944 research outputs found
Energy release rate and quasi-static evolution via vanishing viscosity in a fracture model depending on the crack opening
No full textIrreversibility and alternate minimization in phase field fracture: a viscosity approach
No full textThis work is devoted to the analysis of convergence of an alternate (staggered) minimization algorithm in the framework of phase field models of fracture. The energy of the system is characterized by a nonlinear splitting of tensile and compressive strains, featuring non-interpenetration of the fracture lips. The alternating scheme is coupled with an L2-penalization in the phase field variable, driven by a viscous parameter δ> 0 , and with an irreversibility constraint, forcing the monotonicity of the phase field only w.r.t. time, but not along the whole iterative minimization. We show first the convergence of such a scheme to a viscous evolution for δ> 0 and then consider the vanishing viscosity limit δ→ 0
ALMI: An Application Level Multicast Infrastructure
No full textThe IP multicast model allows scalable and efficient multi-party communication, particularly for groups of large size. However, deployment of IP multicast requires substantial infrastructure modifications and is hampered by a host of unresolved open problems. To circum-vent this situation, we have designed and implemented ALMI, an application level group communication mid-dleware, which allows accelerated application deploy-ment and simplified network configuration, without the need of network infrastructure support. ALMI is tailored toward support of multicast groups of relatively small size (several 10s of members) with many to many se-mantics. Session participants are connected via a vir-tual multicast tree, which consists of unicast connections between end hosts and is formed as a minimum span-ning tree (MST) using application-specific performance metric. Using simulation, we show that the performance penalties, introduced by this shift of multicast to end sys-tems, is a relatively small increase in traffic load and that ALMI multicast trees approach the efficiency of IP mul-ticast trees. We have also implemented ALMI as a Java based middleware package and performed experiments over the Internet. Experimental results show that ALMI is able to cope with network dynamics and keep the mul-ticast tree efficient.
1° Mosquée El-Almi
No full textFranz Julius, Baudry Ambroise, Ezzat , Ismaïl, Grand Pierre. 1° Mosquée El-Almi . In: Comité de Conservation des Monuments de l'Art Arabe. Fascicule 3, exercice 1885, 1886. pp. 1-2
Analysis of Staggered Evolutions for Nonlinear Energies in Phase Field Fracture
No full textWe consider a class of separately convex phase field energies employed in fracture mechanics, featuring non-interpenetration and a general softening behavior. We analyze the time-discrete evolutions generated by a staggered minimization scheme, where fracture irreversibility is modeled by a monotonicity constraint on the phase field variable. After recasting the staggered scheme by means of gradient flows, we characterize the time-continuous limits of the discrete solutions in terms of balanced viscosity evolutions, parametrized by their arc-length with respect to the L2-norm (for the phase field) and the H1-norm (for the displacement field). By a careful study of the energy balance we deduce that time-continuous evolutions may still exhibit an alternate behavior in discontinuity times
Energy release rate and stress intensity factors in planar elasticity in presence of smooth cracks
No full textIn this work we first analyze the singular behavior of the displacement u of a linearly elastic body in dimension 2 close to the tip of a smooth crack, extending the well-known results for straight fractures to general smooth ones. As conjectured by Griffith (Phys Eng Sci 221:163–198, 1921), u behaves as the sum of an H2-function and a linear combination of two singular functions whose profile is similar to the square root of the distance from the tip. The coefficients of the linear combination are the so called stress intensity factors. Afterwards, we prove the differentiability of the elastic energy with respect to an infinitesimal fracture elongation and we compute the energy release rate, enlightening its dependence on the stress intensity factors
Multivariate linear regression analysis for ALMI with fasting insulin.
No full textMultivariate linear regression analysis for ALMI with fasting insulin.</p
Multivariate linear regression analysis for ALMI with FAI.
No full textMultivariate linear regression analysis for ALMI with FAI.</p
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