Short-time Dynamics of Frictional Strength in Dry Friction
... Slip, δ(X,t), will evolve at any given location, X, traversed by a detachment front (either arrested or not). No slip will occur prior to a front’s arrival. The dynamic evolution of the frictional strength is closely linked to the rapid processes of contact detachment and subsequent reattachment tha ...
... Slip, δ(X,t), will evolve at any given location, X, traversed by a detachment front (either arrested or not). No slip will occur prior to a front’s arrival. The dynamic evolution of the frictional strength is closely linked to the rapid processes of contact detachment and subsequent reattachment tha ...
elastic deformation
... We're all aware that a very large force will produce a permanent, or irreversible, distortion of even a large piece of a strong material. The permanent distortion may be a bending which doesn't spring back when the force is removed or it may be fracture. Designers usually work to assure that their m ...
... We're all aware that a very large force will produce a permanent, or irreversible, distortion of even a large piece of a strong material. The permanent distortion may be a bending which doesn't spring back when the force is removed or it may be fracture. Designers usually work to assure that their m ...
Physical Response to Collision between Deformable Objects
... nature’s laws. It means that they can pass right through each other unless we create mechanisms to impose the same nature’s constraints. In virtual worlds as in the real world, interactions between objects and other environmental effects are mediated by forces applied onto them. In particular, if we ...
... nature’s laws. It means that they can pass right through each other unless we create mechanisms to impose the same nature’s constraints. In virtual worlds as in the real world, interactions between objects and other environmental effects are mediated by forces applied onto them. In particular, if we ...
PM6-93
... Of considerable interest is the lubrication of synovial joints in animals, such as the hip joint. This can be explained neither in terms of hydrodynamic nor boundary layer lubrication. Rather it seems that the lubrication is of another type known as elastohydrodynamic lubrication in which the surfac ...
... Of considerable interest is the lubrication of synovial joints in animals, such as the hip joint. This can be explained neither in terms of hydrodynamic nor boundary layer lubrication. Rather it seems that the lubrication is of another type known as elastohydrodynamic lubrication in which the surfac ...
PM6 FRICTION
... The presence of surface layers can result in a breakdown of the F = mN relationship - the coefficient of friction µ can vary with the load N. This can happen if the layers are such that they remain intact at low loads but break down at higher loads. The coefficient of friction then changes from that ...
... The presence of surface layers can result in a breakdown of the F = mN relationship - the coefficient of friction µ can vary with the load N. This can happen if the layers are such that they remain intact at low loads but break down at higher loads. The coefficient of friction then changes from that ...
Continuous Penalty Forces
... include computation of global penetration depth, but this approach is suited mostly for rigid bodies. Moreover, it is difficult to compute global penetration depth for non-convex objects by taking into account rotational motion [Zhang et al. 2007]. Another issue with penalty methods is that, in orde ...
... include computation of global penetration depth, but this approach is suited mostly for rigid bodies. Moreover, it is difficult to compute global penetration depth for non-convex objects by taking into account rotational motion [Zhang et al. 2007]. Another issue with penalty methods is that, in orde ...
Stress
... 6. Stress: Friction is discussed as an example of shear stress. The stress tensor field is formally introduced. The equations of mechanical equilibrium in all matter are formulated. The symmetry of the stress tensor is discussed. 7. Strain: The displacement field is introduced and analyzed in the li ...
... 6. Stress: Friction is discussed as an example of shear stress. The stress tensor field is formally introduced. The equations of mechanical equilibrium in all matter are formulated. The symmetry of the stress tensor is discussed. 7. Strain: The displacement field is introduced and analyzed in the li ...
Haptic Rendering of Rigid Contacts Using Impulsive and Penalty
... impulses, based on the geometric information provided by a collision detection algorithm that is implemented in the virtual environment. Typically, the collision detection algorithm decomposes each rigid object into a collection of convex polyhedra and computes contacts between pairs of these polyhe ...
... impulses, based on the geometric information provided by a collision detection algorithm that is implemented in the virtual environment. Typically, the collision detection algorithm decomposes each rigid object into a collection of convex polyhedra and computes contacts between pairs of these polyhe ...
Persson2006-Contact_mechanics_for_randomly_rough_+
... contact regions. For small squeezing force it predicts that the contact area A is proportional to the load FN , while as FN increases A approaches A0 in a continuous manner. Thus, the theory is (approximately) valid for all squeezing forces. In addition, the theory is very flexible and can be applie ...
