Model investigation of conoidal shell

Abstract

This report presents a method for fabrication of a conoidal shell model. Moreover the experimental investigation on this model regarding deflection and stress distribution is presented. The aim of the study was to investigate the stress pattern. deflection and overall behaviour of the conoidal shell model at service (design) load level and also at higher load levels. The study includes the comparison of the test results with those available in literature. The test results show that bending moment developed throughout the shell body in addition to the membrane stress resultants. The location of maximum bending moment was near the interfaces of the shell and the edge members. Stress condition near the low end diaphragm was significant. The entire'shell bOdy remained in compression and no tension developed under loading conditions. The deflections were found to be .small at the service load level. The measured compressive stresses were.well below the allowable compressive strength of the constituent materials. moreover,the measured stress resultants were comparable with those obtained from the membrane analysis. From the model testing no crack was observed at s~rvice load level and only a few hair line cracks were observed at the edges of the shell at double the service load. It was thus observed that in the conoidal shell model (which was designed on the basis of membrane analysis) bending moment of small magnitude developed under service load condition. Moreover, the membrane stresses were comparable to those obtained by membrane analysis.