2D Suspension Dynamics Simulator
Interactive quarter-car suspension model showing double wishbone geometry, spring-damper dynamics, and real-time response to road inputs
About this Simulator
This interactive simulator demonstrates how a double wishbone suspension system responds to road inputs. Watch the control arms rotate, the spring compress, and the damper absorb energy as the wheel encounters bumps. Adjust parameters to see how spring rate, damping, and mass affect ride comfort and handling.
Physics & Formulas
Quarter-Car Model Equations:
$$m_s \ddot{z}_s + c(\dot{z}_s - \dot{z}_u) + k_s(z_s - z_u) = 0$$
$$m_u \ddot{z}_u - c(\dot{z}_s - \dot{z}_u) - k_s(z_s - z_u) + k_t(z_u - z_r) = 0$$
Where: m_s = sprung mass, m_u = unsprung mass, c = damping coefficient, k_s = spring stiffness, k_t = tire stiffness, z_r = road input
How to Use
- Click 'Start Simulation' to begin the animation
- Select a road profile (Step Bump, Speed Bump, or Rough Road)
- Adjust Spring Rate to see stiffer vs softer suspension behavior
- Modify Damping Ratio: <0.7 is underdamped (bouncy), >0.7 is overdamped (stiff)
- Toggle 'Show Forces' to visualize spring and damper forces
- Watch the graphs to see body and wheel displacement over time
Frequently Asked Questions
What is a quarter-car model?
A quarter-car model represents one corner of a vehicle, simplifying the full vehicle dynamics to a 2-degree-of-freedom system with sprung mass (body) and unsprung mass (wheel). It's widely used in automotive engineering for suspension analysis.
What does damping ratio mean?
Damping ratio (ζ) describes how oscillations decay. ζ < 1 is underdamped (bouncy), ζ = 1 is critically damped (fastest return without overshoot), ζ > 1 is overdamped (slow return). Most cars use ζ ≈ 0.2-0.4 for comfort.
Why does the upper control arm move differently than the lower one?
In a double wishbone suspension, the arms have different lengths and pivot positions. This creates a specific wheel path (camber change) during suspension travel, optimizing tire contact with the road.
What is tire stiffness?
Tire stiffness (k_t) represents the tire's radial spring rate, typically 150-250 N/mm for passenger cars. It acts as a secondary spring between the wheel and road surface.