... contact regions. For small squeezing force it predicts that the contact area A is proportional to the load FN , while as FN increases A approaches A0 in a continuous manner. Thus, the theory is (approximately) valid for all squeezing forces. In addition, the theory is very flexible and can be applie ...
Two Interpretations of Rigidity in Rigid Body Collisions
... for contact deformations, or for whole-body deformation. Despite the implied deformations in each case, some notion of rigidity can still be retained. Consider for example the Hertzian contact between two frictionless, elastic spheres pressed together with remotely applied, equal and opposite forces ...
... for contact deformations, or for whole-body deformation. Despite the implied deformations in each case, some notion of rigidity can still be retained. Consider for example the Hertzian contact between two frictionless, elastic spheres pressed together with remotely applied, equal and opposite forces ...
Impact Mechanics - Assets - Cambridge University Press
... and consequent indentation; this indentation equals the interference that would exist if the bodies were not deformed. At each instant during impact the interface or contact pressure has a resultant force of action or reaction that acts in opposite directions on the two colliding bodies and thereby ...
... and consequent indentation; this indentation equals the interference that would exist if the bodies were not deformed. At each instant during impact the interface or contact pressure has a resultant force of action or reaction that acts in opposite directions on the two colliding bodies and thereby ...
Energy dissipation and dispersion effects in granular media
... through the network of contacts and be partly dissipated. Establishing a model that can clearly classify the dissipation and dispersion effects is crucial for the understanding of the global behaviors in the granular materials. For particles with rate-independent material, the dissipation effects co ...
... through the network of contacts and be partly dissipated. Establishing a model that can clearly classify the dissipation and dispersion effects is crucial for the understanding of the global behaviors in the granular materials. For particles with rate-independent material, the dissipation effects co ...
Frictionless mutliple impacts in multibody systems. I - HAL
... works related to the multi-impact problems can also be found in several papers (see, e.g. Delassus 1920, Bernoulli 1969–1993, Han & Gilmore 1993 and Brogliato 1999 for references). The contribution of this paper is to extend the Darboux–Keller approach (iv) to multiple impacts. This allows us to dis ...
... works related to the multi-impact problems can also be found in several papers (see, e.g. Delassus 1920, Bernoulli 1969–1993, Han & Gilmore 1993 and Brogliato 1999 for references). The contribution of this paper is to extend the Darboux–Keller approach (iv) to multiple impacts. This allows us to dis ...
Two Interpretations of Rigidity in Rigid Body Collisions
... C and R , may be treated as identical if we ignore some vanishingly small-amplitude phenomena. In energy calculations, the work done by the almost totally converted to kinetic energy of the block, with a vanishingly small port the dashpot. In this sense, for smooth motions under bounded forces, ‘in ...
... C and R , may be treated as identical if we ignore some vanishingly small-amplitude phenomena. In energy calculations, the work done by the almost totally converted to kinetic energy of the block, with a vanishingly small port the dashpot. In this sense, for smooth motions under bounded forces, ‘in ...
Chapter 5 Mutual actions in machinery elements
... constraint reaction: N and T • N and T are calculated by the equilibrium equations and must be verified by the inequality: If inequality (5.1) is satisfied, the two mating surfaces will not slide. friction force is independent from the size of contact area static friction coefficient does not depend ...
... constraint reaction: N and T • N and T are calculated by the equilibrium equations and must be verified by the inequality: If inequality (5.1) is satisfied, the two mating surfaces will not slide. friction force is independent from the size of contact area static friction coefficient does not depend ...
A precise contact force measuring method for overhead catenary
... The contact force between pantograph and contact wire determines the dynamic performance of current collection. Large contact force furthers wear of contact wire and also causes fatigue of the wire. On the other hand, too small contact force gives rise to arcing. Therefore, keeping contact force in ...
... The contact force between pantograph and contact wire determines the dynamic performance of current collection. Large contact force furthers wear of contact wire and also causes fatigue of the wire. On the other hand, too small contact force gives rise to arcing. Therefore, keeping contact force in ...
PPT - Foamtec
... Fog: 12 x 15 room – two foggers for at least two hours Fogging for startup reduces the bioburden in the area Fogging is an excellent way to regain control of a corrupted area Fogging needs to be done at a droplet size of 25 um (1-2 hours) or gap between droplets can occur Fogging requires a release ...
