Macro lambda is a parameter for predicting the weight savings for using different material. Macro lambda approximates the response of a thin-walled structure to a change in material thickness. The relationship between macro lambda and weight savings for material substitution is given. The results of nine major joints for a car cab model are given. Two kinds of structural element for weight advantage of aluminum, magnesium and other light materials are given: curved beam in-plane bending, curved beam out-of-plane bending. Bulkhead reinforcement is given for a T-Joint model. The application shows a dramatic reduction of macro lambda for T-Joint x moment and y moment load, which means the weight advantage of light materials is reduced after the reinforcement applied. For the z moment load T-Joint model, adding center layer reinforcement gives the largest reduction of macro lambda and maximum von Mises stress. The bulkhead reinforcement is then used for two car cab joints: B-pillar to rocker joint and hinge pillar to rocker joint. The results indicate that the bulkhead reinforcement near the center area gives the biggest reduction for macro lambda. Micro lambda, which is a value for element level, is introduced. The relationship between micro lambda and force distribution is given. Then it is used for the analysis of the force distribution along curved beam model when the thickness of the model is doubled. The results indicate that the force is redistributed from the corner to center of the flange for the curved beam model. So for curved beam model, light material such as aluminum, magnesium, which is thicker, is more efficiently used than steel. Micro lambda is used for the analysis of B-pillar to rocker joint of a car cab. The result indicates that the maximum micro lambda area is just the area where we apply the optimum bulkhead reinforcement. Micro lambda is also used for the analysis of AISI PNGV bending model. The result shows that the C-pillar area is the major problem area. Several reinforcements for the C-pillar area are given. The result shows that layer 31172 is most important for increasing the stiffness.

This study uses numerical design optimization with advanced metamodeling techniques to investigate the effects of material substitution and dummy models on crashworthiness characteristics of automotive structures. A full-scale Dodge Neon LS-DYNA finite element model is used in all structural analysis and optimization calculations. Optimization is performed using vehicle-based responses for multiple crash scenarios and occupant-based responses for one crash scenario. An AZ31 magnesium alloy is substituted for the baseline steel in twenty-two vehicle parts. Five base metamodels and an Optimized Ensemble metamodel are used to develop global surrogate models of crash-induced responses. Magnesium alloy is found to maintain or improve vehicle crashworthiness with an approximate 50% reduction in selected part mass using vehicle-based responses while dummy-based designs show less percentage decrease in weight. Vehicle-based responses selected to approximate dummy injury metrics do not show the same relative change compared to dummy-based responses.

Firms developing new products often face the challenge of making investment decisions under uncertain input-cost conditions due to the price volatilities of the materials they use. These decisions need to be made long before the final products are launched on the market. Therefore, firms who invest in the opportunity to switch materials in a timely manner will have the flexibility to react to material price changes and realize competitive advantages. However, volatile material prices may also cause a firm to delay investment. Using real-options reasoning, this article studies the influence of input-cost fluctuations on the timing decision to start new product development (NPD) and thus create the follow-on opportunity to later replace an existing product. A model that combines waiting and switching options to derive influencing factors of the flexibility value which triggers the investment is developed and tested on a sample of material substitution projects from manufacturing firms. The results show how price uncertainty of the new and the old material, their joint price development, the expected project duration, and competitive preemption are related to the propensity to delay the start of NPD. The findings provide new insights on how timing in adopting materials can be used to hedge exposure to volatile material prices. The insights are relevant for adopters and producers of new materials, as well as for policy makers who strive for supporting the diffusion of new materials. (authors' abstract)

The benefits of lighter auto bodies are discussed, and aluminum is compared to steel as an alternative material for auto body construction. The concept of a structural index, lambda, is developed using the simple example of a hollow beam of wall thickness, t, with a cantilever load case. It is shown that the bending stiffness, K, of the beam can be defined as a function of t^lambda, that 1 < lambda < 3, and that lambda can be used to predict the weight savings from material substitution where stiffness is held constant. It is then demonstrated that lambda can be used to predict the weight savings from material substitution in the more complex cases of the joints of a light truck cab.

