Papers by Keyword: Analytical

Abstract: In the structure of passenger vehicles there are components that absorb the impact load, which components are commonly thin-walled square tube. The design of the impact energy absorber model can be carry-out by experiment, simulation, and analysis. In the design of this impact energy absorbing component, an elliptical hole was used as a crush initiator to reduce peak loads and set the start of the bending pattern. Analytical predictions were made to reduce costs and speed up time to obtain mean load and peak loads values from the same shape model. In this study, a thin-walled square tubes model is used with an elliptical hole that have ratio of horizontal axis and vertical axis is from 3:7 until 7:3. The result of this study showed that the prediction of the peak load and average load by analytical means has a good conformity with the simulation. Keywords: Impact energy absorber, analytical, square tube, elliptical hole.

Abstract: Piezoelectric materials, typically used as intelligent materials, can respond according to the design demands of the composite structures autonomously. The excitation of piezoelectric actuators generates the bending effect on the hybrid composite plates. An analytical methodology is developed to calculate the displacements of simply supported laminated composite plates induced by piezoelectric actuators and validate the results by generating MATLAB code. Further, the laminated hybrid composite plates reinforced with carbon nanotubes(CNT) are excited by piezoelectric actuators bonded to the surface on both sides with a variable electrical voltage across the thickness. The effects of location, size and thickness ratio of piezoelectric actuators on the deflection of hybrid composite plates are carried out by extending the code. The transverse displacements vary linearly with the applied voltage and size of the piezoelectric actuators. The effect of CNT volume fraction and the position of CNT lamina plays a vital role in deflections, and also it is observed that maximum displacements decrease rapidly as thickness ratio increases from 0.5 to 5 and from 10 to 50, the maximum displacements gradually decrease. Hence, it illustrated that the present technique provides a simple solution for predicting and controlling the deformed shape of reinforced hybrid composite plates induced by distributed piezoelectric actuators.

Abstract: Drying is a complex process of coupledheat and mass transfer of wet porous material. Wet clay products when exposed to drying without control can suffer cracks and deformations, reducing its quality post-drying. Thus, this work aims to study the hollow ceramic materials drying with arbitrary shape using lumped models. Here, the exact solution of the governing equations were obtained using the method of separation of variables. Results of the average moisture constant and temperature of the material along the process are presented and analyzed. It was observed that the moisture loss process occurs at a lower speed than the heating of the ceramic material because its thermal diffusivity is greater than the mass diffusivity and that the area/volume relationship strongly affects the heat and mass transfer of the material.

Abstract: In the recent years, blood flow through an aorta has been the main focus of many investigators. It shows particular interest in analyzing human aortic stiffness and blood flow behavior. Mainly, an unsteady state is applied for incompressible fluid, which is assumed to be newtonian. Artery is considered an elastic tube and the wall boundaries are isotropic. The analytical modeling of blood involves adopting an asymptotic approach according to a small aspect radio, which is inversely proportional to Reynolds number. The wall has been assumed a thin shell, which generates a small axisymmetric vibration. The mathematical model of the wall is developed using the thin shell theory based on geodesic curvature parameter. In the end, the analytical results simulation is applied to have better understanding of the effects of blood flow behavior over the elasticity aortic wall properties.

Abstract: The drying is a thermodynamic process of simultaneous heat transfer and moisture removal of a porous material. Clay products when exposed to drying without control can suffer cracks and deformations, reducing its quality post-drying. Thus, this work aims to study the holed solid drying with arbitrary shape using the global capacitance method. Application has been made for the drying of clay products. The analytical solution of the governing equations was made using the method of separation of variables.Kinetic results for mass loss and heating of the material are presented and analyzed. It was observed that the moisture loss process occurs at a lower speed than the heating of the ceramic material because its thermal diffusivity is greater than the mass diffusivity and that the area/volume relationshipstrongly affects the phenomena of heat and mass transport.

Abstract: This work aims to study convective drying of ellipsoidal solids. Aplication has been done to drying of wheat Kernel. Diffusion equation in cylindrical coordinates has been solved via Galerkin-based integral method considering convective boundary conditions and constant thermo-physical properties. Results of the temperature and moisture content are presented and compared with wheat experimental drying data at relative humidity 33.8 % and temperature 47.0°C. It was verified that heat transfer in the drying process occurs much faster than the mass transfer, thus providing a rapid heating of the product, which reduces grain quality.

Abstract: Airbag is widely used in heavy equipment dropped field with its efficient cushion performance and low cost. The calculation method used now for the process of airbag landing mainly is simulative calculation: analytical analysis and finite element simulation, but there are less systematic introduction for the mathematical model behind these methods in past papers. This paper mainly does the summary for the mathematical model of vented airbag which is usually used.

Abstract: The drawing of wires with round cross section is a widely used technological method for making a great number of wire products of different range of sizes having excellent material- and surface quality. The planning of any kinds of wire drawing technology is greatly facilitated by knowing the models describing the technological parameters in the best possible way. Mainly the finite element method (FEM) and the analytical method are used for modelling the above parameters. Contrary to FEM, the advantage of the continuous analytical models is that they require less calculation processes and this fact seems to be really a great advantage when planning the technology in industrial circumstances. In the course of planning, the choosing of the individual technological parameters is determined by the cost effectiveness (i.e. the min. specific energy consumption), the quality of products and the productivity. The aim of our research work was to determine and develop a complex optimizing target function for the cold drawing technology which takes into consideration each of the above conditions and hasn’t been published in the references yet. By utilizing the fast computability of analytical model, a design software meeting all the expectations and giving IN-TIME result in industrial circumstances was developed by means of the complex optimization target function

Abstract: Considering the valuation of forest stands based on revenue from wood sales, concession policy (such as carbon subsidies) and associated costs, the paper focuses on the stochastic control model to study the forest asset dynamic management. The key contribution is to find the optimal dynamic strategy about harvesting quantity in the continual and multiple periods in conditions of stochastic commodity price and timber growth by using portfolio approach. Finally, an analytical optimal strategy is obtained to analyze the quantification relations through which some important conclusions about the optimal forest management can be drawn.

Abstract: This paper presents a theoretical investigation of the mass transfer during the drying of solids of revolution with arbitrary shape. A two-dimensional mathematical model by assuming the liquid diffusion to be the sole mechanism of moisture transport, constant thermophysical properties and convective boundary condition at the surface of the solid is presented. The resulting equation is solved analytically by using the Galerkin-based integral method. Results of the mean moisture content and moisture content distribution within the porous solid are present and analyzed during the process, for different Biot number and aspect ratio. We conclude that solid drying rate is affected by Biot number and area/volume relationships, and which drying process is faster in sharp areas and closed to surface of the solid.