What is Hertz theory?
The Hertz theory of contact mechanics has been extended, as in the JKR theory, to describe the equilibrium contact of adhering elastic solids. The JKR formalism has been generalized and extended by Maugis and coworkers to describe certain dynamic elastic contacts.
What is Hertz pressure?
When two surfaces of different radii are in contact and a load is applied (even an extremely small load), a small contact area is formed, and the surfaces experience very high stresses. These stresses are known as Hertz (or Hertizian) contact stresses.
What is contact stress?
Description. Contact stress happens when force is concentrated on a small area of the body, pinching or crushing tissue and causing discomfort and often pain. You experience contact stress, for example, when the edge of a work surface digs into your forearm or wrist.
What is the basic difference between the Hertz and JKR contact models?
The Hertz model does not consider the adhesion in contact. The JKR model includes only a short-range adhesion in the contact area, actually it is a ± function with the work of adhesion 1° . The DMT model shows a long- range surface force which acts outside the radius of the circle of contact.
What is the bearing stress?
Bearing stress is the contact pressure between the separate bodies. It differs from compressive stress, as it is an internal stress caused by compressive forces.
What is Hertzian contact?
Hertzian contact stress refers to the localized stresses that develop as two curved surfaces come in contact and deform slightly under the imposed loads. This amount of deformation is dependent on the modulus of elasticity of the material in contact.
How do you reduce contact stress?
Modify the task to reduce or eliminate the use of tools.Add padding to tools and/or wear padded gloves.Check to be sure the tool fits the user’s hand and replace or modify the grip if it doesn’t fit well.
What is an elastic half space?
2.1 The Elastic Half-Space. This idealisation, in which bodies of arbitrary surface profile are regarded as semi-infinite in extent and having a plane surface, is made almost universally in elastic contact stress theory.
What does residual stress mean?
Contact Us. Residual stresses are those stresses that remain in an object (in particular, in a welded component) even in the absence of external loading or thermal gradients. In some cases, residual stresses result in significant plastic deformation, leading to warping and distortion of an object.
What is soil contact pressure?
Contact pressure is the actual pressure transmitted from the foundation to the soil. On the assumption that the vertical settlement of the foundation is uniform, it is found from the elastic theory that the stress intensity at the edges of a foundation on cohesive soils is infinite.