Over the last decades, wood has encountered increasing competition from other building materials. Hence, it is relevant to study the underlying factors of material substitution. The market for repair and remodelling (R&amp;R) is growing in importance. The end-consumer´s, or the household?s, assessments as to material selection are generally more crucial in R&amp;R than in construction of new houses, a circumstance highlighting the importance of the end-consumer. Consequently, this thesis deals with material substitution within an end-consumer context. Proper market segmentation and targeting presuppose an understanding of why households differ as to material preferences. Prioritising customer needs in quality improvement and/or product development requires information as to the importance of different customer requirements or needs as well as the performance of wood, relative substitutes, in providing for these needs. The thesis proposes a coherent approach for market segmentation and for prioritising customer needs: (i) how to provide a basis for market segmentation and targeting, i.e., to extract the distinguishing features of different material preferences; (ii) how to extract information enabling the prioritising of customer needs, i.e., importance and performance information. Identifying prominent discriminating factors of building application material preference, in order to subsequently explain why households differ within and between samples/cultures as to material preferences, and finally assessing customer requirements or needs as to the importance and the performance of wood relative substitutes in fulfilling them, presuppose an approach for data collection and analysis, which in turn requires a theoretical frame of reference. Hence, in the thesis a theoretical framework and different methods, for extracting decisive preferential predictors and assessing customer needs respectively, are suggested and evaluated. A pronounced design profile and distinct material alternatives make floorcovering a good illustrative example. The results indicate that material substitution with an end-consumer focus should be studied within a contextual framework. Hence, the usage context, the type of room refloored and whether the dwelling is owned or not, seems to define the types of materials actively considered. Further, households obviously differ in how they perceive the concept of floorcovering in a given usage context, depending on the general life situation and individual experience. Data collection, with the aim of identifying distinguishing factors of building application material preferences, must thus handle the collection of data related to usage context as well as the general life situation and individual experience. To obtain a deeper understanding of the underlying motives open-ended questions are called for. Performance benchmarking as to customer requirements or needs should be relative competitors in the same market segment, i.e., close substitutes. The assessment of customer needs should allow analysis on benefit levels, as alternatives in material substitution most readily can be compared in terms of the more abstract benefits/consequences they provide rather than concrete attributes. The apparent causal complexity, resulting from contextual influences, severely limits the usefulness and adequacy of traditional, additive, statistical analysis. Multivariate projection methods like partial least square discriminant analysis (PLS-DA); in coping with collinear variables, as well as the Boolean approach of qualitative comparative analysis (QCA); enabling data reduction in a theoretically guided manner, have potential for handling multiple conjunctural causation when analysing material preferences. Furthermore, both methods are able to handle binary variables resulting from open-ended questions, dependent as well as independent. PLS-DA can, however, more readily than Boolean algebra capture contextual influences. Analysis by means of PLS-DA thus seem to provide the information necessary for market segmentation and targeting, i.e., the causes of preferential differences both between and within cultures: evaluative criteria and variables related to the context. The output from the analysis of material preferences serve as input to the subsequent assessment of customer needs, as to the make-up of customer needs and as to which materials constitute close substitutes, i.e., share usage context. Customer satisfaction modelling (CSM) using partial least squares (PLS) seems well adapted for extracting the information necessary for prioritising customer needs: the impact on customer satisfaction of the fulfilment of different customer requirements or needs, and the performance of wood, relative substitutes, in providing for these needs. A valuable asset of CSM is the ability to allow analysis on customer benefit as well as attribute level. Usage context and data connected with the life situation provide instruments for market segmentation and targeting. For example: according to the present results, users of wooden flooring in the Netherlands are house owners to a greater extent and generally have a higher household income than users of laminated flooring. One of the apparently salient reasons for choosing wood, the natural material property, is part of the intrinsic nature, character, of the material. This quality of wood could provide an edge on the close substitute, laminated flooring. The results presented in the thesis further indicate that practical, functional, benefits exert the greatest impact on customer satisfaction, for wooden flooring as well as its closest substitutes laminate and carpet. This is noteworthy, as the salient evaluative criteria for choosing wooden flooring, unlike the other materials studied, were of a non-practical nature. This circumstance highlights the necessity of considering substitutes to identify latent needs. A low cost over the life cycle and hygiene are apparently the most important benefits to improve for wooden flooring manufacturers, as importance is high and performance relatively low.

