A study on the stress distribution in coil wrapping and its effect on final coil deformation

Excessive coil deformation can hamper the normal operation of coil handling and bring difficulties in mass production. Experiences and previous researches have identified four critical factors: i.e., radial stiffness of coil material, winding tension, stiffness of core which supports the coil, and lubrication. In this paper, we advance our understanding of coil deformation by developing both linear and nonlinear models to predict the stress distribution in a coil during/after winding process and using a multi-layer equivalent model to study the coil deformation under gravity load. Using the proposed framework, the contribution of each factor to the coil deformation can be quantified and therefore provide scientific assistance in the engineering decision making process.