针刺密度对碳/碳复合材料力学行为影响的仿真分析  

Effects of Needle Density on Mechanical Behavior of Carbon/Carbon Composite

作　　者：董洪年 杨明 林天一 陈沛然 魏婷婷 DONG Hongnian;YANG Ming;LIN Tianyi;CHEN Peiran;WEI Tingting(Shanghai Space Propulsion Technology Research Institute,Shanghai 201108,China)

机构地区：[1]上海航天动力技术研究所,上海201108

出　　处：《材料导报》2025年第9期52-57,共6页Materials Reports

基　　金：装备预先研究共用技术项目(50920020101)。

摘　　要：针刺工艺参数的优化控制,对综合改善碳/碳复合材料的力学性能至关重要。发展基于仿真技术的“虚拟现实试验”方法,可快速、并发地优选出最优的针刺工艺参数组合方式。本工作建立了不同针刺密度(25针/cm^(2)、36针/cm^(2)、64针/cm^(2)和100针/cm^(2))下的针刺碳/碳复合材料单胞模型,并分别将最大应力准则和Hashin失效准则应用于网胎层和无纬布层的失效分析中,结合周期性边界条件,分析得到了针刺密度对碳/碳复合材料损伤失效模式及力学行为的影响机制。研究发现:随着载荷的增加,无论是网胎层,还是无纬布层,裂纹都萌生于针刺纤维束的圆周边界,且裂纹呈现出与加载方向成近±45°的“十”字交叉型式。对于高针刺密度的碳/碳复合材料,由于针刺纤维束对其面内造成的损伤区域占比更高,使其更容易出现垂直于加载方向的横向裂纹损伤,从而削弱了材料的承载能力。相比于25针/cm^(2),针刺密度为36针/cm^(2)、64针/cm^(2)和100针/cm^(2)的碳/碳复合材料,其断裂强度分别下降了约3%、5%和19%。此外,割线刚度退化结果表明,在失效前,针刺碳/碳复合材料的力学行为表现出了一定的非线性。这主要是由拉伸开裂过程中的渐进损伤所引起的。本工作所建立的仿真模型可用于指导针刺碳/碳复合材料预制体构型的优化设计。The optimal control of needle punching process parameters is very important to improve the mechanical properties of carbon/carbon compo-site.The development of“virtual reality test”method based on simulation technology can quickly and concurrently optimize the optimal combination of needle punching process parameters.In this work,the unit cell model of needle-punched C/C composites(NP C/C)with different needling densities(25 pin/cm^(2),36 pin/cm^(2),64 pin/cm^(2) and 100 pin/cm^(2))is established,and the maximum stress criterion and Hashin failure criterion are applied to the failure analysis of fiber web layer and weft-free layer,respectively,based on the periodic boundary condition.The mechanism of the influence of the needling density on the damage failure mode and mechanical behavior of NP C/C is analyzed.It is found that with the increase of loading,the cracks first appear at the circumferential boundary of the needle-punched fiber bundle in both the fiber web layer and the weft-free layer.Moreover,the cracks appear a“Cross”type which is nearly±45°with the direction of loading.For C/C composite with higher needled density,the proportion of damage area caused byneedle-punched fiber bundles is higher,making it more prone to transverse cracks perpendicular to the loading direction,thereby weakening the material’s load-bearing capacity.Compared to 25 pin/cm^(2),the fracture strength of NP C/C with needle density of 36 pin/cm^(2),64 pin/cm^(2),and 100 pin/cm^(2) decreases by 3%,5%,and 19%,respectively.In addition,the results of secant stiffness degradation indicate that the mechanical behavior of NP C/C exhibits non-linearity before failure.This is mainly caused by progressive cracking damage during the tensile process.The model established in this paper can be used to guide the optimal design of the preform of NP C/C.

关 键 词：碳/碳复合材料 针刺 工艺参数 单胞 力学性能 

分 类 号：TB332[一般工业技术—材料科学与工程]