Search results for "shear"
showing 10 items of 804 documents
Polyelectrolyte Molecule in an Elongational Flow
1995
The theory describing the stretching of a weakly charged polyelectrolyte molecule by elongational shear flow is developed. It is shown that for a polyelectrolyte immersed in a salt-added solution two critical values of shear flow gradient exist: the lower critical point corresponds to the chain stretching on the scale of superblobs of size equal to the Debye screening length and the upper critical point corresponds to the complete stretching of the chain on the scale of monomer units.
Shear induced deformation of polystyrene coils in dilute solution from small angle neutron scattering
1985
The deformation of the overall conformation of polystyrene,Mw=280000 g/ mole in dilute solution in a constant shear gradient has been investigated by small angle neutron scattering (SANS).
Influence of a temperature-dependent shear viscosity on the azimuthal asymmetries of transverse momentum spectra in ultrarelativistic heavy-ion colli…
2012
We study the influence of a temperature-dependent shear viscosity over entropy density ratio $\eta/s$, different shear relaxation times $\tau_\pi$, as well as different initial conditions on the transverse momentum spectra of charged hadrons and identified particles. We investigate the azimuthal flow asymmetries as a function of both collision energy and centrality. The elliptic flow coefficient turns out to be dominated by the hadronic viscosity at RHIC energies. Only at higher collision energies the impact of the viscosity in the QGP phase is visible in the flow asymmetries. Nevertheless, the shear viscosity near the QCD transition region has the largest impact on the collective flow of t…
Response behaviour of reinforced concrete beams strengthened in shear with FRP
2019
In this paper an analytical model, able to predict the shear-displacement response of slender RC beams reinforced in shear with FRP, is presented. It allows to evaluate the complete strain and stress fields, for each load step, on the basis of the MCFT framework. The key role of the effective strain of FRP reinforcement at failure has been investigated. At the same time, the interaction FRP-steel stirrups has been taken into account by introducing an appropriate factor. It is able to reproduce the decrease of stirrups stress level when an external reinforcement is used. The proposed model has been validate against a database of specimens collected in literature. Results have shown the remar…
A combined molecular dynamics and Monte Carlo study of the approach towards phase separation in colloid-polymer mixtures.
2011
A coarse-grained model for colloid-polymer mixtures is investigated where both colloids and polymer coils are represented as point-like particles interacting with spherically symmetric effective potentials. Colloid-colloid and colloid-polymer interactions are described by Weeks-Chandler-Andersen potentials, while the polymer-polymer interaction is very soft, of strength k(B)T/2 for maximum polymer-polymer overlap. This model can be efficiently simulated both by Monte Carlo and molecular dynamics methods, and its phase diagram closely resembles that of the well-known Asakura-Oosawa model. The static and dynamic properties of the model are presented for systems at critical colloid density, va…
Asymmetric Single Point Incremental Forming of Sheet Metal
2005
The use of computers in manufacturing has enabled the development of several new sheet metal forming processes, which are based upon older technologies. This paper describes modifications that have been made to traditional forming methods such as conventional spinning and shear forming, forming processes in which deformation is localized. Recent advances have enabled this localized deformation to be accurately controlled and studied. Current developments have been focused on forming asymmetric parts using CNC technology, without the need for costly dies. Asymmetric Incremental Sheet Forming has the potential to revolutionize sheet metal forming, making it accessible to all levels of manufac…
A Rayleigh-Ritz approach for postbuckling analysis of variable angle tow composite stiffened panels
2018
Abstract A Rayleigh-Ritz solution approach for generally restrained multilayered variable angle tow stiffened plates in postbuckling regime is presented. The plate model is based on the first order shear deformation theory and accounts for geometrical nonlinearity through the von Karman’s assumptions. Stiffened plates are modelled as assembly of plate-like elements and penalty techniques are used to join the elements in the assembled structure and to apply the kinematical boundary conditions. General symmetric and unsymmetric stacking sequences are considered and Legendre orthogonal polynomials are employed to build the trial functions. A computer code was developed to implement the propose…
Post-buckling analysis of cracked multilayered composite plates by pb-2 Rayleigh–Ritz method
2015
Abstract A pb-2 Rayleigh–Ritz variational approach for the analysis of post-buckling behavior of cracked composite plates is presented. The plate is modeled by the first order shear deformation theory taking geometric nonlinearities into account through the von Karman’s theory. General stacking sequences are considered. Cracks are modeled by using subdomain decomposition of the plate coupled with penalty techniques, used to augment the variational statement with the needed continuity conditions along the connected subdomains edges. Numerical procedures have been developed and used to validate the present solution by comparison with available literature results. Original results are then pre…
Post-Buckling Analysis of Damaged Multilayered Composite Stiffened Plates by Rayleigh-Ritz Method
2016
A Rayleigh-Ritz approach for the analysis of buckling and post-buckling behavior of cracked composite stiffened plates is presented. The structure is modeled as the assembly of plate elements modeled by the first order shear deformation theory and taking geometric nonlinearities into account through the von Karman’s theory assumptions. Continuity along the plate elements connected edges and the enforcement of rigid and elastic restraints of the plate boundaries are obtained by using penalty techniques, which also allow to straightforwardly implement efficient crack modeling strategies. General symmetric and unsymmetric stacking sequences are considered and numerical procedures have been dev…
Local disequilibrium of plagioclase in high-temperature shear zones of the Ivrea Zone, Italy
1995
Microstructural and chemical analysis of plagioclase in 20 superficially similar amphibolite facies ductile shear zones in metagabbors and amphibolites of the Ivrea Zone in Italy reveals significant differences in An and Ba contents. Plagioclase, which was deformed at P-T conditions lower than those of the wall rocks, occurs in the following four different microstructural situations with different chemical compositions: (i) relatively undeformed porphyroclasts, (ii) dynamically recrystallized grains and subgrains rimming the porphyroclasts, (iii) infill of microcracks cross-cutting the porphyroclasts and (iv) fine-grained recrystallized grains in the matrix of the shear zones. The differenc…