the effects of ultraviolet irradiation on the mechanical properties of a biopolymer for a wide range of strain rates. In order to determine the effects, the change in the chemical structure after specimens were irradiated with ultraviolet was measured by Fourier Transform Infrared spectroscopy (FT-IR) and various mechanical tests were performed; the second paper focuses on the viscoelastic behaviour of polyurethane (PU) foam undergoing large compressive deformation. It exhibits highly nonlinear elasticity. The paper deals with the difficulty of finding accurate results verify the thermodynamic conditions for the identification of a memory integer model describing the nonlinearity using a polynomial function and the viscoelasticity using a convolution function; in the third paper, results are presented for a Kevlar woven composite material, used for passive safety structures, subjected to low velocity impact. A comparison is made between composites made with matrix filled with nanoparticles and without nanoparticles; next, an original study using vibration analysis is reported in order to understand damage in filled composites. A link is proposed between two fields: physical and mechanical analysis concerning the dynamic behaviour of filler polymer; then an application to railway structures is proposed. A reliability approach is developed for designing composite plates forming part of a railway structure to withstand low velocity impact loading. After using experimental design to approximate correctly the interaction force between the structure and the striker during impact, genetic algorithms were principally investigated using numerical methods. To close this special issue, the confined behaviour of PMMA under quasistatic and dynamic loading is discussed. The so-called Quasi-Oedometric Compression (QOC) experimental method (formerly used to test geomaterials) was adapted to PMMA. Thus, a new constitutive law derived from the work of G’Sell and Jonas (1979) was developed and fitted to experimental data from confined and unconfined quasi-static and dynamic compression tests. We wish to thank all the authors for the scientific interest and quality of their papers.