Troubleshooting and rectifying structural mechanics problems –- applied mechanics in industry

This paper outlines the general process of troubleshooting and rectifying unexpected structural mechanics problems in industrial plant and infrastructure. Typically the process includes the combination and correlation of site measurements (strain, vibration), and computational simulations (finite element analysis, computational fluid dynamics) to identify root cause sources and guide redesign and rectification means. Details of typical site installations are outlined, including mining machinery, gas pipelines, railway lines, manufacturing plant and ships. Four case studies are included, ranging from resin manufacturing tubular agitators suffering vortex induced resonance, ore grinding mills needing better access manhole design, mine dump trucks, and ship shafting issues

Redesign of Centrifugal Compressor Impeller by means of Scalloping

Case StudyImpellers of centrifugal compressors may experience resonance with vane passing frequencies, especially when operated away from the design conditions. Resonance can cause a serious structural damage to impeller. Complete redesign of an impeller to avoid resonance often requires major changes of the compressor stage design. This case study illustrates alternative approach to redesigning an impeller - scalloping of its coverplate and backplate. Scalloping changes impeller’s natural frequencies and allows achieving a separation margin from resonance, which is sufficient for reliable operation. At the same time, scalloping does not have a detrimental effect on impeller’s performances and allows to maintain existing configuration of compressor stage