Service load analysis and ply stacking optimization for composite tool of aerospace cryogenic tank

Abstract

The integrated manufacturing of aerospace composite cryogenic tanks is crucial for enhancing payload efficiency, reducing costs, and leading the aerospace industry upgrade. Composite segmented tool, which balances internal support and mold surface, must not only meet the requirements of disassembly and demolding but also ensure sufficient stiffness without deformation under loads like winding tension and curing shrinkage during tank formation. This article addresses the challenge faced by composite tool with uniformly thick ply stacking schemes, where the weight increases significantly with the rocket body diameter, rendering functions such as disassembly and demolding unfeasible. A global–local optimization approach aimed at achieving variable‐thickness ply stacking designs for composite tooling was proposed. Starting with a defined segmented tool design for the Φ3.35 m tank, models for calculating winding tension under complex service conditions and finite element models for curing shrinkage were established. Optimization of ply shapes, dimensions, and sequences using OptiStruct was conducted, which achieved a weight reduction of 34.48% while ensuring that deformations under loading met design standards. Subsequently, the engineering trials for the composite melon petal and wallboard corresponding to the Φ600 mm tank were conducted based on the optimized scheme. The maximum deformations for the two components were 0.43 mm and 0.15 mm, respectively, meeting the manufacturing requirements for engineering applications. The results provide a lightweight, high‐stiffness, and detachable tool design scheme for achieving the integrated manufacturing of extra‐large (Φ10 m) composite tanks.Highlights The external load was analyzed through theoretical and simulation approaches. The weight of composite tool was significantly reduced after optimization. The engineering prototypes of the segmented tools were achieved.