... Fog: 12 x 15 room – two foggers for at least two hours Fogging for startup reduces the bioburden in the area Fogging is an excellent way to regain control of a corrupted area Fogging needs to be done at a droplet size of 25 um (1-2 hours) or gap between droplets can occur Fogging requires a release ...
dynamic monitorization in slip translation cyclic movement
... The experimental data obtained on the basis of the tribomodel in sliding conditions at cyclic movement of translation have emphasized a dynamic floating behavior in the evolution of both friction force and contact processes for a series of tribomaterial couples. For the analysis of the friction forc ...
... The experimental data obtained on the basis of the tribomodel in sliding conditions at cyclic movement of translation have emphasized a dynamic floating behavior in the evolution of both friction force and contact processes for a series of tribomaterial couples. For the analysis of the friction forc ...
Dynamic Simulation of Non-penetrating Flexible Bodies
... flexible bodies that covers collisions and continuous contact as well as free motion. The model, which draws on the flexible-body model proposed by Witkin and Welch[9] and on the analytical contact force model for rigid bodies presented by Baraff[1,2], centers on the idea that flexible body simulati ...
... flexible bodies that covers collisions and continuous contact as well as free motion. The model, which draws on the flexible-body model proposed by Witkin and Welch[9] and on the analytical contact force model for rigid bodies presented by Baraff[1,2], centers on the idea that flexible body simulati ...
Contact Improvisation: Concepts of Physics Transformed into Art
... found in the moments when the action/reaction pairs are unplanned and authentically affected by the bodies in the space and their relationship to gravity. In contact improvisation, the floor not only exists but also can act as a second body or partner. The dancers’ awareness of gravity and sensitivi ...
... found in the moments when the action/reaction pairs are unplanned and authentically affected by the bodies in the space and their relationship to gravity. In contact improvisation, the floor not only exists but also can act as a second body or partner. The dancers’ awareness of gravity and sensitivi ...
Single Point of Contact Manipulation of Unknown Objects
... forces at all points. – Behaviors are a way to deal with this • Slide (maintaining current contact face) • Switch contact face (a.k.a roll) ...
... forces at all points. – Behaviors are a way to deal with this • Slide (maintaining current contact face) • Switch contact face (a.k.a roll) ...
ppt
... A way out of Da Vinci’s paradox has been suggested by Bowden and Tabor, who distinguished between the real contact area and the geometric contact area. The real contact area is only a small fraction of the geometrical contact area. ...
... A way out of Da Vinci’s paradox has been suggested by Bowden and Tabor, who distinguished between the real contact area and the geometric contact area. The real contact area is only a small fraction of the geometrical contact area. ...
Contact Resistance vs Contact Pressure
... Contact resistance (i.e. the sum of the resistances mentioned above) is important on several fronts for our power relays. Firstly, it will contribute to heat rise inside the relay, and secondly it will waste energy, mostly as heat, which might be important in a battery application (for example). Loo ...
... Contact resistance (i.e. the sum of the resistances mentioned above) is important on several fronts for our power relays. Firstly, it will contribute to heat rise inside the relay, and secondly it will waste energy, mostly as heat, which might be important in a battery application (for example). Loo ...
Contact mechanics
Contact mechanics is the study of the deformation of solids that touch each other at one or more points. The physical and mathematical formulation of the subject is built upon the mechanics of materials and continuum mechanics and focuses on computations involving elastic, viscoelastic, and plastic bodies in static or dynamic contact. Central aspects in contact mechanics are the pressures and adhesion acting perpendicular to the contacting bodies' surfaces (known as the normal direction) and the frictional stresses acting tangentially between the surfaces. This page focuses mainly on the normal direction, i.e. on frictionless contact mechanics. Frictional contact mechanics is discussed separately.Contact mechanics is part of Mechanical engineering; it provides necessary information for the safe and energy efficient design of technical systems and for the study of tribology and indentation hardness. Principles of contacts mechanics can be applied in areas such as locomotive wheel-rail contact, coupling devices, braking systems, tires, bearings, combustion engines, mechanical linkages, gasket seals, metalworking, metal forming, ultrasonic welding, electrical contacts, and many others. Current challenges faced in the field may include stress analysis of contact and coupling members and the influence of lubrication and material design on friction and wear. Applications of contact mechanics further extend into the micro- and nanotechnological realm.The original work in contact mechanics dates back to 1882 with the publication of the paper ""On the contact of elastic solids"" (""Ueber die Berührung fester elastischer Körper"") by Heinrich Hertz. Hertz was attempting to understand how the optical properties of multiple, stacked lenses might change with the force holding them together. 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. 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. Hertzian contact stress forms the foundation for the equations for load bearing capabilities and fatigue life in bearings, gears, and any other bodies where two surfaces are in contact.