杨成鹏
,
矫桂琼
,
王波
无机材料学报
doi:10.3724/SP.J.1077.2009.00919
基于陶瓷基复合材料拉伸试验现象引入了主裂纹损伤带的概念, 并将其宽度定义为界面脱粘长度. 由于界面性能对纤维应力集中有较大影响, 并且控制着材料的断裂模式, 分别给出了脆性断裂和韧性断裂的强度计算公式, 并引入了应力集中系数和界面脱粘能量释放率. 分析结果表明, 拉伸强度随着应力集中系数和界面脱粘能量释放率的增大而减小. 文中公式给出的预测值与试验值吻合较好, 表明断裂时纤维所承担的应力用脱粘段纤维平均应力来衡量是合适的.
关键词:
界面性能
,
ceramic matrix composites
,
stress concentration
,
energy release rate
,
tensile strength
马小明
,
黄志华
机械工程材料
某聚丙烯挤出机在运行中发生螺杆轴断裂,采用断口宏观分析、扫描电镜观察、化学成分分析、显微组织检验、力学性能测试等方法对断裂轴开展失效分析.结果表明:螺杆轴的断裂为扭转疲劳断裂,裂纹起源于花键根部;螺杆轴的疲劳强度低、花键槽根部应力集中、材料内部微孔聚集、材料组织不均匀等原因共同导致螺杆轴发生早期疲劳断裂;建议采取改进热处理工艺、提高安装精度、检查表面缺陷等措施.
关键词:
螺杆轴
,
疲劳断裂
,
组织不均匀
,
微孔聚集
,
应力集中
祝世兴
,
梁媛媛
腐蚀与防护
研究了地板梁上的表面蚀坑尺寸不同时剩余静强度安全系数的变化规律;基于ABAQUS建立了地板梁有限元模型,分析在蚀坑尺寸不同时应力集中系数的变化规律及蚀坑位置对剩余静强度安全系数的影响规律.为地板梁腐蚀损伤修理提供理论依据.
关键词:
地板梁
,
点蚀
,
剩余强度
,
应力集中
,
有限元
Author H.J. Shi1)
,
S.L. Liu2)
,
Y.H. He1) and Z.X. Duan2) 1) Department of Engineering Mechanics
,
Tsinghua University
,
Beijing 100084
,
China2) Laboratory of Material Mechanical Properties
,
Beijing Institute of Aeronautical Materials
,
Beijing 100095
,
ChinaManuscript received 18 October 1998
金属学报(英文版)
A series of low cycle fatigue and creepfatigue tests on smooth specimens and notched specimens were performed with a high temperature alloy used in the manufacture of aeroengine turbine discs. The cyclic stressstrain behavior and fracture characteristics of the notched specimens were emphatically investigated. A comparison of fatigue behavior between smooth and notched specimens was done and lifetime of notched specimens was evaluated. At the same temperature, the fatiguecreep lives of the smooth specimens are far greater than that of the notched specimens.
关键词:
low cycle fatigue
,
null
,
null
,
null
