Session: CT-11-01 Computational FEA for Limit Load and Elastic-Plastic Analysis and Creep

Paper Number: 151435

151435 - Innovative 3D FE Modeling of Mechanical Rolling in Tube-to-Tubesheet Joints: A Comparative Analysis with Hydraulic Expansion 

Abstract: 

Since its emergence, mechanical rolling of tube-to-tubesheet has provided reliable joint integrity for many industrial applications. Over the years, researchers have dedicated extensive studies to the various aspects and parameters influencing the reliability of tube-to-tubesheet joints expanded by the mechanical rolling process. These investigations have highlighted the critical importance of several factors, including the tube-to-tubesheet contact friction, the tubesheet thickness, the spring back of the tube after rolling, the ratio of the tube’s outer radius to its wall thickness, the ratio of the pitch to the tubesheet hole diameters, and ultimately the materials of the tube and tubesheet. Each of these variables plays a pivotal role in determining the strength and durability of the joint, which is essential for safe and efficient industrial operation.

Despite the considerable technological and industrial advancements over the past decades, mechanical rolling remains the process of choice for many industries. This is largely due to its short preparation time, ease of application, and relatively low cost compared to alternative expansion methods. In this paper, an innovative 3D modelling of mechanical rolling is presented to shed light on this complex process and its impact on the integrity of the tube-to-tubesheet joint. Two models are investigated; the first one is with three rollers sliding on the tube inner surface, and the second one is with three rollers spinning on the tube inner surface in order to cover the two possible cases reported in the literature while being in line with industrial applications. The sliding scenario was examined as it is a likely occurrence during mechanical rolling, where the rollers become lodged inside the mandrel and are unable to rotate as intended. The investigation not only explores the complex nature of the mechanical rolling but also highlights the potential limitations and challenges that arise in real-world. applications.Furthermore, three metrics: residual contact pressure, pull-out force and wall thinning obtained from the mechanical rolling modelling have been compared with their hydraulic expansion counterparts obtained from analytical modeling proposed in the literature and finite element modeling. The results indicate that hydraulic expansion improves joint integrity by providing higher residual contact pressure for low and medium tube ID expansions. For higher tube ID expansions, the sliding model generates higher residual contact pressure. Nonetheless, the wall thinning at this expansion level shows that the joint integrity is compromised due to significant deformation and dentation. In both scenarios, spinning rollers yield lower integrity and demand greater roller thrust, which is the real case in the industry. However, the wall thinning is less significant in hydraulic expansion.

Presenting Author: Mohammad Pourreza ETS Montreal

Presenting Author Biography: Mohammad Pourreza is a PhD candidate at the École de technologie supérieure (ETS) in Montreal. He is a senior mechanical engineer at WSP Canada with over 17 years of experience across various industries, including oil and gas, petrochemicals, mining, and water treatment. Mohammad specializes in finite element analysis (FEA) of static equipment and flexibility analysis of piping systems.

Authors:

Mohammad Pourreza ETS Montreal
Hakim Bouzid ETS
Khaled Benfriha Arts et Metiers Institute of Technology, HESAM University