Research features of voltage static load characteristics in the electric system of Russia
At the present time using the standard (generalized) voltage static load characteristics which can differ from actual considerably is provided in software packages for calculations of the steady-state mode and steady-state stability (in the absence of exact data). Absence of the metering or the incorrect metering of the actual voltage static load characteristic, and also using the standard (generalized) static load characteristics could lead to considerable errors and the incorrect final results while making calculations. The definition experience of actual voltage static load characteristics in different ways made by authors is given in this paper: making tests in situ in electric power systems by allocation of energy area load or separately taken electric power substation to the isolated electric supply, load allocation of the power supply from the power plant generator; registration data using of crash conditions of the electric power system. Such test of actual voltage static load characteristics definition in electric system of Russia it is reduced by authors in making tests in situ technique. Error estimation which can appear in calculations of steady-state modes with the absence of the voltage actual load characteristics is executed.
Forecasting of Staff Resistance Level in the Process of Introduction of New Standards
Human factor plays a crucial role at a company. Thus, it is important to consider and forecast its reaction (such as resistance) at implementation of changes. Our paper suggests an approach which compares models of new management standards to be introduced with key concepts of a management system as seen by management staff. If we define the coordination degree between management model suggested by an official standard and conceptual subjective model of a member of managerial staff, we can make a conclusion about the resistance degree to changes. Assessment of the resistance degree and evaluation of resistance causes allows us organizing special training aimed at elimination of unharmonious and conflictive aspects of new standards. As a result of the training the most compromise pilot project can be chosen to valuate changes.
Damage initiation and propagation in composite shells subjected to impact
Abstract The paper investigates the impact-induced damage initiation and propagation for laminated composite shells under low-velocity impact. A three-dimensional eight-node non-conforming element is described to analyze interlaminar stress distribution, and progressive failure. The damage analysis is performed by using Tsai–Wu quadratic failure criterion, Tsai’s damage modes and an additional delamination formula at all Gaussian points. The damage modes considered are matrix cracking, fiber breakage and delamination. The progressive failure is expressed by reducing stiffness of the material at all failed Gaussian points. Special attention is centered on curved laminates. Impact energy threshold for the onset of damage and transient damage size are predicted for composite shells. The analyses of the flat and curved laminates are compared for discussing their different damage mechanism. In addition, the influence of the stacking sequence, the thickness and the radius of curvature on damage behavior of composite shells are studied.