新的缺口试样尺寸系数经验公式

华南理工大学学报(自然科学版) ›› 2012, Vol. 40 ›› Issue (12): 35-40.

新的缺口试样尺寸系数经验公式

黄宁黄明辉湛利华

中南大学高性能复杂制造国家重点实验室，湖南长沙 410083

收稿日期:2012-06-06 修回日期:2012-10-08 出版日期:2012-12-25 发布日期:2012-11-02
通信作者: 黄宁(1974-) ，男，博士生，讲师，主要从事结构疲劳研究． E-mail:hning_123@sohu.com
作者简介:黄宁(1974-) ，男，博士生，讲师，主要从事结构疲劳研究．
基金资助:
国家"973”计划项目( 2011CB706802) ; 国家重大科技专项( 2010ZX04017-013)

New Empirical Formula of Size Coefficient of Notched Samples

Huang Ning Huang Ming-hui Zhan Li-hua

State Key Laboratory of High-Performance Complex Manufacturing,Central South University,Changsha 410083,Hunan,China

Received:2012-06-06 Revised:2012-10-08 Online:2012-12-25 Published:2012-11-02
Contact: 黄宁(1974-) ，男，博士生，讲师，主要从事结构疲劳研究． E-mail:hning_123@sohu.com
About author:黄宁(1974-) ，男，博士生，讲师，主要从事结构疲劳研究．
Supported by:
国家"973”计划项目( 2011CB706802) ; 国家重大科技专项( 2010ZX04017-013)

摘要/Abstract

摘要： 为了全面分析缺口试样尺寸效应，对两种材料( 45# 和Q235 钢) 的缺口板试样进行循环拉伸作用下的疲劳性能试验．结果显示: 几何相似试样的缺口形状对疲劳寿命影响很小，可以忽略不计; 除应力梯度外存在厚度效应，即该方向尺寸具有一个临界值，超过此值时会导致疲劳寿命下降．通过引入表征尺寸变化对疲劳性能影响的特征参量L /珔G，对几何相似试样的疲劳强度测试结果进行曲线拟合，并与采用Peterson 法得到的计算值比较，发现文中提出的疲劳强度拟合表达式更有效．最后，根据疲劳强度表达式和尺寸系数的定义得到了拉伸作用下缺口试样尺寸系数的经验公式，该公式与实际情况吻合良好．

关键词: 几何相似试样, 缺口试样, 尺寸系数, 梯度效应, 厚度效应

Abstract:

In order to comprehensively analyze the size effect of notched samples,the fatigue performance of notched samples was experimentally investigated for two kinds of materials ( 45# steel and Q235 steel) under cyclic tension. The results show that,for geometrically similar specimens,the effect of notch shape on the fatigue life can be neglected because it is too slight,and that there exists a thickness effect apart from the stress gradient,namely a critical thickness exceeding which the fatigue life may reduce. Moreover,by introducing the characteristic parameter L /G that represents the effect of geometric size on the fatigue performance,the test results of fatigue strength of geometrically similar specimens are fitted and compared with the calculated values obtained by the Peterson method,finding that the proposed fitting expression is more effective. Finally,an empirical formula of size coefficient of notched samples under tension,which well accords with the actual situation,is presented according to the equation of fatigue strength and the definition of size coefficient.

Key words: geometrically similar specimen, notched sample, size coefficient, gradient effect, thickness effect

黄宁黄明辉湛利华. 新的缺口试样尺寸系数经验公式[J]. 华南理工大学学报(自然科学版), 2012, 40(12): 35-40.

Huang Ning Huang Ming-hui Zhan Li-hua. New Empirical Formula of Size Coefficient of Notched Samples[J]. Journal of South China University of Technology(Natural Science Edition), 2012, 40(12): 35-40.