Types of Stresses
Types of Stresses: only two basic stresses exists : (1) normal stress and (2) shear shear stress. Other stresses either are similar to these basic stresses or are a combination of these e.g. bending stress is a combination tensile, compressive and shear stresses. Torsional stress, as encountered in twisting of a shaft is a shearing stress.
Let us define the normal stresses and shear stresses in the following sections.
Normal stresses : We have defined stress as force per unit area. If the stresses are normal to the areas concerned, then these are termed as normal stresses. The normal stresses are generally denoted by a Greek letter ( s )
This is also known as uniaxial state of stress, because the stresses acts only in one direction however, such a state rarely exists, therefore we have biaxial and triaxial state of stresses where either the two mutually perpendicular normal stresses acts or three mutually perpendicular normal stresses acts as shown in the figures below :
Tensile or compressive stresses : The normal stresses can be either tensile or compressive whether the stresses acts out of the area or into the area
Bearing Stress : When one object presses against another, it is referred to a bearing stress ( They are in fact the compressive stresses ).