Structural Engineering & Statics
where the load goes
Concept

Shear strength — where it appears

The stress at which a material fails in shear, which for a ductile metal is inferred from a yield criterion rather than measured. Von Mises gives 0.577 of the yield stress and Tresca half of it; for timber and concrete the property is measured, and it is far below the compressive strength.

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

10321003161000316201234size (mm, logarithmic)nominal strength (N/mm²)the specimen: 3.10the structure: 1.14the plastic limitfracture mechanicsthe test overestimates by 2.71× · D₀ = 120 mm

The bigger one is the weaker one

Two geometrically similar beams of the same concrete should fail at the same nominal stress, because a strength is supposed to be a material property. They do not. The large one fails at less, and the reason is that a crack releases energy in proportion to a volume and consumes it in proportion to an area.

materials · size effect 02040608005101520angle to the grain (degrees)strength (N/mm²)Hankinsona straight linetension4.47 at 45°, not 11.821 per cent of the strength along the grain, at half a right angle

The material that has a direction

Every material in this collection so far has had one modulus and one strength. Timber has three of each, differing by more than an order of magnitude, and the consequence is not a correction to steel design — it is a different set of checks with a different one governing.

materials · anisotropy

Named alongside it

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

AnisotropyBearingBrittle failureCharacteristic lengthConcrete strengthCrackElastic modulusFlawFractureFracture energyFracture mechanicsGrain

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