Validation
Fifty eight cases with known answers run through the same pipeline your studies use, and every one lands inside its tolerance.
58 of 58 within tolerance
Each bar runs from 0 to the case’s tolerance, so a shorter bar means a closer answer.
| Case | Known answer | Wobbl | Error | Tolerance | Result | Confidence |
|---|---|---|---|---|---|---|
| Textbook formulas | ||||||
| Cantilever tip deflectionA steel bar fixed at one end with a weight at the tip, and how far the tip drops | 0.8016 mm | 0.7956 mm | 0.74% | 3% | Pass | High |
| Cantilever bending stress at mid spanThe same steel bar, and the bending stress halfway along it | 30 MPa | 29.94 MPa | 0.21% | 3% | Pass | High |
| Cantilever on an elastic root | 2.002 mm | 2.002 mm | 0.01% | 3% | Pass | High |
| Plate with a hole in tensionA flat plate with a hole in the middle, pulled in tension | 30.35 MPa | 29.89 MPa | 1.54% | 4% | Pass | High |
| Thick walled pressure vesselA thick walled tube holding very high pressure inside | 231.3 MPa | 232.3 MPa | 0.43% | 3% | Pass | High |
| Round shaft in torsionA round steel shaft held at one end and twisted at the other | 55.13 MPa | 55.6 MPa | 0.85% | 3% | Pass | High |
| Cantilever under its own weightA one meter steel bar, fixed at one end, sagging under its own weight | 1.443 mm | 1.441 mm | 0.16% | 3% | Pass | High |
| Industry benchmarks | ||||||
| NAFEMS LE1 elliptic membraneAn oval ring pulled outward around its outer edge, a standard test for stress solvers | 92.7 MPa | 92.92 MPa | 0.23% | 4% | Pass | High |
| NAFEMS LE10 thick plate under pressureA thick oval plate pressed on its top face, a standard test for 3D stress | -5.38 MPa | -5.412 MPa | 0.59% | 5% | Pass | Medium |
| Real parts from the bake off | ||||||
| Cast motor mount with a belt pull through four boltsA cast aluminum motor mount pulled by a conveyor belt through four bolts | 124.3 MPa | 123.7 MPa | 0.49% | 5% | Pass | Medium |
| ABS enclosure shell pressed near a cornerThe molded plastic shell of a device, pressed with 250 N near one corner | 93 MPa | 92.98 MPa | 0.02% | 10% | Pass | Medium |
| PA12 truss drone arm at full thrustA printed drone arm with truss windows, at full motor thrust and torque | 11.5 MPa | 11.49 MPa | 0.11% | 8% | Pass | High |
| PLA shelf bracket, 0.5 mm inside cornerA printed shelf bracket with a sharp inside corner, resting against a wall | 78 MPa | 80.48 MPa | 3.18% | 8% | Pass | High |
| PLA shelf bracket, 6 mm filletThe same shelf bracket with its inside corner rounded to 6 mm | 25.3 MPa | 26.38 MPa | 4.26% | 5% | Pass | Medium |
| Heat | ||||||
| Conduction through a slab into convectionAn aluminum bar held at 100 C at one end and cooled by air at the other | 97.67 C | 97.67 C | 0.00% | 1% | Pass | High |
| Aluminum cube cooling in airA small aluminum cube cooling down in air for ten minutes | 58.01 C | 58.27 C | 0.44% | 1% | Pass | High |
| Aluminum bar whose end jumps to 120 CAn aluminum bar at 20 C whose end is suddenly held at 120 C, read 10 mm in after 2 s | 52.68 C | 52.23 C | 0.85% | 2% | Pass | High |
| Circuits | ||||||
| Red LED on 5 V through 150 ohmA red LED on 5 V through a 150 ohm resistor | 20 mA | 20 mA | 0.00% | 0.5% | Pass | High |
| RC chargingA capacitor charging through a resistor | 3.161 V | 3.161 V | 0.00% | 0.2% | Pass | High |
| Buck converter output rippleThe output ripple of a 12 V to 5 V buck converter | 7.949 mV | 8.561 mV | 7.70% | 15% | Pass | High |
| 12 V divider of 10k over 4.7k, as a netlist | 3.837 V | 3.837 V | 0.00% | 0.1% | Pass | High |
| 9 V through 470 ohm into a 1N4148, as a netlist | 17.55 mA | 17.55 mA | 0.00% | 0.5% | Pass | High |
| 1 kohm into 100 nF, swept in frequency | 1592 Hz | 1591 Hz | 0.01% | 1% | Pass | High |
| LM358 non inverting stage, 100k over 10k | 3.322 V | 3.322 V | 0.00% | 0.2% | Pass | High |
| LM317 with 240 and 720 ohm at 100 mA | 5.036 V | 5.028 V | 0.17% | 1% | Pass | High |
| NE555 astable, 1k, 10k and 100 nF | 1.455 ms | 1.48 ms | 1.67% | 4% | Pass | High |
| Motion | ||||||
| Ball dropped 300 m without airA ball dropped 300 m with the air taken away, and how long it takes to land | 7.822 s | 7.822 s | 0.00% | 0.1% | Pass | High |
| Granite sphere dropped 300 m through airThe falling rock example’s granite sphere dropped 300 m through air of one density, and how fast it lands | 56.7 m/s | 56.7 m/s | 0.00% | 0.1% | Pass | High |
| Ball thrown at 30 m/s and 40 deg without airA ball thrown at 30 m/s and 40 degrees with no air, and how far it goes | 90.38 m | 90.38 m | 0.00% | 0.1% | Pass | High |
| Vertical rocket at constant thrust in a vacuumA rocket climbing straight up at a constant thrust in a vacuum, and its speed at burnout | 412.8 m/s | 412.8 m/s | 0.00% | 0.1% | Pass | High |
| Vertical rocket at constant thrust in a vacuumThe same rocket, and how high it is at burnout | 757.7 m | 757.7 m | 0.00% | 0.1% | Pass | High |
