Numerical and Analytical Modelling of Hat-section Web Crippling Behaviour

Hat-sections of thin-walled steel are subject to a concentrated load and a bending moment at an interior support. For a large concentrated load and a small bending moment, two failure mechanisms can occur: the yield-arc and the rolling mechanisms. Research indicated that the corner radius has a strong influence on the failure mechanism to occur [1-2}. It has been investigated whether small strips of the hat-section cross-sections can be used to gather insight into the differences of the two failure mechanisms. For small corner radii, strip behaviour and section behaviour are comparable. For large corner radii, this is not the case. Finite element models have been used to describe the cross-sectional behaviour of hat-sections for varying corner radii. Relatively simple analytical models have been derived which determine the location of first yield in the cross-section's web and the cross-section's rigid-plastic behaviour. Except for the largest corner radius, analytical models and finite element models give comparable results.