Papers by Keyword: MATLAB

Abstract: The Brookfield_to_MATLAB and ViscosityApproximation codes for processing of experiments results for determination of viscosity on a rotational Brookfield DV3T viscometer is developed in the MATLAB. The codes allow to carry out automatic capture data, to calculate the shear rate for standard spindles RV-1 ... RV-7, to sort the measurement results on temperatures, to combine the experimental data and to determine the coefficients of the Andrade type power-law model. Paper describes experiment results on determination of viscosity of the epoxy binder reinforced by short carbon fibers. The coefficients of the viscosity model are determined by the linear regression coefficients. The obtained determination coefficient shows a good agreement of the model with the experimental data. The results are used for study various contents of a mass fraction of fibers: 0%, 5%, 10%, and 15%.

Abstract: This study has been carried out to demonstrate the control of a reactive distillation process in which the production of biodiesel was taken as the case study using an advanced control method, which is known as dynamic matrix control. The control was accomplished by employing the transfer function model of the reactive distillation process developed, using the System Identification Toolbox of MATLAB, from the dynamic data generated when the prototype plant of the process was simulated with the aid of ChemCAD process simulator. The results obtained from the dynamic matrix control were compared with those of a proportional-integral-derivative (PID) control system tuned with Ziegler-Nichols and Cohen-Coon methods, and it was discovered that the dynamic matrix control was able to perform best among the three (dynamic matrix control method, PID tuned with Ziegler-Nichols method and PID tuned with Cohen-Coon method) because it (the dynamic matrix control) was able to make the biodiesel mole fraction response not to exceed the maximum limit value of 1 in addition to having the lowest sum of absolute errors (SAE) and sum of squared errors (SSE) from the control systems that were simulated.

Abstract: Modal analysis is a method to describe the dynamic properties of structure such as natural frequency, mode shape and damping ratio. These properties are important for design and analysis of structure in dynamic condition. MATLAB is a high-performance numerical computation and visualization software package. It provides an interactive environment with hundreds of built-in functions for technical computation, graphics, and animation. In present analysis, use of MATLAB is done for finding the free vibrational characteristics of a structure made of composite material. The study involves finding the natural frequencies of structure made of Glass-epoxy, Carbon-epoxy and Graphite fiber reinforced polyamide materials. In this case Euler’s-Bernoulli beam theory is used for analytical solution and to construct MATLAB codes. The structure considered here is a beam with fixed-free condition. The results obtained from the MATLAB are accurate comparatively, the results obtained shows that the MATLAB can be further used to write programs which involve complicated iterations and cannot be done manually. The further work can be extended for writing the programs of much more complex equations in MATLAB and obtains exact solution.

Abstract: The different approaches were analyzed to investigate the buckling problems of structurally-anisotropic panels made from composite materials. Aircraft composite structure design in the field of production technology is the outlook research trend. New mathematical model relations for the buckling investigation of structurally-anisotropic panels comprising composite materials are presented in this study. The primary scientific novelty of this research is the further development of the theory of thin-walled elastic ribs related to the contact problem for the skin and the rib with an improved rib model. One considers the residual thermal stresses and the preliminary tension of the reinforcing fibers with respect to panel production technology. The mathematical model relations for the pre-critical stressed state investigation of structurally-anisotropic panels made of composite materials are presented. Furthermore, the mathematical model relations for the buckling problem investigation of structurally-anisotropic panels made of composite materials are presented in view of the pre-critical stressed state. The critical force definition of the general bending form of the thin-walled system buckling and the critical force definition of the many-waved torsion buckling are of the most interest in accordance with traditional design practices. In both cases, bending is integral with the plane stress state. Thus, the buckling problem results in the boundary value problem when solving for the eighth order partial derivative equation in the rectangular field. The schematization of the panel as structurally-anisotropic has been proposed as a design model when and the critical forces of total bending form of buckling are determined. For a many-waved torsion buckling study, one should use the generalized functions set. The solution is designed by a double trigonometric series and by unitary trigonometric series. A computer program package is developed using the MATLAB operating environment. The computer program package has been utilized for multi-criteria optimization of the design of structurally-anisotropic aircraft composite panels. The influence of the structure parameters on the level of critical buckling forces for bending and for torsion modes has been analyzed. The results of testing series are presented.

