1,721,208 research outputs found
Introduction to Polymer Viscoelasticity by Montgomery T. Shaw, William J. MacKnight
No full text. AVERSA, ITALY. MACROMOLECULAR CHEMISTRY AND PHYSICS (2006), 207(16), 1526. PUBLISHER: WILEY-VCH VERLAG GMBH & CO. KGAA, CODEN: MCHPES ISSN: 1022-1352. JOURNAL; BOOK REVIEW WRITTEN IN ENGLISH
"Volume relaxation and related dynamic-mechanical properties change during the physical aging of PEEK"
No full textHierarchical damage mechanisms in composite materials subjected to fatigue loadings
No full textThe strength degradation of fiber reinforced composites subjected to constant amplitude (CA) fatigue loadings can be described by a two-parameter residual strength model. From the analytical approach it results that under moderate loadings the multiple damage mechanisms develop with different kinetics and manifest their effectiveness at different time scales highlighting the three-Stage hierarchical nature of damage accumulation in composites. The model captures the sequence of damage accumulation mechanisms from diffuse matrix cracking (I), to fiber/matrix interface failure (II) to fiber and ply rupture and delamination (III). Further, by increasing the loading severity it appears that the different mechanisms superpose witnessing their simultaneous co-existence
Constitutive law describing the phenomenology of (sub-yield) mechanically stimulated glasses
No full textThe principal features of the volumetric as well as the viscoelastic response of mechanically stimulated glasses can be summarized as follow: (i) the time-aging time shift factors contract upon increasing the probe stress (i.e., the stress apparently modifies the volume recovery kinetics), (ii) the volume recovery baseline remains unaltered (i.e., the underlying structure of the stimulated glass remains unchanged). Here we present a series of numerically simulated results concerning the responses of glassy polycarbonate that simultaneously fulfill these apparent contradictions. The problem was tackled coupling a modified Kalroush, Aklonis, Hutchinson, Ramos equation with the constitutive law for linear viscoelasticity within the domain of the reduced time. It was argued that the relaxation times under isobaric conditions depend on the temperature, the dimen- sionless volume, and the isotropic components of the stress tensor. Simulations are obtained with a minimum of experimental (PVT and linear viscoelastic) data inputs. Different loading protocols consisting of complex combinations and/or sequences of large and small mechanical stimuli were tested. Volumetric as well as viscoelastic behavior are systematically reported. A tentative explanation of the origin of the time-aging time contraction was finally proposed while some additional features concerning the volumetric response emerged
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