Abstract:The finite element model of the packer rubber was established and the deformation process of the rubber was simulated.The hydrogenated nitrilebutadiene rubber(HNBR) material was selected to analyze the stability of free deformation and constrained deformation stages.Under different ratios of height to diameter,the requiring the minimum load during the free deformation stage to make the rubber and the sleeve contact,and the load making the deformation of the rubber from unstable to stable during constrained deformation stages were investigated with HNBR,nitrilebutadiene rubber(NBR),fluorine rubber(FKM),and Polyurethane rubber(PU) as the materials of packer rubber.The results show that the difference of the heighttodiameter ratio and the materials will result in stable and unstable deformation of the packer rubber during the free and constrained deformation stages.Under different heightdiameter ratios,the effect of materials difference on the change trend of the minimum load during the free deformation stage to make the rubber and the sleeve contact,and the load making the deformation of the rubber from unstable to stable during constrained deformation stages is not significant,but it has a significant effect on the load.Among the four materials,PU can obtain the highest minimum load during the free deformation stage to make the rubber and the sleeve contact,and the highest load making the deformation of the rubber from unstable to stable during constrained deformation stages,followed by HNBR,NBR and FKM.When the heighttodiameter ratio of HNBR and NBR is less than 1234,and the heighttodiameter ratio of FKM and PU is less than 1225,the unstable deformation of the rubber tube does not occur.