Numerical assessment of bolt-tightening procedures in HDPE-steel flange assemblies

The interaction between elastic materials, particularly when joining materials with vastly different stiffness, such as high density polyethylene (HDPE) pipes and steel flanges, can significantly influence the bolt pre-load and tightness of the bolted joint. This study investigates the impact of elastic interaction on bolt pre-load in assemblies of HDPE pipes and steel flanges, using finite element analysis (FEA). The work compares the Tetra-Parametric Assembly Method (TAM) with the Elastic Interaction Coefficient Method (EICM) to enhance the bolt tightening procedure in such assemblies. FEA simulations reveal that TAM achieves more uniform load distribution and contact pressure compared to EICM. The study evaluates six different configurations, including both 8-bolt and 28-bolt models, highlighting that assemblies involving HDPE and steel exhibit higher elastic interaction and flange rotation than those with only steel components. Key findings include that TAM effectively predicts the behavior of HDPE and steel assemblies. The results indicate that larger sizes and more bolts increase elastic interaction, which is particularly pronounced in cases with HDPE and steel due to the significant stiffness contrast between the two materials. The 30-30-40 tightening rule proves effective for HDPE-to-steel flange connections, suggesting that TAM is a robust method for achieving uniform contact pressure in such assemblies. This research contributes to developing more reliable designs in industrial applications requiring HDPE and steel flange assemblies.