What is the formula of contact pressure?
Contact pressure = Applied Load/ Area of contact.
What is Hertz pressure?
The Hertz contact stress usually refers to the stress close to the area of contact between two spheres of different radii. After Hertz’s work, people do a lot of study on the stresses arising from the contact between two elastic bodies. An improvement over the Hertzian theory was provided by Johnson et al.
What is Hertzian stress?
Hertzian contact stress refers to the localized stresses that develop as two curved surfaces come in contact and deform slightly under the imposed loads. It gives the contact stress as a function of the normal contact force, the radii of curvature of both bodies and the modulus of elasticity of both bodies.
What is maximum contact pressure?
The maximum contact pressure which is carried purely elastically in the steady-state is known as the ‘shakedown limit’ and is the rational design criterion for tribological contacts such as ball bearings and railway rails and wheels.
What is contact radius?
The contact radius between two objects depend on their material properties (e.g. elasticity) and on their geometry. If you press a rigid sphere into a fluid then after a while the wet area has radius a = sqrt(2Rh-h^2).
What does Hertzian mean?
Definition of hertzian : of, relating to, or developed by the physicist Hertz.
What is Hertz model?
The Hertz model. The most widely used model for data processing in AFM nanoindentation experiments is the Hertz model. In particular, if the AFM tip has a spherical shape and if the indentation depth is significantly smaller than the tip radius then the loading data are fitted into the equation [7, 13, 14]:
What is the JKR model?
The JKR model [1] (Johnson, Kendall, Roberts – 1964-1971) applies to tips with large curvature radius (most likely to macroscopic bodies) and small stiffness. Such systems are called strongly adhesive. The model accounts for the influence of Van der Waals forces within the contact zone.
What will be shape of the contact between 2 cylinders at the tip?
In theory, the contact between two spheres occurs at a point, and the contact between two cylinders occurs as a line. In the analysis of Hertz contact stresses, a convex surface (the ball or roller) has a positive radius and the concave surface (the raceway) has a negative radius.
What is contact stress?
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.
How do you calculate contact stiffness?
the base structural stiffness is calculated by multiplying the base eigenvalue (or frequency) with its associated effective modal mass; the contact stiffness of each individual contact element is set equal to the base structural stiffness over the element contact area, multiplied by a scale factor. 2.
What is a Hertzian contact stress calculator?
HertzWin is a free Hertzian contact stress calculator. It can be used to calculate mechanical point and line contact dimensions and material stresses. The application performs all calculations automatically. A clearly laid-out window allows you to enter material properties, dimensions and loads.
How to calculate the pressure distribution proposed by Hertz?
The summary of this is that pressure distribution proposed by Hertz p= p 0(1 (r=a)2)1=2(4) where ris the radius of the measure pressure and p 0is the maximum pressure of contact between two solids. This relation with the geometry determined for contact of two spheres results in the radius of the area of contact as a= ˇp 0R e
What is the theory of Hertzian contact?
Hertzian theory of non-adhesive elastic contact In Hertz’s classical theory of contact, he focused primarily on non-adhesive contact where no tension force is allowed to occur within the contact area. The following assumptions are made in determining the solutions of Hertzian contact problems: The strains are small and within the elastic limit.
These stresses were first studied by the German physicist Heinrich Hertz in 1881. In this honor, the name of this stress is given as Hertzian Stress (Contact Stress). > The surfaces are smooth and frictionless. > The contact area is small compared to the size of the bodies.