PSM Opening Checker

Openings in primary supporting member webs — DNV-RU-SHIP Pt.3 Ch.3 Sec.6 [7.2], Sec.7 [1.4.7], Ch.6 Sec.6 [2.2.2]

v2.7
Project information
Acceptance criteria — Ch.6 Sec.6 [2.2.2] Table 2

Per-beam yield from the model overrides this.

β / α0.85 / 0
C_s-max / C_t0.85 / 0.85
C_s applied0.85
σ_allow = C_s · R_eH—
τ_allow = C_t · R_eH/√3—
Scope
Computed by this tool
  • Shear on the net section: effective web height of Sec.7 [1.4.7] (opening plus any stiffener cut-out in the same section), A_shr = (h_w + t_f + t_p)·t_w·10−² of [1.4.6], τ_net ≤ C_t·τ_eH.
  • Bending on the net section through the opening, Z recomputed with the hole removed — Ch.6 Sec.6 [2.2.2].
  • [7.2.3] depth, edge distance, length, spacing of adjacent openings, hole in a bracket.
  • [7.3.2] for shell / longitudinal bulkhead / longitudinal girder: 2× opening breadth below the strength deck.
  • [7.2.4] + Ch.8 Sec.2 [7.1]: the required depth of the edge stiffener when the limits are exceeded.
  • Ch.6 Sec.6 [2.1.2] prescriptive shear area with f_shr of Table 1, as a second opinion where there is no beam model.
  • Ch.8 Sec.2 [5.1.1] tripping bracket spacing, since an opening close to the flange weakens its lateral support.
  • Secondary (Vierendeel) bending of the strips above and below the opening — a screening calculation, see the note on that panel.
Not computed — stays with the engineer
  • Web buckling in way of the opening: η_Opening ≤ η_all per Ch.8 Sec.1 Table 1 → DNV-CG-0128 Sec.3 [3.4]. The tool prepares the panels P1/P2 and the stresses that check needs (including τ_av = τ_av,web·h/(h−h_0) of CG-0128 Table 6) but does not evaluate the reduction factors.
  • Fatigue of the free edge and of the reinforcement welds.
  • Corner radii, edge preparation, local stress concentration.
  • The proximity rules of [7.2.1] are a checklist on the detail page, not a calculation: bracket toes, pillars, span ends of floors and girders, narrow cofferdam diaphragms. Aft peak heavy floors in way of the rudder horn (Ch.3 Sec.5 [4.2.2]) and structure under windlass / crane (Ch.11 Sec.2 [5.4.3]) are on that list too.
  • Whether the beam model itself is right — spans, fixity, effective breadth.
Model XML (sections, beams, material)

Click to upload the model XML

Sectionsnone loaded
Results XML (stresses)

Click to upload the results XML

Components found—
Stress unit in the file—
Beams with results0

The opening cuts the web, so the shear carried by the web governs: Q_z for a horizontal girder, Q_y for a vertical web frame.

Opening definition

Sec.7 [1.4.7]: a cut-out for a passing stiffener eats the same web section. Enter its height here and it is deducted from h_eff together with the opening.

par is the relative position along the beam in the results file: 0 at the first node, 1 at the second, 0.5 at mid-span. The file carries only the stations the analysis wrote (often 0 / 0.5 / 1); a position between them is interpolated linearly.
This setting only decides which stresses the beam check table and the detail checks use, as a single-point screening. It does not move the opening: the layout page evaluates every opening at its own x with the shear that belongs there. Leave it on the envelope maximum unless you know where the opening will sit.

Manual beam (works without XML)
Beams
0
checked
Opening accepted
0
stress + [7.2.3]
Reinforcement needed
0
[7.2.4]
Max UC
—
shear or bending
Beam layout — plan view
Colour = max(UC shear, UC bending). Click a beam to take it to the layout page.
UC ≤ 0.85 0.85 < UC ≤ 1.0 UC > 1.0 selected opening needs reinforcement support point
Beam by beam

Click a column heading to sort, click a row to open that beam in the opening layout.

BeamSectionh_wh_effR_eH ττ_netUC shear σσ_netUC bend h_o max[7.2.3]Status
Governing beam — what may be cut
Layout input

Or click the beam in the plan view on the beam check page.

[7.2.3] separates "mid-span" from "ends of the span" without giving a number; 0.2ℓ is the support region of Ch.6 Sec.6 Table 1 notes 1 and 2.

[7.2.1]: no openings at bracket toes and span ends of floors and girders. Default is one web depth, which is the usual yard practice; 200 mm is the figure [7.1.2] uses for stiffener openings.

Answer
Plan — click a beam
Elevation of the selected beam
Opening by opening
#x (mm)parZoneh_ow_oClear to nextττ_netUCh_o max hereStatus
All beams — how many openings fit

Each beam with its own length from the model and its own shear at each position; the opening size is the one entered on the input page. Ends is how many other beams meet at each end of that beam, with S when the model has a support point there — an end where several members meet is an intersection or a support, an end where none do is either a boundary condition or a free end, and only you can tell which. Click a row to open that beam above.

BeamL (m)EndsOpeningsPitchPositions x (mm)max UCh_o maxElevationStatus
Number of openings vs. their length

Uniform pitch over the usable length. [7.2.3]: the length of an unreinforced opening is limited to the clear distance to the adjacent opening at mid-span, and to 25% of it at the ends of the span; in single skin sections also to the greater of the web depth and 0.6·s.

N openingsPitchMax w_o, mid-spanMax w_o, end regionGoverning limit
Reinforcement — [7.2.4] and Ch.8 Sec.2 [7.1]
Buckling input — CG-0128 Sec.3 [3.4]
Secondary (Vierendeel) bending — screening
Position rules
Prescriptive shear area — Ch.6 Sec.6 [2.1.2]
Flange support — Ch.8 Sec.2 [5.1.1] Table 4
[7.2.1] — where an opening shall not be cut

These are locations, not formulae; the tool cannot see them in the model. Confirm each one on the drawing.