EXPERT SYSTEM BASED APPROACH FOR MATERIAL SELECTION OF AUTOMOBILE BODY-IN-WHITE STRUCTURAL PANELS USING NUMERICAL RANKING AND SUSTAINABILITY INDICES

The goal of this work is to establish a set of quantifiable measures for design for sustainability (DFS) that can be applied to automotive applications in terms of environmental, social, economic and technical aspects. In this study, a comprehensive analysis was made in order to develop a methodology that can evaluate different body-in-white designs in terms of major sustainability aspects. Besides the complete life cycle analysis, environmental impacts and cost factors will be analyzed over vehicle\u27s entire life-cycle (fuel extraction and refining, Pre-manufacturing, Manufacturing, Use, and Post-use stages). The considered material options include: conventional steel, high strength steel, aluminum, magnesium, titanium and composites that are currently used in body-in-white (BIW) structures and exterior body panels. Sustainability scoring method was developed and used to decide on how using lighter materials in auto body applications is beneficial or not. The proposed major sustainable factors are categorized into four major groups: environmental, economical, social and technical groups. Also, each group has corresponding factors which were chosen by extensive search and screening, so only important sustainability aspects for auto body design have been selected in this study. Then the dissertation proceeds to show some sustainability scoring methods in order to get better understanding as well as relative ranking for different materials from sustainability point of view. Moreover, this work discusses the role and application of some multi-criteria decision making methods in materials selection, namely quality function deployment (QFD) and analytic hierarchy process (AHP). However, multi-criteria decision making methods are efficient tools to choose alternative from large set of alternatives, especially when two or more conflicting goals are present. Besides that, knowledge based system (KBS) was established for eco-material selection for auto-body structural panels. The goal behind using KBS is to help designers in material selection process which usually needs experience, time and effort

Influence of the composition on the environmental impact of a casting magnesium alloy

The influence of the composition of magnesium alloys on their environmental impact was analyzed. In order to perform a more accurate environmental impact calculation, life cycle assessment (LCA) with the ReCiPe 2016 Endpoint and IPCC 2013 GWP (100 y) methodology was used, taking the EcoInvent AZ91 magnesium alloy dataset as reference. This dataset has been updated with the material composition range of several alloys included in the European standard EN 1753:2019. The balanced, maximum, and minimum environmental impact values were obtained. In general, the overall impact of the studied magnesium alloys varied from 3.046 Pt/kg to 4.853 Pt/kg and from 43.439 kg CO2 eq./kg to 55.427 kg CO2 eq./kg, depending on the composition. In the analysis of maximum and minimum environmental impacts, the alloy that had the highest uncertainty was 3.5251, with a range of ±7.20%. The element that contributed the most to increase its impact was silver. The AZ91 alloy, provided by the EcoInvent dataset, had a lower environmental impact than all the magnesium alloys studied in this work. The content of critical raw materials (CRMs) was also assessed, showing a high content in CRMs, between 89.72% and 98.22%

Application of Surrogate Based Optimisation in the Design of Automotive Body Structures

