Verification
How ILX Structures is tested
Software you trust with a structure has to show its work. The analysis engine and the design checks are tested automatically, on every change, against answers that are known independently of the program.
Every release passes over 1,000 automated checks: closed-form solutions, textbook benchmarks, published code examples and whole-model regression tests, run on every change.
ILX Studio, LLC is not affiliated with or endorsed by AISC, ACI, AWC, TMS, ASCE or any other code organization.
The method
Closed-form solutions
Beams, cantilevers, frames, columns and plates with a known exact answer are solved by the engine and compared with the published formula, within a stated tolerance. Deflections, moments, reactions, buckling loads and natural frequencies all have their own cases.
Textbook and code benchmarks
Published benchmark problems for plates, thick-walled cylinders, deep beams and dynamic response, and worked examples from the AISC Steel Construction Manual and ACI 318-19 hand calculations, are re-run and must agree.
Whole-model regression
Complete models (a portal frame, a continuous beam, a truss) are solved on every change and every deflection, reaction and member end force is compared with the stored result. Global equilibrium is checked for every load case.
Code provisions, clause by clause
Load combinations, wind, snow and seismic loads, steel, concrete, wood and masonry checks, seismic frame provisions and pushover hinge rules are tested against the tables and equations of ASCE 7-22, AISC 360-16, AISC 341-22, ASCE 41-23, AISC 342-22, ACI 318-19, NDS 2018 and TMS 402-16.
Honest tolerances
Where a mesh or an iteration cannot reach the exact answer, the test states the engineering tolerance and checks that the error shrinks as the mesh is refined. A tolerance is never loosened to hide a real difference.
Every change, before every release
The whole suite runs automatically on every change. A release ships only when every check passes.
Example problems
A selection of the problems the engine solves on every change, each compared with an answer that does not come from ILX Structures.
| Problem | Compared against | Area |
|---|---|---|
| Simply supported beam, point load at midspan | Closed-form deflection, moment and reactions | Static analysis |
| Cantilever with a tip load | Closed-form tip deflection and fixed-end moment | Static analysis |
| Fixed-fixed beam with a point load | Closed-form end and midspan moments | Static analysis |
| Portal frame under a lateral load | Hand calculation of sway and base moments | Static analysis |
| Pinned and cantilever columns | Euler buckling loads | Buckling |
| Cantilever and simply supported beams | Exact fundamental frequencies | Modal analysis |
| Simply supported square plate, uniform load | Thin-plate theory (Timoshenko), with a mesh convergence check | Plates and shells |
| Thick-walled cylinder under pressure | Lamé hoop and radial stresses | Axisymmetric solids |
| Deep and slender beams | Shear deformation theory against the slender-beam limit | Beam theory |
| Column under axial load and sway | Second-order amplification against the closed form | P-Delta |
| Multi-story frame, design spectrum | Base shear against the combination of the modes; ASCE 7-22 scaling | Response spectrum |
| W14x90 column, 14 ft | AISC Steel Construction Manual column table, within 1% | Steel design |
| Rectangular concrete beam and tied column | ACI 318-19 hand calculations of flexural and axial strength | Concrete design |
| Portal frame, complete model | Stored results of every deflection, reaction and member force, plus global equilibrium | Regression |
Your part
Testing shows that the program solves the equations right. Whether the model represents the structure is engineering judgment: you, or the engineer of record you work for, review and approve every model, result and report. ILX Structures shows every assumption it makes, asks for the inputs the code leaves to the engineer, and marks any check outside its scope instead of passing it. See the Disclaimer.