fatigue Analysis of Neuman & Esser Reciprocating Compressor Crankshaft under Cyclic Loading

Abstract

Reciprocating compressors are among the most critical equipment in the oil, gas, and petrochemical industries, with the crankshaft serving as their primary rotating component, subjected to severe cyclic bending and torsional loads. In this research, fatigue analysis of a Neuman & Esser reciprocating compressor crankshaft was performed numerically using the finite element method. A three-dimensional model of the crankshaft made of AISI 4140 steel (quenched and tempered condition) was developed, and fatigue analysis was conducted under real-world cyclic loading conditions. Results revealed that the highest stress concentration occurs in the fillet regions of the main bearing journals and crankpins, where the alternating stress reaches 680–740 MPa significantly exceeding the modified fatigue endurance limit of the material (485 MPa). Based on the S-N curve and the Goodman criterion, the crankshaft fatigue life was predicted to be approximately 800000 cycles, showing excellent agreement with actual operational data from Neuman & Esser compressors in Iranian refineries. This study provides a reliable reference for optimized design, predictive maintenance planning, and enhanced reliability of heavy-duty reciprocating compressor crankshafts.