Effects of Silicon Oxide Filler Material and Fibre Orientation on Erosive Wear of GF/EP Composites
Materials added to the matrix help improving operating properties of a composite. This experimental study has targeted to investigate this aim where Silicon Oxide particles were added to glass fibre and epoxy resin at an amount of 15% to the main material to obtain a sort of new composite material. Erosive wear behavior of epoxy-resin dipped composite materials reinforced with glass fibre and Silicon Oxide under three different impingement angles (30°, 60° and 90°), three different impact velocities (23, 34 and 53 m/s), two different angular Aluminum abrasive particle sizes (approximately 200 and 400 μm) and the fibre orientation of 45° (45/-45) were investigated. In the test results, erosion rates were obtained as functions of impingement angles, impact velocities, particle sizes and fibre orientation. Moreover, materials with addition of Silicon Oxide filler material exhibited lower wear as compared to neat materials with no added filler material. In addition, SEM views showing worn out surfaces of the test specimens were scrutinized. Keywords—Erosive wear, fibre orientation, GF/EP, silicon oxide
Effect of impinging velocity on the erosive wear behaviour of polyamides
Various parameters, such as type, size and velocity of erodent and impact angle, are important for the erosive wear behaviour of materials. In this work, the erosive wear behaviour of various polyamides (PAs), viz. PA 6, PA 66, PA 66/610, PA 11, PA 12 and aromatic PA with difference in the methylene to amide (CH2/CONH) ratio in the backbone, was evaluated at two impact angles (30° and 90°) and at two impact velocities (80 and 140 m/s) using silica sand as erodent. The influence of impact velocity on erosion rate was more dramatic at an oblique impact angle (30°) than at normal impact angle (90°). Microscopic analysis of the eroded samples revealed that brittle fracture was the principal mode of failure in all the PAs at the normal impact. At the oblique impact, on the other hand, chipping off of material by microcutting and severe plastic deformation were observed.
Political Developments: Some Conclusions and an Interpretation
When the political decisions and achievements of the post-Khrushchev Soviet leadership are considered as a whole, it is not immediately obvious that there is any pattern to them. It may, nevertheless, be useful to begin by devoting attention to some of the major policy tendencies and outcomes of the past decade, most of which have already been considered in greater detail by other contributors, before going on to enquire if any broad strategy underlying them may be discerned and to attempt to place the various changes in a broader political context.