in this research, al-ni particle composite strips are formed by accumulative roll bonding (arb) process using al strips and ni powder. the rule of arb cycles and volume percentage (vol%) of ni powder on the microstructure, wear resistance and mechanical properties of the formed composites are investigated. according to the tensile test results, the yield stress and tensile strengths of the al -...

Ultra-high molecular weight polyethylene (UHMWPE) wear in total knee arthroplasty (TKA) components is one of the main reasons of the failure of implants and the consequent necessity of a revision procedure. Experimental wear tests are commonly used to quantify polyethylene wear in an implant, but these procedures are quite expensive and time consuming. On the other hand, numerical models could ...

We present a classical rolling contact apparatus where two discs roll and slide under a constant normal loading. Experimental results concerning bearing steel used in ambient air or under severe temperature conditions (Liquid Nitrogen) are presented. A simplified model proposed by Kalker (Fastsim) is used to identify the dynamic friction coefficient between these discs and to study the apparatu...

In this paper, the manipulability analysis of a new parallel-type rolling mill “Paramill” in its conceptual design stage is investigated. Paramill uses two Stewart platforms (SPs) in opposite direction for the generation of 6 degree-of-freedom motions of each work-roll. The objective of this new technology is to permit an integrated control of the strip thickness, strip shape, pair-crossing ang...

Wear particles in a hard disk drive may cause the head/disk interface to fail. We have experimentally investigated wear particle generation resulting from fretting wear between the dimple on the suspension and the gimbal spring. We have found that increasing the normal load as well as using a low friction coating reduces the formation of wear particles. INTRODUCTION Examination of failed hard d...

In the present work, both symmetric and asymmetric rolling processes were investigated by means of numerical approaches. From algorithm presented, values pressure sliding velocity in roll gap determined. These variables allow estimation tribological parameters a given material. To determine wear rolls rolled materials Archard's law has been employed. Results simulations show that quantitative c...

Following two months of very successful commissioning and the first science observations on the GBT (see the following articles), operation was suspended in early April, one month earlier than planned, to work on the azimuth track. As described in previous NRAO Newsletters, the azimuth track wear strips, on which the azimuth wheels roll, were shifting slightly in a circumferential direction as ...