Richard Roth

Evaluating rare earth element availability: a case with revolutionary demand from clean technologies.

The future availability of rare earth elements (REEs) is of concern due to monopolistic supply conditions, environmentally unsustainable mining practices, and rapid demand growth. We present an evaluation of potential future demand scenarios for REEs with a focus on the issue of comining. Many assumptions were made to simplify the analysis, but the scenarios identify some key variables that could affect future rare earth markets and market behavior. Increased use of wind energy and electric vehicles are key elements of a more sustainable future. However, since present technologies for electric vehicles and wind turbines rely heavily on dysprosium (Dy) and neodymium (Nd), in rare-earth magnets, future adoption of these technologies may result in large and disproportionate increases in the demand for these two elements. For this study, upper and lower bound usage projections for REE in these applications were developed to evaluate the state of future REE supply availability. In the absence of efficient reuse and recycling or the development of technologies which use lower amounts of Dy and Nd, following a path consistent with stabilization of atmospheric CO(2) at 450 ppm may lead to an increase of more than 700% and 2600% for Nd and Dy, respectively, over the next 25 years if the present REE needs in automotive and wind applications are representative of future needs.

Materials selection and multi-attribute utility analysis

SummaryMulti-attribute utility analysis (MAUA) has emerged as a powerful tool for materials selection and evaluation. An operations research technique, MAUA has been used in a wide range of engineering areas, of which materials science and engineering is one of the more recent. Utility analysis affords a rational method of materials selection which avoids many of the fundamental logical difficulties of many widely used alternative approaches. However, MAUA has traditionally been used in materials selection problems only, in which there is certainty regarding the attribute levels of the alternatives. For many new technologies this is not the case. Another operations research technique, subjective probability assessment (SPA), can be used to address this issue. SPA makes it possible to measure a probabilistic distribution describing the confidence of the decision maker in the levels of attributes for which there is a high degree of uncertainty. These probability distributions can be used in conjunction with MAUA to provide a consistent framework for making materials selection decisions. Furthermore, the use of these techniques extends beyond the problem of materials selection into the more speculative areas of materials competitiveness and market demand in cases involving new, unproven technologies.

Mass Decompounding and Vehicle Lightweighting

Although mass reduction can be associated with additional costs, a decision to lightweight a structural subsystem may, depending on when in the vehicle development process the decision is taken, result in secondary (additional) mass savings such that the value of lightweighting is substantially increased. This paper overviews a method to estimate the potential for secondary mass savings in different vehicle subsystems. We close by describing current research efforts aimed at developing new lightweight product solutions for both body and powertrain applications along with commensurate manufacturing processes.

Evaluating the potential for secondary mass savings in vehicle lightweighting.

Secondary mass savings are mass reductions that may be achieved in supporting (load-bearing) vehicle parts when the gross vehicle mass (GVM) is reduced. Mass decompounding is the process by which it is possible to identify further reductions when secondary mass savings result in further reduction of GVM. Maximizing secondary mass savings (SMS) is a key tool for maximizing vehicle fuel economy. In todays industry, the most complex parts, which require significant design detail (and cost), are designed first and frozen while the rest of the development process progresses. This paper presents a tool for estimating SMS potential early in the design process and shows how use of the tool to set SMS targets early, before subsystems become locked in, maximizes mass savings. The potential for SMS in current passenger vehicles is estimated with an empirical model using engineering analysis of vehicle components to determine mass-dependency. Identified mass-dependent components are grouped into subsystems, and linear regression is performed on subsystem mass as a function of GVM. A Monte Carlo simulation is performed to determine the mean and 5th and 95th percentiles for the SMS potential per kilogram of primary mass saved. The model projects that the mean theoretical secondary mass savings potential is 0.95 kg for every 1 kg of primary mass saved, with the 5th percentile at 0.77 kg/kg when all components are available for redesign. The model was used to explore an alternative scenario where realistic manufacturing and design limitations were implemented. In this case study, four key subsystems (of 13 total) were locked-in and this reduced the SMS potential to a mean of 0.12 kg/kg with a 5th percentile of 0.1 kg/kg. Clearly, to maximize the impact of mass reduction, targets need to be established before subsystems become locked in.