Abstract: The paper deals with the analysis of fire resistance of concrete structural members exposed to fire based on different fire models. An illustrative example of the assessment of a slab panel is presented. Several fire models are employed in order to predict the evolution of temperature in a selected fire compartment. Some of these fire models, namely the ISO fire curve and the parametric fire curve, are implemented in an in-house MATLAB code. For the more comprehensive fire models, external scientific software tools are used, namely the CFAST software for the zone model and the FDS software for the CFD (computational fluid dynamics) model. By employing the results of the fire simulations, the fire resistance of the slab panel is assessed. It is performed by a one-way coupled numerical procedure based on a well-known heat transfer finite element model and iterative sectional mechanical analysis. The procedure is implemented in an in-house MATLAB code. It is shown that (i) the numerical procedure can be employed in connection with different fire models and (ii) the fire resistance prediction can be strongly influenced by the type of selected fire model.

Abstract: Currently, nanofluids have been found to have enriched physical and thermal properties such as thermal conductivity, viscosity and convective heat transfer coefficients. The aim of this research is to analyse the performance characteristics of punga oil and plastic oil based nanolubricants. The nanoparticle of graphite with 0.1% weight was added to the base oils. Hydraulic oil of VG32 is used as standard oil to compare the performance with the nanolubricants. Basic properties such as viscosity, flash and fire point were measured for the prepared nanolubricants. Coefficient of friction for the selected oils was measured with help of reciprocating friction monitor and load wear index was also measured with the help of four ball tester. The performance of these oils for load ball bearing lubrication was carried out numerically with the help of Comsol software and its analytical validation was done with the help of MATLAB software. From the observed results it was found that, the power loss was decreased by about 77.4% and 78% by plastic oil and plastic oil based nanolubricant respectively and load carrying capacity was also decreased by about 78.3% and 78.8%.

Abstract: The reduction of ilmenite by a gas comprising of CNG, hydrogen and nitrogen mixture was investigated by experimental and kinetic modeling in MATLAB. The CNG flow time was varied from 15 to 45 minutes at the temperatures of 1100-1200°C for 1-3 hours. In order to predict the extent of reduction, a shrinking core model (SCM) and crackling core model (CCM) were employed for the kinetic modeling. The results showed that the extent of reduction of 80% was achieved by using a CNG flow time of 45 minutes at 1200°C for 1 hour. The kinetic modeling for non-isothermal SCM at the same conditions gave a predicted value of 87%. The CCM gave a predicted value of about 100% at the same conditions. The non-isothermal SCM showed a closer trend to the experimental results. The deviation between SCM and CCM with the experimental data was attributed to porosity, thermodynamic properties and minute thermal fluctuations within the sample during the reduction process.

Abstract: The course of electromagnetic fields and waves has properties of abstract concept, strong theory and complex calculation, thus this course is difficult to study and understand, and then is also difficult to teach. In order to make the understanding of the course easier, MATLAB software is used as a platform in classroom teaching of electromagnetic fields and waves. This paper mainly discusses the electrical field intensity distribution of media sphere materials and the properties of electromagnetic wave propagation with MATLAB software. The optical properties of dielectric-metal core-shell multi-layered nano-shell are also studied with Laplace's equation. To enrich the teaching content and improve a better teaching effect, the optical property of nano-materials and electromagnetic wave propagation are visualized with MATLAB software, which makes the properties of nano-materials and electromagnetic wave propagation understand easily.

Abstract: In this work, novel types of internally reinforced hollow-box beams were structurally optimized using a Finite Element Updating code built in MATLAB. In total, 24 different beams were optimized under torsion loads. A new objective function was defined in order to consider the balance between mass and deflection on relevant nodal points. New formulae were developed in order to assess the efficiency of the code and of the structures. The efficiency of the code is determined by comparing the Finite Element results of the optimized solutions using ANSYS with the initial solutions. It was concluded that the optimization algorithm, built in Sequential Quadratic Programming (SQP) allowed to improve the effective mechanical. Therefore, the developed algorithm is effective in optimizing the novel FEM models under the studied conditions.

Abstract: In this work, novel types of internally reinforced hollow-box beams were structurally optimized using a Finite Element Updating code built in MATLAB. In total, 24 different beams were optimized under bending loads. A new objective function was defined in order to consider the balance between mass and deflection on relevant nodal points. New formulae were developed in order to assess the efficiency of the code and of the structures. The efficiency of the code is determined by comparing the Finite Element results of the optimized solutions using ANSYS with the initial solutions. It was concluded that the optimization algorithm, built in Sequential Quadratic Programming (SQP) allowed to improve the effective mechanical behavior under bending in 8500%.Therefore, the developed algorithm is effective in optimizing the novel FEM models under the studied conditions.