| Payload under a 2 m parachuteA 5 kg payload sinking under a 2 m parachute, and how fast it comes down | 4.122 m/s | 4.122 m/s | 0.00% | 0.1% | Pass | High |
| Uncertainty | ||||||
| Cantilever with load and stiffness scatter, mean deflection | 0.8036 mm | 0.7982 mm | 0.67% | 3% | Pass | High |
| Cantilever with load and stiffness scatter, spread of deflection | 0.08993 mm | 0.08917 mm | 0.85% | 3% | Pass | High |
| Sobol indices of the Ishigami function | 0.2437 | 0.243 | 0.29% | 2% | Pass | Not rated |
| Modulus calibrated from synthetic cantilever gauges | 194000 MPa | 194200 MPa | 0.09% | 1% | Pass | Not rated |
| Film coefficient and air temperature from a synthetic cooling curve | 12 W/m2K | 12.12 W/m2K | 0.97% | 5% | Pass | Not rated |
| Buckling, vibration and fatigue | ||||||
| Steel column clamped at the base and free at the topA steel column clamped at its base and pushed down at its free top, and the load it buckles at | 2.57 x | 2.574 x | 0.13% | 2% | Pass | High |
| Cantilever strip, first three bending frequenciesA steel strip clamped at one end, and how fast it rings in its first three bending modes | 953.9 Hz | 951.7 Hz | 0.23% | 2% | Pass | High |
| Simply supported plate, first three frequenciesA steel plate resting on all four edges, and its first three natural frequencies | 1081 Hz | 1078 Hz | 0.32% | 2% | Pass | High |
| Tip mass on a strip shaken through resonanceA heavy weight on the end of a strip, shaken at the base through resonance, and how far the weight swings | 175.3 mm | 175.9 mm | 0.35% | 2% | Pass | High |
| Tip mass on a strip pushed through resonance by a swept forceThe same weight on the strip, now pushed at the tip by a force swept through resonance, and how far it swings | 5.209 mm | 5.192 mm | 0.33% | 2% | Pass | High |
| Shigley Example 6-2, 1050 HR steel at 55 kpsiShigley’s textbook example of a polished steel bar bent back and forth, and how many cycles it lasts | 77500 cycles | 79270 cycles | 2.28% | 3% | Pass | Medium |
| Combustion | ||||||
| Stoichiometric methane in air | 2226 K | 2225 K | 0.04% | 0.5% | Pass | High |
| LOX and LH2 at 1000 psia, O/F 6 | 2304 m/s | 2305 m/s | 0.05% | 0.5% | Pass | Not rated |
| LOX and LH2 at 1000 psia, O/F 6, area ratio 40 | 451.7 s | 451.7 s | 0.00% | 0.5% | Pass | Not rated |
| KNSU propellant at 1000 psia | 919 m/s | 918.8 m/s | 0.02% | 1% | Pass | Not rated |
| Motor | ||||||
| End burner at a steady Kn of 150 | 2848000 Pa | 2848000 Pa | 0.00% | 0.5% | Pass | Not rated |
| Tube burning inside and out | 0.5419 s | 0.5435 s | 0.30% | 1% | Pass | Not rated |
| MIT O3800 APCP motor static fire | 31540 N s | 34460 N s | 9.26% | 10% | Pass | High |
| MIT O3100 APCP motor static fire, wider throat | 30970 N s | 32470 N s | 4.85% | 10% | Pass | Medium |
| Battery | ||||||
| Charged LiCoO2 18650 in an oven | 155 C | 156 C | 0.62% | 3% | Pass | Not rated |
| Mechanism | ||||||
| Pendulum released at 120 degrees | 2.755 s | 2.755 s | 0.00% | 0.1% | Pass | High |
| Crank rocker four bar of 120, 30, 125 and 45 mm | 87.98 deg | 87.97 deg | 0.00% | 0.2% | Pass | High |
| Two link arm holding 300 g at its pick point | 0.9128 N m | 0.9128 N m | 0.00% | 0.5% | Pass | High |
| FA-130 through 12:36 and 10:40 against 5 mN m | 624 rpm | 623.9 rpm | 0.03% | 0.5% | Pass | High |
| Steel balls of 1 and 3 kg, elastic | 0.5 m/s | 0.5 m/s | 0.00% | 0.5% | Pass | Medium |
| Steel balls of 1 and 3 kg, restitution 0.5 | 0.375 m/s | 0.3752 m/s | 0.05% | 0.5% | Pass | Medium |
Every number above comes from one full run of wobbl validate, which took 29 minutes on a 2018
six core laptop. Cases added since then come from runs of their own, such as the bar whose end
jumps to 120 C in 0.1.1 and the six motion cases, which take under three seconds together. Each case whose reference is exact for the modeled setup lands within 2%. The
real parts are compared with reference models that were refined until they stopped changing,
and their tolerances follow how settled those references were.
Medium confidence in this table is Wobbl naming what a number leans on, not a miss. On NAFEMS LE10 the 2 mm band that stands in for the benchmark’s line support makes a peak far above the answer, which is excluded and named. On the cast motor mount the verdict flips if the servo is treated as rigid instead of a bolt group. On the enclosure shell large deflection theory lowers the peak by 11%, so the linear answer is the conservative one, and the reference is linear too. On the filleted bracket the bonded screw bore reads nearly twice the real peak. The buck converter is compared with the ideal waveform formula, which leaves out the switch and diode drops that ngspice models, so it gets a wider tolerance.
You can run every case yourself with wobbl validate.