Abstract
Nonlinear stress-strain curve of high polymer material with plastic deformation was estimated from load-deflection curve of 3-point bending test. Equations of curvature and strain were derived from load-deflection curve by applying geometrical relation. An equation was derived for estimating stress from moment and curvature. Finite element analysis was conducted for verifying these equations for estimating stress-strain curve. Deflection of simply supported beam model with rectangular cross-section was calculated for a certain stress-strain relation. The stress-strain relation estimated using the equations showed good agreement with the actual one. We verified that the proposed method for estimating stress-strain relation from the load-deflection curve of 3-point bending test was useful.
