Evaluating the mechanical behaviour of orthotropic 3D woven carbon fibre reinforced composites

Laminated composites are increasingly employed in a variety of industries ranging from Aerospace to Wind Power. The high specific stiffness and strength of these materials renders their wider application advantageous in many fields. However, the broader implementation of such composites is frequently restrained by their poor impact resistance and damage tolerance. Even events as innocuous as a dropped tool can impart significant damage to such materials. Such damage can lead to drops in the strength and stiffness that are unacceptable for many applications, particularly those in Aerospace. 3D woven composites present a possible means of improving the impact resistance and damage tolerance of composite materials. The incorporation of out-of-plane fibres, transversely passing through layers of in-plane fibres, is the means by which this improvement in performance is obtained. This body of work presents an investigation into the behaviour of three dimensionally woven carbon fibre composites. Specifically, the subject composite fabric had an orthogonally woven three dimensional structure. The novelty of these materials is such that knowledge and understanding of their mechanical behaviour is very limited. The purpose of this work was to remedy this through experimental and analytical analysis of these composites. The 3D woven materials were characterized experimentally using a variety of techniques. In addition to evaluating the material experimentally, analytical methods were also used. Current analytical methods were found to be deficient in their incapacity to account for in-plane crimp on a micro scale. As a result a new micro scale approach for predicting the stiffness and strength of these 3D woven materials was developed. The composites used for this thesis were tested using a variety of means. The range of test methodologies used subjected the materials to in-plane, out-of-plane, dynamic and quasi- static loadings. Techniques used included; tension, shear, impact, compression after impact, bolt shear out and bearing pull through. Other means implemented included microscopy, C-scanning and Digital Image Correlation. In addition, conventional composites made from unidirectional pre-pregs or Non-Crimp Fabrics (NCFs) were tested to provide a basis for comparison. Analysis and prediction of the behaviour of conventional laminated composites can be performed using a variety of methods. While the range of methods available is broad, they commonly use individual plies of composite as their fundamental building blocks. This is both convenient analytically and experimentally as the properties of such individual lamina may be found with reasonable ease. However, 3D woven composites are integrated laminates due to the out‐of‐plane fibres they possess. As a result, the accuracy of conventional experimental or analytical methods for evaluating these materials is likely to be poor. In order to gain a better understanding of the behaviour of these 3D woven materials a new micromechanics model was developed. In contrast to other available methods, this micromechanics approach examines the effect of crimp at the fibre level. The method proposed is also distinct in its capability of simultaneously accounting for varying crimp across and along a section of composite

Are biases towards the recent past causing us to unintentionally expose personnel to increased levels of risk?

PresentationThis paper focuses on the consideration of an unbiased approach to assessing risk to push the industry towards proactively addressing risk rather than reactively allowing cognitive biases to drive process safety culture and personnel risk management solutions. Scientifically proven to affect the way we process and interpret the world around us, cognitive biases allow us to shortcut the complexities of the world when making decisions. In some cases, biases can be surprisingly accurate, while in other instances they can lead to making poor judgements and decisions based on the limited information available to us. Specifically damaging in the process safety industry are the availability heuristic and the confirmation bias, which together cause us to focus on information that comes to mind quickly, justifies our opinions, and favors our existing beliefs. With recent industrial accidents that have resulted in fatalities and a push toward regulatory change in response to explosion events, we have seen a rise in the availability of blast resistant structures such as BRMs and hardened stick-built buildings to protect onsite personnel from explosions. The availability of such blast hardened structures has produced an unfortunate trend of moving personnel back in closer to processing areas. Recent advancements in full-scale testing and computer modeling capabilities suggests that even though such buildings may protect for some level of blast hazards, this approach may result in increased levels of personnel risk from other hazard types, specifically impinged jet fires and toxic exposure. This raises the question: are employees being placed in risky locations in a BRM or hardened building with a false sense of security

Potenciando la formación investigativa de los estudiantes de ciencia de la computación mediante un instrumento didáctico

The work exemplifies a way to enhance the research formation of students of Computer Science through the application of a didactic procedures system created by the authors themselves. The exemplification is distinguished by simulating the resolution process carried out by professors and students in a practical class, using a problematic situation, with the purpose of serving as a guide in the preparation and development of said classes. This process is conducted by the teacher through the three procedures of the system, which are: interpretive of the user system, translator of the intermediary and valorative system of the computer information system. It was concluded that the system of didactic procedures, exemplified, influences positively in the development of investigative skills

