On the Predictive Tools for Assessing the Effect of Manufacturing Defects on the Mechanical Properties of Composite Materials

Abstract Despite the recent advances in the field of manufacturing of composite materials, with both thermosetting and thermoplastic matrix, the presence of irregularities that influence their mechanical properties and behavior remains a critical issue to the industry. The defects with the form of porosity, fiber misalignment, delamination and poor consolidation are considered an unavoidable form of initial damage to composite materials. The reduction of the defects by optimizing the manufacturing process and the creation effective tools for predicting the residual properties of these materials during the design and/or the manufacturing phase are of great interest. In the present work, presented are these numerical tools and methodologies based either on the idea of optimizing the manufacturing process or by using data derived from non-destructive tests. Finally, the possibility of combining the two approaches is being proposed

Virtual manufacturing: prediction of work piece geometric quality by considering machine and set-up

Lien vers la version éditeur: http://www.tandfonline.com/doi/full/10.1080/0951192X.2011.569952#.U4yZIHeqP3UIn the context of concurrent engineering, the design of the parts, the production planning and the manufacturing facility must be considered simultaneously. The design and development cycle can thus be reduced as manufacturing constraints are taken into account as early as possible. Thus, the design phase takes into account the manufacturing constraints as the customer requirements; more these constraints must not restrict the creativity of design. Also to facilitate the choice of the most suitable system for a specific process, Virtual Manufacturing is supplemented with developments of numerical computations (Altintas et al. 2005, Bianchi et al. 1996) in order to compare at low cost several solutions developed with several hypothesis without manufacturing of prototypes. In this context, the authors want to predict the work piece geometric more accurately by considering machine defects and work piece set-up, through the use of process simulation. A particular case study based on a 3 axis milling machine will be used here to illustrate the authors’ point of view. This study focuses on the following geometric defects: machine geometric errors, work piece positioning errors due to fixture system and part accuracy

ARMD Workshop on Materials and Methods for Rapid Manufacturing for Commercial and Urban Aviation

This report documents the goals, organization and outcomes of the NASA Aeronautics Research Mission Directorates (ARMD) Materials and Methods for Rapid Manufacturing for Commercial and Urban Aviation Workshop. The workshop began with a series of plenary presentations by leaders in the field of structures and materials, followed by concurrent symposia focused on forecasting the future of various technologies related to rapid manufacturing of metallic materials and polymeric matrix composites, referred to herein as composites. Shortly after the workshop, questionnaires were sent to key workshop participants from the aerospace industry with requests to rank the importance of a series of potential investment areas identified during the workshop. Outcomes from the workshop and subsequent questionnaires are being used as guidance for NASA investments in this important technology area

Numerical and experimental analysis of the thermoforming process parameters of semi-spherical glass fibre thermoplastic parts

Abstract The thermoforming process is considered among the most promising manufacturing processes for delivering both high quality and volume of thermoplastic composite parts as it exploits all the principal advantages these materials provide. Nevertheless, a series of critical defects may be introduced during the process such as wrinkles, shear deformation of the textile, variation on the thickness as well as geometric distortions and residual stresses which are highly dependent on the material characteristics and the parameters of the process itself. In the present work presented is an analysis of these parameters and their influence on a simple semi-spherical geometry using finite element modelling. The results are also compared with actual experimental results

A critical review on the numerical simulation related to Physical Vapour Deposition

Physical Vapour Deposition (PVD) is a process usually used for the production of advanced coatings regarding its application in several industrial and current products, such as optical lens, moulds and dies, decorative parts or tools. This process has several variants due to its strong evolution along the last decades. The process is commonly assisted by plasma, creating a particular low pressure and medium temperature atmosphere, which is responsible for the transition of atomic particles between the target and the parts to be coated into a vacuum reactor. Several parameters are directly affecting the deposition, namely the substrate temperature, pressure inside the reactor, assisting gases used, type of current, power supply, bias, substrate and target materials, samples holder and corresponding rotation, deposition time, among others. Many mathematical models have been developed in order to allow the generation of numerical simulation applications, trying to combine parameters and expect the corresponding results. Numerical simulation applications were created around the mathematical models previously developed, which can play an important role in the prediction of the coating properties and structure. This paper intends to describe the numerical simulation evolution in the last years, namely the use of Finite Elements Method (FEM) and Computational Fluid Dynamics (CFD).LAETA/CETRIB/INEGI Research Center- FLAD – Fundação Luso-Americana para o Desenvolvimento | Ref. 116/2018Fundação para a Ciência e a Tecnologia | Ref. UID/EMS/0615/201

An Assessment of PIER Electric Grid Research 2003-2014 White Paper

This white paper describes the circumstances in California around the turn of the 21st century that led the California Energy Commission (CEC) to direct additional Public Interest Energy Research funds to address critical electric grid issues, especially those arising from integrating high penetrations of variable renewable generation with the electric grid. It contains an assessment of the beneficial science and technology advances of the resultant portfolio of electric grid research projects administered under the direction of the CEC by a competitively selected contractor, the University of California’s California Institute for Energy and the Environment, from 2003-2014

A critical review on the numerical simulation related to Physical Vapour Deposition

Physical Vapour Deposition (PVD) is a process usually used for the production of advanced coatings regarding its application in several industrial and current products, such as optical lens, moulds and dies, decorative parts or tools. This process has several variants due to its strong evolution along the last decades. The process is commonly assisted by plasma, creating a particular low pressure and medium temperature atmosphere, which is responsible for the transition of atomic particles between the target and the parts to be coated into a vacuum reactor. Several parameters are directly affecting the deposition, namely the substrate temperature, pressure inside the reactor, assisting gases used, type of current, power supply, bias, substrate and target materials, samples holder and corresponding rotation, deposition time, among others. Many mathematical models have been developed in order to allow the generation of numerical simulation applications, trying to combine parameters and expect the corresponding results. Numerical simulation applications were created around the mathematical models previously developed, which can play an important role in the prediction of the coating properties and structure. This paper intends to describe the numerical simulation evolution in the last years, namely the use of Finite Elements Method (FEM) and Computational Fluid Dynamics (CFD).info:eu-repo/semantics/publishedVersio

Corrosion Prediction Model Of Corroded Pipeline Using Gumbel

Corrosion is an important degradation mechanism that can affect the reliability and integrity of the pipeline. Offshore pipelines are usually inspected using MFL Intelligent Pigging method; this is how internal pipeline corrosion can be definitively measured. However, a huge amount of thickness profile data was not used optimally to predict the corrosion rate. A reliable corrosion rate model is paramount to determine the re-inspection time interval and corrosion mitigation for pipelines. The objective of this final year project is to predict and analyze the internal pipeline corrosion for the chosen case study and develop a corrosion model. The methodology used in this project includes data gathering, data review, classification into defect type, data analysis, corrosion modelling, validation and discussion. The IP data was modelled with Gumbel distribution and result show that the data fits the curve and predicted the time to failure was for another 60 years. The result from Gumbel was compared to the deterministic approach of average time to failure of 149 years. The percent error was 40%. The project met the objective and can be further developed