A go kart with front brakes has an axle that attaches the front wheels and brakes...

    

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A go kart with front brakes has an axle that attaches the front wheels and brakes to the go kart via two bearings. The brake disc is attached to the inboard side of the axle and the wheel is on the outboard side of the axle, as illustrated by the schematic in Figure 2. The race-ready go kart weighs 75kg and the driver weighs 75kg with all necessary driver safety equipment. The front wheels have a rolling diameter of 270mm, where the tyres have a braking friction coefficient of 2 and a cornering friction coefficient of 1.5. Notably the center of the tyre contact patch is 100mm from the nearest bearing (see Figure 2). The go kart typically drives around tracks with a 1km lap, where the tracks can be divided into three segments; namely 55% straights, 30% corners and 15% braking zones. Assume there is equal weight distribution across all four wheels and there is no weight transfer during driving. The axle is made of forged steel that has an Ultimate Tensile Strength of 700MPa and a 450MPa Yield Strength. The axle is 40mm diameter at the bearings and then reduces to 25mm at the wheel attachment with a 1.25mm radius at the diameter transition (See Figure 2). There is a 12mm diameter hole going through the axle for weight reduction. Your task is to determine (with 90% reliability) how many laps the go kart can travel until axle failure at the above conditions. Then discuss whether you believe the axle is adequately sized or not, justifying your answer, and recommend any changes if not adequately sized. Road Wheel 100mm 1.25mm 25mm Bearings 40mm |12mm Brake Disc Hole Axle A go kart with front brakes has an axle that attaches the front wheels and brakes to the go kart via two bearings. The brake disc is attached to the inboard side of the axle and the wheel is on the outboard side of the axle, as illustrated by the schematic in Figure 2. The race-ready go kart weighs 75kg and the driver weighs 75kg with all necessary driver safety equipment. The front wheels have a rolling diameter of 270mm, where the tyres have a braking friction coefficient of 2 and a cornering friction coefficient of 1.5. Notably the center of the tyre contact patch is 100mm from the nearest bearing (see Figure 2). The go kart typically drives around tracks with a 1km lap, where the tracks can be divided into three segments; namely 55% straights, 30% corners and 15% braking zones. Assume there is equal weight distribution across all four wheels and there is no weight transfer during driving. The axle is made of forged steel that has an Ultimate Tensile Strength of 700MPa and a 450MPa Yield Strength. The axle is 40mm diameter at the bearings and then reduces to 25mm at the wheel attachment with a 1.25mm radius at the diameter transition (See Figure 2). There is a 12mm diameter hole going through the axle for weight reduction. Your task is to determine (with 90% reliability) how many laps the go kart can travel until axle failure at the above conditions. Then discuss whether you believe the axle is adequately sized or not, justifying your answer, and recommend any changes if not adequately sized. Road Wheel 100mm 1.25mm 25mm Bearings 40mm |12mm Brake Disc Hole Axle

Answer rating: 100% (QA)

1 Determine forces on axle during braking Total vehicle mass go kart mass 75kg driver mass 75kg 150kg Assume braking force is distributed equally betw... View the full answer