Finding the Maximum Displacement and Time of a Piston in a Spring-Damper System

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In summary, the conversation is about a question regarding the maximum displacement and time taken for a piston traveling in a tube with a spring and damper. The equation for force and damping is mentioned, along with a known solution. The conversation ends with a question about finding a link between the known data and displacement. The conversation also mentions finding a solution in a textbook.
  • #1
Lukergr
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I know this question has already been asked, but the given answer di not help me. Hopefully someone can post their full solution?

A piston of mass 4.53(kg) is traveling in a tube with a velocity of 15.24(m/s). It engages a spring of stiffness 350 (N/cm) and a damper with a coefficient of 1.75 (N.s/cm)

What is the maximum displacement of the piston and how long does it take to reach this point?

Homework Equations


F= -kx
where
x is the displacement vector - the distance and direction in which the spring is deformed
F is the resulting force vector - the magnitude and direction of the restoring force the spring exerts
k is the spring constant or force constant of the spring.

velocity=displacement/time

Damping : http://en.wikipedia.org/wiki/Damping

The Attempt at a Solution


I have the solutions, Max. Displacement = 128.6(mm), Time Taken = 0.0157(s). I am stuggling to find a link between the known data and the displacement. Hope you can help

Homework Statement


Homework Equations


The Attempt at a Solution

 
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  • #2
Hi Lukergr. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif

The damper resists with a force proportional to velocity, with units N per m/s, written F=-k.x' so it's a 2nd order differential equation you'll be looking to solve. Motion of the piston is resisted by both the spring and the damper. You'll find a worked example in almost every textbook on physics or calculus 101.
 
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  • #3
Is this a diff eq based course?
 

1. What is meant by "free vibrations"?

Free vibrations refer to the vibrations of a system that occur without any external force or input. This means that the system is able to oscillate freely, without any external energy source or disturbance affecting its motion.

2. How do you calculate the natural frequency of a system?

The natural frequency of a system can be calculated using the formula fn = 1/2π√(k/m), where fn is the natural frequency, k is the stiffness of the system, and m is the mass of the system.

3. What factors affect the natural frequency of a system?

The natural frequency of a system is affected by the stiffness of the system, the mass of the system, and the boundary conditions (such as fixed or free ends). Changes in any of these factors can result in a different natural frequency.

4. How do you determine the mode shapes of a vibrating system?

The mode shapes of a vibrating system can be determined by solving the eigenvalue problem for the system. This involves finding the eigenvalues and eigenvectors of the system's mass and stiffness matrices using mathematical techniques such as matrix diagonalization.

5. What is the difference between free vibrations and forced vibrations?

Free vibrations occur without any external force or input, while forced vibrations occur when an external force or input is applied to the system. In forced vibrations, the system's motion is influenced by the frequency and amplitude of the external force, whereas in free vibrations the system's natural frequency determines its motion.

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