Response Function for a Damped, Linear Oscillator

In summary, the conversation is about finding the response function for a damped linear oscillator subjected to a forcing function. The person is having trouble understanding the problem and is seeking tips and resources to get started. They have found the response function for each condition, but are unsure how to find the impulse to the response function and which response function to use for each condition. They have also received private help and are familiar with the step function u(t).
  • #1
piano.lisa
34
0
I have a damped linear oscillator, originally at rest in its equilibrium position [therefore, x(0)=0 and x'(0)=0]. It is subjected to a forcing function:
F(t)/m =
{0, if t<0
{a(t/tau), if 0<t<tau
{a, if t>tau

I have to find the response function. However, when I attempt to find the step function H(t), I will end up with 0 as my constants [because of the a(t/tau) when t=0], therefore, saying that there is no step function.
The textbook and my lecture notes are not great aids at solving this problem. Please provide me with any tips to getting started, or any useful websites.

Thank you.
 
Last edited:
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  • #2
piano.lisa said:
I have a damped linear oscillator, originally at rest in its equilibrium position [therefore, x(0)=0 and x'(0)=0]. It is subjected to a forcing function:
F(t)/m =
{0, if t<0
{a(t/tau), if 0<t<tau
{a, if t>tau

I have to find the response function. However, when I attempt to find the step function H(t), I will end up with 0 as my constants [because of the a(t/tau) when t=0], therefore, saying that there is no step function.
The textbook and my lecture notes are not great aids at solving this problem. Please provide me with any tips to getting started, or any useful websites.

Thank you.
Your forcing function is a ramp between 0 and tau and a step for t > tau. A ramp is 0 for t = 0. I don´t see what is your problem.
How are you trying to calculate the response function?
 
  • #3
The true problem is the fact that we weren't properly taught response functions and our textbook is lacking.
Therefore, by following the example in the textbook, I simply get x(t) = 0.
What I really need here is not only help, but a quick tutorial.

How do you start a problem about finding the response function?
There is no reference to "ramps" in the textbook, so I don't know how to treat them in the response function. The only thing in the textbook is the step function.
 
  • #4
piano.lisa said:
The true problem is the fact that we weren't properly taught response functions and our textbook is lacking.
Therefore, by following the example in the textbook, I simply get x(t) = 0.
What I really need here is not only help, but a quick tutorial.

How do you start a problem about finding the response function?
There is no reference to "ramps" in the textbook, so I don't know how to treat them in the response function. The only thing in the textbook is the step function.
There is no way to help you if we don't know what the problem is. Could you transcribe the text of your problem and the example in your textbook?
 
  • #6
jalaldn said:
http://id.mind.net/~zona/mmts/functionInstitute/functionInstitute.html
http://www.ima.umn.edu/~arnold/graphics-g.html

I'm sorry, but those links were of no help.

SGT: I will scan the long question later tonight.

Any other help is strongly appreciated. I really need it!
 
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  • #7
Attached are what I have done for the question so far. I have found the Response function for each condition. However, in order to find the "response" that the professor will be looking for, do I have to find the impulse to the response function?
If so, how can I achieve this? Do I take x(t) = H(tau) - H(t) - H(0) ? Also, which response function do I use for each of H(tau), H(t), and H(0)?

Please answer as soon as possible. Thank you.

http://www.oksana-design.com/response_function_p1.jpg"
http://www.oksana-design.com/response_function_p2.jpg"
 
Last edited by a moderator:
  • #8
piano.lisa said:
Attached are what I have done for the question so far. I have found the Response function for each condition. However, in order to find the "response" that the professor will be looking for, do I have to find the impulse to the response function?
If so, how can I achieve this? Do I take x(t) = H(tau) - H(t) - H(0) ? Also, which response function do I use for each of H(tau), H(t), and H(0)?

Please answer as soon as possible. Thank you.

http://www.oksana-design.com/response_function_p1.jpg"
http://www.oksana-design.com/response_function_p2.jpg"
I have already answered to your private message.
There is an alternate way to find the response. Are you familiar with the step function u(t)?
 
Last edited by a moderator:
  • #9
Thanks for your help SGT.
 

1. What is a response function for a damped, linear oscillator?

A response function for a damped, linear oscillator is a mathematical representation of how a system responds to an external force or input. It describes the relationship between the input and the resulting output of the system.

2. How is the response function for a damped, linear oscillator calculated?

The response function for a damped, linear oscillator is calculated using the transfer function of the system. This transfer function takes into account the system's natural frequency, damping coefficient, and the external force or input.

3. What is the significance of the damping coefficient in the response function for a damped, linear oscillator?

The damping coefficient in the response function for a damped, linear oscillator determines the rate at which the system dissipates energy. A higher damping coefficient means the system will reach its equilibrium state more quickly, while a lower damping coefficient means the system will oscillate for a longer period of time.

4. How does the natural frequency affect the response function for a damped, linear oscillator?

The natural frequency of a system is the frequency at which it oscillates in the absence of external forces. In the response function for a damped, linear oscillator, a higher natural frequency means the system will oscillate at a faster rate, while a lower natural frequency means the system will oscillate at a slower rate.

5. Can the response function for a damped, linear oscillator be used to predict the behavior of a system?

Yes, the response function for a damped, linear oscillator can be used to predict the behavior of a system. By analyzing the response function, we can determine how a system will respond to different inputs and make predictions about its behavior, such as stability, amplitude, and frequency of oscillation.

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