Structural Engineering & Statics
where the load goes
Concept

Thermal movement — where it appears

The strain a temperature change asks a member for, which costs nothing if the member is free and produces stress in proportion to how much it is not.

Named by 2 essays across 2 fields — each of them below, with the objects they name alongside it.

free at one end10.8 mmno stressheld at both ends75.6 MPaheld by a spring of 100 kN/mm53.2 MPaE·α·ΔT = 210000 × 12×10⁻⁶ × 30 = 75.6 MPa, at every length

The movement nobody applied

A temperature change is the only load in this collection that a structure can decline. Let it move and it produces a movement with no stress; hold it and it produces a stress with no movement — and that stress contains no length, no area and no second moment, so a bracket and a bridge girder carry exactly the same one.

deflection · thermal movement the sectionstrainfreeplanestress-3.98+1.83resultant force 8.3e-14 kN · resultant moment 3.0e-12 kNmno restraint anywhere, and the member is stressed from end to end

The stress nobody restrained

A bridge deck lying loose on its bearings, with nothing holding it anywhere, develops four newtons per square millimetre when the sun comes out. The stress is not caused by restraint. It is caused by plane sections, and it is invisible to every equilibrium check that could be made on the member.

sections · thermal gradient

Named alongside it

The objects these essays reach for when they reach for this one.

RestraintServiceabilityThermal gradientBridge deckBucklingCrackingCurvatureEigenstressExpansion jointIndeterminacyPlane sectionsResidual stress

All concepts