Mechanical Properties of Metals

Provides, authority, determine, motivate, influenced, guided, arranged, failure, subordinates, available, employee.

1. We are looking for someone who will be able to ….. the staff to work hard.

2. She had many ….. before finding the right method.

3. An experienced lawyer ….. them through the complex application procedure.

4. Sheila and Tom work under my authority. I am their boss and they are my ….. .

5. We want to make our product ….. to a wider market.

6. At least 50% of our ….. have been with the company over ten years.

7. He doesn’t have the necessary ….. to make this sort of decision.

8. I’ve ….. that one of our representatives will meet you at the airport.

9. The hotel ….. a shoe-cleaning service for its residents.

10. We should first try to ….. how much it is going to cost.

11. What were the factors that ….. you to take the job.

WORD-BUILDING

Exercise 1. Form new words with the help of the suffix – er-or and translate the words into Russian.

Er – to manage, to teach, to use, to speak, to dictate, to buy, to govern, to begin, to drive, to employ.

Or – to visit, to conduct, to sail, to inspect, to invent, to act, to elect, to direct

Exercise 2. Form new words with the help of the suffix – ly and translate the words into Russian.

Normal, cheap, main, night, kind, bad, day, friend, time, month, quick, nice, brave.

COMPREHENSION QUESTIONS

1. What is management?

2. Why are goal setting and planning so important for an organization?

3. What is understood by organizing?

4. What does leading mean?

5. Why does an organization fail if doesn’t pay attention to controlling?

6. How do the management functions work in practice?

I. Divide the text into logical parts.

II. Give a summary of the text.

Mechanical Properties of Metals

1. Introduction

Often materials are subject to forces (loads) when they are used. Mechanical engineers calculate those forces and material scientists how materials deform (elongate, compress, twist) or break as a function of applied load, time, temperature, and other conditions.

Materials scientists learn about these mechanical properties by testing materials. Results from the tests depend on the size and shape of material to be tested (specimen), how it is held, and the way of performing the test. That is why we use common procedures, or standards, which are published by the ASTM.

2. Concepts of Stress and Strain

To compare specimens of different sizes, the load is calculated per unit area, also called normalization to the area. Force divided by area is called stress. In tension and compression tests, the relevant area is that perpendicular to the force. In shear or torsion tests, the area is perpendicular to the axis of rotation.

s = F/A₀ tensile or compressive stress

t = F/A₀ shear stress

The unit is the Megapascal = 10⁶ Newtons/m².

There is a change in dimensions, or deformation elongation, DL as a result of a tensile or compressive stress. To enable comparison with specimens of different length, the elongation is also normalized, this time to the length L. This is called strain, e.

e = DL/L

The change in dimensions is the reason we use A₀ to indicate the initial area since it changes during deformation. One could divide force by the actual area, this is called true stress.

For torsional or shear stresses, the deformation is the angle of twist, q and the shear strain is given by:

g = tg q

Date: 2015-01-02; view: 1115