Samples
Sample engineering calculations
15 worked examples across 8 disciplines, each set out the way an engineer would on paper: the inputs, the working, the checks and a results summary. Open one, change an input and watch every result below it update — no account needed.
Electrical
A single-phase 230 V final subcircuit feeds a 32 A load at the end of a long run. Current flows out on the active and back on the neutral, so the circuit…
Sizing the battery and PV array for a small off-grid cabin. Power (W) is a rate; energy (Wh) is what batteries store and loads consume — the schedule…
Facade
A glazed panel spans between vertical mullions; each mullion spans floor to floor and hands the wind load to slab fixings. From a specified design wind…
Geotechnical
A basement excavation partly reused as site fill: the same soil occupies different volumes as bank (in the ground), loose (in the truck) and compacted (in…
Sliding, overturning and bearing checks for a mass-concrete gravity wall retaining level granular backfill, per metre of wall. Active pressure from…
Hydraulics
The motor power needed to pump water up to a header tank: velocity from the flow, friction from the Darcy–Weisbach equation with an explicit Swamee–Jain…
Mechanical
The wrench torque that develops a target preload in a metric bolt, split into its thread and collar (under-head friction) parts, with the bolt stress…
Sizing the electric motor of a winch that lifts a load through a single gear stage: the torque to accelerate the load and both shafts, the steady lifting…
A fan on resilient mounts, modelled as a single degree of freedom: one mass on the summed mount stiffness with light damping. The question is how much of…
Stopping distance on a downhill grade, split into thinking and braking parts. Braking model: constant deceleration at the friction limit, a = g(μ·cosθ −…
Process
Diluting a concentrate to a working-strength batch: how much concentrate and water make the target mass, checked by a mass balance on the active…
Structural
Ultimate-limit-state bending design of a singly reinforced rectangular beam using the rectangular stress block of AS 3600:2018. Scope: bending strength…
A simply supported steel beam carries a strip of office floor. The area loads become a line load, then bending strength and deflection are checked and two…
Thermal
Sizing the area of a water-to-water counterflow exchanger by the LMTD method: the duty from the hot stream, the cold outlet from an energy balance, the…
Heat leaks into an esky by conduction through its foam walls and lid and melts the ice inside. Steady one-dimensional conduction through all six faces…