What Defines 'n' in the Equation r = n+3?

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In summary: The variable n represents the number of internal hinges or joints that may join two members together. This can cause confusion, so it is best not to focus too much on these equations. In the given example, r is 3 and n is 0 because there are no internal hinges between the supports.
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chetzread
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Homework Statement


from the equation r = n+3 , some notes stated n = number of hinges , while some book stated n as number of joints ...Which is true ?

Homework Equations

The Attempt at a Solution


taking the example 3.1 , if it's number of joints , then there are 1 hinge (pin) , right ? I don't really understand the notes on the internet ... What does joints in beam mean ?
 

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your tiny attachment is unreadable.
 
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phinds said:
your tiny attachment is unreadable.
phinds said:
your tiny attachment is unreadable.
 

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phinds said:
your tiny attachment is unreadable.
i checked it an open the uploaded image ...There's no problem . Perhaps you can refresh your browser and try ?
http://imgur.com/a/IDi0d
 
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in this equation for beam determinancy, r is the number of possible force and moment reactions at the external supports, and n is the number of internal hinges (pins, or joints) that sometimes join 2 members together.

In the example, the left support can support forces in 2 directions, and the other support just a vertical force, so r is 3 , and since there are no internal hinges in between supports, n is 0.

These equations tend to cause confusion so don't dwell on them too much.
 
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  • #6
PhanthomJay said:
in this equation for beam determinancy, r is the number of possible force and moment reactions at the external supports, and n is the number of internal hinges (pins, or joints) that sometimes join 2 members together.

In the example, the left support can support forces in 2 directions, and the other support just a vertical force, so r is 3 , and since there are no internal hinges in between supports, n is 0.

These equations tend to cause confusion so don't dwell on them too much.
although there's pin and roller , but there's only 1 member ( not joining 2 members together) , so n = 0 ?
 
  • #7
chetzread said:
although there's pin and roller , but there's only 1 member ( not joining 2 members together) , so n = 0 ?
Yes
 
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Related to What Defines 'n' in the Equation r = n+3?

1. What is stability and determinacy?

Stability and determinacy refer to the ability of a system to maintain its equilibrium or steady state in the face of external disturbances or changes. It also relates to the uniqueness of solutions in a dynamic system.

2. How do stability and determinacy differ?

Stability and determinacy are related concepts but differ in their focus. Stability is concerned with the ability of a system to resist changes and return to its original state, while determinacy is concerned with the uniqueness of solutions in a system.

3. What factors affect stability and determinacy?

There are a variety of factors that can affect stability and determinacy, including the nature and strength of external disturbances, the complexity of the system's dynamics, and the initial conditions of the system.

4. Why are stability and determinacy important in science?

Stability and determinacy are important concepts in science because they allow us to understand and predict the behavior of complex systems. They also help us identify potential vulnerabilities or instabilities in systems, which can inform decision-making and problem-solving.

5. How can stability and determinacy be measured or analyzed?

There are various mathematical and computational methods for measuring and analyzing stability and determinacy in a system. These include stability analysis, bifurcation analysis, and numerical simulations. Real-world experiments and observations can also provide valuable insights into the stability and determinacy of a system.

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