基于树脂流动的变截面复合材料结构固化过程热-流-固多场强耦合数值仿真

在考虑树脂流动对固化温度场影响的基础上，将树脂流动引入经典热-化学模型，并在考虑了固化过程材料性能时变特性条件下，建立了复合材料热-流-固多场强耦合有限元模型。通过对比文献中未考虑树脂流动对温度场的影响，本文所建模型温度场较实际结果的最大温差更低，厚度密实精度更高，模型可靠性更好。基于所建热-流-固强耦合有限元模型，对变截面复合材料结构固化过程进行数值仿真。研究发现，变截面复合材料结构较厚区域存在明显温度场、固化度场及树脂流场分布梯度，纤维体积分数分布不均性较大，这与结构不同区域的厚度、固化过程温度传递滞后及局部树脂流动受固化效应不同步产生的影响有关。变截面复合材料结构厚度由3.52 mm增加至42.24 mm，截面最大温差由0.3℃增加到34.3℃，纤维体积分数分布不均匀性由0.1%增加到1.3%。

Numerical simulation of heat-flow-solid multi-field strong coupling in curing process of variable cross-section composite structures based on the resin flow

On the basis of considering the influence of resin flow on the curing temperature field, the resin flow was introduced into the classical thermo chemical model. In addition, in consideration of the time-varying characteristics of material properties during curing process, the heat-fluid-solid multi-field strongly coupled finite element model was established. It can be found through the comparison with the references in which the effect of resin flow on the temperature field is not considered, the maximum temperature difference is lower, the thickness accuracy is higher, and the model reliability is better. Based on the established heat-fluid-solid strongly coupled finite element model, the curing process of composite structure with variable thickness section was numerically simulated. It is found that the obvious distribution gradient of temperature field, curing degree field and resin flow field exists in the thicker composite structure, and the distribution of fiber volume fraction is uneven. This is related to the structure thickness, the temperature transfer lag of different zones and the influence of the local resin flow on the effects of curing. With the thickness of variable cross-section composite structures increasing from 3.52 mm to 42.24 mm, the maximum temperature increases from 0.3℃ to 34.3℃, and the nonuniformity of the fiber distribution increases from 0.1% to 1.3%.