Journal of Engineering Research and Reports

Aims: This study aims to conduct a comprehensive static analysis and lightweight multi-objective optimization of the spiral sorting device (auger) used in coal mine roadway concrete pavers. The primary objective is to fundamentally enhance the economic efficiency, structural reliability, and operational stability of the equipment under the harsh, confined, and demanding underground environments typical of modern coal extraction facilities.

Study Design: A rigorous numerical computational design combining advanced Finite Element Analysis (FEA) and statistical Response Surface Methodology (RSM) was deployed to systematically evaluate and optimize the mechanical structure.

Methodology: Initially, a rigorous mesh independence verification was discussed to ensure the absolute accuracy and computational efficiency of the numerical solutions. Subsequently, a  detailed static analysis was performed by fixing both ends of the spiral shaft to simulate bearing constraints, applying a substantial surface load of 15000 N on the active faces of the spiral blades to simulate concrete resistance, and subjecting the spiral shaft to a driving torque of 573 N·m. Building upon the baseline static analysis results, a central composite design (CCD) was employed to construct a  accurate mathematical response surface model. The spiral shaft diameter and blade thickness were selected as independent design variables, while the total structural mass, maximum total deformation, and maximum equivalent stress were established as the targeted objective functions. Finally, a Multi-Objective Genetic Algorithm (MOGA) was utilized to navigate the complex design space for global optimal searching based on Pareto efficiency.

Results: The initial comprehensive static analysis indicated that the maximum equivalent stress of the spiral sorting device was intrinsically located at the root of the blade, peaking at 126.46 MPa. Concurrently, the maximum deformation was recorded at 1.2891 mm at the outermost blade tip. Both baseline values fully met the rigorous safety design requirements. Detailed sensitivity analysis subsequently revealed that the spiral shaft diameter possessed the most significant dominant impact on both total mass and structural deformation, whereas the blade thickness exerted a more pronounced, localized influence on the stress distribution at the blade roots. Through extensive MOGA optimization iterations, the optimal geometric parameters were mathematically determined and engineering-rounded to a shaft diameter of 44 mm and a blade thickness of 4 mm. Consequently, the mass of the newly optimized device was remarkably reduced from an initial 28.411 kg down to 23.056 kg. Simultaneously, the maximum stress increased to 196.56 MPa and the maximum deformation shifted to 2.4121 mm, both of which dynamically remain strictly and safely within the allowable physical limits of the selected material.

Conclusion: The optimized design strategy successfully and significantly reduced the unnecessary dead mass of the spiral sorting device, achieving the coveted lightweight construction without compromising the essential structural strength and operational stiffness. This in-depth research provides a solid theoretical foundation, robust numerical validation, and a practical engineering reference for the future development, upgrading, and manufacturing of intelligent paving equipment operating under severely constrained underground conditions.