AERx Pulmonary Drug Delivery System, Remmele Engineering, Inc.

Steering Bracket Design Validation

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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)

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Design for Strength

Steering Force = 6000 NHinges

Setup

Stress Plot FOS = 2.24

Normal

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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

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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.

Bracket design is safe and out of the frequency range of 1 – 30 Hz

Mode shapes animation

Mode No. Frequency(Hertz) 1 23132 34313 78384 9080

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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%

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Additional Demo - Design Optimization

What would be the optimum design for a minimum factor of safety requirement?

Bracket Weight 90.66g

Reduced weight by ~10%Bracket Weight 103.22g

Original Design Optimized Design

Variable Settings:Radius = 8-12mmThickness = 3.5- 5mmStress < 150MPa

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Additional Demo - Design Optimization

Fatigue is impacted by the new design

So 3.875mm thickness will not survive 1 million cycles