Mechanical Properties and Failure Analysis Lab Report

Part 1 – Lab Report

During the practical sessions, a tensile test experiment will be carried on two samples. By taking the data of load vs. elongation, try to find out the following mechanical properties:

• Yield strength

• Ultimate Tensile Strength

• Ductility

• Modules of Elasticity

Based on these outcomes, what mechanical product do you suggest to be made from each material, and give your reasons?

Note: the report should include theory part, experimental data, calculations, discussion, and references.

Preparing 5-10 minutes presentation to study a case study failure, showing the reasons behind the failure and the precautions that had to be done to avoid the failure, in terms of materials selection, design, service conditions and environment.

Think of four deformations or fracture failures that have actually occurred either from your personal experience or from items that you have read about in newspapers, magazines or books. Classify each according to specific category built by you and briefly explain the reason(s) for your classification.

In December of 1986, Rutan and Yeager flew around the world, without refuelling, in an aircraft named the Voyager. Consult news magazines and other sources, and obtain information on the materials used to construct the aircraft. Explain why was the choice of materials critical? Could the flight have been accomplished with a metal aircraft? Yes or No?

Classify each of the following failures and explain the reasons for each choice:

• A glass bowl with a small crack breaks into two pieces when it is immersed, while still hot into cold water.

• The steel radiator fab blades in an automobile develop small cracks near the base of the blades.

You are an engineer designing pressure vessels to hold liquid nitrogen. What general characteristics should the material to be used have? Of the various types of materials tests described in this module, which would you employ to aid in selecting among candidate materials? Explain the reasons you need for each chosen test to select a proper material. 

Cold working a metal by rolling it to a lesser thickness or hammering it introduces different defects in the crystal structure. Would you expect the yield strength to be affected by this, and if so, would it increase or decrease, then explain the reasons. What about the elastic modules, does it change?