Detection of Higher Harmonics in a Slider Crank Mechanism of Variable Obliquity Ratio and its Use in the Determination of Displacement Transmissibility

2012 ◽  
Vol 40 (2) ◽  
pp. 146-159
Author(s):  
Devesh Kumar Jha ◽  
Santanu Das ◽  
A. Nandi ◽  
S. Neogy
Keyword(s):  
Finite Elements ◽  
Engineering Education ◽  
Experimental Work ◽  
Fourier Transforms ◽  
Fast Fourier Transforms ◽  
Higher Harmonics ◽  
Design And Manufacture ◽  
Theoretical Results ◽  
Crank Mechanism

The present paper deals with the design and manufacture of a slider crank mechanism with a variable obliquity ratio. It uses a double eccentric to serve this purpose. The slider crank mechanism can be operated at various speeds and different obliquity ratios. An accelerometer attached to the slider helps obtain its acceleration. The presence of higher harmonics is detected using fast Fourier transforms. The experimentally obtained values are compared with standard theoretical results. Further, a cantilever can be fixed to the slider under displacement excitation. Accelerations measured at the root and tip of the cantilever are used to calculate displacement transmissibility. The experimentally obtained values are compared with those obtained using finite elements. It is expected that such an approach will boost the interest of the students as it bridges theory with experimental work, which is so vital for engineering education.

scholarly journals Revaccination as a measure of immunity to smallpox

1944 ◽  
Vol 43 (5) ◽  
pp. 337-340 ◽  
Author(s):  
E. S. Horgan ◽  
Mansour Ali Haseeb
Keyword(s):  
Experimental Work ◽  
Diagnostic Method ◽  
Sufficient Accuracy ◽  
Variola Virus ◽  
Elementary Body ◽  
High Potency ◽  
Insertion Technique ◽  
Immune Reactions ◽  
Full Immunity

1. Serological methods for the determination of smallpox immunity are briefly discussed, and it is concluded that they are unlikely to provide a diagnostic method of sufficient accuracy.2. Experimental work is recorded which shows certain differences in the response of previously vaccinated individuals, revaccinated simultaneously with a standard vaccine lymph and an elementary body suspension (vaccinia) of high potency. The significance of these differences is discussed.3. The results indicate that although the advantage of the e.b. suspension over vaccine lymph is relatively insignificant, that of two insertions over one is very marked. In revaccination the routine use of one insertion only may result in a certain number of semi-immunes (vaccinoids) being erroneously reported as immunes.4. It is concluded that if the two insertion technique be practised, persons showing immune reactions (negatives) may be considered, in all probability, as possessing full immunity to vaccinia-variola virus.

scholarly journals IV. On the dynamical theory of incompressible viscous fluids and the determination of the criterion

1895 ◽  
Vol 186 ◽  
pp. 123-164 ◽  
Keyword(s):  
Singular Solution ◽  
Physical State ◽  
Theoretical Calculations ◽  
Equations Of Motion ◽  
Dynamical Theory ◽  
Viscous Fluids ◽  
Linear Functions ◽  
Incompressible Viscous Fluids ◽  
Theoretical Results

1. The equations of motion of viscous fluid (obtained by grafting on certain terms to the abstract equations of the Eulerian form so as to adapt these equations to the case of fluids subject to stresses depending in some hypothetical manner on the rates of distortion, which equations Navier seems to have first introduced in 1822, and which were much studied by Cauchy and Poisson) were finally shown by St. Venant and Sir Gabriel Stokes, in 1845, to involve no other assumption than that the stresses, other than that of pressure uniform in all directions, are linear functions of the rates of distortion, with a co-efficient depending on the physical state of the fluid. By obtaining a singular solution of these equations as applied to the case of pendulums in steady periodic motion, Sir G. Stokes was able to compare the theoretical results with the numerous experiments that had been recorded, with the result that the theoretical calculations agreed so closely with the experimental determinations as seemingly to prove the truth of the assumption involved. This was also the result of comparing the flow of water through uniform tubes with the flow calculated from a singular solution of the equations so long as the tubes were small and the velocities slow. On the other hand, these results, both theoretical and practical, were directly at variance with common experience as to the resistance encountered by larger bodies moving with higher velocities through water, or by water moving with greater velocities through larger tubes. This discrepancy Sir G. Stokes considered as probably resulting from eddies which rendered the actual motion other than that to which the singular solution referred and not as disproving the assumption.

Analysis of Stress Concentrations in Thick Cylinders With Sideholes and Crossholes

1972 ◽  
Vol 94 (3) ◽  
pp. 815-824 ◽  
Author(s):  
J. C. Gerdeen
Keyword(s):  
Stress Concentration ◽  
Stress Concentrations ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Experimental Values ◽  
Pressure Stress ◽  
Shrink Fit ◽  
Outside Diameter ◽  
Theoretical Results

An approximate theoretical analysis is presented for the determination of stress concentration factors in thick walled cylinders with sideholes and crossholes. The cylinders are subjected to both internal pressure and external shrink-fit pressure. Stress concentration factors are plotted as functions of the geometrical ratios of outside diameter-to-bore diameter, and bore diameter-to-sidehole diameter. Theoretical results are compared to experimental values available in the literature and results of experiments described in a separate paper.

Determination of residual stresses in disk keyways by the finite-elements method

1982 ◽  
Vol 14 (7) ◽  
pp. 865-867
Author(s):  
B. A. Kravchenko ◽  
V. G. Fokin ◽  
G. N. Gutman
Keyword(s):  
Finite Elements ◽  
Residual Stresses ◽  
Finite Elements Method
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