Influence of Crack on Modal Parameters of Cantilever Beam Using Experimental Modal Analysis

In this paper, the dynamic behavior of a cantilever beam without and with crack is observed. An elastic Aluminum cantilever beams having surface crack at various crack positions are considered to analyze dynamically. Crack depth, crack length and crack location are the foremost parameters for describing the health condition of beam in terms of modal parameters such as natural frequency, mode shape and damping ratio. It is crucial to study the influence of crack depth and crack location on modal parameters of the beam for the decent performance and its safety. Crack or damage of structure causes a reduction in stiffness, an intrinsic reduction in resonant frequencies, variation of damping ratios and mode shapes. The broad examination of cantilever beam without crack and with crack has been done using Numerical analysis (Ansys18.0) and experimental modal analysis. To observe the exact higher modes of beam, discretize the beam into small elements. An experimental set up was established for cantilever beam having crack and it was excited by an impact hammer and finally the response was obtained using PCB accelerometer with the help sound and vibration toolkit of NI Lab-view. After obtaining the Frequency response functions (FRFs), the natural frequencies of beam are estimated using peak search method. The effectiveness of experimental modal analysis in terms of natural frequency is validated with numerical analysis results. This paper contains the study of free vibration analysis under the influence of crack at different points along the length of the beam

Contribution of Drude and Brendel Model Terms to the Dielectric Function; A case of TiO2:Nb Thin Films

oai:article.journals.aijr.in:article/299Parametric modeling provides a mean of deeper understanding to the properties of materials. Dielectric function is one of the key parameters which can provide information on the dielectric nature of a thin film or bulk materials. It can be obtained by modeling the material using appropriate existing, new or modified models. In our work, we utilized existing Brendel and Drude models to extract the optical constants from spectrophotometric data of fabricated undoped and niobium doped titanium oxide thin films. The individual contributions by the two models were studied to establish influence on the dielectric function. The effect of dopants on their influences was also analyzed. Results indicate a minimal contribution from the Drude term due to the dielectric nature of the undoped films. However as doping levels increase, the rise in the concentration of free electrons favors the use of Drude model

Contribution of Drude and Brendel Model Terms to the Dielectric Function; A case of TiO2:Nb Thin Films

oai:ojs2.journals.aijr.org:article/299Parametric modeling provides a mean of deeper understanding to the properties of materials. Dielectric function is one of the key parameters which can provide information on the dielectric nature of a thin film or bulk materials. It can be obtained by modeling the material using appropriate existing, new or modified models. In our work, we utilized existing Brendel and Drude models to extract the optical constants from spectrophotometric data of fabricated undoped and niobium doped titanium oxide thin films. The individual contributions by the two models were studied to establish influence on the dielectric function. The effect of dopants on their influences was also analyzed. Results indicate a minimal contribution from the Drude term due to the dielectric nature of the undoped films. However as doping levels increase, the rise in the concentration of free electrons favors the use of Drude model

Importance of Modeling and Simulation of Materials in Research

All researchers have experience with various complicated phenomena and processes in materials and have contact with understanding of different complex dynamical systems. Consequently, one has to predict and optimize the system under study and compare the output results to its experimental setup. The experimental setup is done to confirm and spread out information about the system; however still, many researchers are not familiar with the results arising from the experimental setup or fabrications processes. To obtain valid experimental results, it is necessary to pay carful attentions to the tools, devices and the applied techniques for measuring and observations detectors. This experimentations and fabrications process cover all area from forming and characterizations of nanostructures to macrostructures. In system characterizations, it is common to apply system modeling to predict and represent the system by a mathematical model that is accomplishable due to the relations between the inputs and outputs defined by formulas

Study of Combined Effect of Inclination and Partial Fins on Melting of Phase Change Material in A Rectangular Enclosure Using CFD

This study presents the combined effect of inclination and internal fins on melting rate of PCM in a rectangular enclosure (8.89cm×6.35cm). Rectangular enclosure has a hot wall with a temperature of 311K, a cold wall with a temperature of 301.3K and the other two walls are insulated. Gallium with very low prandtl number is taken as the PCM in this study. First, the individual effects of different inclinations (0⁰, 45⁰ and 90⁰) of the enclosure on melting rate of PCM are studied followed by the study of the effect of internal fins. Then we provide a combined environment of inclination and partial fins and obtain the results of liquid fraction, velocity contours and temperature distributions. Plots for liquid fraction and average temperatures with respect to time are also obtained. Finally, the results and plots of combined effect are compared with those of other conditions. From the comparison we conclude that combined effect of inclination and partial fins under constant normal gravity condition greatly enhances the heat transfer in PCM

Evaluation of Stiffness and Parametric Modelling of XY Flexure Mechanism for Precision Applications

In miniaturized scale electro-mechanical framework (MEMS) flexural instruments are generally utilized in light of their preferences, frictionless and wear less movement and high accuracy. Flexures rely upon material versatility for their usefulness. In flexure component, movement is created because of flexibility of the shaft from which it is made. One of the run of the mill favorable circumstances of flexural system is to increase exact twisting and adaptability to acquire movement wanted way. This paper manages outline, examination and displaying of XY flexure instrument which depends on twofold parallelogram flexure (DFM). The XY system exhibited has solid structure and it depends on twofold parallelogram flexure. Limited component model and investigation is completed in ANSYS 15. Static examination is done to discover constrain avoidance attributes of instrument. Parametric examination is utilized to improve outline parameters of flexure shaft. Limited component examination (FEA) result approves investigative outcomes of component

Influence of Crack on Modal Parameters of Cantilever Beam Using Experimental Modal Analysis

In this paper, the dynamic behavior of a cantilever beam without and with crack is observed. An elastic Aluminum cantilever beams having surface crack at various crack positions are considered to analyze dynamically. Crack depth, crack length and crack location are the foremost parameters for describing the health condition of beam in terms of modal parameters such as natural frequency, mode shape and damping ratio. It is crucial to study the influence of crack depth and crack location on modal parameters of the beam for the decent performance and its safety. Crack or damage of structure causes a reduction in stiffness, an intrinsic reduction in resonant frequencies, variation of damping ratios and mode shapes. The broad examination of cantilever beam without crack and with crack has been done using Numerical analysis (Ansys18.0) and experimental modal analysis. To observe the exact higher modes of beam, discretize the beam into small elements. An experimental set up was established for cantilever beam having crack and it was excited by an impact hammer and finally the response was obtained using PCB accelerometer with the help sound and vibration toolkit of NI Lab-view. After obtaining the Frequency response functions (FRFs), the natural frequencies of beam are estimated using peak search method. The effectiveness of experimental modal analysis in terms of natural frequency is validated with numerical analysis results. This paper contains the study of free vibration analysis under the influence of crack at different points along the length of the beam