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Steering Bracket Design Validation. Steering Bracket Design Validation. Goals Design for strength – Keep stress below 150 MPa Design for life – Last 1 million load cycles; last a season of 10~20 rallies Frequency Check – Avoid frequency in range 1 – 30 Hz.
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Steering Bracket Design Validation • Goals • Design for strength – Keep stress below 150 MPa • Design for life – Last 1 million load cycles; last a season of 10~20 rallies • Frequency Check – Avoid frequency in range 1 – 30 Hz The part is from a Group N rally car (modified road cars)
Design for Strength Setup Normal Hinges Steering Force = 6000 N FOS = 2.24 Stress Plot
Design for Life • Optimized steering bracket should last for 1 million cycle load of 6000 N. • Fatigue results show that around 38% of part life is used around hot spots
Mode No. Frequency(Hertz) 1 2313 2 3431 3 7838 4 9080 Frequency Check • Natural frequency of steering bracket shouldn’t fall in range from 1 – 30 Hz. • Under this road range vibrations are transferred to the driver through steering column. This should be avoided at all cost. Mode shapes animation Bracket design is safe and out of the frequency range of 1 – 30 Hz
Design Insight • Use insight to make simple change to reduce weight • Mention option of doing in context of assembly or at part level Can reduce weight by 7~10%
Additional Demo - Design Optimization • What would be the optimum design for a minimum factor of safety requirement? Optimized Design Original Design Variable Settings: Radius = 8-12mm Thickness = 3.5- 5mm Stress < 150MPa Bracket Weight 90.66g Reduced weight by ~10% Bracket Weight 103.22g
Additional Demo - Design Optimization • Fatigue is impacted by the new design So 3.875mm thickness will not survive 1 million cycles