The rapid development of automotive industry requires manufacturers to continuously reduce the development cost and time and to enhance the product quality. Thus, modern automotive design pays more attention to using CAE analysis based optimisation techniques to drive the entire design flow. This thesis focuses on the optimisation design to improve the automotive crashworthiness and fatigue performances, aiming to enhance the optimisation efficiency, accuracy, reliability, and robustness etc. The detailed contents are as follows: (1) To excavate the potential of crash energy absorbers, the concept of functionally graded structure was introduced and multiobjective designs were implemented to this novel type of structures. First, note that the severe deformation takes place in the tubal corners, multi-cell tubes with a lateral thickness gradient were proposed to better enhance the crashworthiness. The results of crashworthiness analyses and optimisation showed that these functionally graded multi-cell tubes are preferable to a uniform multi-cell tube. Then, functionally graded foam filled tubes with different gradient patterns were analyzed and optimized subject to lateral impact and the results demonstrated that these structures can still behave better than uniform foam filled structures under lateral loading, which will broaden the application scope of functionally graded structures. Finally, dual functionally graded structures, i.e. functionally graded foam filled tubes with functionally graded thickness walls, were proposed and different combinations of gradients were compared. The results indicated that placing more material to tubal corners and the maximum density to the outmost layer are beneficial to achieve the best performance. (2) To make full use of training data, multiple ensembles of surrogate models were proposed to maximize the fatigue life of a truck cab, while the panel thicknesses were taken as design variables and the structural mass the constraint. Meanwhile, particle swarm optimisation was integrated with sequential quadratic programming to avoid the premature convergence. The results illustrated that the hybrid particle swarm optimisation and ensembles of surrogates enable to attain a more competent solution for fatigue optimisation. (3) As the conventional surrogate based optimisation largely depends on the number of initial sample data, sequential surrogate modeling was proposed to practical applications in automotive industry. (a) To maximize the fatigue life of spot-welded joints, an expected improvement based sequential surrogate modeling method was utilized. The results showed that by using this method the performance can be significantly improved with only a relatively small number of finite element analyses. (c) A multiojective sequential surrogate modeling method was proposed to address a multiobjective optimisation of a foam-filled double cylindrical structure. By adding the sequential points and updating the Kriging model adaptively, more accurate Pareto solutions are generated. (4) While various uncertainties are inevitably present in real-life optimisations, conventional deterministic optimisations could probably lead to the violation of constraints and the instability of performances. Therefore, nondeterministic optimisation methods were introduced to solve the automotive design problems. (a) A multiobjective reliability-based optimisation for design of a door was investigated. Based on analysis and design responses surface models, the structural mass was minimized and the vertical sag stiffness was maximized subjected to the probabilistic constraint. The results revealed that the Pareto frontier is divided into the sensitive region and insensitive region with respect to uncertainties, and the decision maker is recommended to select a solution from the insensitive region. Furthermore, the reduction of uncertainties can help improve the reliability but will increase the manufacturing cost, and the tradeoff between the reliability target and performance should be made. (b) A multiobjective uncertain optimisation of the foam-filled double cylindrical structure was conducted by considering randomness in the foam density and wall thicknesses. Multiobjective particle swarm optimisation and Monte Carlo simulation were integrated into the optimisation. The results proved that while the performances of the objectives are sacrificed slightly, the nondeterministic optimisation can enhance the robustness of the objectives and maintain the reliability of the constraint. (c) A multiobjective robust optimisation of the truck cab was performed by considering the uncertainty in material properties. The general version of dual response surface model, namely dual surrogate model, was proposed to approximate the means and standard deviations of the performances. Then, the multiobjective particle optimisation was used to generate the well-distributed Pareto frontier. Finally, a hybrid multi-criteria decision making model was proposed to select the best compromise solution considering both the fatigue performance and its robustness. During this PhD study, the following ideas are considered innovative: (1) Surrogate modeling and multiobjective optimisation were integrated to address the design problems of novel functionally graded structures, aiming to develop more advanced automotive energy absorbers. (2) The ensembles of surrogates and hybrid particle swarm optimisation were proposed for the design of a truck cab, which could make full use of training points and has a strong searching capacity. (3) Sequential surrogate modeling methods were introduced to several optimisation problems in the automotive industry so that the optimisations are less dependent on the number of initial training points and both the efficiency and accuracy are improved. (4) The surrogate based optimisation method was implemented to address various uncertainties in real life applications. Furthermore, a hybrid multi-criteria decision making model was proposed to make the best compromise between the performance and robustness

Life Cycle Impact of Different Joining Decisions on Vehicle Recycling

Stricter vehicle emission legislation has driven significant reduction in environmental impact of the vehicle use phase through increasing use of lightweight materials and multi-material concepts to reduce the vehicle mass. The joining techniques used for joining multi-material designs has led to reduction in efficiency of the current shredder-based recycling practices. This thesis quantifies this reduction in efficiency using data captured from industrial recycling trials. Life Cycle Assessment has been widely used to assess the environmental impact throughout the vehicle life cycle stages. Although there is significant research on material selection or substitution to improve the vehicle’s carbon footprint, the correlation between multi-material vehicle designs and the material separation through commonly used shredding process is not well captured in the current analysis. This thesis addresses this gap using data captured from industrial trials to measure the influence of different joining techniques on material recycling efficiencies. The effects of material degradation due to joining choices are examined using the life cycle analysis including exergy losses to account for a closed-loop system. The System Dynamics approach is then performed to demonstrate the dynamic life cycle impact of joining choices used for new multi-material vehicle designs. Observations from the case studies conducted in Australia and Europe showed that mechanical fasteners, particularly machine screws, are increasingly used to join different material types and are less likely to be perfectly liberated during the shredding process. The characteristics of joints, such as joint strength, material type, size, diameter, location, temperature resistance, protrusion level, and surface smoothness, have an influence on the material liberation in the current sorting practices. Additionally, the liberation of joints is also affected by the density and thickness of materials being joined. The life cycle analysis including exergy losses shows a significant environmental burden caused by the amount of impurities and valuable material losses due to unliberated joints. By measuring the influence of joints quantitatively, this work has looked at the potential of improving the quality of materials recycled from ELV to be reused in a closed-loop system. The dynamic behaviours between the joining choices and their delayed influence on material recycling efficiencies from the life cycle perspective are performed using the data from case studies. It shows that the short-term reduction in environmental impact through multi-material structures is offset over the long-term by the increasing impurities and valuable material losses due to unliberated joints. The different vehicle recycling systems can then be resembled using two widely known system archetypes: “Fixes that Fail” and “Shifting the Burden”. Despite the adoption of more rigorous recycling approaches, the life cycle impact of different joining techniques on vehicle recycling continue to exist. The enactment of strict regulations in current ELV recycling systems is unable to solve the underlying ELV waste problem, and only prolongs the delay in material degradation due to joining choices. This work shows that the choice of joining techniques used for multi-material vehicle designs has a significant impact on the environmental performance during the ELV recycling phase

