The production of biodegradable plastic is increasing. Given the augmented littering of these products an increasing input into the sea is expected. Previous laboratory experiments have shown that degradation of plastic starts within days to weeks. Little is known about the early composition and activity of biofilms found on biodegradable and conventional plastic debris and its correlation to d...

In this technology report, three test methods were developed to characterize the degradation of plastic in marine environment. The aim was to outline a test methodology to measure the physical and biological degradation in different habitats where plastic waste can deposit when littered in the sea. Previously, research has focused mainly on the conditions encountered by plastic items when float...

In this paper, the stress concentration around a hole in the single layer composite materials with long fibers is examined. The single layer has an infinite length, limited with and instant thickness and is loaded by a constant tension force p at infinity. The width of the lamina is considered to be finite and bears a hole as a defect. Due to presence of excessive shear stress in the matrix bay...

This paper is concerned with the problem of plastic zone at the tip of an edge crack in an isotropic elastoplastic strip under anti-plane deformations. By means of complex potential and Dugdale model, the stress intensity factor and the size of plastic zone are obtained in closed-form. Furthermore, the analytic solutions for an edge crack at the free boundary of a half-space and a semi-infinite...

We use considerations of energy balance and dissipation to derive a self-consistent version of the shear-transformation-zone (STZ) theory of plastic deformation in amorphous solids. The theory is generalized to include arbitrary spatial orientations of STZs. Continuum equations for elasto-plastic material and their energy balance properties are discussed.

Two parameters are identified for characterizing the deformation in the plastic zone near the tip of a crack when mixed mode conditions prevail. Details of the near-tip stress and strain distributions are presented f or hardening materials in which a diffus e plastic zone occurs under plane stress conditions. For small scale yielding the two near-tip parameters are related to the two elastic s ...

It is a highly nonlinear problem of 3-D elastoplastic contact with friction. To obtain the key information about the real size, displacement and traction in contact zone, the elements in contact and plastic zone should be subdivided. However, the increase of degrees of freedom is limited by the problem-solving scale when traditional BEM is used, for a larger memory size is required and the solu...

In this paper we present an elastic-plastic analysis of the small-scale yielding crack-tip fields for pressure-sensitibe materials. Mode 1 loading and plane-strain conditions are assumed. The yield criterion is chosen to be a linear combination of the effective stress and the hydrostatic stress. For power-law hardening materials. our elastic-plastic finite element analysis shows that HRRtype cr...

plastic recycling is the process of recovering scrap or waste plastics and reprocessing thematerial into useful products that sometimes differ completely in form from their original state. an importantissue in plastic recovery and recycling is that plastic waste usually contains a variety of plastics that differ intheir physical and chemical properties. separation of recovered plastics into dis...