Selecting Suitable Bolt Parameters to Achieve Ductility at Elevated Temperatures

Detailed FE study is presented investigating the factors affecting failure modes of bolt assemblies under tensile force at ambient and elevated temperatures. Axissymmetric FE models incorporate important behavioural aspects including surface interaction and damage modelling of steel at elevated temperatures was developed. The stripping failure is generally undesired because it results in premature failure of the bolt which can deteriorate the rotational capacity of
connections and robustness of steel frames. The paper discusses how thread length in the grip 𝐿t can affect the failure mode of bolt assemblies at elevated temperature. This paper concludes that at ambient temperature, stripping can occur at certain 𝐿􀯧 length depend on the nut dimension deviation from the basic profile, however this length reduces with temperature.