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Hole Near an Edge — Stress Concentration (Kt) Calculator

PartialIntermediateANSYSSW SimGeneralStress concentrationMaterials

What you'll get

Find Kt and the stress at the free edge and both sides of a hole close to a plate edge, the load on the ligament, and whether it yields.

Put a hole close to a free edge and the thin strip of material between them — the ligament — has to carry the load the hole can't. The stress at the hole edge nearest the free edge climbs well above the textbook 3σ of an isolated hole.

How to use it

  • Enter the hole radius a, the distance c from the hole centre to the free edge, the thickness h and the remote tensile stress σ.
  • Pick a material, or choose Custom and enter the yield strength.
  • Results update as you type. Units are mm, N and MPa.

Rule of thumb: keep c at least 2a to 3a.

Semi-infinite plate in tension σ with a hole of radius a whose centre is distance c from the free edge; point A on the free edge, B on the hole edge nearest the free edge, C on the far side of the hole; thickness h
Inputs
mm
mm
mm
MPa

Sy 250 MPa · Sut 460 MPa · E 200 GPa — typical values, verify against the datasheet.

Results

MARGINALFoS = 1.35
a/ca/c
0.500
KtgAK_{tgA} (free edge)
0.700
KtgBK_{tgB} (hole, near edge)
3.699
KtgCK_{tgC} (hole, far side)
3.198
KtnK_{tn} (on ligament A–B)
2.136
σmax\sigma_{max} (peak, at B)
184.96 MPa
vs 3σ\text{vs } 3\sigma (isolated hole, 150.00 MPa)
+23.3%

Design tip: keep c at least 2a to 3a.

Step-by-step hand calculation

Full working with your numbers

Every step to the factor of safety, written out with your own inputs — the way you'd write it in an exam.

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Charts

Kt chart with your design point

Kt at A, B and C against a/c with your design point marked, and a side-by-side of the stresses at A, B and C.

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Validate it in ANSYS / SolidWorks Simulation

  1. Use a half model with a symmetry plane through the hole centre, normal to the load.

The full validation guide

Model setup, mesh refinement, where to probe, and how close your FEA result should land.

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Related resources

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