目录摘要........................................................1Abstract.....................................................2第1章绪论..................................................31.1激光增材制造技术的简介................................31.2LENS成形金属零件的国内外研究现状......................41.3LENS成形金属零件存在的问题以及解决措施...............61.4本文研究思路..........................................7第2章有限元热分析理论基础与模型建立........................82.1有限元传热理论模型.....................................82.2有限元热弹塑性理论模型.................................92.3物理模型建立..........................................112.3.1模型假设...........................................112.3.2结构单元的选择.....................................122.3.3材料热物性参数.....................................122.3.4几何模型的建立与网格划分............................132.3.5激光热源模型........................................132.4采用ANSYS的关键技术.................................142.4.1生死单元法..........................................142.4.2激光热源模型的加载.................................15第3章LENS熔覆层温度场及应力场计算分析.....................163.1正交实验法的介绍与设计................................163.2温度场模拟计算.......................................173.3应力场模拟计算.......................................203.4正交实验结果的分析与讨论.............................213.5优化结果的验证与分析.................................25第4章结论.................................................29参考文献....................................................30致谢........................Error:Referencesourcenotfound2摘要激光近净成形技术（laserengineerednetshaping，LENS）是增材制造中具有代表性的一种先进制造工艺，可以制造具有复杂结构和性能优异的金属零件。然而，利用该技术在成形金属零件时，由于局部急冷急热的特点，会在成形零件内部出现较大残余应力，进而影响零件的力学性能与精度。因此探索如何减小残余应力在激光增材制造领域中具有重大的研究意义。本文利用ANSYS软件模拟LENS成形金属零件的过程，并对成形过程中的温度场和应力场进行分析。采用正交实验法来探究激光工艺参数（如：激光功率，扫描速度与光斑直径）对残余应力的影响规律，并且研究各个参数对残余应力的影响权重，最后找出最优参数。得到最优的参数组合是：激光功率1000w，扫描速度5mm/s，光斑直径2.5mm，此时熔覆层上的残余应力为192MPa。关键字：增材制造，LENS，数值模拟，正交实验AbstractLaserengineerednetshaping(LENS),whichisasatypicalrepresentativeofadditivemanufacturing,canfabricatemetalpartswithcomplexstructureandfineproperties.However,theresidualstressinthemetalpartswillbeproducedinmanufacturingprocessduetothefeaturesoflocalhightemperatureandfastcoolingrate,whichwillhaveabadeffectonthemechanicalpropertiesandprecisionofmetalparts.Therefore,itisimportanttoexplorehowtoreduceresidualstressinmetalparts.ANSYSsoftwarewasusedtosimulatetheLENSprocessofmetalpartsanditstemperaturefieldsandresidualstressfieldswerealsoinvestigated.Adoptingorthogonalexperiments,theeffectsoflaserparameterssuchaslaserpower,scanningspeedandspotdiameterontheresidualstressdistributionsincladdinglayerswereanalyzedandtheinfluenceweightofdifferentparameterswerealsoexplored.Accordingtotheresults,thebestparameterscombinationwaslaserpower1000w,scanningspeed5mm/sandspotdiameterwas2.5mm,whichcanleadtotheminimumresidualstress(192MPa)inmetalpartsdepositedbyLENS.Keywords:AdditiveManu...
