ANALYSIS OF THE CONTRIBUTION OF PROTECTIVE BELLOWS ON THE STABILITY OF ALUMINUM FRAMES USED IN PIVOTING JOINT

Abstract

Numerical analysis of protective bellows attached to aluminum frames of pivoting joints is presented in this research. Five aluminum frames connected by protective bellows are attached to the circular rod and have been extracted from the original geometry of passenger bridge used on ocean cruisers. It was assumed that the circular rod was fixed since the main emphasis in the analysis was on the displacements and stresses of aluminium frames, not rods. The main load considered in the analysis was a force of 2,500 N (simulating the mass of 250 kg) acting perpendicularly to three middle frames. Three frames were loaded since it had been estimated that an average person can apply pressure (with his/her body) on a maximum of three frames at once. The mass of 250 kg was used in calculations to ensure the value of safety factor =2.5. Since no data were available about the type of contact between the rod and ends of frames, two approaches were used in the analysis: firstly, contact was considered to be sliding without friction, and secondly contact was considered to be sliding with friction with the value of friction coefficient =0.2. Values of displacements and stresses obtained using finite element analyses (FEA) for both approaches and both positions of frames (firm 0 and max. angle45) are shown and discussed.