Presentation by Mr. Sumedh Kousadikar Mr. Santosh Kumar Mr. Atul Patil January 22 , 2013 Pune, India Bending fatigue life evaluation of Crankshaft with induction hardening effect via FEMFAT boundary layers R&D CDFD Engineering Bharat Forge Ltd. Pune, India FEMFAT USER CONFERENCE 2013
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Presentation by
Mr. Sumedh Kousadikar
Mr. Santosh Kumar
Mr. Atul Patil
January 22 , 2013 Pune, India
Bending fatigue life evaluation of
Crankshaft with induction hardening effect
via FEMFAT boundary layers
R&D CDFD Engineering
Bharat Forge Ltd. Pune, India
FEMFAT USER CONFERENCE 2013
Presentation Sequence
• Introduction
• Kalyani Group & Bharat Forge Overview
• Objective & Methodology
• Approach 1: Introducing hardness effect via Boundary layer
Fatigue testing of crankshaft is a complex engineering process, which requires lot of
theoretical calculations, practical work, time & cost.
Crankshaft fatigue life can be improved by optimizing design & process parameters. But
it’s physical test validation needs lot of testing time & other expenses. So to reduce these
complexities, it is important to virtually simulate the crankshaft fatigue testing process &
predict the fatigue life.
Introduction
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Bending fatigue life evaluation of crankshaft with induction hardening effect via FEMFAT
boundary layers.
Crankshaft bending fatigue life correlation between FEMFAT & physical test results.
Methodology:
Import ANSYS stress
results into FEMFAT &
apply different IH
process parameter effect
via boundary layers
Conduct FE analysis Predict fatigue life
& validate results
Objective & Methodology
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Following input parameters are taken for bending fatigue life evaluation of five different
capacity crankshafts.
The load spectra applied is actual (B50) mean fatigue strength of crankshaft.
All analysis are performed on load ratio (R=-1) fully reverse condition.
Other parameters like technological size influence, forge factor, are activated based on pin
diameter of crankshaft.
Crankshafts Input data for FEMFAT Analysis
S.N. Crankshaft Material Pin Dia(Ø) mm UTS (MPa) YS (Mpa) Surface Hardness
(HRc) Surface finish
(Ra) µ
1 A Micro alloyed 70 780-930 450 52 0.25
2 B Micro alloyed 90 750-900 450 53 0.25
3 C Q & T 94 930-1080 760 50 0.25
4 D Micro alloyed 95 850-1000 550 55 0.25
5 E Micro alloyed 100 850-1000 550 56 0.25
Input data for analysis
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Following parameters are considered for analysis, Material: Micro alloyed steel. Applied stress level 875 MPa UTS 850 MPa Pin Diameter: 94 mm Technological size influence ON Forge Factor ON Surface Roughness 0.2 µ Stress ratio R=-1 B50 fatigue life
FEMFAT fatigue
life Expected
fatigue life % of variation
5.82E+03 10E+06 99.94%
Fatigue life Requirement:
10Million no. of cycles for 875 MPa
Without Induction hardening effect
Fatigue life analysis using FEMFAT
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Similarly fatigue life evaluated for other sizes of crankshafts as shown below.
BENDING FATIGUE TEST CORRELATION
Sr No. Crankshaft B50 physical
test (MPa) Pin Diameter
(mm) Number of cycles
Calculated cycles by FEMFAT
% Difference
1 A 875 70 10E+06 2.38E+04 99.76%
2 B 757 90 10E+06 2.69E+05 97.31%
3 C 880 94 10E+06 5.56E+04 99.44%
4 D 875 95 10E+06 4.47E+04 99.55%
5 E 875 100 10E+06 2.99E+04 99.70%
Without hardening Influence, the fatigue life achieved is very small as compared to
expected no. of cycles (10 Millions)
Fatigue life analysis using FEMFAT
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Hardness 55 HRC
Fatigue life Requirement:
10Million no. of cycles for 875 MPa Achieved fatigue life: 9.1 Million cycles
Result correlates well
Approach 1: Introducing hardness effect via Boundary layer
One of the crankshaft is simulated for fatigue life evaluation using FEMFAT with introducing
hardness effect in terms of UTS at 3mm boundary layer.
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Following parameters are considered for analysis Material: Micro alloyed steel. Pin Diameter: 94 mm Technological size influence ON Forge Factor ON (default taken as 1) Surface Roughness 0.2 µ Stress ratio R=-1 B50 fatigue life Mechanical properties (YS, UTS 850 MPa) Applied stress level 875 MPa
Following parameters are considered for analysis Material: Micro alloyed steel. Pin Diameter: 94 mm Technological size influence ON Forge Factor ON introduced as 1.9 Surface Roughness 0.2 µ Stress ratio R=-1 B50 fatigue life Mechanical properties (YS, UTS 850 MPa) Applied stress level 875 MPa IH Boundary layer ON