SiC/C功能梯度材料的热-应力耦合分析
来源期刊：中南大学学报(自然科学版)2012年第9期
论文作者：蔡艳芝 尹洪峰 袁蝴蝶
文章页码：3408 - 3414
关键词：SiC/C；梯度复合材料；热应力；有限元
Key words：SiC/C; functionally graded materials (FGMs); thermal stress; finite element
摘 要：建立SiC/C功能梯度材料(FGMs)和SiC、石墨直接结合层状材料(无过渡层)的热应力耦合问题的计算数学模型；采用ANSYS10.0有限元分析程序对2类材料的应力场分布进行模拟，获得其在1 000 ℃热载荷下的应力场分布图，并比较二者应力分布状态，以实现SiC/C FGMs组分与结构的优化设计。研究结果表明：SiC/C FGMs比SiC和石墨直接结合层状材料具有显著的缓和热应力的优势，前者的最大应力比后者的小，过渡层数愈多，最大应力愈小，SiC/C-11的最大应力约为后者的1/2；2类材料的应力分布形态均呈轴对称的平行排列的带状，所受应力均在界面层达到极大值，在各层中部达到极小值；随过渡层数增多，应力梯度减小，且沿厚度方向自SiC层至石墨层，界面层应力带愈来愈窄直至消失，界面应力实现最小化，SiC/C FGMs的过渡层数N以≥ 9为宜。
Abstract: The mathematic modes of the thermal stress coupled problem of SiC/C functionally graded materials (FGMs) and the layered material by joining two dissimilar materials of SiC and graphite (without transition layer) were established. The simulated diagrams of stress distribution of these two types of materials under thermal load of 1 000 ℃ were achieved by using finite element method and ANSYS10.0 software. The comparison between their thermal stress distributions was made to realize the optimized design on compositions and microstructures of SiC/C FGMs. The results show that SiC/C FGMs has obvious advantages to reduce thermal stresses compared to the layered material without transition layer. The maximum stress of the former is lesser than that of the latter. The more the transition layers, the lesser the maximum stress. The maximum stress of SiC/C-11 is about one half of that of the latter. The shapes of their stress distribution are parallel bands with axial symmetry. The stress is maximum in the interfaces and minimal in the middle regions of the layers. With the growth in number of the transition layers, the stress gradient decreases, and the stress bands in the interfaces becomes narrower until it narrower and disappears along the thickness direction from the SiC layer to the graphite layer, and the stress in the interfaces achieves the minimum. The optimum transition layer number for SiC/C FGMs is N ≥9.
蔡艳芝，尹洪峰，袁蝴蝶
(西安建筑科技大学 材料与矿资学院, 陕西 西安，710055)
摘 要：建立SiC/C功能梯度材料(FGMs)和SiC、石墨直接结合层状材料(无过渡层)的热应力耦合问题的计算数学模型；采用ANSYS10.0有限元分析程序对2类材料的应力场分布进行模拟，获得其在1 000 ℃热载荷下的应力场分布图，并比较二者应力分布状态，以实现SiC/C FGMs组分与结构的优化设计。研究结果表明：SiC/C FGMs比SiC和石墨直接结合层状材料具有显著的缓和热应力的优势，前者的最大应力比后者的小，过渡层数愈多，最大应力愈小，SiC/C-11的最大应力约为后者的1/2；2类材料的应力分布形态均呈轴对称的平行排列的带状，所受应力均在界面层达到极大值，在各层中部达到极小值；随过渡层数增多，应力梯度减小，且沿厚度方向自SiC层至石墨层，界面层应力带愈来愈窄直至消失，界面应力实现最小化，SiC/C FGMs的过渡层数N以≥ 9为宜。
关键词：SiC/C；梯度复合材料；热应力；有限元
CAI Yan-zhi, YIN Hong-feng, YUAN Hu-die
(College of Materials and Mineral Resources, Xi’an University of Architecture and Technology, Xi’an 710055, China)
Abstract:The mathematic modes of the thermal stress coupled problem of SiC/C functionally graded materials (FGMs) and the layered material by joining two dissimilar materials of SiC and graphite (without transition layer) were established. The simulated diagrams of stress distribution of these two types of materials under thermal load of 1 000 ℃ were achieved by using finite element method and ANSYS10.0 software. The comparison between their thermal stress distributions was made to realize the optimized design on compositions and microstructures of SiC/C FGMs. The results show that SiC/C FGMs has obvious advantages to reduce thermal stresses compared to the layered material without transition layer. The maximum stress of the former is lesser than that of the latter. The more the transition layers, the lesser the maximum stress. The maximum stress of SiC/C-11 is about one half of that of the latter. The shapes of their stress distribution are parallel bands with axial symmetry. The stress is maximum in the interfaces and minimal in the middle regions of the layers. With the growth in number of the transition layers, the stress gradient decreases, and the stress bands in the interfaces becomes narrower until it narrower and disappears along the thickness direction from the SiC layer to the graphite layer, and the stress in the interfaces achieves the minimum. The optimum transition layer number for SiC/C FGMs is N ≥9.
Key words:SiC/C; functionally graded materials (FGMs); thermal stress; finite element
