Describe how Aluminium can corrode or degradein Aircraft Fuselage.

And methods for avoid degradation in Aircraft Fuselage.

1. Rocket motor cases may be fabricated as thin walled tubes from:

a) Low alloy steel of proof stress 1200 MPa and G_C = 24 kJ/m measured in sheet of an appropriate thickness, or

b) Maraging steel of proof stress 1800 MPa and G_C = 24 kJ/m

In a particular application the design code specifies that the design stress is StressY/1.5 where Y

is the proof stress. Calculate the minimum defect size

required to give brittle fracture in service for the two materials. Comment

on your result. You may take Young’s modulus to be 200 GPa in both cases.

2)If the fracture stress of a large sheet of

maraging

steel containing a central

crack of length 40 mm is 480 MPa, calculate the fracture stress of a similar

sheet containing a crack of length 100 mm.

Q] What are the advantages and disadvantages of acceptance sampling over 100% inspection? Under what conditions should acceptance sampling be preferred over 100% inspection?

Subject - Materials Management

3. One mole of air is compressed isothermally at 300K from one atmosphere to fifteen atmospheres.  
a) Calculate the amount of work required in the compression.
b) How much heat must be added or removed from the gas to maintain its temperature at 300K.  
c) Does the enthalpy of the gas change? If so, how much?
d) Does the entropy of the gas change? If so, how much?  
DATA: You may assume that air is an ideal gas with a constant volume heat capacity of 5/2R

Liquid penetrant testing is a suitable method for almost any material. What can not be inspected by liquid penetrant testing method?

Explain why pre-cleaning is the most important step

Imagine a part that contains fatigue cracks which are detectable under no load using liquid penetrant technique. Would they still be detectable under tensile and compressive loads and why?

List the main human factors that affect the probability of detection in liquid penetrant testing.

What control measures should be considered in developer thickness layer?

List the advantages and disadvantages of the various developer types.

Additionally there are 10 marks given for organisation and presentation. You will be expected to show evidence of research and well balanced arguments supported by academic literature relevant to the problem (in addition to the learning package material). Note that that the marking scheme gives an indication of the expected length of each section. Explanations and descriptions should reflect this balance between sections and sub-sections.

A nozzle is is designed to achieve M=4 under expanded exit flow conditions. For the given total pressure and total temperature, calcuate:

a) exit Mach

b)mach at which normal shock occurs in the model

13.3     Why are clear objectives and standards needed in the appraisal process?

13.2     Why do supervisors appraise their employees? What in the process will benefit supervisors? What will benefit their employees?

In a surface condenser a section of the tubes near to the air pump suction is
screened off so that the air is cooled to a temperature below that of the condensate, separate extraction
pumps being provided to deal with air and condensate respectively. 5448 kg of steam are condensed
per hour and the air leakage is 4.54 kg/h. The temperature of the exhaust steam is 31°C, the temperature
of the condensate is 27°C, and the temperature at the air pump suction is 21.1°C. Assuming a constant
vacuum throughout the condenser, find
() The mass of steam condensed per hour in the air cooler;
(i) The volume of air in m3/h to be dealt with by the air pump;
(ii) The percentage reduction in necessary air pump capacity following the cooling of the air..

15.3     What does the Wagner Act prohibit?

Why are the parts manufactured using powder metallurgy of near net shape? For mixtures of dissimilar metal powders, explain how (a) blending/mixing, and (b) compaction are carried out before sintering. Explain how (i) blending/mixing and (ii) compaction steps influence the (a) sintering step and (b) porosity development in the processed part.

Define the phenomenon of Springback in sheetmetal forming, and provide a detailed explanation of the methods used to compensate for springback in finished sheetmetal products.

For each of the following pairs of polymers, plot and label schematic stress-strain curves on the same

graph [i.e. make separate plots for parts (a), (b) and (c)].

(a) Polychloroprene rubber having a number-average molecular weight of 100,000 g/mol and 15% of available sites cross-linked; liner polypropylene having a number-average molecular weight of 150,000 g/mol.