We study the spatially uniform case of the problem of quasistatic evolution in small strain nonassociative elastoplasticity (Cam-Clay model). Through the introdution of a viscous approximation, the problem reduces to determine the limit behavior of the solutions of a singularly perturbed system of ODE’s in a finite dimensional Banach space. Depending on the sign of two explicit scalar indicator...

Apricots (Prunus armeniaca L.), a kind of climacteric fruits, are favored by consumers for their flavor and texture, but they are highly perishable. Apricots soften rapidly after harvest. Once softened, they are easily damaged such as latent damage, which limits their marketing time [1, 2]. Therefore, a common practice for handling and storing apricots is early harvest and applying postharvest ...

We study a relaxed formulation of the quasistatic evolution problem in the context of small strain associative elastoplasticity with softening. The relaxation takes place in spaces of generalized Young measures. The notion of solution is characterized by the following properties: global stability at each time and energy balance on each time interval. An example developed in detail compares the ...

In recent years it has become possible to study the properties of nanocrystalline metals through atomic-scale simulations of systems with realistic grain sizes. A brief overview of the main results is given, such as the observation of a reverse Hall-Petch effect — a softening of the metal when the grain size is reduced. The limitations of computer simulations are discussed, with a particular fo...

A deeper understanding of the mechanical behavior of ultra-fine (UF) and nanocrystalline (NC) grained metals is necessary with the growing interest in using UF and NC grained metals for structural applications. The cyclic deformation response and behavior of UF and NC grained metals is one aspect that has been gaining momentum as a major research topic for the past ten years. Severe Plastic Def...

ing momentum p from ζ(q, ω) in equation (14) results to a relation 〈〈c†p+q,↑cp,↓;S (0, 0)〉〉 = cJ 2 〈c†p,↓cp,↓〉 − 〈c † p+q,↑cp+q,↑〉 ω − εp + εp+q − cJ〈Sz〉 ×G(q, ω). (15) Combining equations (10) and (14) results to a closed form of Green’s function equation G(q, ω), (ω − cJ〈σ〉 + cJ 2 〈S〉 ∑ p 〈c†p,↓cp,↓〉 − 〈c † p+q,↑cp+q,↑〉 ω − εp + εp+q − cJ〈Sz〉 )

We have studied the spin dynamics in Pr0.63Sr0.37MnO3 above and below the Curie temperature TC = 301 K. Three distinct new features have been observed: a softening of the magnon dispersion at the zone boundary for T < TC , significant broadening of the zone boundarymagnons as T → TC , and no evidence for residual spin-wave like excitations just above TC . The results are inconsistent with doubl...

Modelling gravity is a fundamental problem that must be tackled in N -body simulations of stellar systems, and satisfactory solutions require a deep understanding of the dynamical effects of softening. In a previous paper (Romeo 1997), we have devised a method for exploring such effects, and we have focused on two applications that reveal the dynamical differences between the most representativ...

Non-local damage model for strain softening in a machining simulation is presented in this paper. The coupled damage-plasticity model consists of a physically based dislocation density model and a damage model driven by plastic straining in combination with the stress state. The predicted chip serration is highly consistent with the measurement results.