a. r. fathi

In the present work, the effect of smart shape-memory alloys on thermal buckling and post-buckling of monoclinic and unidirectional composite panels has been investigated. The aerodynamic pressure applied to the system was modeled using the piston theory method. The effect of thermal heating for ultrasonic flows was also estimated from the reference temperature method. The panel is modeled nonlinearly with large deformations based on Van Karmen's theory. The obtained results show that the shape-memory alloy was able to increase the critical temperature of thermal buckling. The effect of the arrangement of composite layers on increasing the thermal buckling temperature was also studied. The results show that the amount of thermal deflection is greatly reduced due to the use of this alloy. Also, in the higher temperature differences, the rate of reduction of the panel increases. In this work, the effects of thermal stress on buckling and thermal buckling in a rectangular composite panel with hinge-hinge boundary conditions were investigated. Also, the effect of shape retention alloy in controlling these two phenomena has been studied. The shape memory alloy wire was placed in martensitic mode to apply a compressive force to the panel to control the heating and aerodynamic forces after changing the phase to austenite. The governing equations of the system were extracted through the layer theory method to show the effects of in-plane displacements better. Investigations on the effect of different layers (symmetry effects and arrangement angle of composite sheets) were performed to investigate thermal buckling. According to the obtained results, the layer arrangement of plates (0.90 / 0.90), (-45.45), (30/60), and (0.90 / 90.0), respectively, had the greatest effect on raising the critical temperature of thermal buckling in dimensional ratios equal to or greater than one. This shows that the symmetry of the arrangements has a greater effect than the angle of the arrangements. Examining the buckling diagrams for the effect of a shape memory alloy, it can be concluded that by placing this alloy in the composite panel, in addition to raising the buckling temperature, this alloy has a greater effect on displacement control by increasing the temperature after the critical buckling temperature.

The aim of this research is to introduce a semi-analytical approach for the analysis of the free and forced nonlinear vibrations of a bending shape memory alloy (SMA) beam; while, considering the effect of its pseudo-elastic behavior. In order to create a primary deflection, an appropriate pre-strain is applied to the SMA beam using a compression spring. A new material model was utilized to simulate the nonlinear hysteric behavior of the SMA beam, while the differential equations of motion of the beam were derived based on Euler–Bernoulli beam theory and Hamilton principle. The extracted nonlinear partial differential equations of motion are semi-analytically solved by utilizing the Galerkin method. The pseudo-elastic behavior and energy dissipation of the SMA beam were studied in the free and forced nonlinear vibration regimes. Finally, the influences of the system parameters such as the spring constant, amplitude, and frequency of the excitation force on the absorber efficiency were investigated, and its stability was studied. The numerical results depict that the SMA beam exhibits a highly nonlinear dynamical behavior, and can be used as an actuator for energy dissipation.

Knowledge management is one of the great achievements of the information and knowledge age. Research shows that the most important factor in the success of knowledge is knowledge-based culture. Therefore, it is necessary to examine the impact of organizational culture on knowledge management; the aim of this study is to examine the impact of organizational culture elements on knowledge management in educational-treatment hospitals in Kerman. This descriptive, cross-sectional and applied study was carried out in 2012 in Afzalipour educational-treatment hospitals of Kerman. Statistical universe included all administrative and Para-clinical staff of this hospital; of them, 86 ones were selected using random cluster sampling method. Data was collected through questionnaires and was analyzed using Pearson correlation and spss statistical software. most studied subjects considered status of organizational culture average (average score: 3.07). The highest score was related to the component “adaptability culture” with average score of 3.18, and the lowest was related to “collaboration culture” with average score of 2.97. Knowledge management was also in poor condition with average score of 2.73. Finally, a statistically significant relationship was obtained between organizational culture and knowledge management with a correlation coefficient of r=0/56; therefore, as organizational culture increases, knowledge management increases too, and all organizational culture components affect knowledge management. organizational culture was in average condition and knowledge management was in poor condition. Concerning a statistically significant relationship between organizational culture and knowledge management, it can be concluded that it will result in successful changes in hospitals and will help mangers make a systematic prediction of change priorities and codify strategies to perform management techniques and processes successfully.