Abstract: The critical influential factors of axial load uniform distribution in bolted joint are explored by theoretical analysis and numerical simulation. Firstly， theoretical analysis was done toward the axial load distribution of the bolted joint. An analytical method of confirming the axial load distribution by using the relationship between axial load per unit length F and relative deformation u is proposed. Besides， the result of theoretical analysis shows that the axial load distribution is more uniform when the shape of F-u curve presents yield-type. Secondly， through the analysis on Spiralock thread， the shape of F-u curve is also observed as yield-type. Then the mechanics mechanism for the Spiralock thread having better distribution uniformity is clarified from three aspects: tooth design， material plasticity and thread slip. Lastly， the factors， such as radial dimension coefficient， friction coefficient and material elastic modulus ratio which affect the load distribution are systematically studied.

Key words: bolted joint, load distribution, uniformity, Spiralock thread, finite element analysis