14713

13242

كارشناسي ارشد

طراحي كاربردي

اصفهان : دانشگاه صنعتي اصفهان

1398

پانزده، 145ص.: مصور (رنگي)، جدول، نمودار

رضا جعفري ندوشن

سعيد ضيايي راد

محمد مشايخي، مهدي جوان بخت

1398/04/11

كتابنامه

مهندسي مكانيك

مهندسي مكانيك

1398/04/12

2545292

146 Experimental study and modeling of damage in dual phase steel using micro scale approach Mostafa Azizi Sales Mostafa azizi@me iut ac ir Date of Submission 2019 06 24 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Reza Jafari Nedoushan rjafari@cc iut ac irAbstractFerritic Martensitic dual phase steel has good strength and ductility due to the hardness of Martensite andsoftness of Ferrite phases This property has led to the widespread application of the current steel in variousindustries especially for automotive industry Among the several manufacturing methods for the productionof dual phase steel Rolling is one of the most common method to manufacture this type of steel due to itsquality improvement and economic efficiency It is expected from this kind of manufacturing that a portionof produced steel granules to be appeared in the stretched or banding form Nevertheless investigation ofthe damage of dual phase steel in the banding form is one the subject that has been rarely considered byresearchers Therefore the purpose of this thesis was to investigate the damage of this type of steelexperimentally and by computer simulation In this regard the micro structure of the dual phase steelDP600 was investigated in different planes According to the laboratory observations indicating that themicrostructure of this type of steel is granular and banding in the RD TD and RD ND planes respectively thus the damage mechanisms in the each of these planes has been investigated by uniaxial tension ofspecimen in various directions For this purpose the prepared surface of specimen before and afterdeformation was analyzed by field emission scanning electron microscopy FESEM Observations showeddifferent damage behavior in RD TD and RD ND planes Ferrite Martensite interface decohesion in firstplane and Ferrite Martensite interface decohesion and Martensite Cracking in second plane arepredominating damage mechanism In addition to the aforementioned damage mechanisms the damagemechanism of Ferrite placed between the Martensite granules has also been observed for both of the planes Moreover the damage in the Ferrite is observed in the first plane In the following the micro structure ofthis type of steel has been simulated and investigated by ABAQUS In this simulation the damage ofFerrite was modeled according to the GTN damage model The approximate value of the fracture stress ofMartensite was also obtained according to the literature for the modeling of damage in Martensite Resultsobtained from simulation had acceptable agreement with experimental data Therefore it can be concludedthat the damage of dual phase steel would led to wrong results in the analysis only from above plane i e RD TD So for the comprehensive investigation of damage in this type of steel the micro structure shouldbe investigated in the both of the planes i e RD TD and RD ND Also an in situ tensile set up wasdesigned in this project for the installation under the optical microscope Keywords Dual Phase Steel Banding Microstructure Simulation of Microstructure GTN DamageModel Frecture of Martensite

رضا جعفري ندوشن

سعيد ضيايي راد

محمد مشايخي، مهدي جوان بخت