Engineering Commons^™

Friction And Adhesion In Rigid Surface Indentation Of Nitrile Rubber, Stephen Jerrams

Articles

When a rigid body in the form of a plane strain indentor is forced into an elastomer, the asperities on the surface of the indentor are filled by the softer material. As depth of ingress increases, the rubber displaced into the indentor asperities exhibits stick-slip behaviour. The rubber adheres to the rigid body and if the depth of ingress is held at a maximum, the level of adhesion remains constant despite short-term load relaxation occurring in the rubber.

This text describes the influence of a range of factors on indentation forces and adhesion in rigid indentation of hydrogenated nitrile rubbers. …

Analysis Of Computational Methods For The Treatment Of Material Interfaces, Minh C. Nguyen

Theses and Dissertations

Rocket sled tests at the Air Force Research Laboratory's Holloman High Speed Test Track frequently approach velocities where gouging development becomes the limiting factor to achieving higher operating velocities. Direct observation of the gouging process is not possible so computational modeling is necessary to study the phenomenon. Since gouging development is dependent on the impact surface conditions, the method used to model material interfaces directly affects the accuracy of the solution. Three methods are available in the hydrocode CTH to handle material interfaces: 1) materials are joined at the interface, 2) a frictionless slide line is inserted, and 3) a …

Friction In The Roll Bite Under Various Hot Rolling Conditions, Weihua Sun, A. K. Tieu, Hongchun Li, Zhengyi Jiang, Guodong Wang, Xianghua Liu

Faculty of Engineering - Papers (Archive)

In this paper, the effect of hot rolling parameters on the friction coefficient was studied by inverse calculation on the experimental roll loads where the hot rolling experiments were carried out at

7.5-45.0% reductions, 0.12-0.72m/s speeds and temperature of 850-1025°C. Dry rolling, water, oil/water mixture emulsion and pure oil were used as lubricants in the experiments. In carrying out the calculation, a flow stress model for the present test material was first obtained experimentally. Hot rolling parameters, including reduction, roll speed, work piece entry temperature and lubrication conditions, were investigated to determine their effect on friction coefficient and mill loads. …

Friction And Asperity Contact In Strip Rolling, A. K. Tieu, Zhengyi Jiang, Cheng Lu, Prabuono B. Kosasih

Faculty of Engineering - Papers (Archive)

This paper reviews different aspects of friction and asperity contacts in strip rolling. The mixed film lubrication model considers the effect of asperity flattening and the lubrication within the working zone. The oil concentration of the emulsion at entry and throughout the roll bite is considered together with the thermal effects of the contacts. The actual area of contact due to asperity deformation can be determined from a 3-wavelength FEM model. The deformation of a randomly generated surface of the hot strip with oxide scale can also be modeled by an FEM method. The friction variation in the roll bite …

3d Finite Element Analysis Of Surface Roughness And Friction In Hot Strip Rolling, Zhengyi Jiang, A. K. Tieu

Faculty of Engineering - Papers (Archive)

Surface roughness of oxide scale and strip in hot strip rolling has a significant influence on the friction and lubrication conditions. In this paper, the authors present the measured surface roughness of oxide scale and strip by Atomic Force Microscope (AFM) and Surface Profilometer respectively for hot rolled strip on a Hille 100 experimental rolling mill. Based on the friction coefficient determined through a sensor roll on the rolling mill, a 3D rigid visco-plastic finite element simulation was carried out, and the relationship between the surface roughness and friction coefficient was investigated. Results show that the lubrication in hot strip …