脆性材料三点弯曲试样的最大荷载及其挠度和刚度.pdfVIP

第 37 卷 第 6 期 四 川 大 学 学 报 工 程 科 学 版 Vol. 37 No. 6 2005 年 11 月 JOURNAL OF SICHUAN UNIVERSITY ENGINEERING SCIENCE EDITION Nov. 2005 文章编号 2005 0座机电话号码 脆性材料三点弯曲试样的最大荷载及其挠度和刚度 王启智 ,汪　坤 四川大学 建筑与环境学院, 四川 成都 610065 摘 　要 :三点弯曲试样广泛用于测定各种材料的强度 ,断裂能和断裂韧度。利用材料力学和断裂力学原理 ,得到脆 性材料三点弯曲试样的最大荷载及其挠度和刚度的无量纲化显式表达式 ,并给出这些无量纲化力学量的图表 ,揭 示它们随切槽深度变化的规律。两种力学分析方法所得结果基本一致 ,还指出使它们进一步完善的研究方向。验 证和讨论了与文献[6～8 ] 中相应的实验荷载 - 挠度曲线 ,理论与实验结果比较吻合。利用得到的表达式和图表 , 可以鉴别脆性材料荷载 - 位移曲线峰前 最大荷载前 部分所显示的无量纲化最大荷载及其挠度和刚度的变化合 理性 , 以及预测实验时这些力学量随切槽深度变化的情况。 关键词 :脆性材料 ;三点弯曲试样 ;最大荷载 ;挠度 ;刚度 ;无量纲化 中图分类号:O341 ;O346. 1 文献标识码 :A Maximum Load and Its Deflection and Stiffness for ThreePoint Bending Specimens of Brittle Materials WANG Qizhi , WANG Kun School of Architecture and Environment ,Sichuan Univ. ,Chengdu 610065 , China Abstract :Threepoint bending specimens are widely used in testing strength , fracture energy and fracture toughness for various materials. Based on the principles of mechanics of materials and fracture mechanics , explicit formulas , figures and tables of normalized maximum load , its corresponding deflection and stiffness are obtained for threepoint bending specimens of brittle materials. The variation laws of these normalized mechanics quantities with respect to the notch depth are obtained. Basic coincidence for the results of the two mechanics methods is shown , and direction for further improving the analysis is pointed out. The obtained theoretical results are compared with the experimental loaddeflection plots shown in three papers of prestigious journals , favorable agreement of these results is demonstrated. Concerning the nor malized maximum load , deflection and stiffness , the presented formulas , figures and tables can be used to testify the rea sonability of the prepeak loaddeflection curve up to the maximum load for brittle materials , they can also be used to pre dict the variations of these mechanics quantities with respe