An Innovative Method of Preventing Bolt Hole Crack …
433
Fig. 8 Schematic representation of CFT test setup as per SAE J267 standard
4 Product Validation and Results Discussion
4.1 Cornering Fatigue Testing (CFT)
As discussed on Sect. 1.2, SAE J267 is used for test setup and bending moment
calculation. The bottom flange of the wheel is held and a known mass attached
eccentrically to the shaft, in its very bottom rotates with a given rpm, which will be
equal to the calculated Bending Moment (BM) (Fig. 8).
4.2 Results of Cornering Fatigue Testing (CFT)
Bolt hole failure due to fretting is one of the common issues of forged aluminium
wheels in the cornering fatigue test. But in laser peened product, even though fretting
was observed, bolt hole crack was completely eliminated and fatigue life of the wheel
significantly improved than the normal product, because of the hardness improvement
above the bolt hole area.
5 Conclusion
The methodology described in this paper collectively gives an inference that Laser
peening has prevented wheel crack above bolt hole. Laser peening has proved that,
if high stresses are observed in highly localized areas, those areas can be treated
with it, so as to achieve localized hardness. This method may also be extended to
other areas of the high-stress location on the wheel rim to enhance surface hardness
thereby improving the overall performance of the wheel.
433
Fig. 8 Schematic representation of CFT test setup as per SAE J267 standard
4 Product Validation and Results Discussion
4.1 Cornering Fatigue Testing (CFT)
As discussed on Sect. 1.2, SAE J267 is used for test setup and bending moment
calculation. The bottom flange of the wheel is held and a known mass attached
eccentrically to the shaft, in its very bottom rotates with a given rpm, which will be
equal to the calculated Bending Moment (BM) (Fig. 8).
4.2 Results of Cornering Fatigue Testing (CFT)
Bolt hole failure due to fretting is one of the common issues of forged aluminium
wheels in the cornering fatigue test. But in laser peened product, even though fretting
was observed, bolt hole crack was completely eliminated and fatigue life of the wheel
significantly improved than the normal product, because of the hardness improvement
above the bolt hole area.
5 Conclusion
The methodology described in this paper collectively gives an inference that Laser
peening has prevented wheel crack above bolt hole. Laser peening has proved that,
if high stresses are observed in highly localized areas, those areas can be treated
with it, so as to achieve localized hardness. This method may also be extended to
other areas of the high-stress location on the wheel rim to enhance surface hardness
thereby improving the overall performance of the wheel.