Tension system design based on heated-mandrel winding process

Heated-mandrel winding is the main process of modern composite material molding because of its characteristics of winding and curing in one step. Winding tension is a key factor in the molding process and has an important impact on the molding effect. Excessive winding tension will cause the inner looseness and outer tightening, and too small winding tension will cause the outer looseness and inner tightening. In short, the stratification will occur during the curing as long as the winding tension value is not set properly, which will seriously affect the molding quality of composite materials. The tension system of single winding process is difficult to apply to the heated-mandrel winding process because winding and curing are separate in the traditional single winding process, there is no need to consider the diversification of parameter state caused by curing reaction in winding process. In the heated-mandrel process, the balance of forces between adjacent layers is broken, the stress changes in adjacent layers affected by the temperature field are considered during winding. The tension values are obtained by adopting the tension system model established in this paper and the traditional finite element iterative search calculation method is replaced by numerical analysis method. An analytical algorithm for the method of winding with tension as the interference fit of the thin layers is adopted in the calculation procedures and the nonlinear tension solution problem is converted into a linear displacement-stress calculation problem. The lengthy and complicated traditional tension calculation method is simplified.