Energy Dissipation Calculator for Construction

Calculator Inputs

Fields update based on your selected method.

Calculation method

Pick the scenario that matches your design check.

Input type

Use weight when you know dead load directly.

Mass, m (kg)

Example: equipment skid mass, moving slab, or vehicle mass.

Weight, W (kN)

Converted to mass using g = 9.80665 m/s².

Initial velocity, v₁ (m/s)

Common for drop or impact checks.

Final velocity, v₂ (m/s)

Use 0 for a complete stop.

Dissipation efficiency, η (0–1)

Models fraction of ΔKE absorbed by the system.

Stiffness, k (kN/m)

Effective lateral stiffness for the selected mode.

Displacement amplitude, X (mm)

Peak response amplitude used in the cycle estimate.

Damping ratio, ζ (0–0.50)

Typical structural range: 0.02–0.10.

Number of cycles, N

Use a demand estimate from loading history.

Flow rate, Q (m³/s)

Discharge through the jump region.

Upstream depth, y₁ (m)

Depth before the jump (supercritical region).

Downstream depth, y₂ (m)

Depth after the jump (subcritical region).

Density, ρ (kg/m³)

Default is fresh water at ~1000 kg/m³.

Duration, t (s)

Optional; used to convert power into energy.

Result appears above this form after submission.

Formulas used

Impact / Kinetic reduction: ΔKE = ½ m (v₁² − v₂²); dissipated energy E = η · ΔKE.
Structural damping (SDOF, approximate): E_cycle ≈ 2π ζ k X²; total energy E_total = N · E_cycle.
Hydraulic jump head loss: ΔE = (y₂ − y₁)³ / (4 y₁ y₂); power P = ρ g Q ΔE; energy over time E = P · t.

Use consistent units. The calculator converts kN/m→N/m and mm→m automatically.

How to use this calculator

Select the method that matches your problem: impact, damping, or hydraulic jump.
Enter inputs with their stated units. Keep velocities and depths positive.
Click Submit to see results above the form and below the header.
Review warnings, notes, and the “full output values” section for assumptions.
Use Download CSV or Download PDF for documentation.

Example data table

These examples show typical inputs and outputs for each method.

Method	Key inputs	Output (headline)
Impact	m=2500 kg, v₁=2.0 m/s, v₂=0.0 m/s, η=0.90	4.50 kJ dissipated
Impact	W=30 kN, v₁=1.5 m/s, v₂=0.5 m/s, η=0.80	2.45 kJ dissipated
Damping	k=8000 kN/m, X=25 mm, ζ=0.10, N=10	78.54 kJ total
Damping	k=5000 kN/m, X=15 mm, ζ=0.05, N=20	35.34 kJ total
Hydraulic jump	Q=3.5 m³/s, y₁=0.45 m, y₂=1.20 m, ρ=1000	~13.41 kW dissipated
Hydraulic jump	Q=2.0 m³/s, y₁=0.35 m, y₂=0.90 m, t=60 s	Power and energy reported

Practical notes

For damping checks, k and X should reflect the same mode and direction.
For impact checks, η can approximate losses in bumpers, pads, or soil crushing.
For hydraulic jumps, confirm y₁ and y₂ are physically consistent with your channel control.
Always apply project-specific safety factors and code requirements.

Calculator Inputs

Formulas used

How to use this calculator

Example data table

Practical notes

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