Cushion Curve Chart Simulator (2D)

Real protective-packaging engineers size a cushion pad using a "cushion curve" — a chart of peak impact deceleration against a product's static stress, generated once per material and thickness by an energy-balance calculation rather than by dropping every possible product. This 2D simulator draws that exact chart live: pick a cushion material and thickness, and it solves the nonlinear stress-strain energy balance across a sweep of static stresses to plot the curve, then marks your current product's operating point on it. Beside the chart, a genuinely separate time-stepped spring-damper simulation animates one real drop test with the same parameters, so you can see where the idealized energy-method curve and the messier, damped, sometimes-bottoms-out reality agree — and where they don't. Push the fragility threshold, pad thickness and material against each other to find the thinnest, lowest-volume cushion whose curve still stays under the product's fragility line.