第2期 2018年2月
组合机床与自动化加工技术
Modular Machine Tool &Automatic Manufacturing Technique
文章编号：10012265(2018)02-001205
D0I:10.13462/j. cnki. mmtamt.2018.02.004
喷丸表面粗糙度对疲劳寿命影响研究
王帅，王建明，吕鹤婷
（山东大学机械工程学院CAD/CAM研究所，济南250061）
No.2 Feb.2018
摘要：为研究喷丸处理对铝合金表面粗糙度及其抗疲劳性能的影响，文章提出一种采用数值模拟计算表面粗糙度的方法。首先利用ABAOUS有限元软件建立多丸粒喷丸强化数值模型，将得到的残余应力结果与文献实验结果进行对比以验证该模型的准确性。然后选用轮廊最大高度Rz作为表面粗糙度参数，设计正交试验研究弹丸尺寸、冲击角度、冲击速度和弹丸数量对工件表面粗糙度的影响程度,进而分析喷丸表面粗糙度对应力集中系数和疲劳裂纹萌生寿命的影响。结果表明：四固素对R 的影响程度依次为：弹丸直径>冲击角度>冲击速度>弹丸数量。疲劳裂纹明生寿命受表面粗糙度的影响，但两者间并非一一对应关系。应力集中系数由工件表面粗糙度和弹坑底部曲率率径共同影
响，且两者呈反比关系，即应力集中系数越大，疲劳裂纹萌生寿命越短。关键词：喷丸：粗超度：应力集中系数：疲劳寿命
中图分类号：TH162;TG178
文献标识码：A
Researchfor SurfaceRoughness of Shot-peening Affecting on the Fatigue Life
WANG Shuai, WANG Jian-ming, LV He-ting
( School of Mechanical Engineering, Shandong University, Jinan 250061, China)
Abstract: In order to research to the effects of shot-peening on surface roughness and fatigue life about a-luminum alloy, a shot-peening numerical model with multi pellets was put forward using ABAQUS soft-ware to simulate shot-peening roughness in this paper. The residual stress numerical results were compared with experimental results to verify the model. Then an orthogonal experiment was carried out to study the effects of pellet size, impact angle, impact speed and the number of projectile impact on the surface rough-ness, which chose maximum contour height Rz as the surface roughness parameter. Furthermore, the rela-tionships among shot-peening surface morphology, stress concentration coefficient and fatigue crack initia-tion life were analyzed. The results showed that the influence degree of four factors on Rz in descending order was projectile diameter > angle of impact > impact velocity > number of projectile. Fatigue crack initiation life was indeed affected by the surface roughness, but their relationship was not one-to-one corre-spondence. Stress concentration coefficient was affected by both surface roughness and curvature radius at the bottom of crater. In addition, the stress concentration coefficient was proportional inversely with the fatigue crack initiation life, which meant the greater the stress concentration coefficient, the shorter the fa-tigue crack initiation life
Key words: shot peening ;roughness; stress concentration factor; fatigue life
引言 0
喷丸处理是国内外普追认可的提高结构件抗疲劳性能的表面强化技术[1-3]，受喷工件表面及次表层中存在残余压应力，该残余压应力可部分抵消交变外载荷所产生的拉应力，并对微裂纹形成闭合效应以阻止其扩展，即喷丸残余压应力被公认为是提高工件表面抗
收稿日期：2017-03-14修回日期：2017-04-18*基金项目：国家自然科学基金资助项目（51375267）
疲劳性能的主要强化因素[45]。但喷丸处理不仅得到有利的表面残余压应力层，也会在工件表面留下大量致密的弹坑，使工件表面高低不平，引起表面粗糙度发生变化，在凹凸不平的工件表面谷底处容易引起应力集中和出现微裂纹6，从而对工件抗疲劳性能产生不利的影响，可被视为喷丸对工件抗疲劳性能的弱化因
作者简介：王帅（1992—），男，郑州人，山东大学硕土研究生，研究方向为喷丸强化与计算机辅助工程，（E-mail）xiaoyaowang321@163.com；通讯
考；手建明（1962—），男，济南人，山东大学教授，博士，研究方向为喷丸强化，计算力学，多体动力学，（E－mail）wangjianming@sdu，万发数据