CHAPTER 6 Research methodology
6.2 Overview of research methodologies
Research is defined as “a careful, systematic investigation in some field of knowledge, undertaken to establish facts or principles or to find answers to a problem” (Grinnell and Unrau, 2010) and it has been stated that the purpose of the research is to use a systematic controlled, empirical and critical approach to investigate the propositions about the presumed relationships about various phenomenon (Kerlinger, 1986). Research activities can be classified in terms of five principal attributes that are represented in Figure 6.1 (Kumar, 2010; Kothari and Grag, 2014).
In terms of application, research can be classified in a number of ways, including as fundamental or applied research. Fundamental research may be concerned with an intellectual hypothesis or a formulated theory that may lack practical application at the present or in the near future. Also, fundamental research focuses on the development of an existing techniques, methods, theories or procedures through adding information to the existing organised body of scientific knowledge. In the case of applied research, the principal aim is to discover and identify a solution for some pressing practical problems in a specific situation. Following the definition of the research aim and objective in Chapter 2, it has been identified that the thesis will incorporate mainly applied research, since it collates information about a specific problem (namely EoL management of EVs), with an element of fundamental research, since it involves the development and refinement of the methodology which incorporates both existing procedure and novel techniques and tools.
Figure 6.1 Overview of different research types (adapted form Kumar, 2010; Kothari and Garg 2014).
According to the attribute objectives, Kumar (2010) defines descriptive research as the research aims to systematically collect information to “describe what is prevalent”. Exploratory approaches, in order to address the objectives defined in Chapter 2. Descriptive research is required in order to develop a thorough understanding of the nature of EoL waste arising from EVs, relevant legislative requirements and existing recycling techniques for ELV management.
Exploratory research is used in the definition of the research aims and scope, and it is also employed in the stage of validation and optimization of automated disassembly. Correlational and exploratory research is required in terms of the association between automation and disassembly, pre‐concentration and recycling processes.
With regard to inquiry mode, qualitative research is concerned with the analysis of the variation in a qualitative phenomenon, situation or attitude under clear methodological principals. In addition, quantitative research, based on quantitative measurement, is
Research
applicable to phenomena that can be expressed in terms of quantities. Within the thesis, the emphasis is primarily on quantitative methods, such as the estimation of disassembly time, material concentration, and economic assessment, which are data based. Qualitative method is also required to analyse various factors when the quantitative measurement is not feasible or reliable.
Kothari and Grag (2014) further classify research type by experience. Conceptual research is concerned with some abstract ideas or theory, generally employed for new concept development and existing theory reinterpretation. Where research hypothesis is given, and research is based on experiments, observation and empirical studies, it is defined as empirical research. Within the thesis, empirical method is appropriate when proof of association of variables can be sought through experiments. Finally, another classification method is based on the environment in which the research is to be carried out. Research can be field‐setting research or laboratory‐based research or simulation research. And within the thesis, the research involves laboratory activities, such as manual disassembly and automated disassembly using robot arm.
Effective integration of these different types of research into a coherent methodology will provide a systematic approach to addressing the research aim and objectives defined in Chapter 2. This research methodology is described in Section 6.3.
6.3 Research methodology
This research is a hybrid integration of qualitative and quantitative methods. The experimentation of the disassembly is primarily quantitative methods, which are data driven.
Qualitative methods will also be employed to evaluate environmental benefits, technological feasibility and economic impacts. The qualitative approaches are useful in supporting the development of the research in areas where data are unavailable.
In this context, the research methodology adopted in this thesis consists of four distinct stages:
review and background, modelling and framework development, testing and validation of the research concept along with the research conclusion. These stages together with a series of steps and actions that are necessary to carry out the research in an effective way are illustrated in Figure 6.2.
It begins with the initial exploration involved with setting the research assertions and hypothesis, and the refinement of the hypothesis into specific aims and objectives. These were
Figure 6.2 Research methodology applied within the thesis.
