Engineering paper tubes to improve winding performance of various materials

Abstract

Over the past 10 years, Sonoco has conducted fundamental, solid mechanics research concerning structural behavior of spirally wound paper tubes. The scope of this program has included experimental, numerical, and analytical mechanics approaches as documented in references (1-7). For recent non-linear finite element research, we have used ABAQUS and developed user-defined material subroutines. These subroutines feature a proprietary 3D constitutive model for paperboard. The model uses non-linear stress-strain properties of Sonoco paperboard measured in 3 principle directions. An important research objective is to develop innovative tube designs that enable our customers to improve their winding operations. To achieve this objective, we have developed several patented test devices that measure tube properties fundamental to winding applications. Tests to measure core radial stiffness on the inside and outside (Ec) with respect to an external pressure and radial strength have been developed. This paper describes the test methods and presents data to verify mechanics research findings by way of two core applications. These are examples of where cores were engineered using mechanics technology to improve winding capability: (1) development of an extremely high Ec core for winding low friction, coated aluminum, and (2) cores for winding textile yarns based on radial stiffness of inside diameter.