Shear strain

...The vertical strain minus the horizontal strain is collectively called the normal strain, and the ratio of the horizontal strain ε ₁ to the vertical strain ε is called the Poisson's ratio. Next, as shown in Figure 2, when a rectangular parallelepiped of height h ₀ is deformed (sheared) so that two parallel faces are displaced from each other, if the angle of the displacement (shear angle) is γ (units are rad), this γ is called the shear strain (since strain is the amount of deformation per unit dimension, shear strain is originally defined as λ/ h ₀ = tan γ in the figure, but if the deformation is small, it can be set as tan γ = γ, and is given as the change in angle). The strains mentioned here use the original dimensions as the basic dimensions, and are called nominal strains. ...

*Some of the terminology that mentions "shear strain" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…縦ひずみ‐横ひずみを垂直ひずみnormal strainと総称し，横ひずみε₁と縦ひずみεの比はポアソン比と呼ぶ。　次に図2に示すように，高さh₀の直方体を互いに平行な2面がずれるように変形(せん断変形)させたとき，そのずれの角(せん断角)をγ(単位はrad)とすると，このγをせん断ひずみshear strainという(ひずみは単位寸法あたりの変形量であるから，本来，せん断ひずみは図においてλ/h₀＝tanγで定義されるが，変形が微小であればtanγ＝γとおくことができ，角度の変化として与えられる)。ここに述べたひずみは基本寸法として原寸法を用いており公称ひずみnominal strainsと呼ぶ。…

※「shear strain」について言及している用語解説の一部を掲載しています。

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