Explain the finite element method for stress analysis as you would to a high school student who is interested in becoming an engineer. Note that this could be the deciding factor for the student to choose Engineering at University. As such keep your answer relevant, interesting and succinct (furthermore, the student is young so they get bored easily...).

[Word limit: 200]

Infrared Soldering

(FOR REPORT PURPOSE)

1. Synopsis
2. Introduction (Applications/Industries)  
3. Mechanism and Metallurgy

Derive the formula (together with diagram/s where applicable) for the critical load of an eccentric loading conditions.  

Why is three wire method preferred for measuring the effective diameter of thread over two wire method? derive mathematical equation of with worth thread

Students will design a mutually operating gear system under the conditions given in this question. (Sizing will be done as a result of calculations according to working conditions, material, construction status and strength). In this design, shaft and bearing calculations will not be made. Only mutual gears will be designed according to the data and acceptance. The student will make assumptions for the values and information that are not given and will explain why he made this assumption.

Input Power: 8 Kw

Input Cycle : 1224

Cycle Rate: 4

Gear Material: 1050 Steel

A high carbon steel shaft is used in an engine and subjected to different loads. In order to
analyse the stress in the shaft, consider a rectangular element within the material. This
element is subjected to compressive stress of 135 MPa and shear stress of 166MPa in the
vertical direction. The compressive stress in the horizontal direction is 176MPa with a shear
stress of 115MPa.
a. Sketch the state of stress on this element.
b. Determine the maximum and minimum normal and shear stresses and their plane of
orientation.
c. If the yield strength of the material is 350MPa, Poison’s ratio is 0.32, and factor of
safety is 5, determine the diameter of the shaft to avoid failure.
d. What will be the difference in the analysis above if there is an additional torsional
load (T) and bending moment (M).
e. Show how you can use any theory of failure to design this shaft.
f. What are the challenges of applying the theories of failure in actual engineering
practice and as a design engineer, how would you deal with these challenges.

A simple R134a plant is develop 70000kJ/hr of refrigerant leaves the evaporator as saturated vapor at 10 degree c. After isentropic compression the pressure of refrigerant is 10 bar. Draw the P-h diagram and determine 1) the refrigerant flow rate 2) the compressor discharge temperature 3) the heat rejected to the condenser in KW 4) The COP 5) the power required to drive the compressor

Why do we may avoid normal shocks when designing aircraft geometries?

A syngas fuel consists of these following volumetric composition: 75% methane and 25% butane. The syngas at 100 kg/hour and 25oC is mixed with 20% excess air at 30oC. Due to incomplete combustion mechanics, 10%v of the syngas carbon is partially oxidized and forms carbon monoxide.
If the products of combustion are at 600K, obtain the combustion heat transfer rate from the system.

a) Briefly write down the basic heat gains that make up the cooling load in items.

b) A desired feature from refrigerants is that the evaporation pressure is high and the condensing pressure is low. Explain the main reason for this by drawing the T-s diagram of a single-stage cooling cycle.

1. How would you expect a flaw to affect the mechanical properties of brittle materials?

A tank of water is emptied by the force of gravity through a syphon. The difference in water levels between the two tanks is 3 m and the highest point of the syphon is 2 m above the top surface level and the length of the pipe from inlet to the highest point is 2.5 m. The pipe is designed with a bore of 25 mm and the length 6 m. The pipe frictional coefficient is 0.007 and the inlet loss coefficient K is 0.7. Calculate the following:
4.1 the volume flow rate and,
4.2 the pressure at the highest point in the pipe