基于有限元模型的三维随机纤维材料微结构设计

Micro-structural Design of 3D Random Fibrous Materials Based on Finite Element Model

为研究三维随机纤维材料服役环境下的力学性能,提高热防护系统安全服役性能和结构寿命。利用有限元建模软件,建立三维随机纤维材料微结构模型,研究其面内和厚度两个方向的三维随机纤维材料宏观力学性能与几何参数(纤维方向、纤维长度和纤维直径)的关系,获得了三维随机纤维材料厚度和面内宏观力学性能演化规律。结果表明:三维随机纤维材料内部偏移纤维比重越大,厚度方向压缩强度就越高,面内方向压缩强度就越低;压缩强度随纤维长度增加呈上升趋势,在0.9 mm左右时达到临界值;压缩强度随纤维直径增加呈下降趋势。该研究结果可为三维随机纤维材料制备提供理论基础。

In order to investigate the mechanical properties of the three-dimensional(3D)random fibrous(RF)materials under the service condition and improve the safe service performance and structural life of the thermal protection system(TPS),a 3D finite element model of 3D RF materials with morphology characteristics was developed based on the finite element modeling software.The macro-mechanical properties of 3D RF materials related with geometric parameters(fiber direction,fiber length and diameter)in the TTT(Through-the-thickness)and IP(in-plane)directions was studied and the evolution law of mechanical properties of 3D RF materials in both directions was uncovered.The results show that the higher rate of sloped fibers in the material is,the higher TTT strength is and the lower IP strength is.As the fiber length increased,the compressive strength of the material increases until the fiber length reaches 0.9 mm.When the fiber diameter decreases,the compressive strength decreases.These results can be applied as the theoretical basis for the material production of 3D RF materials.