Potenciando la formación investigativa de los estudiantes de ciencia de la computación mediante un instrumento didáctico

The work exemplifies a way to enhance the research formation of students of Computer Science through the application of a didactic procedures system created by the authors themselves. The exemplification is distinguished by simulating the resolution process carried out by professors and students in a practical class, using a problematic situation, with the purpose of serving as a guide in the preparation and development of said classes. This process is conducted by the teacher through the three procedures of the system, which are: interpretive of the user system, translator of the intermediary and valorative system of the computer information system. It was concluded that the system of didactic procedures, exemplified, influences positively in the development of investigative skills

Estudio exploratorio sobre la formación investigativa de los estudiantes de Licenciatura en Ciencia de la Computación

The article analyzes the results obtained in a diagnosis study on the investigative formation of the students of the career of Licentiate in Computation Science, in Oriente University. The investigation, of exploratory character,combines quantitative and qualitative methods, to determine the main difficulties related withthe behaviorof this formation.The obtained results indicate that there are inadequacies based in the faulty form in that thedynamics of the formative process is developed insubjects of the career, that facilitate opportunities for apedagogic intervention in this dynamics

Perfeccionando los procedimientos didácticos para la formación investigativa de estudiantes de Ciencia de la Computación

The application of Computational Sciences is one priority for the development of any society, for this reason the research training of the students of these courses needs continuous improvement. This work aims to corroborate the relevance and validity of a system of didactic procedures to perfect this training. This system was applied through a quasi-pedagogic experiment in Computer Science career at the Oriente University, Cuba. Was concluded in the context studied that system of didactic procedures increase significantly the apprehension of computational research thinking in students

DINÁMICA DEL PROCESO DE FORMACIÓN INVESTIGATIVA EN LA CARRERA DE LICENCIATURA EN CIENCIA DE LA COMPUTACIÓN

It is presented a doctoral research report that proposes a model of the dynamics of investigative formation process in the bachelor's degree in Computing Sciences. This model was structured in three dimensions: computational hermeneutic of the user system, computational hermeneutic of the intermediary system and computational hermeneutic of the information system, which is an expression of the inner movements of said dynamic and allow reveal its transformation, aimed at formation a systemic-investigative-computational thinking. The novelty of the proposed model lies in having revealed the integrative logic between a systematization of relevant information of the user system and a validation of the computational information system, relationship that reflects the computational hermeneutical transit that has to carry out the student of Computing Science by the systems (user-intermediary-information) during investigation of a problem situation.  Se presenta un informe de investigación doctoral que propone un modelo de la dinámica del proceso de formación investigativa en la carrera de Licenciatura en Ciencia de la Computación. Dicho modelo fue estructurado en tres dimensiones: hermenéutica computacional del sistema usuario, hermenéutica computacional del sistema intermediario y hermenéutica computacional del sistema de información, las que son expresión de los movimientos internos de la citada dinámica y permiten revelar su transformación, encaminada a la formación de un pensamiento sistémico-investigativo-computacional. La novedad del modelo propuesto radica en haber revelado la lógica integradora entre una sistematización de la información relevante del sistema usuario y una validación del sistema de información computacional, relación que a la vez da cuenta del tránsito hermenéutico computacional que tiene que llevar a cabo el estudiante de Ciencia de la Computación por los diversos sistemas (usuario-intermediario-de información) durante el proceso de investigación de una situación problémic

Una alternativa didáctica para perfeccionar las habilidades investigativas del licenciado en Ciencia de la Computación

In the work, a system of didactic procedures is proposed to perfect the investigative skills of Computer Science students. It was prepared as part of a doctoral thesis, using the Functional Structural Systemic Method. It has been applied at the Universidad de Oriente (UO) for five courses, with results that have confirmed that the system provides sufficient evidence about its possibilities of improving the investigative skills of the aforementioned stud ents, by contributing to the development of computational investigative thinking in them

Perfeccionando los procedimientos didácticos para la formación investigativa de estudiantes de Ciencia de la Computación

The application of Computational Sciences is one priority for the development of any society, for this reason the research training of the students of these courses needs continuous improvement. This work aims to corroborate the relevance and validity of a system of didactic procedures to perfect this training. This system was applied through a quasi-pedagogic experiment in Computer Science career at the Oriente University, Cuba. Was concluded in the context studied that system of didactic procedures increase significantly the apprehension of computational research thinking in students