EML 2023 – Stress Analysis

Lecture 1 – Stress State

EML 2023Department of Mechanical and Aerospace Engineering

Static Stress Analysis

• The material we will cover in this topic will be studied in detail in the courses:– EGM 3520, Mechanics of Materials– EML 4500, Finite Element Analysis and Design

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EML 2023Department of Mechanical and Aerospace Engineering 3

EML 2023Department of Mechanical and Aerospace Engineering 4

EML 2023Department of Mechanical and Aerospace Engineering

Stress and Strain

strain,

forcestress,

area

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EML 2023Department of Mechanical and Aerospace Engineering

Loading conditions

axial loading torsion bending

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EML 2023Department of Mechanical and Aerospace Engineering

Stress state

an orientation can be found such thatthere are no shear stresses

the normal stresses are called theprincipal stresses

the stress state at any point can bedescribed by 6 values: three normal stresses and three shear stresses

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EML 2023Department of Mechanical and Aerospace Engineering

von Mises stress

• Von Mises defined a single value for the stress state at a point based on the six stress values

• in terms of the principal stresses

2 22 2 2 213

2von mises x y x z y z xy xz yz

2 2 2

1 2 1 3 2 3

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2von mises

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EML 2023Department of Mechanical and Aerospace Engineering

von Mises stress

• design objective– at every point, keep the von

Mises stress below the yield stress of the material

strain,

forcestress,

area

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