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Materials And The Environment Eco Informed Material Choice

Material criticality assessment in early phases of sustainable product development

Sustainability is increasingly recognized as a key innovation capability in the organization. However, it is not always evident for manufacturers how sustainability targets shall be “mixed and matc ...

https://www.mdpi.com/2071-1050/11/7/1952/pdf

Multi-Criteria Decision Making for Sustainability and Value Assessment in Early PSS Design

This paper presents a comprehensive review on the sources of model inaccuracy and parameter uncertainty in metal laser powder bed fusion (L-PBF) process. Metal additive manufacturing (AM) involves multiple physical phenomena and parameters that potentially affect the quality of the final part. To capture the dynamics and complexity of heat and phase transformations that exist in the metal L-PBF process, computational models and simulations ranging from low to high fidelity have been developed. Since it is difficult to incorporate all the physical phenomena encountered in the L-PBF process, computational models rely on assumptions that may neglect or simplify some physics of the process. Modeling assumptions and uncertainty play significant role in the predictive accuracy of such L-PBF models. In this study, sources of modeling inaccuracy at different stages of the process from powder bed formation to melting and solidification are reviewed. The sources of parameter uncertainty related to material properties and process parameters are also reviewed. The aim of this review is to support the development of an approach to quantify these sources of uncertainty in L-PBF models in the future. The quantification of uncertainty sources is necessary for understanding the tradeoffs in model fidelity and guiding the selection of a model suitable for its intended purpose.

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A Review of Model Inaccuracy and Parameter Uncertainty in Laser Powder Bed Fusion Models and Simulations

The decisions made during product development (PD) lock in 70–80 % of total product cost, and the quality of the product is also largely fixed. Therefore, these decisions have a great influence on product life cycle cost, quality, and sustainability. To improve such decisions, designers need to make high-level trade-offs among various criteria to see their effects. Therefore, developing a model to support trade-offs for sustainable product development is a significant concern for designers. This research attempts to consider sustainability, quality, and cost simultaneously to make trade-offs between environmental issues and other customer requirements to select the best design specifications on their basis. Sustainability is considered as a customer requirement, which then is translated into design specifications. In this study, sustainable design is treated as an optimization problem to maximize value-added activities while minimizing environmental effects. Multi-attribute utility theory is utilized in order to formulate combination of the customer’s opinions and make a trade-off between different groups of customer requirements in the final model. An optimization model is then defined to model sustainability, quality, and cost in the product development process in order to find the optimum level of their combination thereof. By using this model, designers need not select between different solutions since they can find the optimal solution. A case study is illustrated and the results are discussed.

A new model of sustainable product development process for making trade-offs

Systematic consideration of environmental aspects within the early stages of product development (PD) can be considered highly significant in order for the overall environmental performance of the product to be improved. Many methods and tools have been developed aiming to enable this consideration and provide the properties that need to be considered and improved. This article provides an overview of some well-known and more applicable tools and methods that have been developed and are available today. The identified tools are generally classified in two groups: Guidelines and Analytical tools. The limitations and barriers of current tools are assessed and categorized and two areas for work are proposed in order to address current limitations in the existing literature. One of the areas is followed and a scoring model is proposed as a new tool for sustainable PD.

A proposed approach to improve current sustainable product development

Systematic consideration of environmental aspects within the early stages of product development (PD) can be considered highly significant in order for the overall environmental performance of the product to be improved. Many methods and tools have been developed aiming to enable this consideration and provide the properties that need to be considered and improved. This article provides an overview of some well-known and more applicable tools and methods that have been developed and are available today. The identified tools are generally classified in two groups: Guidelines and Analytical tools. The limitations and barriers of current tools are assessed and categorized and two areas for future work are proposed in order to address current limitations in the existing literature. Key worlds: Sustainability, Product development, Product life cycle, Triple bottom line (TBL), Sustainable product development, Environmental impacts.

/pdf/assessment-of-sustainable-product-development-tools-and-1t0lb60ggz.pdf

Assessment of Sustainable Product Development Tools and Methods

Geometric factors of nanofillers considerably govern the properties of conductive polymer composites (CPCs). This study provides insights into how geometrical alteration through nanotube-to-nanoribbon conversion affects the electrical properties of solid and microcellular CPCs. In this regard, polyvinylidene fluoride (PVDF)-based nanocomposites are synthesized using both the parent multi-walled carbon nanotube (MWCNT) and its chemically unzipped product, i.e., graphene nanoribbons (GNRs). Theoretical and experimental results show that GNR-based composites exhibit 1-4 orders greater conductivities than MWCNT-based composites at the same filler loading because of the larger number of filler-filler junctions as well as the significantly greater contact areas. On the other hand, the conductivities of MWCNT-based and GNR-based composites are significantly increased by 230 times and 121 times, respectively, through microcellular foaming. The effective rearrangements of rigid MWCNTs and flexible GNRs (having 4 and 5 orders less bending stiffness) for network formation during cellular growth are compared. The GNR-based composites also exhibit a superior dielectric permittivity (e.g., 2.6 times larger real permittivity at a representative frequency of 103 Hz and a nanofiller loading of 4.2 vol%) compared to their MWCNT-based counterparts. This study demonstrates how the modification of the carbon fillers and the polymer matrix can dramatically enhance EMI shielding.

Enhanced electrical properties of microcellular polymer nanocomposites via nanocarbon geometrical alteration: a comparison of graphene nanoribbons and their parent multiwalled carbon nanotubes.

In this work, hybrid polypropylene (PP)-based composites reinforced with graphene nanoplatelets (GnPs) and glass fiber (GF) were fabricated by injection molding to elucidate how the hybrid approach can produce synergistic effects capable of achieving properties and functionalities not possible in biphasic composites. Synergism between the reinforcements translated to improved mechanical performance, which was attributed to the chemically and/or electrostatically assembled hierarchical structure that facilitates load transfer at the interface while simultaneously tailoring the crystalline microstructure of the matrix by inducing transcrystallization and β-crystal formation. It was demonstrated that there exists an optimal concentration of 0.5 wt % GnP, producing the greatest mechanical properties and synergistic effect, corresponding to the highest degree of crystallinity (∼6% greater than Neat PP) and peak formation of β-crystals within the PP matrix. The greatest synergistic effect was found to be ∼52 and ∼39% for the specific tensile strength and flexural strength, respectively. The same optimal concentration of GnPs was found to produce the highest synergistic effect for thermal conductivity of ∼68% due to the volume exclusion effect induced by the GFs combined with the higher crystallinity of the microstructure, promoting the formation of thermally conductive pathways. Ultimately, the mechanisms contributing to the synergistic effect presented in this work can be used to maximize the performance of hybrid composite systems, giving them the potential to be tailored for a variety of high-performance industrial applications to meet the rising demands for ultra-strong, thermally conductive, and lightweight materials.

Meysam Salari

Papers

A new model of sustainable product development process for making trade-offs

A proposed approach to improve current sustainable product development

Assessment of Sustainable Product Development Tools and Methods

Enhanced electrical properties of microcellular polymer nanocomposites via nanocarbon geometrical alteration: a comparison of graphene nanoribbons and their parent multiwalled carbon nanotubes.

Tailoring Multifunctional and Lightweight Hierarchical Hybrid Graphene Nanoplatelet and Glass Fiber Composites.