Numerical study on fatigue crack growth of CT specimens treated by laser shot peening
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摘要: 为了研究激光喷丸强化对疲劳裂纹扩展的影响,采用有限元分析软件ABAQUS和MSC.Fatigue相结合,以6061-T6铝合金CT件即紧凑拉伸试样为研究对象,数值模拟其经1次～3次激光双面喷丸处理后的残余应力大小、疲劳寿命、裂纹扩展速率及最终裂纹尺寸。在理论分析的基础上,建立面向抗疲劳制造的激光喷丸工艺有限元分析模型,首先在ABAQUS中模拟出激光喷丸诱导的残余应力场,再将其导入疲劳分析软件MSC.Fatigue进行激光喷丸后疲劳裂纹扩展及其性能的数值模拟分析。结果表明,激光喷丸处理可以有效抑制疲劳裂纹的扩展,降低裂纹扩展速率和增大最终断裂尺寸长度,从而达到延长疲劳寿命的目的,喷丸次数的增加在一定程度上增大了激光喷丸强化的效果,但增益的效果会减弱。这为激光喷丸强化抗疲劳制造的理论分析和后续试验提供了必要的依据。Abstract: In order to investigate the effect of laser shot peening upon the growth of fatigue cracks,definite element analysis softwares,i.e.,finite element analysis code ABAQUS and MSC.Fatigue were used to simulate the distribution of compressive residual stress,the fatigue life,rate of crack growth and the size of final crack with different laser peening times from one to three on compact tension (CT) specimens of 6061-T6 aluminum alloy.Based on theoretical analysis,the forecasting model of fatigue life for laser shot peening (LSP) process was established.The residual stress field induced by LSP was analyzed with ABAQUS code firstly,and then the stress field model was imported into MSC.Fatigue code for the crack growth analysis.It showed that LSP could effectively inhibit the crack growth,decrease the rate of crack growth as well as the size of final crack,and then the fatigue life was extended.The increase of peening times could increase the effect of LSP to some extent.However,the effect gradually became weak.The results afford a foundation for theoretical analysis and experiments about the effect of laser shot peening upon the growth of fatigue cracks.
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Keywords:
- laser technique /
- fatigue crack growth /
- numerical simulation /
- shot peening /
- residual stress
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