- Steering Bar Front Wheel Fig Qla Electric Scooter Parts And Their Functions Decker Plate Platform For Rider And Is M 1 (160.24 KiB) Viewed 20 times
(h) Considering the following requirements for the scooter frame tube as illustrated in Fig. Qla: Service requirement: • The frame tube must exhibit the least amount of elastic deformation under the strong force produced when a rider is riding on a bumpy road. Production requirement: • A straight tube section is used for the bending operation in order to form the scooter frame tube with the required shape. Bending force required for the bending operation must be at a low level with no fracture on the bent tube. Two candidate materials (A and B) are available for choice to make the scooter frame tube. Material A is carbon steel (0.3% carbon) and Material B is carbon steel (0.6% carbon). The resulting tensile stress-strain curves as obtained from a tensile test is shown below. Stress, o A B Strain, & Fig. Q1b Stress-strain curves in tensile testing (i) State which of these materials is more ductile. (1 mark) (ii) Explain why this material is more ductile. (1 mark) (iii) State which of these two materials has the greater stiffness. (1 mark) (iv) Explain why this material has greater stiffness. (1 mark) (v) Compare the yield stresses of the two materials. (1 mark) (vi) Compare the required bending force levels in bending operation of the two materials when they are used for making the scooter frame tube. Explain why. (4 marks) (vii) Which of these two materials should be selected for making the scooter frame tube? Explain why the material is selected based on both the production and service requirements. If pre-treatment or secondary operation is needed, state what it is and briefly explain the reason why. (4 marks)