R.N. Rao

The Effect of Alkali Treatment on Dielectric Properties of Roystonea regia/Epoxy Composites

The present study investigates the electrical conductivity and dielectric properties of untreated and alkali-treated Roystonea regia natural fiber–reinforced epoxy composites at different frequencies along with compression and water absorption properties. Fiber was treated with 5% NaOH and characterized by chemical, thermogravimetric, tensile test, and SEM methods before and after alkali treatment. The interface between matrix and fiber was studied by SEM. Conductivity of alkali-treated fiber composites is lower than that of untreated fiber composites and increased with increase in frequency. The dielectric constant and loss tangent values of the composites were found to decrease after alkali treatment, and these values decreased with increase in frequency. Alkali-treated fiber composites showed improvements in compressive strength and water resistance when compared with untreated fiber composites.

Mechanical and electrical performance of Roystonea regia/glass fibre reinforced epoxy hybrid composites

The present paper investigates mechanical and electrical properties of Roystonea regia/glass fibre reinforced epoxy hybrid composites. Five varieties of hybrid composites have been prepared by varying the glass fibre loading. Roystonea regia (royal palm), a natural fibre was collected from the foliage of locally available royal palm tree through the process of water retting and mechanical extraction. Roystonea regia, E-glass short fibres were used together as reinforcement in epoxy matrix to form hybrid composites. It has been observed that tensile, flexural, impact and hardness properties of hybrid composites considerably increased with increase in glass fibre loading. But electrical conductivity and dielectric constant values decreased with increase in glass fibre content in the hybrid composites at all frequencies. Scanning electron microscopy of fractured hybrid composites has been carried out to study the fibre matrix adhesion.

Abrasive grit size effect on wear depth of stir cast hybrid Al–Mg–Si composites at high stress condition

The grit size effect on high stress abrasive wear depth of stir cast hybrid self-lubricating Gr/SiC/Al composites was investigated in both as cast (AC) and heat treated (T6) condition. The tests were done at grit size of 100–200 µm, sliding distance of 75 m and applied loads of 5–15 N. The results obtained were differentiated with matrix alloy and SiC/Al composites. At 15 N load, the wear depth of hybrid composites w.r.t. matrix alloy reduced around 19.6% (at 100 µm grit size) and 16.4% (at 200 µm grit size) in AC condition; 26.9% (at 100 µm grit size) and 27% (at 200 µm grit size) in T6 condition. The wear mechanism was analyzed through wear surface analysis of pin and emery paper.

A mathematical model to evaluate wear depth of an aluminium alloy reinforced with a silicon carbide particle composite using finite element analysis

In the present study, an attempt is made to synthesize an aluminium alloy—silicon carbide (SiC) particle composite using a liquid metallurgy route and to characterize the composites in terms of sliding wear behaviour and numerical simulation by finite element analysis. The sliding wear behaviour was studied using a pin-on-disc apparatus with the composite pin sliding against an EN32 steel counter surface at different applied loads and sliding speed. The experimental results for the aluminium alloy—SiC particle composite were validated using a mathematical model. A wear equation was used to predict the steady-state wear rates. It is based on an exponential transient wear volume equation and Archards equation. An algorithm for the finite element model to simulate wear tests was also developed. The predicted results were in good agreement with the experimental values.

Effect of applied pressure on high-stress abrasive wear behavior of hybrid Al–Mg–Si composites

In this experimental investigation, the effect of applied pressure on high-stress abrasive wear resistance characteristics of stir-cast Al 6082-5 wt% SiC-5 wt%Gr (Al–SiC–Gr) hybrid metal matrix composites was studied and compared with its unreinforced matrix alloy and 10 wt% SiC-reinforced (Al–SiC) composites. The tests were carried on pin-on-disc equipment at applied pressures of 0.1–0.3 MPa, sliding distance of 75 m, and SiC abrasive grit size of 100 µm and 200 µm. It was noted that the wear resistance decreases with increase in applied pressure in both as-cast and T6 conditions. The improvement in wear resistance was 1.63 (alloy) to 3.29 m/mm3 (Al–SiC–Gr) in case of lower grit size and applied pressures. However, the marginal improvement of wear resistance was observed i.e. 0.67 (alloy) to 1.05 m/mm3 (Al–SiC–Gr) at higher grit size and applied pressures. Relative wear resistance plots indicate that hybrid composites conceded better wear resistance properties compared to SiC-reinforced composites. The evaluation of wear mechanisms, worn surfaces of the pins, emery papers, and debris was also studied using scanning electron microscopy.

High-stress abrasive wear behavior of Al–Mg–Si hybrid composites using regression analysis

Purpose The purpose of the present study is to analyze the wear behavior of developed aluminum hybrid composites under high-stress conditions through developed power law and quadratic equations. Design/methodology/approach The abrasive wear behavior of Al–Mg–Si (Al 6082) alloy reinforced with hard silicon carbide (SiC) and soft graphite (Gr) particulates fabricated by stir casting route was studied at loads of 5-15 N, sliding distance of 75 m and abrasive grit size of 100-200 μm. The power law and quadratic equations were developed to understand the wear behavior with respect to the load applied and the abrasive grit size. The worn surfaces of the test specimens and grit papers were examined under scanning electron microscope. Findings The density and hardness of the hybrid composites decreased when compared to Al–SiC composites, whereas the wear properties improved because of the presence of Gr. There was further improvement in the wear properties of the materials because of T6 heat treatment. The change in abrasive wear mechanism was observed at a grit size of 125 μm when traversed from alloy to hybrid composite as indicated in terms of exponents in the power law equation. The worn surfaces of hybrid composite pins were comparable with those of alloy pins. Practical implications In the automobile sector, components like cylinder liner, piston, crankshafts, brake drums, etc. also undergo abrasive wear along with sliding against the counter surface in working conditions. Originality/value The results prove that better wear resistance was obtained under the abrasion condition.

A Review on Automotive Seat Comfort Design

Seats are one of the most important components of automotive. In recent years, customer approaches for automotive comfort are growing, and the advance of automotive seats that origin minute fatigue for extensive distance driving is essential. Automotive makers recognize comfort as one of the major trade point, as it plays a significant role for buyers as well. This literature review incorporates previous studies related to automotive seating comfort and discomfort. It reviews key writings related to seating design and criteria and reviews comfort issues in automotive seating. The objective of this paper is to designate the measurement methods that are used to improve the physiological comfort of an automotive drivers seating. In this paper, first, we describe the background of sitting comfort besides discomfort. Then, we turn to the subjective and objective measurement methods that are used to evaluate the automotive seat. Thirdly, we propose a methodology for the development of comfortable drivers seats.

Effect of surface modification and hybridization on dynamic mechanical properties of Roystonea regia/glass–epoxy composites

The paper evaluates effect of fibre surface modification and hybridization on dynamic mechanical properties of Roystonea regia/epoxy composites. Surface modification involved alkali and silane treatments. Alkali treatment proved to be more effective on dynamic mechanical properties as compared to silane treatment. Storage and loss modulus values increased after treatments with simultaneous decrease in tan δ values. Roystonea regia and glass fibres were used together with varying proportions as reinforcement in epoxy matrix to study the hybridization effect on dynamic mechanical properties. Storage and loss modulus values increased with increase in glass fibre content whereas tan δ values were found to decrease. Scanning electron microscopy of tensile fractured surfaces was carried out to study the interface adhesion of different composites.