According to such experiments, the kind of failure depends on the type of material. Failure of ductile materials most of metals occurs when the elastic limit is reached and yielding commences. Failure of non-ductile materials e. For ductile materials, one failure theory is that of maximum shear stress. The actual failure mode of each material is unique, though certain criteria can be applied to classes of materials.
From Wikibooks, open books for an open world. There is 1 pending change awaiting review. Category : Book:Strength of Materials. The maximum stress is called the Principal stress and the plane at which the maximum stress induced is called the Principal plane and the shear stress will be zero on the principal planes. When a force is applied normal Along X-axis to the surface area of the disc as shown then there will be normal stress on the YZ plane.
There will be no shear stresses. When a force is applied tangentially to the disc surface along Z-axis then there will be shear stress induced in the layers of the disc. When a force is applied neither tangentially nor normally as shown in the above fig then there will be both shear and the normal stress will be induced.
Now we have the idea how the normal stress and the shear stress will be induced by applying the different types of loads. All we need to do is consider there are so many numbers of planes which are passing thru a single point in an object. All these planes will have the normal stress as well as the shear stress as we mentioned above case iii. The resulted Normal stress and the shear stress will be represented as shown in the below figure.
We already have some standard formulas to find the Normal stresses and the shear stresses Referred from the standard textbooks of the strength of materials. To avoid brittle failure, the principal stresses at any point in a structure should lie within the square failure envelope based on the maximum normal stress theory. The shear stresses are denoted by And the principal stresses are denoted by.
For three-dimensional case, all three planes have zero shear stresses, and these planes are mutually perpendicular, and normal stresses have maximum and minimum stress values and these are the normal stresses that represent the principal maximal and minimal stress. Example: 3D Stress in hub-a a steel shaft is force-fitted into the hub. Principal deviatoric stresses are obtained by subtracting mean Stress from each principal Stress.
Orientation of the principal Stress is computed by equating shear stress to zero in x-y direction at the principle plane rotated through an angle theta. Normal Stress is the force applied to the body per unit area. Principal Stress is the stress applied to the body having zero shear stress principal Stress is in the form of normal Stress giving maximum and minimum stresses on the principal plane.
Bending Stress is the Stress that occurs in the body due to the application of a large amount of load that causes the object to bend. Principal Stress shows the maximum and minimum normal stress. The shear stress due to torque has maximum magnitude at the outer fiber. The bending stress is due to horizontal loads horizontal gear forces, belt, or chain forces that induce bending stresses which are maximum at the outer fibers.
Solution: Given: Principal stresses are calculated as,. Your email address will not be published. Save my name, email, and website in this browser for the next time I comment. Principal Stress.
0コメント