An adjustable device is designed to apply a traction to stretch the tibia. It is attached to the tibia by rigid pins as illustrated below. There is a mechanism for length adjustable in the centre of the vertical section. Draw a free-body diagram for each of the three straight sections of the device, showing the forces and bending moments to which each is subjected. Discuss the criteria that you would use to determine the required dimensions of this device. What are the potential failure mechanisms? What materials might be appropriate for the manufacture of this device, and why?
Estimate the mean cross-sectional area of the tibia and, assuming that its Youns's modulus is 10000 Mpa,
calculate the load required to stretch it by 1mm over a length, L, of 300mm. Determine appropriate cross-sectional dimensions for the vertical section of the traction device to enable it to sustain this applied load.
Review critically the assumptions that you have made in your analysis of this device.
(Diagram and full question attached.)
The solution provides the required specifications for designing a device to stretch a person's tibia along with potential pitfalls and criticisms of the assumptions made in the design process. It includes detailed diagrams and supporting theory and calculations in the attachment.