Jayashree Bijwe - Academia.edu (original) (raw)

Papers by Jayashree Bijwe

De Gruyter eBooks, Sep 24, 2018

Tribology International, Mar 1, 2022

Lubrication science, 2001

Cryogenic treatment of polytetrafluoroethylene (PTFE) has proved beneficial in improving the abra... more Cryogenic treatment of polytetrafluoroethylene (PTFE) has proved beneficial in improving the abrasive wear resistance of several polymers, and it was thus assessed in an adhesive wear mode, as well. Preliminary investigations on the effect of cryogenic treatment on the tribological properties, in adhesive wear mode, and mechanical properties of neat PTFE and it composites filled with bronze or short glass fibres (GF) were carried out. It was found that, although the improvement in the wear and friction pei$ormance of neat PTFE and a GF + PTFE composite was signifcant, no such positive effect was observed for the bronze + PTFE composite. On the contrary, this composite showed a deterioration in pedormance. The reason behind the improvement in the tribological behaviour of neat PTFE and the GF + PTFE composite could not be clearly understood. However, it was confirmed that, if the treatment adversely affected the mechanical properties, then the tribological performance also deteriorated, An exanzination of the worn suface of the material and the countetfiace ctisc using n scanning electron microscope revealed changes in the microstructure due to the treatment. It was also confirmed from these SEM studies that the compatibility of bronze and PTFE was very poor, which led to poorper$ormance ofthe composite both in the untreated and the cryo-treated form. Further detailed investigation and analysis of various materials and composites, however, are necessary to establish the utility of this technique.

Journal of Materials Science, Sep 8, 2010

SAE technical paper series, Oct 5, 2020

Surface topography, May 28, 2020

Nano-particles (NPs) are extensively explored as additives (anti-friction- AF, anti-wear AW and e... more Nano-particles (NPs) are extensively explored as additives (anti-friction- AF, anti-wear AW and extreme pressure- EP) in oils and greases. Combinations of NPs of graphite and hexagonal boron nitride (hBN) were tried in Group III oil keeping total amount constant (4 wt.%) along with dispersant (Polyisobutylene succinimide -PIBSI- 1 wt. %) to explore the possible synergism in AW and EP performance. Combo-oils with 2 % of each NPs showed synergistic effect in AW performance with 63% improvement compared to the parent oil. The SEM and EDAX studies on ball surface worn in this oil revealed best quality film (smooth, thin and coherent) and also with lowest roughness of 56 nm as confirmed from the atomic force microscopy (AFM). In case of EP test, however, no synergism was observed. Graphite NPs (4 %) proved most effective with 78% improvement. Step-wise inclusion of hBN deteriorated the performance.

Composites Science and Technology, Feb 1, 2022

Journal of Reinforced Plastics and Composites, Apr 1, 2005

Wear, Nov 1, 2015

Polybenzimidazole (PBI) is a specialty polymer with highest thermal stability. However, its poten... more Polybenzimidazole (PBI) is a specialty polymer with highest thermal stability. However, its potential to develop composites has not yet been explored because of problems associated with processing. To overcome this problem, blend of Polyetherketone (PEK) and PBI was developed for the first time, and its mechanical and tribological properties were investigated. Further, a systematic series of composites containing solid lubricants (SLs), short fibers of glass and carbon was developed and its physical, mechanical, thermal and tribological properties were investigated. The composites with either SLs or fibers did not show good tribo-potential. However, when these were used together, performance was significantly better. When compared to the commercial composite based on PBI-PEEK blend and with similar composition, the new composites demonstrated excellent tribo-potential with very low friction coefficient (m) E0.05 and specific wear rate (K 0)E 1 Â 10 À 16 m 3 /N m along with very high PV safe-limit value E63 MPa m/s.