Stochastic comparative assessment of life-cycle greenhouse gas emissions from conventional and electric vehicles

PurposeElectric vehicles (EVs) are promoted due to their potential for reducing fuel consumption and greenhouse gas (GHG) emissions. A comparative life-cycle assessment (LCA) between different technologies should account for variation in the scenarios under which vehicles are operated in order to facilitate decision-making regarding the adoption and promotion of EVs. In this study, we compare life-cycle GHG emissions, in terms of CO2eq, of EVs and conventional internal combustion engine vehicles (ICEV) over a wide range of use-phase scenarios in the USA, aiming to identify the vehicles with lower GHG emissions and the key uncertainties regarding this impact.MethodsAn LCA model is used to propagate the uncertainty in the use phase into the greenhouse gas emissions of different powertrains available today for compact and midsize vehicles in the US market. Monte Carlo simulation is used to explore the parameter space and gather statistics about GHG emissions of those powertrains. Spearman’s partial rank correlation coefficient is used to assess the level of contribution of each input parameter to the variance of GHG intensity.Results and discussionWithin the scenario space under study, battery electric vehicles are more likely to have the lowest GHG emissions when compared with other powertrains. The main drivers of variation in the GHG impact are driver aggressiveness (for all vehicles), charging location (for EVs), and fuel economy (for ICEVs).ConclusionsThe probabilistic approach developed and applied in this study enables an understanding of the overall variation in GHG footprint for different technologies currently available in the US market and can be used for a comparative assessment. Results identify the main drivers of variation and shed light on scenarios under which the adoption of current EVs can be environmentally beneficial from a GHG emissions standpoint.

Market model simulation: The impact of increased automotive interest in magnesium

Due to increasing energy and environmental concerns automakers have recently become more interested in lightweight alternatives to traditional component designs. Magnesium, the lightest standard engineering metal, has often been cited as showing potential in the automotive world, but has been resisted by automakers due to high prices and limited availability. Small production resources of magnesium limit the potential of magnesium in the automotive arena if growth in interest leads to material shortages and price volatility. To investigate the dynamics of the magnesium market, a system dynamics simulation model of the market was created. The model, which simulates supply, demand, and price interactions, was used to investigate market stability strategies that will benefit all market players

Modeling Costs and Fuel Economy Benefits of Lightweighting Vehicle Closure Panels

This paper illustrates a methodology in which complete material-manufacturing process cases for closure panels, reinforcements, and assembly are modeled and compared in order to identify the preferred option for a lightweight closure design. First, process-based cost models are used to predict the cost of lightweighting the closure set of a sample midsized sports utility vehicle (SUV) via material and process substitution. Weight savings are then analyzed using a powertrain simulation to understand the impact of lightweighting on fuel economy. The results are evaluated in the context of production volume and total mass change.

Achieving An Affordable Low Emission Steel Vehicle; An Economic Assessment of the ULSAB-AVC Program Design

