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Technology 3 - Building Science and Structures > Mechanical Properties > Flashcards

Flashcards in Mechanical Properties Deck (25):
1

What provides the cohesive forces necessary to produce the solid state.

Chemical Bonds

2

Chemical Bonds provide what?

the cohesive forces necessary to produce the solid state.

3

In solids, atomic and molecular movement is restricted to?

Thermal Vibration

4

If the temperature of a solid is raised, the amplitude of vibration increases and will eventually...

Disrupt the order of the structure.

5

to disrupt the order of the structure in a solid, we need to.

Increase vibration by raising the temperature.

6

There's tendency for high melting point metals to have high

Young's Moduli

7

Young's Modulus is related to...

The strength of the chemical bond

8

What are the assumptions to Griffith's theory of fracture

Hooke's law is obeyed up to fracture point

All stressed solids store strain energy

All surfaces have an associated energy characteristic of the material

The process of the fracture can be considered a conversion of stored strain energy to surface energy

9

Materials which fail in a brittle manner often contain strong...

Chemical Bonds.

10

Ceramics are normally found to be extremely weak in their

Bulk Form

11

What are the defects that can attribute towards weakness in a bulk material (3)

Cracks
Holes
Steps

12

What do the Stress concentrators (Cracks, Holes, Steps) subject a components surface to

Stress connectors breakdown the chemical bonds at the crack tip and are subjected to stress will in excess of the average stress.

13

The degree of stress concentration is

proportional to the crack length

14

The magnitude of stress concentration was first calculated for an..

Elliptical hole by Inglis in 1913.

15

Stress concentration alone is insufficient to initiate fracture. for crack propagation to occur, two conditions must be fulfilled.

The stored energy released must exceed the energy needed to create the fracture stress.

There must be a molecular or atomic mechanism by which this energy transformation can take place.

16

What is more important than stress concentration to determine a materials response to stress.

The critical crack length.

17

What is the greatest safe guard against brittle fracture.

having a very high value of W

18

The process of slip in which adjacent layers of atoms move relative to each other is known as...

The mechanism of plastic deformation in metals.

19

The mechanism of plastic deformation in metals, is the process of what.

slip in which adjacent layers of atoms move relative to each other.

20

The shear stress necessary to cause slip may be calculated from a knowledge of

the strength of the metallic bond.

21

Metal crystals are perfect arrays of

Metallic Ions

22

Linear defects are commonly known as

Dislocations

23

Dislocations are commonly known as

Linear Defects

24

Plastic deformation in metallic crystals are produced by

The movement of dislocations.

25

The movement of dislocations in metallic crystals produce

Plastic deformation