Theoretical Analysis of a Cotton-Stack Breaker with Curved Pegs: Particle Motion, Peg Deflection, and Performance Estimation

Abstract

Background: Cotton-stack breakers loosen stored seed cotton and transfer it to subsequent processing operations. Their performance depends on the interaction between the rotating drum, its pegs, and the fibrous cotton mass. Objective: To develop a theoretical framework for comparing a conventional straight-peg drum with a proposed drum equipped with curved pegs, and to identify the data needed for experimental verification. Methods: The analysis combines drum kinematics, a linear particle-motion model of a cotton fragment under driving, frictional, and resistance forces, a rotor torque balance, Euler–Bernoulli beam and beam-column models of peg deflection, and a throughput relationship. Results: A corrected closed-form solution of the linear particle-motion model is obtained, together with a steady-state torque condition, a bending-stress design criterion, and a dimensionally consistent throughput expression. Preliminary design estimates indicate higher throughput (35–50 vs 25–35 t h−1), lower specific energy consumption (1.2–1.8 vs 1.8–2.5 kWh t−1), and lower cotton damage (1.5–3 vs 4–7 %) for the curved-peg design. These figures are not supported by a documented test protocol or raw measurements and are indicative only. Conclusions: The framework supports further design calculations and controlled testing of cotton-stack breaker working bodies; the reported advantages of curved pegs remain hypotheses until validated experimentally.