Fracture mechanism and fault evolution of piston rod in hydrogen reciprocating compressor

Ensuring the reliable operation of reciprocating compressors is critical in the hydrogen industry chain. Piston rod fracture is one of the most serious failures in compressors, which makes it essential to investigate the mechanism of piston rod fracture under normal operating conditions. Here, a multi-body dynamics model was developed to analyse the operating posture and load pattern of the reciprocating assembly. A finite element model was then constructed to calculate the stress distribution of piston rod threads under cyclic tensile and compressive rod load, lateral force and piston drop. The model was validated by visualization of stress distribution via digital image correlation. The study identifies a propagation chain for fault evolution, and explains the mechanisms that induce fracture in cases from a failure source perspective. This work provides new insights into the fault mechanism of hydrogen reciprocating compressors and advances the theoretical framework for compressor condition monitoring and fault diagnosis.