Research Of Finite Element Simulation For Conical Shell Subjected To External Pressure

The conical shell is an essential part of pressure vessel, it is important to keep the conical shell safe and reliable operation. Simplify the cone into their equivalent cylinder in engineering design, ASME Ⅷ-1, ASME Ⅷ-2, EN13445-3adopted different equivalent rules. The stiffening rings position for cylinder more intuitive than cone because of the large end and small end of the cone geometry asymmetry, the effective strengthen range for cylinder is0.55(?), there is no relevant rules about the position and the effective strengthen range of stiffening rings for cone. Differences between the each standard about external pressure calculated length for cylindrical-conical shell. The minimum required area for cylindrical-conical junction in ASME Ⅷ-1is derived from the Farr theory, didn’t consider the possible strengthening of conical shell, EN13445-3consider cylindrical-conical junction as support line when α≥30°. The existing conventional design standard about the design of conical shell come from theoretical derivation or empirical formula. Many scholars using the finite element numerical simulation technology to study the stability of cone with the rapid development of numerical simulation technology.Research engineering design problems for conical and cylindrical-conical shell subjected to external pressure with finite element simulation.The main work of this research can be summarized as follows:1. The equivalent rules for cone in each standard (GB150, ASME Ⅷ-1, ASME Ⅷ-2, EN13445-3) are discussed. Synthesize theory sources of design methods for conical and cylindrical-conical shell. Analysis the similarities and differences of rules in each standard.2. Research the equivalent method and the effective strengthen range of stiffening rings for cone with finite element simulation. The relationship between correlation coefficient ρ and taper ratio λ, taper angle α, boundary condition are obtained. The results of simulation show that the degree of stress attenuation is different on both sides of the stiffening rings for cone, using0.55(?) calculate the effective strengthen width is feasible when considering the simplicity of engineering calculation.3. The stiffening rings position for conical shell subjected to external pressure with finite element simulation combined with the equivalent method and the equivalent method Ⅱ are researched in detail. A simple solution for the best position of stiffening rings is proposed based on equivalent method Ⅱ. Results show that the best supporting position for stiffening rings k is relevant to taper ratio λ and the best position of supporting k (or values of k1and k2) increase with the rise of taper ratio. The best support position k value from the above-mentioned three methods is similar to each other. The results from the equivalent method and finite element simulation method are relatively close.4. The calculated length for cylindrical-conical shell of ASME Ⅷ-1and EN13445-3are discussed, one equivalent method II of cylindrical-conical shell is presented in order to optimized calculated length. Results show that consider cylindrical-conical junction as support line is feasible when α≥30°, consider small end of flanging as support line is feasible when cylindrical-conical junction is flanging. The calculated length for cylindrical-conical shell takes value L=Lcyl+Le is feasible when α<30°.This paper research engineering design methods for conical shell with finite element simulation, including the equivalent method and the equivalent method II, the position and the effective strengthen range of stiffening rings for conical, the calculated length for cylindrical-conical shell, the results provide some evidences for conical shell engineering design.