- Include gradual transitions in the design. The most common cause of stress concentrations is an abrupt change in geometry or an abrupt shape transition. ...
- Use relief notches. ...
- Opt for several small relief notches as opposed to a single long one. ...
- Avoid sharp corners.
How do you reduce stress concentration in stepped shaft?
- Methods to reduce stress concentration:
- (a) Additional Notches and Holes in Tension Member:
- (b) Fillet Radius, Undercutting and Notch for Member in Bending.
- (c) Drilling Additional Holes for Shaft:
- (d) Reduction of Stress Concentration in Threaded Members.
What is meant by stress concentration?
A stress concentration, also known as a stress riser/raiser, is a point in a part where the stress is significantly greater than its surrounding area . Stress concentrations occur as a result of irregularities in the geometry or within the material of a component structure that cause an interruption of the stress flow.
What is normal stress?
When a force acts perpendicular (or “normal”) to the surface of an object , it exerts a normal stress. When a force acts parallel to the surface of an object, it exerts a shear stress.
What is stress concentration What are the causes of it what are the methods of reducing it?
Stress concentrations occur when there are irregularities in the geometry or material of a structural component that cause an interruption to the flow of stress . This arises from such details as holes, grooves, notches and fillets. Stress concentrations may also occur from accidental damage such as nicks and scratches.
What are the effects of stress concentration?
When a body has stress concentration in it, the chances of its failure increases . The body tends to fail from the place where it has more concentration of stress. A body has less life that has more irregularities within it. In order to increase the life of the body, the intensity of stress should be reduced.
Do chamfers reduce stress concentration?
Fillets generally give a lower stress concentration factor than chamfers . Chamfers are more forgiving when fitting mating parts. i.e. even if there are inaccuracies in a chamfer mating parts might fit together. But if the radius of fillet changes it will be difficult to fit the mating parts.
Which radius provide for reduce stress concentration?
Geometrical features such as notches and corners give rise to stress concentrations. In industrial components these features are often designed with a constant radius, however it is already known that a more complex shape, having a variable radius , can have a much lower stress concentration factor.
What is the maximum stress concentration factor?
A stress concentration factor is the ratio of the highest stress (s max )) to a reference stress (s) of the gross cross-section. As the radius of curvature approaches zero, the maximum stress approaches infinity . Note that the stress concentration factor is a function of the geometry of a crack, and not of its size.
What is stress diagram?
A stress strain diagram or stress strain curve is used to illustrate the relationship between a material’s stress and strain . ... Stress strain curves visually display the material’s deformation in response to a tensile, compressive, or torsional load.
Why stress concentration is important?
Stress concentration factor (Kt), is a dimensionless factor which is used to quantify how concentrated the stress is in a material. ... So it is important to analyze the component for stress concentration in order to have proper functioning of the component with safety .
How do you find KT?
kT = RT/N .
What are the 4 categories of stress?
- Time stress.
- Anticipatory stress.
- Situational stress.
- Encounter stress.
What is formula of stress?
stress = (elastic modulus) × strain .
Is bending stress a normal stress?
Bending stress is the normal stress that an object encounters when it is subjected to a large load at a particular point that causes the object to bend and become fatigued. Bending stress occurs when operating industrial equipment and in concrete and metallic structures when they are subjected to a tensile load.
What is factor of safety and working stress?
It is defined, in general, as the ratio of the maximum stress to. the working stress. Mathematically, Factor of safety = Maximum stress . Working or design stress .
