相变固支梁的横向冲击响应的实验和数值模拟研究-工程力学专业论文.docx

any residualdeformationafterimpactdue tothereverse phasetransition,whichdiffersfromtheconventionalelastic-plasticbeamsandplastichinges.3,Theexperimentalstrainsignalsindicatethereisasignificantaxialtensionstressintheendclampedspecimens,whichcausestheasymmetryoftensionandcompressionstrainsofbothsidesatthesamelocationofthebeam.Duetotheaxialtensionstress,aTHformedattheimpactpositionorthefixedendisprobablyasinglesidehingeatthetensileside.4,TheenergyabsorptioncoefficientηofTiNiendclampedbeamsincreasesconsiderablywiththeinitialkineticenergyoftheprojectileE0,whileimpactingwiththesameE0,theηundershortprojectileimpactishigherthanthatunderlongerprojectileimpact.5,ComparingtheexperimentalresultsofTiNiendclampedbeamswith thatofTiNicantileverbeams,theendclampedspecimenshavesmallerdeflectionand shorterinteraction timewith theprojectile,but largeraxialforcethanthatofcantileversunderimpactofprojectileswiththesamelengthandspeed.Inthenumericalpart,theimpactexperimentforTiNiclampedbeammentionedaboveissimulatedbythefiniteelementsoftwareLS-DYNA.Thenumericalresultsrevealthat:1,TheTHformedattheimpactpositionorthefixedendisconfirmeddefinitelyasinglesidehingeatthetensileside.2,Undertheimpactofprojectile,theload-displacementcurveofTiNiclampedbeamcouldbedividedintoseveralstages,thatis,impactfluctuation,loadhardening, Ⅱphaseelasticstage,unloadlinear,unloadplateauandunloadcompleted.3,Theregularevolutionofmartensiticpercentagecorrelatescloselywiththeimpactresponseofbeam.4,ThedynamicresponseofTiNiclampedbeamisdecidedbyloadingcondition,geometryandsoon.5,TiNiclampedbeamdissipateenergyviamarstensitictransformation, however,whentheinputenergyisuptosomedegree,theenergyabsorptionissaturated.Keywords:Phasetransitionbeam,Pseudo-elastic,Transformationhinge,Martensitefraction,Transversalimpact,Axialforce,Clampedendcondition,Energydissipationrate中国科学技术大学学位论文原创性声明本人声明所呈交的学位论文,是本人在导师指导下进行研究工作所取得的成果。除已特别加以标注和致谢的地方外，论文中不包含任何他人已经发表或撰写过的研究成果。与我一同工作的同志对本研究所做的贡献均已在论文中作了明确的说明。作者签名：签字日期：中国科学技术大学学位论文授权使用声明作为申请学位的