Assessing environmental, technological and economic feasibilities
Manual disassembly
Initial automated disassembly
Optimised automated disassembly
Environmental assessment
Economic assessment Technological feasibility
assessment
Development of a framework for EoL Recycling of EV components
Framework and assessment development
Definition of research assertion and hypothesis Previous background knowledge
Literature review
Refinement of research aims and objectives
Analysis and evaluation
Development of research conclusions Testing and validation
Research concepts testing and validation
Case study 1 Case study 2 Case study 3
Analysis of case study results and validation of research
formulated using the author’s prior knowledge in the subject area, and further developed and refined through reviews of the related literature. To this end, a comprehensive literature review was conducted utilising literature research to understand vehicle evolution, EVs, automotive recycling and recovery technologies and processes, and relevant recycling studies.
This investigation aided in understanding the shortcomings and challenges found with existing vehicle recycling approaches, as well as the opportunities for developing new future vehicle recycling technologies and processes, which provided the information on which the research work was developed. The additional knowledge gained from continuing literature review activities and practical experience informs the refinement of research assertion, specific aims and objectives.
Once the research assertion had been developed, the information gathered from the literature review was used to direct the work of the next development stage. The following stage focussed on further theoretical research in which framework and model for EoL EV recycling were developed. The first step of this stage was to develop concepts for the framework using the findings from literature review and objectives laid out. Based on the research objectives and review findings, robotic automation is embedded into the research as a flexible approach to extract and pre‐concentrate materials from components or subassemblies. A three‐stage automated approach was designed and developed. It involves an initially manual disassembly that is performed in order to explore component design and material content and to identify an initial process plan for robotic disassembly procedures. The second stage utilises this initial plan to disassemble the component, using the robotic cell, and to identify the operating limits of the robotic arm during the disassembly process. The information and knowledge from this second stage was used in the final stage to validate and optimise the robotic disassembly operations.
This phase of research also required the consideration of sustainability in assessing EoL management option for EV components in which technological feasibility replaced social impacts. Therefore, environmental, technological and economic aspects are employed as key factors in this multi‐criteria consideration. This Environmental, Technological and Economic (ETE) feasibility assessment is valuable for assessing individual performance characteristic while the potential benefits of a methodology for amalgamating these three individual assessment results are identified in supporting decision‐making in a user‐friendly manner.
Additionally, the comparison of ETE feasibility assessment of different EV components can be achieved by combining the normalised results from the individual evaluation method into a single representation of overall performance.
The third testing and validation phase of the research involves testing and refining of the framework for EoL EV framework using three case studies. The case study products were selected to test three different applications of the framework, and companies with different component constructions and material recovery values. The first demonstrates simple construction and a low value component. The second explores a component with medium complex construction and high recovery value. The third one focussed on a component with relatively low potential value but complex construction. These case studies were conducted using a systematic application of the framework approach.
The final and fourth stage is the evaluation phase of the research reported in this thesis, involving the analysis of results and findings from the research activities and case studies, to draw concluding discussion and overall conclusions, identifying areas for further research and development in future vehicle component recycling practices.
Although the methodology presented in Figure 6.2 suggests a linear progression through the four stages defined in this section, it is acknowledged and understood that the research has many other facets, thus feedback loops across each stage have been implemented to develop and further refine the research as it was carried forward.
6.4 Chapter summary
This chapter discussed various types of research and identified the research methodology utilised in this thesis to address the research aim and objectives identified in Chapter 2.
Following the general overview, four main stages of research have been illustrated in chronological and schematic order, although due to the iterative nature of the research, some specific aspects may need revisiting and refinement. The research supported by the first phase of the methodology is reported in the earlier part of the thesis, in Chapters 1 ‐ 6. The following sections of the thesis will address the framework and assessment development, testing &
validation, and evaluation phases throughout Chapter 7 ‐ 9. The final sections will detail the case studies in Chapter 10, and the concluding discussions and conclusions & further work in Chapter 11 and Chapter 12, respectively.