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为研究开缝结构降落伞充气过程的流固耦合(FSI)动力学特性,针对某型空投用开缝救生伞的充气过程进行数值模拟研究。基于参数化设计语言开发了伞衣开缝结构的建模方法,建立了开缝降落伞拉直后的初始折叠数值模型。基于欧拉-拉格朗日罚函数法和多物质ALE(Arbitrary Lagrange Euler)算法,对伞衣周围低速黏性不可压缩流场进行数值求解,二次开发了伞绳材料非线性绳索阻尼模型,预测了气动力作用下的伞衣织物三维结构动力学行为,分析了不同来流速度下降落伞开伞性能,包括伞衣投影面积和充气过载变化,并将伞衣变形仿真结果与空投试验结果进行对比。最后对开缝伞充气过程的流固耦合特性进行了分析,包括伞衣结构变形扰动下周围气流的流场衍变特性及气动力作用下伞衣织物的结构强度。仿真结果表明:伞衣外形变化的3D仿真结果与试验结果相符;开缝伞充气过程并无明显的呼吸现象,且能迅速保持稳定;伞缝区域应力明显高于伞衣平均应力水平,在冲击气流作用下易发生破损现象,应布置加强带;充气过程伞顶出现对称的反向旋转涡对,在气流作用下涡对被逐渐拉伸并不对称直至最后分离脱落。
In order to study the fluid-structure interaction (FSI) dynamics of a parachute inflatable parachute structure, a numerical simulation study was conducted on the inflation process of a parachute parachute with some type of airdrop. Based on the parametric design language, the modeling method of umbrella canopy open structure was developed, and the initial folded numerical model of parachute parachute was established. Based on the Eulerian-Lagrangian penalty function and the Arbitrary Lagrange Euler (ALE) algorithm, the low-viscosity viscous incompressible flow field around the parachute is numerically solved, and the nonlinear rope damping model of the parachute material is developed for the second time. The three-dimensional structural dynamic behavior of the fabric under the action of aerodynamic forces is predicted. The parachute-opening performance under different flow velocities is analyzed, including the projection area of the umbrella canopy and the change of the inflation overload. The simulation results of the deformation of the umbrella canopy are compared with the results of the airdrop test Compared. Finally, the fluid-solid coupling characteristics of the parachute inflatable process were analyzed, including the flow field evolving characteristics of the surrounding air flow and the structural strength of the parachute fabric under the aerodynamic force. The simulation results show that the 3D simulation results of the changes in the shape of the umbrella canopy are in good agreement with the experimental results. There is no obvious respiratory phenomenon during the inflation of the slit umbrella and can be quickly maintained. The stress of the umbrella slit is obviously higher than the average stress level of the umbrella canopy. Under the action of air flow, breakage is easy to occur. Reinforcing belts should be arranged. Symmetrical counter-rotating vortex pairs appear on the umbrella dome during the inflation process. The vortex pairs are gradually stretched and asymmetrical until the final separation and falloff under the action of airflow.