Human Aspect on Chain of Custody (CoC) System Performance

The tropical forests cover 24% of tropical land area. They are the most productive terrestrial ecosystems on earth with high priorities for biodiversity conservation. These forests store a substantial amount of carbon in biomass and soil, and they also regulate the transfer of carbon into the atmosphere as carbon dioxide (CO2). Indonesia is having the third tropical forest area in the world after Brazil and Congo. Over 50 years forest has been felled both legally as well as illegally. High rate of forest degradation resulted from unsustainable forest management, rampant illegal logging, forest area encroachment, conversion and natural disaster. All urges rapid improvement of management system of Indonesia’s forest resources (Holmes, 2002). Forest certification is one tool that can support the achievement of sustainable forest management goal. Under current operation of join certification protocol between the Forest Stewardship Council (FSC) and the Indonesian Ecolabelling Institute (LEI) in Indonesia, forest management units must be able to show the required performance indicated in LEI criteria and indicator as well as FSC principles and criteria to attain certification of their products. The gap between current practices and performance required by forest certifications schemes is still enormous. The performance of forest certification system from LEI is determined very much by the human that is involved in the process of planning and operation. The name of certification system is chain of custody (CoC) certification. CoC operation involves activities such as tracing raw material from the forest to the factory, through shipping and manufacturing, to the final end product. In all of the above processes, the roles of human are critical, although the specific roles played from one process to another are different. In this paper we present an identification of human aspect and other factors that predominantly affect CoC system performance

End-of-life vehicle management: a comprehensive review

Waste management is gaining very high importance in recent years. As automotive is one of the most critical sectors worldwide, which is rapidly increasing, the management of end-of-life vehicles (ELVs) gains importance day by day. Due to legislation and new regulations, actors like users, producers, and treatment facilities are being conferred new responsibilities in the ELV management process. Besides, the ELV management is of vital importance for environment conservation, circular economy and sustainable development. All of these reasons are making the ELV management such a crucial issue to study. Today, the ELV management is a well-positioned and emergent research area. However, the available review papers are focused only on a small area of the ELV management, such as reverse logistics, recovery infrastructure, disassemblability, etc. Besides, a review of state-of-the-art mathematical models for the ELV management is still missing. This paper aims to provide an extensive content analysis overview of studies on the ELV management. A total of 232 studies published in the period 2000-2019 are collected, categorized, reviewed and analyzed. A critical review of the published literature is provided. Gaps in the literature are identified to clarify and suggest future research directions. This review can provide a source of references, valuable insights, and opportunities for researchers interested in the ELV management and inspire their additional attention

A study of optimal automotive materials choice given market and regulatory uncertainty

Thesis (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2008.Includes bibliographical references (p. 183-185).This present thesis hypothesized that the increasing demand for fuel-efficient vehicles, recently updated Corporate Average Fuel Economy (CAFE) regulation, and volatile U.S. sales markets may foreshadow a shift in the competitiveness of lightweight alternative materials relative to incumbent steels. To test this hypothesis, a novel automotive materials selection methodology was developed which evaluates the net present value (NPV) of vehicle projects by incorporating five integrated models: (1) an ADVISORbased vehicle performance model, (2) a market model that predicts expected annual sales, (3) a cost model that maps technology decisions and sales levels to fixed and variable costs, (4) a binomial lattice model of demand uncertainty, and (5) a regulatory model that mimics CAFE. The integrated model solves materials selection problems by optimization, using explicit simulation to find the set of materials choices for which the NPV of a vehicle project is maximized. A case study was developed to illuminate the competitive dynamics between incumbent steel and lightweight composite materials in two vehicle subsystems (body-in-white, closure set) and three vehicle markets (small car, mid-size car, luxury car). The results suggest that the value of acceleration improvements due to a lightweight materials enabled vehicle mass reduction is greater than the value of concurrent fuel economy improvements. When the value of acceleration improvements and fuel economy improvements are considered, the production volume at which it becomes economically efficient to switch from using composites to using steel shifts from the cost-competitive production volume to a higher one. The magnitude of this shift depends on the degree to which the car market values performance improvements and the rate at which composites become more costly than steel. Generally, more stringent CAFE policies were found to improve composite materials' competitiveness to a greater degree than the effects of demand uncertainty.by Robert Joseph Cirincione, Jr.S.M.in Technology and Polic

A Review Assessment of Fiber-Reinforced Polymers for Maritime Applications

Composite materials, comprised of fiber-reinforced polymer, offer a high strength-to-weight ratio, making them excellent for the building of complex, lightweight structures in a variety of industries, including the marine sector. There is an improvement in fuel efficiency and cost-effectiveness in general marine component developments as a result of the lightweight and flexible design characteristics. Fiber-reinforced polymer (FRP) composites are often used to construct boats, ships, and other marine compounds, such as the hull, column beams, piling structures, and other internal ship components, since they meet the aforementioned characteristics. In terms of durability, rigidity, and corrosion resistance, these FRPs may readily replace conventional metal counterparts.So,this review gives an overview of FRP Composites usage in marine industries for various potential application.Fiber-reinforced polymer composites offer a significant advantage in strength and weight when compared to conventional materials. Costs are declining and production times are slowly decreasing for maritime components because of their less weight and greater adaptability. &nbsp