ACS omega, Jun 10, 2022

Aramid pulp/fiber is the most vital ingredient of brake friction material (FM) formulation. It is... more Aramid pulp/fiber is the most vital ingredient of brake friction material (FM) formulation. It is perpetually added to achieve quality brake pads/shoes and improve the overall friction and wear performance. Additionally, novel Zylon fibers have a superior property to aramid fibers. However, no studies give insights on their influence on brake noise and vibration (NV) performance. In the current work, a series of six different types of eco-friendly brake pads was developed. The first five contain aramid pulp, aramid short fibers, and Zylon fibers of different sizes (1, 3, and 6 mm) as the theme ingredients (3 wt %) by keeping the parent composition identical. Additionally, one more pad was developed that contains no aramid/Zylon fibers (i.e., reference pad). The pads were characterized for physical and mechanical properties. The damping and natural frequencies of pads were measured experimentally and numerically. All brake pads were evaluated for detailed NV performance by following the SAE J 2521 test schedule. In addition, numerical simulation was performed to validate the experimental brake squeal results. Results revealed that aramid/Zylon fiber-based pads improved the porosity, damping, and compressibility. Overall, brake noise and vibrations were improved for aramid/Zylon fiber-based pads by 1.2–1.5 dBA and 20–25%, respectively, compared to the reference pad. The complex eigenvalue analysis (CEA) proved that squeal was mainly influenced by the damping and density of the pad materials. Thus, aramid/Zylon fiber-based pads can effectively suppress the instability of the brake system and reduce the brake squeal propensity.

Composites Part C: Open Access, Mar 1, 2021

Abstract In this paper tribo-comparison of two SLs viz. graphite and PTFE as a secondary lubrican... more Abstract In this paper tribo-comparison of two SLs viz. graphite and PTFE as a secondary lubricant in composites with identical composition (20 wt%) is presented. The mechanical, thermal and tribological properties as well as mechanism of PAEK composites were investigated in detail. It was found that although incorporation of PTFE reduced most of the mechanical properties and thermal conductivity, it was responsible for increasing the tribo- potential of composites to a significant level. Compared to a composite with graphite as a secondary SL, a reduction in wear rate (18–30 %) and friction (2–18%) was exhibited due to PTFE and nano-PTFE. The composites showed very high PV s a f e (pressure x velocity) value of 182 MPa m/s with low (0.04) and wear rate ( 1.33 × 10 − 16 MPa m/s). It was shown that the formation of a polymeric transfer film on a metal countersurface is crucial in achieving ultralow wear and friction in dry condition. The investigations on worn surfaces and the transfer films with scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) analysis and Raman spectroscopy proved useful to understand wear mechanisms.

Surface & Coatings Technology, Nov 1, 2021

Abstract The present paper reports on the interaction of low-pressure plasma (LPP) with the surfa... more Abstract The present paper reports on the interaction of low-pressure plasma (LPP) with the surfaces of different stainless steels (SS) (viz. austenitic, martensitic, and ferritic). Plasma treatment was standardized by optimizing the power and duration of plasma exposure. The criteria for such standardization were the extent of decrease in contact angle and hence increase in surface energy (SE), which would increase the lap shear strength (LSS) of these surfaces in the form of joints using phenolic resin. It was found that argon LPP was more effective than the argon-oxygen LPP and, the best results were obtained with a plasma exposure of 500W power for 20 min. The LSS of SS316 got improved by almost 100 % for the plasma-treated surface compared to the untreated one. Contact angles got reduced to different extents for all the three types of SS, and a significant improvement (~175 %) in SE was observed. The increase in SE was supported by atomic force micrographs that showed a decrease in the surface roughness. X-ray photoelectron spectroscopy (XPS) indicated a significant change in the surface chemistry due to the Ar-LPP treatment.

Wear, Jul 1, 2021

Abstract A synthetic hydrated calcium silicate (commercially available as Promaxon-D) is used as ... more Abstract A synthetic hydrated calcium silicate (commercially available as Promaxon-D) is used as one of the ingredient in some friction materials (FMs) since it has the ability to improve the porosity of the product due to its very special crystalline structure. The present work aims to evaluate the detailed noise and vibration (NV) performance of Promaxon-D (PD) based pads in comparison with the non-PD based ones. Five different types of Cu-free brake-pads were developed with identical composition but varying wt.% of PD particles (0, 5, 10, 15, and 20) and compensating the difference with barite, a space filler. After characterizing these brake-pads for physical and mechanical properties, NV performance was evaluated following SAE J2521 test standard and also the friction-performance based on the data generated on the same rig. As the PD contents increased, the brake NV performance improved considerably for the selected operating conditions. In view of the overall improvement in both noise and vibration aspects, the pad with 20 wt.% PD (P20) performed best with an overall ~ 3 dBA drop in noise level and ~11% drop in vibration vis-a-vis PD-free pads leading to a conclusion that 20 wt.% PD may be used for improving the NV performance of brake-pads and also increasing the friction level.

