THIS PAPER is concerned with an analysis of strain localization in ductile crystals deforming by single slip. The plastic flow is modelled as rate-insensitive, and localization, viewed as a bifurcation from a homogeneous deformation mode to one which is concentrated in a narrow ‘shear band’, is found to be. possible only when the plastic hardening modulus for the slip system has fallen to a cer...

In this paper the ratcheting behavior of carbon steel(ASTM A106B) and stainless steel(304L) elbows is studied under steady internal pressure and in-plane external moments at frequencies typical of seismic excitations. The finite element analysis with the nonlinear isotropic/kinematic (combined) hardening model has been used to evaluate ratcheting behavior of the elbows. Material parameters have...

Various scaling methods such as relative viscosity, Peclet and Reynolds scaling were used to find the best scaling law. Scaling and modeling of the flow curves of various model emulsions consist of Tragacanth Gum (TG) (0.5, 1 % wt), Oleic acid (5, 10% v/v) and WPI (2, 4 % wt) were investigated and the best models were selected. As these emulsions are non-Newtonian, they do not obey the usual...

Accurate prediction of the burst pressure is essential for structural integrity assessment pipelines. Current design codes and models residual pipelines with surface corrosion defects are only applicable to axially orientated defects. Theoretical empirical thin-walled pipes pre-existing localised arbitrarily oriented defect proposed. The theoretical model based on power-law hardening J2 flow th...

this paper introduces an indirect adaptive fuzzy sliding mode controller as a power system stabilizer for damping local and inter-area modes of oscillations of multi-machine power systems. this controller is designed based on the combination of sliding mode controller and the fuzzy logic systems. the fuzzy systems are used to approximate the unknown functions of power system model. generator sp...

A physically based elasto-visco-plastic constitutive model is presented and compared to experimental results for a DD14 mild steel. The model requires significantly fewer material parameters compared to other visco-plasticity models from the literature while exhibiting very good accuracy. Accordingly, the parameter identification is simple and intuitive, requiring a relatively small set of expe...

this paper presents a novel indirect adaptive power system stabilizer (pss) via a developed synergetic control methodology and fuzzy systems. fuzzy system is utilized in an adaptive scheme to estimate the system using a nonlinear model. the synergetic control guarantees robustness of the controller and makes the controller easy to implement because of using a chatter free continuous control law...

Fourier series solutions to the deflection and magnification by a family of three-dimensional cusped two power-law ellipsoidal mass distributions are presented. The cusped two power-law ellipsoidal mass distributions are characterized by inner and outer power-law radial indices and a break (or, transition) radius. The model family includes mass models mimicking Jaffe, Hernquist, and η models an...

the galerkin finite element method is used to solve the three dimensional continuity, momentum and energy equations for laminar newtonian and power-law model non-newtonian flow through horizontal circular tube. the governing equations are non-dimensionalized with respect to specific variables and converted into algebraic equations using appropriate elements. to accelerate convergence a combinat...

optimization of process parameter is one of the ideal goals in laser sintering. the results of this process were measured as output parameters like: density, micro hardening, macro hardening, tension, roughness, stiffness, balling. in this paper, the influence of input parameter such as laser power, scan speed, material powder and etc are surveyed on output parameter like balling affection and ...