Laser micromachining for fatigue and fracture mechanics applications
Laser micromachining for fatigue and fracture mechanics applications
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DOI：
10.1016/j.optlaseng.2009.09.003
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发表时间：
2010-04
影响因子：
4.6
通讯作者：
M. Gupta;B. Li;S. Gadag;K. Chou
中科院分区：
文献类型：
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作者：
M. Gupta;B. Li;S. Gadag;K. Chou
激光微加工（LMM）的方法，以启动疲劳和断裂力学应用的缺陷成功地证明。采用能量积分法，结合温度相关的热物性参数和三维传热程序，对钛合金（Ti-3.5Al-2.5V）激光熔凝过程中移动能量脉冲的动态响应进行了数值模拟。采用非线性有限元分析（FEA），对外径（OD）为9.53 mm、壁厚（WT）为0.81 mm、纵向激光微加工切口为0.23 mm、长度为1.83 mm的钛管进行应力和应变分析。为了比较，放电加工（EDM）的缺口管与激光制备管相同的缺口轮廓也进行了研究。当R比为0.03，ΔP=45、50和55 MPa时，计算得到的电火花加工管缺口根部的环向应力和应变幅值分别约为激光加工管的64%和63%。采用LMM方法可以最小化裂纹萌生过程引起的疲劳寿命。因此，所描述的LMM方法比EDM更适合于完成裂纹形成以研究各种材料的疲劳和断裂行为。
A laser micromachining (LMM) method to initiate flaws for fatigue and fracture mechanics applications is successfully demonstrated. Dynamic response of moving energy pulses during LMM of titanium alloy (Ti–3.5Al–2.5V) was numerically simulated by an integrated energy approach using temperature-dependent thermophysical properties and 3D heat transfer code. Stress and strain analyses were performed for a titanium tube of 9.53mm outer diameter (OD) and 0.81mm wall thickness (WT) with a 0.23mm deep and 1.83-mm-long longitudinal laser micro-machined notch, using nonlinear finite element analysis (FEA). For comparison, an electric-discharge-machined (EDM) notched tube with the same notch profile as the laser-prepared tube was also investigated. The calculated hoop stress and strain amplitudes at the notch root of the EDM-prepared tube were approximately 64% and 63% of the stress and strain amplitudes in the laser-prepared tube, respectively, when two tubes were subjected to inner pressures for R ratio of 0.03 and ΔP=45, 50, and 55MPa. Fatigue life due to crack initiation process can be minimized using LMM method. The described LMM method is, therefore, more appropriate than EDM for accomplishing flaw formation to study fatigue and fracture behavior of various materials.