The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform

G Pohit - One of the best experts on this subject based on the ideXlab platform.

  • study of non linear dynamic behavior of open cracked functionally graded timoshenko beam under forced excitation using Harmonic balance method in conjunction with an iterative technique
    Applied Mathematical Modelling, 2018
    Co-Authors: B Panigrahi, G Pohit
    Abstract:

    Abstract The nonlinear modeling and subsequent dynamic analysis of cracked Timoshenko beams with functionally graded material (FGM) properties is investigated for the first time using Harmonic balance method followed by an iterative technique. Crack is assumed to be open throughout. During modeling, nonlinear strain–displacement relation is considered. Rotational spring model is adopted in order to model the open cracks. Energy formulations are established using Timoshenko beam theory. Nonlinear governing differential equations of Motion are derived using Lagrange's equation. In order to incorporate the influence of higher order Harmonics, Harmonic balance method is employed. This reduces the governing differential equations into nonlinear set of algebraic equations. These equations are solved using two different iterative techniques. Methodology is computationally easier and efficient as well. This is observed that although assumption of Simple Harmonic Motion (SHM) simplifies the problem, it yields to erroneous results at higher amplitude of Motion. However, accuracy of the solution is improved considerably when the contribution of higher order Harmonic terms are considered in the analysis. Results are compared with the available results, which confirm the validity of the methodology. Subsequent to that a parametric study on influence of forcing term, material indices and crack parameters on large amplitude vibration of Timoshenko beams is performed for two different boundary conditions.

F. Fajardo - One of the best experts on this subject based on the ideXlab platform.

  • Experimental study of Simple Harmonic Motion of a spring-mass system as a function of spring diameter
    Revista Brasileira de Ensino de Física, 2013
    Co-Authors: C. A. Triana, F. Fajardo
    Abstract:

    The Simple Harmonic Motion of a spring-mass system generally exhibits a behavior strongly influenced by the geometric parameters of the spring. In this paper, we study the oscillatory behavior of a spring-mass system, considering the influence of varying the average spring diameter Φ on the elastic constant k, the angular frequency ω, the damping factor γ, and the dynamics of the oscillations. It was found that the elastic constant k is proportional to Φ -3, while the natural frequency ω0 is proportional to Φ - 3 / 2, and γ decreases as Φ increases. We also show the differences obtained in the value of the angular frequency ω when the springs are considered as ideal (massless), taking into account the effective mass of the spring, and considering the influence of the damping of the oscillations. This experiment provides students with the possibility of understanding the differences between theoretical models that include well-known corrections to determine the frequency of oscillations of a spring-mass system.

  • The influence of spring length on the physical parameters of Simple Harmonic Motion
    European Journal of Physics, 2011
    Co-Authors: C. A. Triana, F. Fajardo
    Abstract:

    The aim of this work is to analyse the influence of spring length on the Simple Harmonic Motion of a spring–mass system. In particular, we study the effect of changing the spring length on the elastic constant k, the angular frequency ω and the damping factor γ of the oscillations. To characterize the behaviour of these variables we worked with a series of springs of seven different lengths, in which the elastic constant was found by means of the spring-elongation measurement and ω was obtained from the measurement of the oscillation period T of a suspended mass. The oscillatory movement was recorded using a force sensor and the γ value was determined by the fit of the envelope oscillations. Graphical analysis of the results shows that k, ω and γ decrease when the natural spring length increases. This experiment can be performed with equipment normally found in undergraduate physics laboratories. In addition, through graphical analysis students can deduce some relationships between variables that determine the Simple Harmonic Motion behaviour.

Wenyuah Shih - One of the best experts on this subject based on the ideXlab platform.

  • estimating step distance using Simple Harmonic Motion
    Vehicular Technology Conference, 2012
    Co-Authors: Kunchan Lan, Wenyuah Shih
    Abstract:

    Some prior studies proposed the use of Pedestrian Dead Reckoning (PDR) for indoor localization. The PDR system does not require a beacon-based infrastructure, in which a small number of sensors are put on the pedestrian. These sensors (such as G-sensor and Gyro) are used to estimate the distance and direction that the user traveled. The PDR approach can be generally categorized into two types: foot-mounted and waist-mounted. In general, the foot-mounted system can get accurate step length, but perform poorly in estimated heading direction. On the other hand, the waist-mounted system can estimate direction with high accuracy, but is hard to measure the step length. In this work, we proposed a waist-mounted based PDR to estimate step length using one 3-axis accelerometer. We utilize vertical acceleration to implement double integral for measuring the user's instant height change and use some physical features of vertical acceleration during the walking to calibrate the measurement. Based on the Pythagoras' Theorem, we can then estimate each step length based on the user's height change during his/her walking.

