A Probabilistic Study of the Influence of Hanger Alignment on the Reliability of Refractory Furnace Roof Anchors

A probabilistic fracture methodology was applied to an analysis of refractory anchors used for furnace roof construction. Initially, strength data were obtained from modulus of rupture (MOR) specimens machined from refractory anchors composed of three different materials. For all of the fracture strength tests, the tension side of the MOR specimens was always taken from the as-pressed/fired surface of a sectioned anchor to ensure that the resulting data accurately reflected the strength of the as-used materials. The resulting Weibull data were then used in conjunction with a finite-element stress analysis and probabilistic reliability assessment to determine the influence of the alignment of the metal hangers used to secure the anchors. While all three materials exhibited a vulnerability to brittle fracture under the applied loads, the risk was clearly the highest when the metal hanger was not properly aligned and loads therefore not properly distributed over the entire contact region.