Finite element simulation of bolt-up process of pipe flange connections

Achieving uniform bolt preload is difficult when tightening a pipe flange w ith a number of bolts. Several bolt-tightening strategies have been propose d so far for achieving uniform bolt preloads. It seems, however, that effec tive guidelines for tightening pipe flange connections have not been establ ished. In this study a numerical approach is presented for estimating the s catter in bolt preloads and achieving the uniform bolt preloads when tighte ning each bolt one by one in an arbitrary order. Numerical analyses are con ducted using three-dimensional FEM as an elastic contact problem. The analy tical objects are pipe flanges specified in JIS B 2238 with an aluminum gas ket inserted. Ae validity of the numerical procedures proposed here is asce rtained by experiment.