Stress–Strain Analysis of S-Shaped Welded Metal Bellows Under Axial Load Based on Finite Element Analysis and Experimental Validation

Abstract

Welded metal bellows are commonly used in mechanical sealing devices. Its properties directly affect the sealing effect, and thus it is very important to study its stress–strain for a high reliability. In this study, to explore the stress–strain state of the diaphragm of welded metal bellows under axial force, based on the elastic mechanics, S-shaped welded bellows of single-layer (SL) and double-layer (DL) with small diameters (D1, size 60 mm) and large diameter (D2, size 95 mm) were used as materials. ANSYS Workbench was used for simulation, and a digital image correlation (DIC) method was carried out for experimental validation. The results of finite element analysis (FEA) showed that the greater the compression, the greater the strain. The DIC analysis showed that the strain increased with the increase of the amount of compression. However, the diaphragm of DL metal bellows showed a lower stress than that of the SL metal bellows. Moreover, the strain of S-shaped welded bellows at larger-diameter was less than at small-diameter. This trend applied to single and double layers. In some layers, the strain showed abrupt changes. The Principal strain was 0.02563 at P6 position of SL-D1 and 0.01333 at P8 position of DL-D1 with compression at 5 mm; while with compression at 4 mm, the Principal strain was 0.0841 at P8 position of SL-D2 and 0.00182 at P6 position of DL-D2. In conclusion, the resistance to elastic deformation of double-layer S-shaped welded metal bellows is better than that of single-layer. Moreover, this study provides a new idea and method for the strain test of S-shaped welded metal bellows.