Single DOF mass-spring-damper system
We begin with the simplest case, a single-degree-of-freedom (S-DOF) mass-spring-damper system.
Simulation Initialization
To initialize the simulation, the following inputs are used:
- Geometry and connection:
- The spring length is \(l_0=1.0\mathrm{~m}\). Since there is only a single node, we only need to input its own initial position at \(x(t=0)=1.0\mathrm{~m}\), which is set to the spring’s equilibrium position \(x=l_0\) in this case.
- Physical parameters:
- (i) Mass \(m = 1.0\mathrm{~kg}\).
- (ii) Damping viscosity \(c = 0.1\).
- (iii) Spring stiffness \(k = 10.0\mathrm{~N/m}\).
- Numerical parameters:
- (i) Total simulation time \(T=10.0\mathrm{~s}\).
- (ii) Time step size \(\mathrm{dt}=0.01\mathrm{~s}\).
- (iii) Numerical force tolerance \(\mathrm{tol}=1\times 10^{-6}\).
- Boundary conditions:
- No boundary condition is applied for this simple S-DOF system.
- Initial conditions:
- (i) Initial position \(x(t=0) = 1.0 \mathrm{~m}\).
- (ii) Initial velocity \(\dot{x}(t=0) = 0.0 \mathrm{~m/s}\).
- Loading steps:
- A periodic external force \(F^{\rm ext} = F_{0}\sin(\omega t)\) is applied to the system, where the force magnitude is \(F_{0}=1.0\mathrm{~N}\) and the frequency is \(\omega=1.0 \mathrm{~rad/s}\).