Multilayer piezoelectric actuators are used in fuel injectors due to their quick response, high efficiency, accuracy, low power consumption, and excellent repeatability. Experimental results for soft lead zirconate titanate (PZT) stack have shown that a significant amount of heat is generated when they driven under frequency and/or electric-field magnitudes, both which occur injectors. Self-heat generation these actuators, mainly caused by losses, can significantly affect reliability...

In high speed machining of hard materials, tools with chamfered edge and materials resistant to diffusion wear are commonly used. this paper, the influence cutting geometry on chip removal process is studied through numerical simulation sharp, or blunt edges carbide CBN tools. The analysis based use ALE finite element method for continuous formation process. Simulations include different chamfer angles speeds. study shows that a region trapped material zone formed under acts as effective...

Abstract Lagrangian and Eulerian finite element formulations have been traditionally used for modeling of the orthogonal metal cutting process. In this paper it is shown that a more general formulation, arbitrary Lagrangian-Eulerian method (ALE), may be to combine advantages avoid drawbacks both methods in single analysis. Due characteristics process, ALE formulation offers very efficient approach A comprehensive model along with strain rate temperature dependent constitutive equations...

Piezoelectric actuators are increasingly used in fuel injectors due to their quick response, high efficiency, accuracy, and excellent repeatability. Current understanding of thermo-electro-mechanical performance under dynamic driving conditions appropriate for injection is, however, limited. In this paper, the soft Lead Zirconate Titanate (PZT) stack is experimentally investigated over a temperature range -30°C 80°C, electric fields up 2.0 kV/mm (using an AC drive method biased DC offset),...

Three variations of the particle swarm optimization (PSO) method are used to solve boundary inverse heat conduction problem, in one, two, and three dimensions. Both steady transient problems studied. It is shown that PSO can be successfully applied problems, alleviate some stability classical approaches. The computational costs (basic, repulsive, complete repulsive) compared with each other, an implementation genetic algorithm. For these variants proven more efficient than other algorithms....

Slippage of bolted joints is an important factor in the behavior transmission towers. Field inspections towers located northern regions Canada show substantial frost-heave induced displacements. The conventional structural analysis software solutions for tower leg axial forces, based on idealized joint under field-observed displacements, are excessively large, implying failure some cases. However, field structurally stable towers, and design engineers often consider slippage as main reason...

Numerical investigation of the optimization stall control efficiency for a high speed centrifugal compressor using air injection is presented. External was injected close to diffuser entrance at shroud surface vaneless region. Injection applied with mass flow rates 0.7%, 1%, and 1.5% design inlet rate six different angles 0 deg, 10 20 30 40 180 deg measured from positive tangential direction Detailed comparisons were made between case without cases by comparing velocity, pressure, force...

Quasi-static thermo-electro-mechanical performance of annular and solid cylindrical piezoelectric actuators was studied by experimental means under electric fields varying from 0.3 to 1.8 kV mm−1 with a preload 4.6 MPa over the temperature range −30 125 °C. It found that, for both actuators, electrically induced stroke increases steadily temperature. Under larger than 1.0 mm−1, nonlinear transition zone exists in stroke–temperature plot 25–50 The dielectric constant also increase Preload...

Abstract A concise survey of formulation methods geometric and material nonlinearity problems is given. Differences between existing formulations in the literature are discussed. consistent Lagrangian updated derived from energy balance equation transformed to proper reference configuration. similar ones found be specific nonlinear terms final incremental as well definition load increment vector. Specific forms constitutive equations for elastic elastoplastic materials presented. Some used...

In this research, boiling heat transfer on a hot moving plate caused by multiple impinging water jets in jet rows is studied. An inverse conduction code developed to analyze the readings of thermocouples that are implemented inside order find surface values temperature and flux. Effects nozzle stagger, velocity, line spacing Nozzle stagger found affect uniformity across width plate. Jet can between two adjacent rows. Plate speed important only higher entry temperatures impingement zone.

To determine the bifurcation types in a rotor-bearing system, it is required to find higher order derivatives of bearing forces with respect journal velocity and position. As closed-form expressions for force are not generally available, Hopf studies systems have been limited simple geometries cavitation models. solve this problem, an alternative nonlinear coefficient-based method representing presented study. A flexible system which modeled linear dynamic coefficients. The proposed model...

In the current study, a modified fast converging, mass-conserving, and robust algorithm is proposed for calculation of pressure distribution cavitated axially grooved journal bearing based on finite volume discretization Adams/Elrod cavitation model. The solution problem shown to strongly depend specific values chosen lubricant bulk modulus. It how new scheme capable handling stiff discrete numerical system any value modulus (β) hence significant improvement in robustness achieved compared...