1,720,956 research outputs found
Modelling and testing of thermoplastic composite components using Building Block approach integrating process simulation.
No full textCurrently, the automotive sector is exploring the feasibility of replacing metals with composite materials for structural and non-structural applications. This is mainly driven by the demand for lighter and increasingly complex components, which will be extremely difficult to fabricate with the traditional metal forming approaches. This prompted the need for exploring textile reinforced composite materials, where they stand out about their ability to allow complex designs with high specific strength and stiffness. Which further helps to reduce mass and increase fuel efficiency. However, a disadvantage right now is the use of composites is limited by an inability to accurately analyse and predict these composite structures for its mechanical performance. This thesis presents methodology employing finite element techniques for predictive modelling of textile reinforced composite materials by considering the process simulations. The Building Block approach is introduced and implemented as a guideline, to efficiently substantiate the durability and performance of the component design sequentially.
FEA simulation of a composite component was done using two composite failure criterions for comparison, Crasurv (modified Tsai-Wu) and Hashin; after completing a detailed material characterisation and card fitting for creating FE material. The results of the structural simulations are compared against experimental results, which is kept as a benchmark for future comparisons and review.
The next step was to conduct process simulations to analyse the composite forming process to investigate the locally varying microstructure to account for the anisotropic behaviour in the composite part during its production that can alter the structural integrity of the component. An additive split between isotropic, elasto-plastic matrix and anisotropic hyper-elastic fibers material card is used in LS-Dyna explicit solver for conducting process simulations. A detailed material characterisation was done on the textile reinforced fabric and the composite laminate at forming temperature to study its tensile, shear, frictional and bending properties. The process simulation helps to obtain reliable structural simulation models by mapping
Building Block Approach’ for Structural Analysis of Thermoplastic Composite Components for Automotive Applications
No full textAdvanced thermoplastic prepreg composite materials stand out with regard to their ability to allow complex designs with high specific strength and stiffness. This makes them an excellent choice for lightweight automotive components to reduce mass and increase fuel efficiency, while maintaining the functionality of traditional thermosetting prepreg (and mechanical characteristics) and with a production cycle time and recyclability suited to mass production manufacturing. Currently, the aerospace and automotive sectors struggle to carry out accurate Finite Elements (FE) component analyses and in some cases are unable to validate the obtained results. In this study, structural Finite Elements Analysis (FEA) has been done on a thermoplastic fiber reinforced component designed and manufactured through an integrated injection molding process, which consists in thermoforming the prepreg laminate and overmolding the other parts. This process is usually referred to as hybrid molding, and has the provision to reinforce the zones subjected to additional stresses with thermoformed themoplastic prepreg as required and overmolded with a shortfiber thermoplastic resin in single process. This paper aims to establish an accurate predictive model on a rational basis and an innovative methodology for the structural analysis of thermoplastic composite components by comparison with the experimental tests results
From thermosetting to thermoplastic composite materials: automotive applications in structural components
No full textProcess analysis for structural optimisation of thermoplastic composite component using the building block approach
No full textThe paper aim is to establish and optimise the prediction model of a thermoplastic fibre reinforced component designed and manufactured through an integrated injection moulding process (Hybrid Moulding). This is done by the Finite Element Analysis (FEA) and then the process simulations, considering the composite material as an elastic anisotropic woven fabric to study the deformations undergone during the manufacturing process. The proposed methodology for creating the predictive model is fairly accurate, and it is a novel method which can be easily integrated and adapted into a components initial design phase. This optimisation technique can replace the expensive and traditional trial and error procedures during the design and prototyping phase, and it significantly decreases the time to build the final component. The final scope of the research is to simplify the product development phase of general lightweight automotive thermoplastic components by creating an innovative methodology for predictive modelling
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
