Laplace Transform of Mass-Spring-Damper System
Published on May 29, 2025
Find the Laplace Transform of the solution for a mass-spring-damper system with an applied force, given initial conditions. The solution involves setting up the differential equation, applying the Laplace Transform, and solving for X(s).
Question
Answer
- Mass,
- Spring constant,
- Damping force: The damping constant is “twice the velocity”. This means the damping force is proportional to the velocity,
. The problem states “damping constant of twice the velocity”, which is a bit ambiguous. However, in the context of a damping force , if the damping constant itself is “twice the velocity”, it would imply , making the damping force , which is non-linear. A more standard interpretation for “damping constant of twice the velocity” in a linear system is that the damping coefficient is 2. Let’s assume the damping force is . - Applied force,
(positive force)
The general form of the equation of motion for a mass-spring-damper system is:
-
is the inertial force. -
is the damping force. -
is the spring force (restoring force). -
is the external applied force.
We need to find the Laplace Transform of the solution,
The initial conditions are given as
-
-
-
-
(for a constant C)
Factor out