Date of Award

13-7-2024

Document Type

Thesis

School

School of Mechanical Engineering

Programme

Ph.D.-Doctoral of Philosophy

First Advisor

Dr.P.Dinesh Babu

Keywords

Biodegradable Polymer, Natural Fibers, Mechanical Behaviours, Machinability Study, Optimization Algorithm

Abstract

The study presents a comprehensive investigation into the development, characterization, and machining analysis of novel bio-based polymer hybrid composites comprising Polylactic acid (PLA), bamboo powders (BP), and montmorillonite clay particles (MMT). Initially, the hybrid composites were fabricated using a solvent-free stir casting process, optimizing the weight percentages of BP and MMT to enhance mechanical and thermal properties.

Mechanical tests, including tensile, flexural, and impact tests, along with thermal analysis using thermogravimetric analysis and differential scanning calorimetry, were conducted to evaluate the performance of the composites. In the subsequent phases, advanced machining techniques were employed to analyze the machining characteristics of the optimized hybrid composite. Abrasive water jet machining was utilized to systematically assess surface roughness, kerf angle, and material removal rate.

A Box-Behnken design of experiments, combined with Response Surface Methodology (RSM), Analysis of Variance (ANOVA) and Multi- Objective Particle Swarm Optimization (MOPSO), allowed for the identification of the best machining parameters, including traverse rate, abrasive feed rate, and standoff distance, to achieve excellent machining performance.

In the final phase, laser machining was investigated as a precise material cutting technique for the PLA/BP/clay hybrid composite. Machinability evaluation focused on key parameters including laser power, scan speed, and gas pressure, with ANOVA utilized to understand their impact on quality characteristics. A model that combines the RSM, ANOVA, and MOPSO algorithms was employed to predict and improve the quality parameters of laser cutting.

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