Vehicle weight reduction, reduced costs and improved safety performance are the main driving forces behind material selection for automotive applications. These goals are conflicting in nature and solutions will be realized by innovative design, advanced material processing and advanced materials. Advanced high strength steels are engineered materials that provide a remarkable combination of formability, strength, ductility, durability, strain-rate sensitivity and strain hardening characteristics essential to meeting the goals of automotive design. These characteristics act as enablers to costand masseffective solutions. The ULSAB-AVC program demonstrates a solution to these conflicting goals and the advantages that are possible with the utilization of the advance high strength steels and provides a prediction of the material content of future body structures. This paper provides an overview of the materials utilized in the ULSAB-AVC body structure and describes how these advanced materials, combined with effective design and advanced material processing, deliver a cost effective light-weight structure that satisfies the demanding crash performance requirements anticipated for 2004. The paper compares the ULSAB-AVC design to the previous ULSAB body structure program to provide a comparison of the influence increased crash performance requirements and materials have on the overall mass and cost of a vehicle body structure. This paper also describes the cost assessment of the ULSAB-AVC, which encompasses the entire vehicle manufacturing and assembly process. INTRODUCTION The ULSAB-Advanced Vehicle Concepts (AVC) Program focused on the development of steel applications for vehicles for the year 2004 and beyond. In its execution, concepts were developed for the popular European C-Class, or so-called Golf Class, and the North American Midsize Class (see Figure 1), which is the target for the PNGV program, hereafter referred to as PNGV-Class vehicle. Therefore, the vehicle body structures employ the unique advantages of advanced steel grades, which provide heightened strength with excellent part forming. ULSAB-AVC vehicle body structure uses 100 percent high-strength steel grades, of which over 80 percent are advanced high-strength steels. These steels are combined with the most advanced manufacturing and joining technologies to achieve the structurally efficient designs and safety features found in ULSAB-AVC concepts. Key to reaching the program objectives was meeting anticipated 2004 crash requirements with steel, achieving the delicate balance of mass efficiency without a compromise to safety. The resulting Midsize Class vehicle concept has a mass of less than a 1000 kg and has the capability of achieving a five-star safety rating. It also approaches the PNGV target mileage by achieving 68 miles per gallon in the combined U.S. Driving Cycle and 78 miles per gallon highway. With high-volume manufacturing of 225,000 units per year, the AVC concept would not cost more to manufacture than comparable family sedans. Benchmarking data indicate that the Midsize Class ULSAB-AVC concept vehicle selling price would be below the selling price of current vehicles in the same class. The ULSAB-AVC is the most recent addition to the global steel industry’s series of initiatives offering steel solutions to the challenges facing automakers around the world today. It succeeds ULSAB [1, 2], ULSAC [3] and ULSAS [4]. The ULSAB-AVC concepts revolutionize the kinds of steels normally applied to vehicle architectures, as well as demonstrating cutting edge steel vehicle design. In addition to extensive use of advanced steels, ULSAB-AVC features a full spectrum of the latest steel technologies, including tailor welded blanks, tailored tubes, advanced joining techniques and tube and sheet hydroforming. This project was envisioned by the collaborative efforts of 33 international steel producers forming the ULSABAVC Consortium. This concept, engineered by Porsche Engineering Services, Inc., Troy, Michigan, USA, brings the potential for safe, affordable, fuel efficient vehicles, which are environmentally responsible, to near-term reality. Detailed information on ULSAB-AVC can be found in reference [5, 6]. BODY STRUCTURE EVALUATION The influence of AHSS grades on an entire body structure is difficult to assess. It is not possible to make a direct comparison of the entire body structure designed to the same criteria. A comparison made between the ULSAB-AVC (PNGV class) and the ULSAB body structures is very similar to the challenge placed on current automotive designs. For the purposes of this comparison one can consider the ULSAB-AVC to be a redesign of the ULSAB. The ULSAB-AVC program was distinctly different from the preceding ULSAB program as described below: ULSAB-AVC: 1. Concept design of entire vehicle. 2. Utilized materials and processing technically feasible in 2004. 3. Designed to meet crash performance requirements anticipated in 2004. ULSAB: 1. Concept design of a body structure. 2. Utilized material and processing technology production capable in 1998. 3. Designed for crash performance requirements of 1996. This comparison is unique from the challenge typically place on the automotive designer in that both design programs are provided the luxury of starting from a clean sheet of paper and are not hampered with the constraints of modifying a previous design. This section of the paper provides a comparison between the body structure of the ULSAB-AVC (PNGV) and the ULSAB program. A comparison is made between the vehicle size, crash performance targets, materials utilized and the corresponding body structure mass and cost. Figure 1 provides a comparison of the overall body sizes and general internal packaging targets. The total length of the body structures are nearly identical. However, as is typically required of new designs to reduce air drag and improve fuel economy, the frontal area is reduced by reducing the width and height of the vehicle with a more streamlined shape to provide a predicted drag coefficient of .25. The reduction in external dimension is accompanied with an increase in internal passenger and cargo space. This complicates the design by reducing and restricting available package space for the body structure and reducing the available space for crush zones required to satisfy the crash performance targets. The difficulties placed upon the designer to satisfy the crash performance requirements with reduced packaging space are further exacerbated with the requirement to satisfy more severe crash events. The influence of Government mandates, the insurance industry and internal marketing strategies require the designer to satisfy increasingly severe crash environments with the expectation that the passenger survives these events with a reduced chance of injury. In addition, many automotive manufactures design their product to be marketed to several regions with different ULSAB ULSAB-AVC Dimension ULSAB

Characterizing the CapEx and OpEx Tradeoffs in Next Generation Fiber-to-the-Home Networks

Network cost analyses based on a new modeling methodology are used to evaluate advanced GPON architectures. The relative merits of reach extension and higher splitter port counts are examined from both CapEx and OpEx perspectives.

Selection of lightweighting strategies for use across an automaker's vehicle fleet

Vehicle lightweighting, or mass reduction, via materials substitution is a common approach to improve fuel economy. The many subsystems in a vehicle, choices of materials, and manufacturing processes available, though, lead to numerous paths to achieving the mass reduction and identifying the best ones for an automaker to implement can be a challenge. In this paper, that challenge is addressed through the development of a selection model designed to inform the lightweighting strategy decision for an automakers fleet. The model, implemented with a genetic algorithm, identifies the strategies that enable an automaker to optimize the net present value of its cash flow, as well as to meet its CAFE obligations over the coming years. A case study of various strategies implemented in three vehicles over a three-year timeframe is used to demonstrate application of the genetic algorithm selection model and contrast it to an alternative period-by-period search implementation.