Abstract
It is very important industrially to estimate the degree of large deflection appearing in such members as a plate spring, plastics and so on. In this report, the problem of large deflection of a simply supported beam in a symmetrical four-point bending test was treated. It was shown that the desired specific quantities such as the maximum deflection, maximum curvature, maximum bending stress and end slope, which are especially matters of great concern in the material testing, were able to be predicted easily from a conventional linear bending theory and three reduction factors derived here newly.
For the convenience of applications, the nomographs of the reduction factors were given graphically in terms of the vertical load, the large deflection at midpoint and the end slope.
The experiment of large deflection in which a PVC thin plate was utilized was carried out to confirm the availability of the newly proposed reduction method. The experimental results obtained were in good agreement with the predicted ones by the reduction method. Therefore, the present simple reduction method can be put into practical use.
