Design and structural engineering

Stresses and stress concentrations

This module remains focused on technical interpretation: nominal stress, structural stress and local notch stress at the toe, root or an undercut. In a welded structure, the decisive question is whether the geometry forces the load path through an abrupt change of direction or a small effective area.

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Topic overview

This module remains focused on technical interpretation: nominal stress, structural stress and local notch stress at the toe, root or an undercut. In a welded structure, the decisive question is whether the geometry forces the load path through an abrupt change of direction or a small effective area.

Stress calculated from the selected load-bearing cross-section. It is used for conventional sizing but does not account for the local weld-toe geometry or imperfections.

Increased stress caused by the geometrical change in the structural detail. It does not yet include the micro-local notch at the weld toe or root.

Maximum local stress at the toe, root, undercut or sharp transition. It is particularly decisive for fatigue.

What the module covers

  • Stresses and stress concentration in welded joints
  • Technical logic for assessing a detail
  • 1. Nominal stress
  • 2. Effective structural stress
  • 3. Notch stress
  • Mohr’s circle — plane stress
  • Fillet weld — indicative calculation
Educational content does not replace current standards, approved WPS/WPQR documentation or decisions by competent welding coordination personnel.