A new evaluation to friction analysis for the ring test

Limiting the influence of friction on the split Hopkinson pressure bar tests by using a ring specimen

“…For a non-zero friction and R i < R n < R o , the inner radius flows outward at a lower rate than the outer one and it becomes more favorable for the ring to bulge [19]. The radial velocity at the interface decreases quickly with the increase of friction and at some critical conditions the specimen 'sticks' on the interface having Fig.…”

CFD 2D Description of Local Flow of Polymer Workpiece through a modified U-Shaped Die During Equal Channel Multiple Angular Extrusion

“…The plasticine rings were made with the following ratio of dimensions D:d:H=6:3:2, where D is external diameter of plasticine ring, d is internal diameter of plasticine ring, and H is the height of plasticine ring (12,13) . It was experimentally determined by authors that the Coulomb friction coefficient is f≈0.181 (τ f =f•σ n ) and the plastic friction factor in the Siebel (Tresca) friction law is m≈0.594 (τ f =m•k; k=σ S /3 0.5 ) for contact pair "wooden die model -plasticine workpiece model", where τ f is the friction stress; σ n is the normal stress; k is the maximum tangential stress for plasticine material with flow stress σ S , i.e.…”

“…Possible applications for ECMAE worked polymers are associated with aeronautical and chemical industry equipment production (1,(4)(5)(6)(7)(8) . The solution of the above mentioned technological problems is within the aims and scopes of research, conducted by Beloshenko et (5)(6)(7)(8)(9) , and Rejaeian and Aghaiae-Khafri (2014) (10) , and a number of other researchers (2,4,12,13) . The 2-turn, 3-turn, ..., and n-turn ECMAE dies with geometries of S -, U -, T -, X -, W -types could be classified as multiple angle dies (1,3,6,7) .…”

Numerical approach to forging process of a gear with inner cam profile using FEM

“…In addition, in order to investigate the effect of the coating treatment on friction characteristic, a series of ring compression tests are executed. The ring compression test has gained wide acceptance in the last decade for friction coefficient measurement [8,9]. When a ring specimen is compressed between two plates, high friction results in an inward flow of the material, while low friction results in an outward flow of the material.…”