Assignment #1 – Beams and Multiforce Members

You are required to analyse the front loader as shown in the diagram below.

Please note that diagrams are not to scale.

Part 01 – Bending and Uniaxial stress

The cantilever part of the front loader in the horizontal (0°) position is to be analysed as a simplified beam of uniform hollow rectangular box section. We will neglect the mass of the material.

Assume a force, , of 10 kN and the dimensions , and are 2.390 m, 0.390 m and 0.225 m, respectively. Letting the value of equal 1.2, determine the following.

• The reactions at the right hand side of the cantilever as a result of the loads. [5 marks]


• The bending moment equation for the beam. [5 marks]


• The maximum stress due to axial forces if the cross sectional area is 0.00098 m². [5 marks]


• The maximum stress in the beam due bending if the height of the beam is 80 mm and the value for is 850×10^-9
  m⁴. [5 marks]


• The maximum stress in the beam. (Note: this will not be the sum of the stress in the previous two steps) [5 marks]


• The vertical deflection of the left hand side of the beam if the value for is 200 GPa. [10 marks]

Part 02 – Frames and Machines

You are required to analyse the system when the loader is in the position of 15° (This corresponds to the angle cylinder ‘FD’ makes with the horizontal axis). The vertical load at point G is 17.2 kN and is spread evenly between the two identical arms of the loader. Using the online spreadsheet to identify the position of each joint, as well as any of the dimensions or angles of interest, complete the following.

• Each component of the loader should be analysed by a sketch and a set of independent equations of equilibrium. [27 marks]


• Calculate the horizontal and vertical components of the forces in each of the joints. [8 marks]


• Adapting the results from the first part of the assignment, calculate the maximum stress in the cantilever part of the loader. [5 marks]


• Adapting the results from the first part of this assignment, calculate the
  vertical
  deflection of the joint at E. [10 marks]

For simplicity it is assumed that the centre of gravity for the bucket does not move relative to other components of the loader during the extension of cylinder ‘AC’ and that cylinder ‘FD’ does not extend or retract.

Part – 03 Design Review

You have been asked to contribute to the next version of the front loader. Consider the design of the front loader from the point of view of function, strength of materials and cost. What changes would you suggest? Justify your answer with a brief description and diagrams as appropriate. [15 marks]

Instructions

Students are required to submit a written report to Turnitin on Blackboard. Optionally, electronic supporting documents, for example spreadsheets, can also be uploaded. This assignment is worth 30% of the marks for this module.