Tribology International, Nov 1, 2018

Wear, Jul 1, 2016

Graphite, a solid lubricant having good thermal conductivity (TC) and lubricity is used as a fric... more Graphite, a solid lubricant having good thermal conductivity (TC) and lubricity is used as a friction modifier in friction material (FM) formulations. Since graphite can be from different origins (synthetic, natural, treated etc.) and particles can be of various sizes, shapes and varying in crystallinity and purity, a careful selection is required for achieving desired performance properties of the FMs. Thermo-graphite (TG), as claimed to be more thermally conducting along with number of beneficial properties by the manufacturer was used to develop multi-ingredient FM. Two FMs differing in only type of graphite (TG and natural graphite-NG) were developed and evaluated for various performance properties. Triboperformance evaluation of both the FMs on inertia dynamometer (schedule JASO C406) led to the conclusion that TG based FM proved superior to NG based one in almost all the properties barring recovery performance.

Tribology International, Feb 1, 2019

Role of micro and nano-particles of hBN as a secondary solid lubricant for improving tribo-potent... more Role of micro and nano-particles of hBN as a secondary solid lubricant for improving tribo-potential of PAEK composite.

Composites Part A-applied Science and Manufacturing, 2019

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Wear, Jul 1, 2005

The formulation of a friction material requires the optimization of multiple performance criteria... more The formulation of a friction material requires the optimization of multiple performance criteria. These include achieving a stable and adequate coefficient of kinetic friction (µ) and minimizing its sensitivity to the brake operating parameters in order to produce low fade and high recovery characteristics. Low wear rates and a resistance to objectionable noise and vibration must be coupled with good strength through appropriate fabrication practices. Among the foregoing requirements, resistance to fade is particularly difficult to achieve. Resin is one of the most important ingredients in friction materials because it binds the ingredients firmly and allows them to contribute effectively to the desired performance. Ideally, there should be no significant deterioration in the function of the binder when the brake is operated under diverse conditions. However, when excessive frictional heat is generated, changes in the resin can deteriorate performance. Consequently, a friction material's thermal stability, its capacity to retain mechanical properties, and its ability to hold its ingredients together under adverse conditions all depend on the resin. Despite this, little or no information on the effects of resin chemistry on friction braking under adverse conditions has been reported in the open literature. Hence, the current work investigates the characteristics of five resins: (i) straight phenolic resin, (ii) alkyl benzene modified resin, (iii) cashew nut shell liquid modified resin, (iv) NBR modified resin, and (v) linseed oil modified resin. The same weight percent of each resin (10%) was used to make friction materials containing similar additions of 10 additives. The mechanical properties of these materials were characterized using ASTM standards. Fade and recovery studies were carried out on a Krauss testing machine following the Economic Commission for Europe regulation for replacement brake linings (ECE R-90). Friction and wear characteristics varied with the type of resin, and no resin proved best for all the selected performance parameters. Alkyl benzene modified resin composite proved best in terms of strength, friction, fade and recovery, but was poorest in wear performance. Results for linseed oil based phenolic resin composites showed exactly the opposite behaviour. Scanning electron microscopy was used to help understand the wear mechanisms and the causes for these differences.

Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, Sep 20, 2022

Although extensive research has been carried out for predicting and mitigating brake noise proble... more Although extensive research has been carried out for predicting and mitigating brake noise problems over the past decades, it is still challenging to predict its occurrence due to the complex nature of the brake system. Friction-induced vibration between the tribo couple (i.e. brake disk-pads) is one of the key players for increasing the noise and vibration issues in the brake system. The composition of friction materials (FMs) (i.e. pads/shoes) controls both tribological and noise-vibration (NV) performance. Binder (i.e. resin) is the heart of FMs which binds all the ingredients firmly and provides strength. A lot is reported on the types and amount of resin on the tribological performance, but no study addresses the noise and vibration performance adequately. This work investigates the role of binder in controlling the NV performance of the Cu-free brake-pads. Four types of copper-free brake-pads were developed with varying content (viz., 6, 8, 10, and 12 wt.%) of phenolic resin as a theme ingredient keeping the parent composition fixed. The natural frequencies and damping ratios for the developed pads were evaluated through experimental modal analysis of the pads. The detailed NV performance was evaluated on the in-house developed brake NV test rig by partly following the SAE J 2521 test schedule. Additionally, friction performance was also studied for different braking conditions. Results revealed that the compressibility, porosity, and damping ratio decreased, whereas hardness and natural frequency increased with the increase in resin content in the brake-pads. Overall, among all the pads, the brake-pad with 6 wt.% resin content proved best for the NV performance.