What is the difference between "Strong" and "Stiff"?

  • Thread starter kenny1999
  • Start date
  • Tags
    Difference
In summary, the conversation discusses the difference between strength and stiffness in a material, with stiffness referring to the amount of deformation under stress and strength referring to the stress at which failure or permanent deformation occurs. The Young's modulus is mentioned as a measure of stiffness. It is also mentioned that a material can be strong but not stiff, or stiff but not strong. The example of concrete is given, where it has high compressive strength but is relatively easy to break off in chunks. The conversation also briefly touches on the difference between strong and stiff drinks in the context of alcohol.
  • #1
kenny1999
235
4
Sometimes I see people saying that a material is strong and stiff and ...

What is the difference between strong and stiff in the chemistry sense?

Could it be strong but not stiff or stiff but not strong?
 
Engineering news on Phys.org
  • #2
I'll let someone else give a more formal/chemical assessment, however the stiffness of a material relates to how much deformation occurs given an applied stress, whilst strength refers to the value of stress at certain reference points: i.e. ultimate tensile strength being the stress at which failure occurs, yield strength being the stress above which permanent deformation occurs, etc.

The Young's modulus of a material is a measure of stiffness, specifically it is a ratio of stress against strain.
kenny1999 said:
Could it be strong but not stiff or stiff but not strong?

Yes, I believe so.
 
Last edited by a moderator:
  • #3
kenny1999 said:
Could it be strong but not stiff or stiff but not strong?
Concrete has incredibly high compressive strength, but it is relatively easy to torque off a chunk.

You could stand on concrete just a couple of inches thick, but that same thickness, if you picked it up, would easily crumble in your hands.

(Actually, I don't think that's what constitutes "stiffness").
 
  • #4
When I saw the title of the thread I thought it would be about alcohol. As in a strong drink against a stiff drink.
 
  • #5
PeroK said:
As in a strong drink against a stiff drink.
strong: straight liquor
stiff drink: a smoothie (more resistant to flow)
 
  • #6
I am afraid it is apples and oranges.
 
  • #7
Borek said:
I am afraid it is apples and oranges.
Welllll, a screwdriver can be made both strong and stiff, but an Appletini is neither.

tenor.gif
 

Related to What is the difference between "Strong" and "Stiff"?

1. What is the definition of "strong" and "stiff"?

Strong and stiff are both terms used to describe the mechanical properties of a material. Strong refers to a material's ability to withstand external forces without breaking or deforming, while stiff refers to a material's resistance to bending or flexing under a load.

2. Can a material be strong but not stiff, or vice versa?

Yes, it is possible for a material to be strong but not stiff, or stiff but not strong. For example, rubber is strong in tension but very flexible and not stiff, while steel is both strong and stiff.

3. How are strength and stiffness measured?

Strength is typically measured by the amount of force a material can withstand before breaking, while stiffness is measured by the material's ability to resist deformation under a load. These properties can be quantified using various tests such as tensile, compression, or bending tests.

4. What factors affect the strength and stiffness of a material?

The strength and stiffness of a material can be influenced by a variety of factors, including the material's composition, microstructure, and processing methods. For example, adding certain alloys or heat treating a material can increase its strength and stiffness.

5. How do strength and stiffness impact the performance of a material?

The strength and stiffness of a material are important factors to consider when determining its suitability for a specific application. For example, a bridge must be strong enough to support the weight of vehicles and stiff enough to resist bending under the weight. In contrast, a spring must be strong enough to return to its original shape after being compressed, but also flexible enough to absorb shock without breaking.

Similar threads

What is the most incompressible elastomer?
    • Mechanical Engineering
Replies
2
Views
841
Structure adding rotational stiffness to a plate
    • Mechanical Engineering
Replies
15
Views
1K
Signal transfer properties of a spring-suspended platform?
    • Mechanical Engineering
Replies
9
Views
1K
What is the density of a constant? (spring constant)
    • Mechanical Engineering
Replies
7
Views
2K
Inverse Kinematics: Oscillators and Multi-Bar Links
    • Mechanical Engineering
Replies
2
Views
288
Stiffness Matrix Method: Symmetry vs Introducing a new node / joint
    • Mechanical Engineering
Replies
1
Views
2K
Why are stiff springs more responsive?
    • Mechanical Engineering
Replies
23
Views
9K
Question about strengths of Aluminum/Titanium Tubing for a White Cane
    • Mechanical Engineering
Replies
19
Views
605
Clutch stiffness and hysteresis - Role in gearbox NVH
    • Mechanical Engineering
Replies
6
Views
3K
What Ansys Element Models Tension-Only Cables with Hyperelastic Materials?
    • Mechanical Engineering
Replies
1
Views
3K

Hot Threads

Recent Insights

Back
Top