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American Society for Testing and Materials

Recently, there has been a rapid growth in research and innovation in the natural fibre composite (NFC) area. Interest is warranted due to the advantages of these materials compared to others, such as synthetic fibre composites, including low environmental impact and low cost and support their potential across a wide range of applications. Much effort has gone into increasing their mechanical performance to extend the capabilities and applications of this group of materials. This review aims to provide an overview of the factors that affect the mechanical performance of NFCs and details achievements made with them.

A review of recent developments in natural fibre composites and their mechanical performance

Haptic interfaces enable person‐machine communication through touch, and most commonly, in response to user movements. We comment on a distinct property of haptic interfaces, that of providing for simultaneous information exchange between a user and a machine. We also comment on the fact that, like other kinds of displays, they can take advantage of both the strengths and the limitations of human perception. The paper then proceeds with a description of the components and the modus operandi of haptic interfaces, followed by a list of current and prospective applications and a discussion of a cross‐section of current device designs.

/pdf/haptic-interfaces-and-devices-afidslr94r.pdf

Haptic interfaces and devices

Highly consistent quality and cost-effective manufacture of advanced composites can be achieved through automation. It may therefore open up new markets and applications for composite products in aerospace, automotive, renewable energy, and consumer goods. Automated Tape Laying (ATL) and Automated Fibre Placement (AFP) are the two main technologies used to automate the layup of prepreg. The historical development and past research of both technologies is reviewed; with an emphasis on past issues in application and capability as well as their solution, including both thermoset and thermoplastic material layup. It is shown that past developments have moved away from simply emulating manual layup into the now unique layup procedures for ATL, and into the current AFP technology base. The state of the art for both technologies is discussed and current gaps in the understanding of both processes highlighted. From this, future research needs and developments are derived and discussed.

The engineering aspects of automated prepreg layup: History, present and future

This paper presents a review of the major fatigue models and life time prediction methodologies for fibrereinforced polymer composites, subjected to fatigue loadings In this review, the fatigue models have been classified in three major categories: fatigue life models, which do not take into account the actual degradation mechanisms but use S-N curves or Goodman-type diagrams and introduce some sort of fatigue failure criterion; phenomenological models for residual stiffness/strength; and finally progressive damage models which use one or more damage variables related to measurable manifestations of damage (transverse matrix cracks, delamination size) Although this review does not pretend to be exhaustive, the most important models proposed during the last decades have been included, as well as the relevant equations upon which the respective models are based

/pdf/fatigue-damage-modeling-of-fibre-reinforced-composite-3ou84s4kuh.pdf

Fatigue damage modeling of fibre-reinforced composite materials: Review

An analytical investigation was performed to study the damage in laminated composites containing an open hole and subjected to compressive loading. A progressive damage model was developed during t...

Damage Tolerance of Laminated Composites Containing an Open Hole and Subjected to Compressive Loadings: Part I—Analysis

http://jafari3000.persiangig.com/document/Article(11-20)/1-s2.0-S0263822310001947-main.pdf

Optimum stacking sequence design of composite materials Part II: Variable stiffness design

In this research a modeling technique for simulating the fatigue behaviour of laminated composite materials, with or without stress concentrations, called progressive fatigue damage modeling, is es...

Progressive fatigue damage modeling of composite materials, Part I : Modeling

http://mdog.mcgill.ca/paper%20pdf%20to%20upload/Optimum%20stacking%20sequence%20design%20part1.pdf

Optimum stacking sequence design of composite materials Part I: Constant stiffness design

The Automated Fiber placement (AFP) process shows great potential for efficient manufacturing of large composite structures. However, uncertainties exist on mechanical performance of final product that are associated with the process induced defects. This experimental work investigates the effect of four principal defect types, namely gap, overlap, half gap/overlap and twisted tow on the ultimate strengths. Tests are executed at the lamina level (fiber tension, fiber compression and in-plane shear), as well as at the laminate level (open hole tension and open hole compression). Then each test is compared with a baseline configuration exempt from defects. Tests have revealed the minimal effects of a single and isolated defects on mechanical performance especially at the lamina level (around 5%) compared to the laminate level (up to 13%).

/pdf/experimental-study-of-the-effect-of-automated-fiber-1w36x6r0f9.pdf

Larry Lessard

Papers

Damage Tolerance of Laminated Composites Containing an Open Hole and Subjected to Compressive Loadings: Part I—Analysis

Optimum stacking sequence design of composite materials Part II: Variable stiffness design

Progressive fatigue damage modeling of composite materials, Part I : Modeling

Optimum stacking sequence design of composite materials Part I: Constant stiffness design

Experimental study of the effect of automated fiber placement induced defects on performance of composite laminates