Handwritten please
2. The principal load bearing structure for a proposed bariatric hoist is shown in figure Q2-1, and consists of a pin-jointed truss attached to an upright beam. 1 1 A B 0 S С 0 0 E E D D Mg h Figure Q2-1: Proposed structure of a bariatric hoist. a) Consider the pin-jointed truss shown with pins at A, B, C, D and E and with a load mass of Mg as shown. Calculate the reaction forces at A and C as well as the force in the link BE. (6 marks) b) Using the results from part (a) draw a shear force and bending moment diagram of beam. You can ignore the compressive force along the principal axis of the beam, but show clearly the dimensions h and s. (6 marks)
c) The following design constraints have already been specified, so that the hoist can support weights up to 80 cm away from the base of the support. 1 = 0.4m h = 1.0m Mg = 2000N Maximum movement of the winch point E = 3.0 cm Choose either steel or aluminium as the material for the vertical beam and decide on an appropriate cross-sectional profile. Hence estimate or calculate the following information so that it can be used to make subsequent design decisions. In all cases justify your decisions. i) Calculate the rotation of the frame ABCDE in response to the endpoint deflection at E. You can assume that the frame does not distort in any way and rotates around point C. ii) Calculate the internal moment (torque) in the vertical beam at C. iii) Give the formula for the endpoint deflection of a beam with a single Moment (torque) loading. Hence find a value for the El value needed to not exceed the 3 cm movement of the winch point E. iv) Given that the beam will be made of a hollow circular section and it will be made of a metal such as aluminium or steel, estimate a value for the second moment of area and hence for the inner and outer radii of the vertical beam. Justify your decisions. You may choose additional design parameters as needed but these choices should be justified in your answer. (8 marks)
d) The person turns the bolt by one turn so the location of the thumb and index finger are now 7, + p and 7i+p where P = [o o pz]" Recalculate the torques on the thumb and finger as well as the total torque applied by the hand and comment on your results. (6 marks) e) Explain the reasons for any remaining torque on the bolt while it is in the threaded hole. (2 marks) f) Considering the bolt when it is held in space by the head with just the finger and thumb and with the shaft horizontal. How is the torque due to the mass of the bold countered by the fingers? You can consider forces due to gravity to operate on either the x-axis or the y-axis. (3 marks)
Handwritten please
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Handwritten please
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