Formability study of layered material based on numerical analysis
INDUSTRIAL DEFINED PROBLEM ONFormability Study of Layered Material Based on Numerical Analysis Submitted by: Name Roll no: 1. Majiwala Hardik 8436 2. Mistry Vikram 8440 3. Patel Ankur 8453 4. Patel Ashish 8454 Guided by: DR. ANISH H. GANDHI C.k.pithawalla college of engineering and technology, surat.
PROBLEM SUMMARY Components press formed from layered or laminatedmetallic materials have wide engineering applications inaerospace, automobile, electrical, electronic and processindustries. High strength ferrous material are widely used inautomobile and aerospace applications for improvingstrength to weight ratio. Forming of high strength materials is difficult.Formability of high strength ferrous materials can beimproved by applying the layering of the higher formabilitymaterials. But to fabricate the layered/laminated blanks it-self is achallenging issue. Further, metal forming mechanics oflayered or laminated materials is complex to understand &development of analytical models for studying and analyzingthe forming mechanics of such materials is difficult.
• If bending is considered as one of the metal forming process in sheet metal forming industries then, the prediction of springback is most important technical issue. What is Springback ? Condition that occurs when a flat-rolled metal or alloy is cold- worked; upon release of the forming force, the material has a tendency to partially return to its original shape because of the elastic recovery of the material. This is called Springback. Springback is a phenomenon in which the strip unbends itself after forming.
ANALYTICAL MODEL FOR INTERNAL BENDING MOMENT AND SPRINGBACK PREDICTIONThe main assumptions made for the presentedanalysis are as follows;1. The material is homogeneous and has a stablemicrostructure throughout the deformation process.2. R>>t so, the neutral axis lies in the mid-plane.3. Analysis is based on σ = Kεn4. Plate is having the uniform radius of curvature forthe supported length.5. b >> t. So width changes are negligible.
Equation for Bending Moment & Spring back K’ is equal to [(1.1547)^(n+1)] K
Table 3 Effect on Springback for material change and thickness same Thickness of Difference Difference Difference Bending Un- Spring- Material Between Between Between Moment loaded back (mm) Yield Strength Strain (N.mm) Radius Radius Strength Coefficient Hardening (Rf) (Rf-R) (σy) (K) exponent (mm) (mm)t1 = 5mm t2 = 1mm (N/mm2) (N/mm2) (n) (2”) (2”) Low RangeSA - 724 SA – 612 170 76 0.06 3600.689 109.491 9.49104SA - 724 SA – 515 255 197 0.05 3592.966 109.4688 9.468755SA - 724 SA – 299 225 164 0.03 3604.44 109.5019 9.501866SA - 724 SA - 36 265 308 0.07 3576.166 109.4203 9.42031
Fig. 5 Effect of difference between yield strength on Springback Radius 9.51 9.5 9.49Springback Radius 9.48 9.47 9.46 9.45 9.44 9.43 9.42 9.41 0 50 100 150 200 250 300 difference between yield strength
Fig. 6 Effect of difference between strength coefficient on Springback Radius 9.51 9.5 9.49Springback Radius 9.48 9.47 9.46 9.45 9.44 9.43 9.42 9.41 0 50 100 150 200 250 300 350 Difference between strength coefficient
Fig. 7 Effect of difference between Strain Hardening exponent on Springback Radius 9.51 9.5Springback Radius 9.49 9.48 9.47 9.46 9.45 9.44 9.43 9.42 9.41 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 difference between Strain Hardening
CONCLUSIONHigh value of strength coefficient and yieldstrength with low value of strain hardening exponentresults into extremely high springback.For materials with constant Young’smodulus, springback increases with; (i) increase instrength coefficient, (ii) increase in yield strength and (iii)reduction in strain hardening exponent.Based on the analytical springback analysis, it isconcluded that as an alternative to the materialsdevelopment, layer of the high ductility ferrous steel canbe used for suppressing the springback during forming ofhigh strength or extra high strength ferrous materials.
FUTURE WORK If we derive equation for bending moment andspringback for multi layer strip for V-Bending, it isbecome very complex. It is derive by W.Y.D Yuen  So, for study behavior of multi layer strip, we useFinite Element Analysis for further detail study.
References A. H. Gandhi and H. K. Raval, “Analytical and empirical modeling of top rollerposition for 3-roller cylindrical bending of plates and its experimental verification,” J.Mater. Process Technol., vol. 197, no. 1-3, pp. 268-278, 2008. Edward M. Mielnik, Metal Working Science and Engineering, NewYork, USA, McGraw Hill Book Co., 1991. Z. Marciniak, J. L. Duncan, Mechanics of sheet metal forming, Edward ArnoldLtd., London, 1992. W.Y.D. Yuen “A generalized solution for the prediction of springback ir. Laminatedstrip” Port Kemblu Laboratories, BHP Research, Po Box 202, Port Kembla, NSW2505,Australia Received 16 February 1995