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International audienceAluminium foams obtained by injecting a gas into the liquid metal are prone to localization of strain and damage. Under compression, crushing bands form, multiply and propagate through the whole sample. A continuum model based on a compressible plasticity framework is presented that is suitable for the simulation of such strain localization bands. The importance of accounting for strain localization phenomena in structural computations is illustrated by finite element simulations of the compression of cube and tapered specimens, and of an indentation test. A regularization procedure is proposed to obtain mesh–independent results

International audienceThis article presents an experimental investigation of a ductile rubber-modified polypropylene. The behaviour of the material is investigated by performing tension, shear and compression tests at quasi-static and dynamic strain rates. Subsequently, scanning electron microscopy is used to analyse the fracture surfaces of the tension test samples, and to relate the observed mechanical response to the evolution of the microstructure. The experimental study shows that the material is highly pressure and strain-rate sensitive. It also exhibits significant volume change, which is mainly ascribed to a cavitation process which appears during tensile deformation. Assuming matrix-particle debonding immediately after yielding, the rubber particles might play the role of initial cavities. It is further found that the flow stress level is highly dependent on the strain rate, and that the rate sensitivity seems to be slightly more pronounced in shear than in tension and compression. From the study of the fracture surfaces it appears that the fracture process is less ductile at high strain rates than under quasi-static conditions

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