A novel method for the measurement of vibration is proposed and demonstrated. The proposed experiment is based on laser triangulation: consists of line laser, object under test and a high speed camera remotely controlled by a software. Experiment involves launching a line-laser probe beam perpendicular to the axis of the vibrating object. The reflected probe beam is recorded by a high speed camera. The dynamic position of the line laser in camera plane is governed by the magnitude and frequency of the vibrating test-object. Using phase correlation technique the maximum distance travelled by the probe beam in CCD plane is measured in terms of pixels using MATLAB. An actual displacement of the object in mm is measured by calibration. Using displacement data with time, other vibration associated quantities such as acceleration, velocity and frequency are evaluated. The preliminary result of the proposed method is reported for acceleration from 1g to 3g, and from frequency 6Hz to 26Hz. The results are closely matching with its theoretical values. The advantage of the proposed method is that it is a non-destructive method and using phase correlation algorithm subpixel displacement in CCD plane can be measured with high accuracy.
One-dimensional transient heat flow is interpreted as a procession of ‘macro-scale translatory motion of indexed isothermal surfaces’. A new analytical model is proposed by introducing velocity of isothermal surface in Fourier heat diffusion equation. The velocity dependent function is extracted by revisiting ‘the concept of thermal layer of heat conduction in solid’ and ‘exact solution’ to estimate thermal diffusivity. The experimental approach involves establishment of 1 D unsteady heat flow inside the sample through Step-temperature excitation. A novel self-reference interferometer is utilized to separate a ‘unique isothermal surface’ in time- varying temperature field. The translatory motion of the said isothermal surface is recorded using digital camera to estimate its velocity. From the knowledge of thermo-optic coefficient, temperature of the said isothermal surface is predicted. The performance of proposed method is evaluated for Quartz sample and compared with literature.