Deflection.
Abstract:
In this experiment, we were needed to find the deflection of Ring, Semicircle and quadrant made from the curved beam. The experiment is carry out by applied these beam with a load that weight 5N for circle and 2N for Semicircle and Quadrat. For the ring shape, the load is added 5N contiuosly until the load 40N and the dial reading is note down every time the load is added. Similar step is repeated using Semicircle and Quadrant that is we add 2N load continuously until 14N and take the dial reading.
For theoretical value we use the Castigliano’s Theorem, theoretical value of deflection can be calculated. Through this experiment, the validity of the Castigliano’s Theorem in curved beam can be proven.Comparison is made between the measured deflection values and theoretical deflection values. Among reasons for discrepancies are likely the parallax errors when reading was being taken from the dial gauge due to the sensitivity of the dial gauge. A slight vibration or impact on the table will affect the reading on dial gauge. Generally, theoretical values exceed experimental values.
Introduction:
The proving of Deflection of Circular shape is based on the diameter deflection elastically under load. Applied load is known from its characteristic load-deflection curve. As far as studies are concerned, Read and Bell(Reid, S.R, and Bell, 1982) pointed out the fact that experiments in which metal rings are compressed to large deflections by a pair of opposed concentrated loads reveal a load-deflection characteristic which varies with the simple theory based upon rigid-perfectly behavior. Thus the influence of strain hardening on the deformation of thin rings subjected to opposed concentrated loads was investigated using a model in an approximate fashion and it is shown how the discrepancies between the experiments and the simple theory arise.
O’Dogherty presented the fundamental formulaefor the moment and strain distributions in circular,
References: 1. Reid, S. R. and Bell, W.W., (1982). Influence of strain hardening on the deformation of thin rings subjected to opposed concentrated loads, International Journal of Solids and Structures, Vol. 8 (8), PP. 643-658 2. O 'Dogherty M. J., (1996). The Design of Octagonal Ring Dynamometers, Journal of Agricultural Engineering Research, Vol. 63 (1), PP. 9-18 3. M. AshiqurRahman and SharifurRahman ,(2005 ), Design Parameters of A Circular Proving Ring of Uniform Strength , international Conference on Mechanical Engineering . 4. Ferdinand P.Beer, E Russell Johnston, Jr and John T. DeWolf (2006),Mechanic of Material,New York: McGraw-Hill Companies. 5. From http://en.wikipedia.org/wiki/Castigliano 's_method.Retrieved 2 May 2012