In this paper $S$ is a monoid with a left zero and $A_S$ (or $A$) is a unitary right $S$-act. It is shown that a monoid $S$ is right perfect (semiperfect) if and only if every (finitely generated) strongly flat right $S$-act is quasi-projective. Also it is shown that if every right $S$-act has a unique zero element, then the existence of a quasi-projective cover for each right act implies that ...

the paper is concerned with a methodology of optimal design of shells of minimum weight with strength, stability and strain constraints. stress and strain state of the shell is determined by galerkin method in the mixed finite element formulation within the geometrically nonlinear theory. the analysis of the effectiveness of different optimization algorithms to solve the set problem is given. t...

Soil-facing mechanical interactions play an important role in the behavior of earth-retaining walls. Generally, numerical analysis structures requires use interface elements between dissimilar component materials to model soil–structure and capture transfer normal shear stresses through these discontinuities. In finite element method software programs, can be modeled using “zero-thickness” soil...

Abstract In this study, geomechanical behavior of fractures and faults in rocks as a saturated deformable discrete fracture-porous medium has been evaluated using coupled fluid flow-geomechanics numerical modeling. The purpose paper is to observe evaluate the effects on pore pressures during flow through reservoirs. This issue involves solving equations that have derived from Biot consolidation...

The ΛN − ΣN coupling in Λ–hypernuclei and ΛΛ − ΞN coupling in ΛΛ– hypernuclei produce novel physics not observed in the conventional, nonstrange sector. Effects of Λ ↔ Σ conversion in ΛH are reviewed. The role of ΛN − ΣN coupling suppression in the A = 4, 5 Λ–hypernuclei due to Pauli blocking is highlighted, and the implications for the structure of 10 ΛB are explored. Suppression of ΛΛ − ΞN co...

The development of interfacial coherency stresses in TiN/AlN bilayer and multilayer films was investigated by finite element method (ABAQUS) using the four-node bilinear quadrilateral axisymmetric element CAX4R. The TiN and AlN layers are always in compression and tension at the interface, respectively, as may be expected from the fact TiN has larger lattice parameter than AlN. Both, the bi-lay...

The elastic-plastic behavior of the material is considered to analyze the effect of an external circumferential crack on a pipe with thickness transition and double slopes. Using the extended finite element method (XFEM), the J-integral of 3D cracks were investigated and compared between straight pipes and pipes with thickness transition and different slopes. Considering internal press...

The analysis of a material that is subjected to variable loads complex subject and generally treated separately by fatigue fracture mechanics. We present an attempt extend the validity conventional approach (here strain-life) in scope fracture. This was achieved introducing zero thickness cohesive contact element coupled with damage parameter developed from observations strain controlled experi...

AbstractHydroforming process is a deep stretching process only with the difference that a fluid is used instead of the mandrel. This paper investigates the hydroforming process of non-cylindrical and non-spherical geometries using finite element analysis software to calculate the influences of effective process parameters such as the coefficient of friction between the surfaces and the pressure...