Internal force per unit area; normal stress σ=F/A, shear stress τ=V/A.
Normal stress σ=F/A acts perpendicular to a surface and shear stress τ=V/A parallel to it. Units are pascals (N/m²). Stress at a point depends on the plane considered. Allowable stress is limited by material strength.
A 10 mm diameter steel rod carrying 20 kN has σ ≈ 255 MPa.
Stress shows how load is shared across a section, and it is the first quantity checked against material strength in any design.
Internal force per unit area; normal stress σ=F/A, shear stress τ=V/A.
Stress shows how load is shared across a section, and it is the first quantity checked against material strength in any design.
Pascals in SI, or newtons per square millimetre, which is equal to megapascals. Engineers usually quote strength in MPa.
They have the same units and are both force per area, but stress is internal in a solid and can be tensile, compressive or shear.
Typical applications include checking the stress in a bolt under preload, sizing a bar to keep normal stress below an allowable value and finding the shear stress in a pin of a clevis joint.
Study "Banked curves" first (topic 42 of 106 in Engineering Mechanics). It covers the groundwork this topic builds on.
Tension positive, compression negative. Bearing stress under bolts. Average vs local stress.
A 10 mm diameter steel rod carrying 20 kN has σ ≈ 255 MPa.
The next topic is "Strain", which builds directly on this one.
It is classed as Intermediate in Engineering Mechanics (topic 43 of 106). It is an intermediate topic. Work through the beginner topics in Engineering Mechanics first.
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