Comparing Modulus & Strength of Metals & Plastics

In summary, the discussion was about an experiment done using a testometric machine to test different materials and generate a stress/strain graph. The questions asked were about the reasons for the difference in modulus and strength between plastics/polymer and metal, and the atomic/molecular level behavior in the elastic and plastic regions of each material. It was suggested to research topics such as covalent bonds, ionic bonds, metallic bonds, crystalline structures, shear angle, and molecular geometry for answers. However, forum guidelines require individuals to give their own thoughts and attempt to answer the questions.
  • #1
yong1986
1
0
We done an experiment of tensile test where we used the testometric machine that pulls different kind of material (aluminium, PVC, steel, brass) and generated graph stress/strain and etc, now we come to these questions:

1. Explain why the plastics/ polymer has a lower modulus and strength than the metal.
2. Explain what is happening at the atomic (or molecular) level in the elastic region and the plastic region of each material.


Can anyone provides complete answers?

Thanks!
 
Physics news on Phys.org
  • #2
The answer to your questions has to do with the types of bonding in the materials along with the crystalline structures. I don't have the time to write an entire post about it but do some research on the following topics.

covalent bonds
ionic bonds
metallic bonds
crystalline structures
shear angle
molecular geometry
 
  • #3
yong1986 said:
We done an experiment of tensile test where we used the testometric machine that pulls different kind of material (aluminium, PVC, steel, brass) and generated graph stress/strain and etc, now we come to these questions:

1. Explain why the plastics/ polymer has a lower modulus and strength than the metal.
2. Explain what is happening at the atomic (or molecular) level in the elastic region and the plastic region of each material.


Can anyone provides complete answers?

Thanks!

Forum guidelines require you to give your thoughts (i.e. make an attempt).

CS
 

What is the difference between modulus and strength?

Modulus refers to the stiffness or rigidity of a material, while strength refers to its ability to withstand external forces without breaking or deforming. In other words, modulus measures a material's resistance to elastic deformation, while strength measures its resistance to plastic deformation.

How do modulus and strength differ between metals and plastics?

Generally, metals have higher modulus and strength compared to plastics. This is because metals have a more ordered atomic structure, allowing for stronger interatomic bonds. Plastics, on the other hand, have a more random molecular structure which makes them more flexible and less resistant to external forces.

How are modulus and strength measured in metals and plastics?

Modulus is typically measured using tensile or compression testing, which involves applying a force to a material and measuring its resulting deformation. Strength, on the other hand, can be measured using various tests such as tensile, compression, or impact tests.

What factors can affect the modulus and strength of metals and plastics?

The modulus and strength of a material can be affected by factors such as temperature, strain rate, and the presence of impurities or defects in the material. Additionally, the type and amount of alloying elements in metals and the type of polymer and its molecular weight in plastics can also impact these properties.

Which is more important in material selection, modulus or strength?

It depends on the specific application and the desired properties of the material. For example, in structural applications where rigidity is crucial, modulus may be more important. On the other hand, in applications where the material needs to withstand external forces, strength may be the more critical factor. Ultimately, both modulus and strength should be considered when selecting a material for a specific application.

Similar threads

Young's Modulus and the Poisson Ratio of Aluminium
    • Introductory Physics Homework Help
Replies
1
Views
1K
Force needed for hole punch in Metal
    • Introductory Physics Homework Help
Replies
1
Views
1K
Stress-Strain Graphs of different materials
    • Introductory Physics Homework Help
Replies
9
Views
3K
What is the Young's Modulus of Aluminum, Steel, and Brass?
    • Introductory Physics Homework Help
Replies
14
Views
2K
12 ton frame lowered on plastic --> What Happens?
    • Engineering and Comp Sci Homework Help
Replies
10
Views
958
Extracting mechanical properties from strain-stress plot (real test)
    • Mechanical Engineering
Replies
5
Views
765
B Question about stress - strain graph and definition of hardness
    • Classical Physics
Replies
4
Views
1K
Measuring Tensile Strength in an alternative way
    • Mechanics
Replies
2
Views
1K
Understanding Yield Strength & Stress Strain Curve
    • Mechanical Engineering
Replies
2
Views
4K
ASTM A1011 CS Type B Steel: Yield Strength & Properties
    • Mechanical Engineering
Replies
1
Views
5K

Hot Threads

Recent Insights

Back
Top