The interactions between small dense particles and fluid turbulence have been investigated in a downflow fully developed channel in air. Particle velocities of, and fluid velocities in the presence of, 50 μm glass, 90 μm glass and 70 μm copper spherical beads were measured by laser Doppler anemometry, at particle mass loadings up to 80%. These particles were smaller than the Kolmogorov lengthscale of the flow and could respond to some but not all of the scales of turbulent motion. Streamwise mean particle velocity profiles were flatter than the mean fluid velocity profile, which was unmodified by particle loading. Particle velocity fluctuation intensities were larger than the unladen-fluid turbulence intensity in the streamwise direction but were smaller in the transverse direction. Fluid turbulence was attenuated by the addition of particles; the degree of attenuation increased with particle Stokes number, particle mass loading and distance from the wall. Turbulence was more strongly attenuated in the transverse than in the streamwise direction, because the turbulence energy is at higher frequencies in the transverse direction. Streamwise turbulence attenuation displayed a range of preferred frequencies where attenuation was strongest.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022112094002703

Particle response and turbulence modification in fully developed channel flow

The increased usage of fiber reinforced polymer composites in load bearing applications requires a detailed understanding of the process induced residual stresses and their effect on the shape distortions. This is utmost necessary in order to have more reliable composite manufacturing since the residual stresses alter the internal stress level of the composite part during the service life and the residual shape distortions may lead to not meeting the desired geometrical tolerances. The occurrence of residual stresses during the manufacturing process inherently contains diverse interactions between the involved physical phenomena mainly related to material flow, heat transfer and polymerization or crystallization. Development of numerical process models is required for virtual design and optimization of the composite manufacturing process which avoids the expensive trial-and-error based approaches. The process models as well as applications focusing on the prediction of residual stresses and shape distortions taking place in composite manufacturing are discussed in this study. The applications on both thermoset and thermoplastic based composites are reviewed in detail.

/pdf/a-review-on-the-mechanical-modeling-of-composite-4qkmjrbd8y.pdf

A Review on the Mechanical Modeling of Composite Manufacturing Processes

With the advent of high performance thermoplastic polymers, structural applications for thermoplastic composites are increasing rapidly. Thermoplastic matrix composites possess distinct advantages vis-a-vis thermoset matrix composites in terms of recyclability, high specific strength and specific stiffness, corrosion resistance, enhanced impact toughness, cost effectiveness, and flexibility of design. Since 1990s, the number of material forms and combinations in fibre reinforced thermoplastic polymers has increased exponentially, thereby expanding application avenues in transportation, automotive, mass transit, marine, aerospace, military and construction sectors. In this paper we review the state of the art in processing of fibre reinforced thermoplastics. We start with a brief description of thermoplastic polymers used in structural applications followed by material forms and methods of impregnation of the reinforcement with polymer. Long fibre based processing methods are described next. A desc...

Processing of fibre reinforced thermoplastic composites

Fiber-reinforced composite materials are replacing metallic components due to their higher specific strength and stiffness. Automation and thermoplastics emerged to overcome the time and labor inte...

Processing of thermoplastic matrix composites through automated fiber placement and tape laying methods: A review

Analysis of transport phenomena governing interfacial bonding and void dynamics during thermoplastic tow-placement

This paper presents analytical and numerical thermal analysis for melting and consolidating impregnated composite tapes in the presence of a localized heat source. This analysis also leads to the prediction of the processing window for a given tape-laying configuration. Heat of melting/solidification is included in the form of a heat generation term. A separation of variables method is employed to solve the governing equations ana lytically. In the numerical analysis, the governing equations are discretized using a non uniform mesh and are solved using a finite difference approach. The processing parame ters, such as consolidation speed, heat intensity, heat source width, etc., as well as material properties are incorporated within the analysis. The results show large thermal gradients in the vicinity of the consolidation point. The error between the analytical solu tion and the numerical result is found to be 3 % for the maximum temperature, and the maximum error for the temperature over the entire domai...

Thermal Analysis of in-situ Thermoplastic Composite Tape Laying

In filament winding of thermoplastics, localized melting/solidification can reduce the residual stresses and allow for improved dimensional stability and performance. This paper presents a three-dimensional thermal analysis for melting and consolidating impregnated tows in the presence of a local heat source during filament winding of thermoplastic composites. The analysis is performed using an Eulerian approach. The anisotropy of the filament wound woven structure is modeled as an orthotropic domain employing the concept of angle-ply sublaminates. The effective orthotropic conductivity tensor incorporates the effect of winding angle. The governing equations are discretized in a nonuniform mesh domain and solved using a finite difference approach. The processing parameters, such as winding angle, winding speed, and heat input, as well as material properties, are incorporated into the analysis. The results show large thermal gradients in the vicinity of the consolidation point. The effects of winding speed and heat input are investigated, and the overall thermal characterization of the process is discussed. The accuracy of the numerical method is assessed by comparing the results of a test problem with an available analytical solution.

Thermal Analysis of In-Situ Thermoplastic-Matrix Composite Filament Winding

Thermoplastic-matrix composites offer the possibility of combining the laydown, melting and consolidation steps of the impregnated tows in a continuous process, avoiding the curing steps which are necessary with thermosetting materials One of the main issues in the fabrication of thermoplastic composites is the residual stresses that build up due to volumetric changes during solidification/ crystallization In filament winding of thermoplastics, localized melting/ solidification can reduce the residual stresses and allow for improved dimensional stability and performance

Prediction of Process-Induced Stresses for In-Situ Thermoplastic Filament Winding of Cylinders

Effects of processing parameters on material responses during in-situ filament winding of thermoplastic composites

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

R. D. Cope

Author Tools

Chat about Author

Papers

Thermal Analysis of in-situ Thermoplastic Composite Tape Laying

Thermal Analysis of In-Situ Thermoplastic-Matrix Composite Filament Winding

Prediction of Process-Induced Stresses for In-Situ Thermoplastic Filament Winding of Cylinders

Effects of processing parameters on material responses during in-situ filament winding of thermoplastic composites