Truss-One
Education
$14.99
Every screen opens on a worked example and redraws as you type. Forty-five of them, from a section's properties to a retaining wall. Offline, no account.
Forty-five screens of structural analysis: section properties and principal
axes, shear flow and the shear centre, the plastic section and its shape
factor, axial members, plane stress and Mohr's circle, strain rosettes,
elastic constants, yield criteria, thin-walled pressure vessels, beam
diagrams, bending stress, transverse shear, transformed sections, combined
axial and bending, deflection by standard case and by integration, trusses by
joints and by sections, force diagrams, a model canvas, matrix solution of
plane frames, circular torsion, non-circular and thin-walled torsion,
combined bending and torsion, Euler columns with seven end conditions, the
column strength curve, columns that started bent, columns loaded off centre by
the secant formula, inelastic buckling by both the tangent and the reduced
modulus, effective length for a column in a frame, plate buckling with its
scalloped envelope, beam-columns, the movement of one chosen joint by virtual
work, energy methods with Castigliano beside the unit load, supports on springs
and beams bedded on soil, the classical methods -- slope-deflection and the
force method -- checked against the matrix answer, second-order analysis with
the buckling load found by counting pivots, plastic collapse by minimising over
mechanisms, torsional and lateral-torsional buckling, the approximate methods
bracketed from both sides, the whole model's own buckling mode, and a gravity
retaining wall with its three failure modes.
Every screen opens on a worked example rather than an empty form, and every
number redraws as you type. There is no calculate button and nothing to wait
for. Drag a span, a thickness or a load and watch the results and the figure
move together — which is the thing a single static answer cannot show you.
WHAT MAKES IT DIFFERENT
Each result names the relation that produced it. A stress that came from
combined axial and bending is labelled as such, so you can see which relation
you are looking at instead of trusting a table.
Where more than one answer is right, the app asks instead of deciding. A
fixed-ended column braced against sway and one free to sway have the same
end conditions on a drawing and critical loads four times apart; the app
makes you say which, and tells you why it matters.
Where a relation genuinely has no value — a bore as wide as the shaft, a
column of no length — it shows a dash or an infinity sign and puts the reason
beside it, rather than a zero you might act on.
Where a model is near the edge of its range, it says so next to the number.
A member too stubby for beam theory gets a note, not a footnote.
HOW IT WAS CHECKED
Every relation is verified against sixty-digit reference values computed
independently of the app itself, from public-domain sources: NACA and NASA
technical reports, MIL-HDBK-5J, and the Forest Products Laboratory's wood
handbook. The macOS and iPadOS implementations are compared against the same
reference values, so both give the same answer to the last few digits.
The theory manual on the support site lists every relation, every assumption,
and every limit. It is worth reading before you buy.
WHAT IT IS NOT
This is a mechanics tool, not a design-code checker. It applies no national or
regional standard, computes no allowable stress, and applies no load factors.
It will not tell you whether a member passes; it will tell you what the
mechanics says, and show you the working.
REQUIREMENTS
macOS 14 or later, iPadOS 17 or later. Works entirely offline: no network
connection is used, no account is needed, and nothing is collected.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
The developer, 德海 于, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- 德海 于
- Size
- 3.7 MB
- Category
- Education
- Compatibility
Requires iPadOS 17.0 or later.
- iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPad
- Age Rating
4+
- 4+
- Copyright
- Copyright © 2026 Yu Dehai
