The second part of your portfolio component for the 7112MECH consists of a small project.
You will be required to answer the questions outlined in this proforma based on the geometry and tasks given to you.
The deliverables for the examination are:
- the completed pro-forma.
- one *.cae (recommended) or *.inp file containing the analysis task required to answer. You need to name the file “yourfamily name”.
These files will be used to check your answers. In their absence you may lose marks.
Insert your name
A small-scale experimental structure is built in order to analyse the effect of structural modification of a helicopter tail. The structure is made of constant cross-section aluminium beams and it needs to be restrained at one end (Figure Q.1). The details about the restrain are given in figure Q3.
Aluminium properties (suggested):
E = 68..70 GPa
= 2650..2800 kg/m3
Based on your study you need to find the exact values!
A sketch of the structure is shown in figure Q1. All the dimensions are given in mm.
Length of the edge AF is 600 mm, length of the edge FB is 300 mm. The angle between AF and FB is . The opposite edges are parallel. On edge AF (and the opposite edge), you can create (if necessary) a partition at 120 mm distance from point A.
The cross sectional area (see Figure Q2) is constant along the length of the structure. All the dimensions are given in mm.
The rotor tail and the gearbox are modelled as a point mass of approximately 0.35 kg and is attached at the top of the structure (point B in Figure Q1). The location of this point mass will be further referred as “rotor”.
In order to simulate a cantilever connection, the structure is restrained as shown in figure Q3. How you decide to simulate the restraint is also your task.
The frequency response of the structure are given for a force applied at Point F (as shown in Figure Q1), first in Y-direction then in Z-direction. The response is measured at the same location (collocated response).
The Frequency response function obtained for the force applied in Y-direction and displacement response measured in Y-direction is shown in figure Q.4
The Frequency response function obtained for the force applied in Z-direction and displacement response measured in Z-direction is shown in figure Q.5