Finite element analysis for adhesive failure of progressive cavity pump with stator of even thickness

• We do finite element simulations to study adhesive failure of even thickness PCP.
• Overlarge shear strain is the primary cause of adhesive failure.
• The simulation results are consistent with the actual adhesive failure cases.
• Two new adhesive methods are presented and validated with finite element analysis.

Compared to conventional progressive cavity pump (PCP), even thickness PCP has numerous advantages such as uniform thermal and swelling expansion, stable operation and high volumetric efficiency. However, adhesive failure occurs on the stator of even thickness PCP more often in actual working conditions, which limits its development and application. In this study, finite element models of conventional PCP and even thickness PCP with the same structural parameters are established and simulated to find the mechanism for adhesive failure. We primarily study the force conditions of adhesive interface which bonds the stator and cylinder sleeve. The results show that shear strain caused by hydraulic pressure difference and interference displacement is quite large around the adhesive interface of even thickness PCP. The too large shear strain around the adhesive interface is the main cause of adhesive failure. Based on this analysis, the relationship between the shear strain and design parameters, such as the rubber adhesion ratio, pressure difference, elastic modulus of stator, magnitude of interference and wall thickness, is investigated. Our results show that the shear strain increases greatly and adhesive failure tends to occur in certain conditions. Furthermore, two new techniques to enhance the adhesive performance are presented and validated with our finite element analysis. Our research can be of great significance for guiding the design and optimization of even thickness PCPs.