Application and limitations of the flexural creep test for polymeric materials

Application and limitations of the flexural creep test are described. For this purpose six different thermoplastic materials are tested under low and moderate stress and temperature conditions. The log-log method and a nonlinear creep compliance is used to analyze and compare the data. In order to assess the applicability range of elementary small deflection theory in calculation of strain values, a large deflection analysis is performed. This analysis indicates the presence of an instability condition. Design curves are drawn to reveal the percentage difference between the deflection values obtained on the basis of small and large deflection theories.