abstract: The focus of this research is to investigate methods for material substitution for the purpose of re-engineering legacy systems that involves incomplete information about form, fit and function of replacement parts. The primary motive is to extract as much useful information about a failed legacy part as possible and use fuzzy logic rules for identifying the unknown parameter values. Machine elements can fail by any number of failure modes but the most probable failure modes based on the service condition are considered critical failure modes. Three main parameters are of key interest in identifying the critical failure mode of the part. Critical failure modes are then directly mapped to material properties. Target material property values are calculated from material property values obtained from the originally used material and from the design goals. The material database is searched for new candidate materials that satisfy the goals and constraints in manufacturing and raw stock availability. Uncertainty in the extracted data is modeled using fuzzy logic. Fuzzy member functions model the imprecise nature of data in each available parameter and rule sets characterize the imprecise dependencies between the parameters and makes decisions in identifying the unknown parameter value based on the incompleteness. A final confidence level for each material in a pool of candidate material is a direct indication of uncertainty. All the candidates satisfy the goals and constraints to varying degrees and the final selection is left to the designer's discretion. The process is automated by software that inputs incomplete data; uses fuzzy logic to extract more information and queries the material database with a constrained search for finding candidate alternatives. / Dissertation/Thesis / Collection of Images used in Thesis / M.S. Mechanical Engineering 2011

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2014-11-10T12:28:16Z No. of bitstreams: 0 / Made available in DSpace on 2014-11-10T12:28:16Z (GMT). No. of bitstreams: 0 / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2014-11-10T12:28:16Z No. of bitstreams: 0 / Made available in DSpace on 2014-11-10T12:28:16Z (GMT). No. of bitstreams: 0 / O dissilicato de ítrio (Y2Si2O7) por apresentar propriedades luminescentes consideráveis, é um potencial substituto dos óxidos de terras raras na tecnologia de queimadores de gás para iluminação. Em processos de conformação a partir de suspensões, o controle da estabilidade das partículas em meio líquido consiste em uma importante etapa para a produção de componentes com microestrutura homogênea e estabilidade estrutural. Neste sentido, este trabalho apresenta estudos sobre o comportamento de superfície, de estabilidade e reológico de suspensões aquosas de Y2Si2O7 e &beta;-Y1,95Dy0,05Si2O7 com o objetivo de preparar suspensões compatíveis para o processo de conformação por réplica, usando-se fibras vegetais como matriz para a confecção de componentes reticulados para queimadores de gás. Neste estudo foram avaliados parâmetros determinantes na estabilidade e comportamento de fluxo das suspensões, como também a luminescência estimulada pela temperatura desses materiais na forma de pó e a eficiência radiante do protótipo de queimador de gás. Os resultados obtidos para o &beta;-Y1,95Dy0,05Si2O7 comparados com a ítria (Y2O3) e concentrado de terras raras contento ítria (YTR) mostram-se promissores. Desenvolveu-se por processamento coloidal do &beta;-Y1,95Dy0,05Si2O7 e utilizando-se o processo de conformação por réplica a partir da esponja vegetal Lufa Cylindrica, um protótipo de lâmpada de queimador de gás com boa resistência mecânica ao manejo, emissividade espectral no visível (&lambda;=580nm) e eficiência radiante de 13%, com grande potencial para iluminação de ambientes internos de acordo com as recomendações da Comissão Internacional de Iluminação (CIE). / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Doctoral thesis Life cycle cost model of an apartment building includes the process of modeling, starting with the theoretical definition and ending up with testing it for practical usage, the error measurement and its recalling abilities. The aim is to construct a model for simulating the life cycle costs of an apartment building during the phase of purchasing it followed with the simulation of life cycle costs having the conditions defined in advance. The method of the model construction shall be found in stating an appropriate representative, setting the entrance parameters and defining the condition under which it is supposed to work. The last step is to test the created model in order to find possible mistakes. Mathematically-statistical methods shall be used for setting the model. Another researching method comprises of creating several exemplary studies which shall correct the costs model and expand its applicability.