  • using Simple Harmonic Motion to estimate walking distance for waist mounted pdr
    Wireless Communications and Networking Conference, 2012
    Co-Authors: Kunchan Lan, Wenyuah Shih
    Abstract:

    A huge body of work utilized signal strength of short range signal (such as WiFi, Bluetooth, ultra sound or Infrared) to build a radio map for indoor localization, by deploying a great number of beacon nodes in the building. The drawback of such an infrastructure-based approach is that the deployment and calibration of the system is costly and labor-intensive. To overcome that, some prior studies proposed the use of Pedestrian Dead Reckoning (PDR) for indoor localization. The PDR system does not require to build a beacon-based infrastructure, in which a small number of sensors are put on the pedestrian. These sensors (such as G-sensor and Gyro) are used to estimate the distance and direction that the user traveled. The PDR approach can be generally categorized into two types: foot-mounted and waist-mounted. In general, the foot-mounted system can get accurate step length, but perform poorly in estimated heading direction. On the other hand, the waist-mounted system can estimate direction with high accuracy, but is hard to measure the step length. In this work, we proposed a waist-mounted based PDR using one 3-axis accelerometer and one gyroscope sensor. We utilize vertical acceleration to implement double integral for measuring the user's instant height change and use some physical features of vertical acceleration during the walking to calibrate the measurement. Then based on the Pythagoras' Theorem, we can estimate each step length based on the user's height change during his/her walking. Our experiment results show that the accuracy is about 98.26% in estimating the user's walking distance.

B Panigrahi - One of the best experts on this subject based on the ideXlab platform.

  • study of non linear dynamic behavior of open cracked functionally graded timoshenko beam under forced excitation using Harmonic balance method in conjunction with an iterative technique
    Applied Mathematical Modelling, 2018
    Co-Authors: B Panigrahi, G Pohit
    Abstract:

    Abstract The nonlinear modeling and subsequent dynamic analysis of cracked Timoshenko beams with functionally graded material (FGM) properties is investigated for the first time using Harmonic balance method followed by an iterative technique. Crack is assumed to be open throughout. During modeling, nonlinear strain–displacement relation is considered. Rotational spring model is adopted in order to model the open cracks. Energy formulations are established using Timoshenko beam theory. Nonlinear governing differential equations of Motion are derived using Lagrange's equation. In order to incorporate the influence of higher order Harmonics, Harmonic balance method is employed. This reduces the governing differential equations into nonlinear set of algebraic equations. These equations are solved using two different iterative techniques. Methodology is computationally easier and efficient as well. This is observed that although assumption of Simple Harmonic Motion (SHM) simplifies the problem, it yields to erroneous results at higher amplitude of Motion. However, accuracy of the solution is improved considerably when the contribution of higher order Harmonic terms are considered in the analysis. Results are compared with the available results, which confirm the validity of the methodology. Subsequent to that a parametric study on influence of forcing term, material indices and crack parameters on large amplitude vibration of Timoshenko beams is performed for two different boundary conditions.

Widha Sunarno - One of the best experts on this subject based on the ideXlab platform.

  • analysis of undergraduate student concept understanding three tier test Simple Harmonic Motion on mass spring system
    INTERNATIONAL CONFERENCE ON SCIENCE AND APPLIED SCIENCE (ICSAS) 2019, 2019
    Co-Authors: Dewanta Arya Nugraha, Cari Cari, A. Suparmi, Widha Sunarno
    Abstract:

    Concept understanding is important in physics. This study focus on the analysis of students’ conception and the analysis of the three-tier test instrument about Simple Harmonic Motion on mass-spring system. The sample of this research was 123 students on 2nd, 4th, and 6th semester of Physics Education program of the university in Jakarta and Bengkulu. The data collected by using a diagnostic test about Simple Harmonic Motion on a spring. The quality of three-tier instruments were analyzed using Quest software. The reliability estimation results obtained the value of person reliability of 0.79, and item reliability of 0.65 is in a good category. The category of understanding students’ concepts using a three-tier test of Scientific Knowledge, Lack of Knowledge, Error, and Misconception. The percentage of calculation results obtained information that the average student at the first level experienced many misconceptions, which has a frequency of 1138 times. At the second level, there are more students in the Scientific Knowledge category than students in the error and misconception categories. While at the third level, the Scientific Knowledge category more students than students who are in the category of lack of knowledge, error, and misconception.

  • Physics students’ answer on Simple Harmonic Motion
    Journal of Physics: Conference Series, 2019
    Co-Authors: Dewanta Arya Nugraha, Cari Cari, A. Suparmi, Widha Sunarno
    Abstract:

    Understanding the concepts of Simple Harmonic Motion will influence students' understanding of other physical phenomena such as the movement of disturbed objects from their equilibrium positions, macroscopic wave phenomena, and quantum phenomena. The aims of this study were to analyze students' answers about the concept of SHM and determine the problems experienced by students in pure Harmonic Motion material. . The sample of this research is 27 physics students on 2nd semester year 2017/2018 in Universitas Sebelas Maret who has received basic physics course. This research using a descriptive method. The data collected by giving 12 multiple choices with reason. The questions are about the concept of Simple Harmonic Motion. The result shows that most of the students only understand a partial concept. 57,10% students can answer the question correctly and the rest still have difficulty in understanding the concept. The most difficult concept is about the relationship among displacement, velocity, and acceleration.