考虑曲线铺丝工艺因素的变刚度层合板的失效机理与优化模型研究

Variable-stiffness laminates with curvilinear tows have a strong advantage in designability. The mechanical properties of variable-stiffness laminates can be improved significantly compared with traditional ones. Nevertheless, if the effects of manufacturing factors are not fully considered, the designed variable-stiffness laminates will be likely to lack manufacturability, or the performance improvement may be less than expected. In particular, the design level of variable-stiffness laminates cannot be further improved since the effects of manufacturing factors on the failure mechanism of variable-stiffness laminates are not fully understood, and there is no accurate and reliable failure prediction method yet. The project intends to first study the failure mechanism of variable-stiffness laminates. A high-precision finite element analysis model and a progressive failure analysis method will be established, considering the manufacturing factors of variable-stiffness laminates. The effects of manufacturing factors on failure will be studied through the parametric analysis. Then a fast and reliable layup optimization model based on genetic algorithm and surrogate model will be proposed, aiming at maximizing the initial failure load of variable-stiffness laminates and taking the manufacturing limits as constraint conditions. Finally, the effectiveness of the failure analysis and optimization design methods will be verified by conducting comparative experiments of variable-stiffness and traditional laminates under static tensile and compressive loading conditions.

曲线铺丝的变刚度层合板具有极强的可设计性，其力学性能较直线铺丝的常规层合板有明显提高。但如果在设计时未充分考虑曲线铺丝的工艺因素，就容易导致变刚度层合板的可制造性不足或性能提升效果不及预期。特别是由于制造工艺因素对变刚度层合板失效机理的影响尚不明确，且缺乏准确可靠的失效预测方法，因此阻碍了变刚度层合板设计水平的进一步提高。本项目拟首先开展变刚度层合板的失效机理研究，建立考虑制造工艺因素的变刚度层合板的高精度有限元模型和渐进失效分析方法，并通过参数化分析研究各制造工艺因素对失效的影响。然后以最大化变刚度层合板的初始失效载荷为设计目标，以制造工艺限制为约束条件，采用遗传算法和代理模型技术建立一种快速可靠的变刚度层合板铺层优化模型。最后进行静力拉伸和压缩载荷下变刚度层合板与常规层合板的对比试验，以验证变刚度层合板失效分析和优化设计方法的有效性。

复合材料的可设计性是其与金属材料最重要的区别之一。传统复合材料层合板的纤维都是直线铺放的，取向一般为0°、90°和±45°，因此不能充分发挥复合材料的方向特性。随着自动铺丝技术的日益成熟和发展，目前已可以实现纤维的曲线铺放。曲线铺丝复合材料层合板的面内刚度可以随着纤维铺放路径的改变而改变，从而优化载荷分布情况，达到减轻结构重量、提高承载效率的目的。本项目开展了变刚度层合板的失效机理与优化模型研究，建立了变刚度层合板的高精度有限元失效预测模型，提出了考虑曲线铺丝工艺因素的变刚度层合板铺层快速优化方法。在此基础上，设计并制造了两种不同铺层的变刚度层合板及基准常规复合材料层合板试验件，通过试验验证了变刚度层合板失效分析和优化设计方法的有效性，结合仿真和试验阐明了变刚度层合板的失效机理。试验结果表明，变刚度层合板的最终失效载荷较常规层合板提高了70%以上，有限元仿真分析结果与试验结果基本一致。