STUDY ON BUCKLING OF CONVEX FILLET WELDED JOINT

In the production of spherical vessels by using single-curvature polyh edron hydrobulging technology, one of the difficulties to be overcome is buckling of a convex fillet welded joint, which can make a polyhedr on fracture along the fillet welded joint during hydrobulging, quality of the spherical vessel bulged from the polyhedron bad. In order to f ind measures to solve the problem, this paper studies the buckling mec hanism of a convex fillet welded joint. It shows that the direct reaso n for buckling is the action of compressive stress along the tangentia l direction of the convex fillet welded joint, and the height of a buc kle increases with the inside pressure of a bulged polyhedron during t he bulging process after buckling occurs. Avoiding a convex fillet wel ded joint forming an enclosed ring or approximately enclosed ring in a section and outside the constant-area sphere of the polyhedron or inc reasing dihedral angle of cover fittet welded joints can decrease the compressive stress along the tangential direction of the convex fillet welded joint. So the measures can prevent buckling from occurring or decrease height of a buckle.