Photoelastic and theoretical analyses of cracked frames

Abstract

Photoelastic and theoretical analyses have been carried out to investigate the effect of cracks on the behaviour of two hinged portal frames subjected to two symmetrical vertical concentrated loads. The distribution of internal shear and normal stresses are obtained at different sections at various crack depth ratio. Also, values of stress intensity factor are obtained based on the measured local stress values.

Based on the present result, an increase in normal stresses occurred at sections far from the crack location and a decrease in stresses occurred at sections close to the crack location. This is due to the fact that a redistribution in internal forces occurred due to crack presence. It is also noticed that a localized shear stress is created in a pure bending zone due to crack presence, the size of this zone is increased as crack size increased. Good agreement is obtained between experimental and theoretical results.