材料力学的2个注记

Two notes of mechanics of materials

运用弹性力学理论,证明了材料力学的2个命题。一个是各向同性材料的3个弹性常数E,G,μ满足关系式G=E/2(1+μ);另一个是主单元体上任一方向截面上的正应力σ与切应力τ都必在三向应力圆的阴影区域内。

This article utilized the theory of elastic mechanics,proved two propositions of materials mechanics.First,three elastic constant E,G,μ of isotropic material satisfy relationship： G=E/2（1＋ μ）,second,the normal stress and the shear stress at any direction section on the main unit-body must be in the shadow region of three-dimensional stress circle.