Composite Structure Research Papers - Academia.edu (original) (raw)

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Recent papers in Composite Structure

This article describes a fiber-optic interrogation device based on the pulsed time-of-flight technique. The apparatus is capable of measuring time delays between wideband reflectors, such as connectors, along a fiber path with a precision... more

This article describes a fiber-optic interrogation device based on the pulsed time-of-flight technique. The apparatus is capable of measuring time delays between wideband reflectors, such as connectors, along a fiber path with a precision of about 280 fs (rms value) and a spatial resolution of about 3 ns (0.30 m) in a measurement time of 25 ms. Potential application areas include measuring integral strain and its derivatives such as cracks, deflections, and displacements, particularly in large civil engineering and composite structures. The operation and basic blocks of the measurement system are presented in detail together with measurement results obtained in laboratory and field conditions. It is shown that by using a fiber loop sensor with a reference fiber, it is possible to achieve a strain precision below 1 microstrain and a measurement frequency of 4 Hz. System performance proved adequate for the study of both static and dynamic phenomena in a bridge deck.

This paper presents ArchiTRIO (Architectural TRIO), a new temporal logic language which combines a subset of the UML notation with a precise formal semantics inspired from the authors’ experiences. ArchiTRIO allows developers to use... more

This paper presents ArchiTRIO (Architectural TRIO), a new temporal logic language which combines a subset of the UML notation with a precise formal semantics inspired from the authors’ experiences. ArchiTRIO allows developers to use standard UML 2.0 notation to describe non-critical aspects of systems, but it also offers a complementary formal notation, fully integrated with the UML one, to represent those system aspects that require precise modeling.

This paper reports the development of natural cellulose technical fibers from soybean straw with properties similar to the natural cellulose fibers in current use. About 220 million tons of soybean straw available in the world every year... more

This paper reports the development of natural cellulose technical fibers from soybean straw with properties similar to the natural cellulose fibers in current use. About 220 million tons of soybean straw available in the world every year could complement the byproducts of other major food crops as inexpensive, abundant and annually renewable sources for natural cellulose fibers. Using the agricultural byproducts as sources for fibers could help to address the concerns on the future price and availability of both the natural and synthetic fibers in current use and also help to add value to the food crops. A simple alkaline extraction was used to obtain technical fibers from soybean straw and the composition, structure and properties of the fibers was studied. Technical fibers obtained from soybean straw have high cellulose content (85%) but low% crystallinity (47%). The technical fibers have breaking tenacity (2.7 g/den) and breaking elongation (3.9%) higher than those of fibers obtained from wheat straw and sorghum stalk and leaves but lower than that of cotton. Overall, the structure and properties of the technical fibers obtained from soybean straw indicates that the fibers could be suitable for use in textile, composite and other industrial applications.

The use of functional repair components stored inside hollow reinforcing fibres is being considered as a self- repair system for future composite structures. This paper considers the problem of introducing a liquid healing resin,... more

The use of functional repair components stored inside hollow reinforcing fibres is being considered as a self- repair system for future composite structures. This paper considers the problem of introducing a liquid healing resin, contained within hollow glass storage vessels, within a space environment. The problem of resin outgassing of a commercially available 2-part epoxy resin system and the thermal cycling of the glass storage vessels, and their sealing caps, are discussed. The mechanical property assessment of the baseline hollow fibre laminate, the damaged hollow fibre laminate and the healed hollow fibre laminate is discussed revealed that a self-healed laminate had a residual strength of 87% compared to an undamaged baseline laminate and 100% compared to an undamaged self-healing laminate. This study provides clear evidence that a FRP laminate containing hollow fibre layers can successfully self-heal.

The development of timberconcrete composite structures has shown that composite systems are a very efficient solution to increase the loadcarrying ca pacity and overall performance of timber structures. The weak� ness of these systems is... more

The development of timberconcrete composite structures has shown that composite systems are a very efficient solution to increase the loadcarrying ca pacity and overall performance of timber structures. The weak� ness of these systems is clearly marked by the stiffness of the bond line, the natural limitations of the timber and defects in wood. An innovative solution of these problems

The present paper reviews the fundamental structural response characteristics and technological issues of composite steel and concrete systems. It assesses the pros and cons of composite structural systems and investigates the efficacy of... more

The present paper reviews the fundamental structural response characteristics and technological issues of composite steel and concrete systems. It assesses the pros and cons of composite structural systems and investigates the efficacy of beam-column members. Design rules for composite constructions are presented and discussed in details in order to get deep insight into their background. Areas of further research are

Present paper describes the facilities of composite material properties identification technique using specimen vibration tests, genetic algorithms, finite elements analysis and specimen shape optimization. In identification process the... more

Present paper describes the facilities of composite material properties identification technique using specimen vibration tests, genetic algorithms, finite elements analysis and specimen shape optimization. In identification process the elastic constants in a numerical model is updated so that the output from the numerical code fits the results from vibration testing. Main problem analysed in this paper is that Poisson's ratio is the worst determined elastic characteristic due to its low influence on specimen eigenfrequencies. It is shown that it is possible to increase its influence by choosing specific test specimen characteristics (side aspect ratio, orthotropy angle, etc.) via optimization routine. In this paper are presented test results of some experiments wherein glass‐epoxy and carbon‐epoxy material properties were identified. Santrauka Straipsnyje aprašomas kompozitiniu medžiagu tamprumo charakteristiku identifikavimo metodas naudojant bandiniu vibracinius bandymus, gen...

A computational methodology is presented for modeling the non-linear mechanical behavior of composite structures made of FRP (Fiber-Reinforced Polymers) laminates. The model is based on the appropriate combination of the constitutive... more

A computational methodology is presented for modeling the non-linear mechanical behavior of composite structures made of FRP (Fiber-Reinforced Polymers) laminates. The model is based on the appropriate combination of the constitutive models of compounding materials, considered to behave as isolated continua, together with additional "closure equations" that characterize the micro-mechanics of the composite from a morphological point of view. To

This paper reviews briefly traditional rehabilitation methods and provides a detailed discussion of design issues along with the advantages and the disadvantages of innovative strategies for seismic retrofitting of steel and composite... more

This paper reviews briefly traditional rehabilitation methods and provides a detailed discussion of design issues along with the advantages and the disadvantages of innovative strategies for seismic retrofitting of steel and composite structures. Special emphasis is placed on base isolation and supplemental damping devices. The viability and cost-effectiveness of these strategies are assessed on the basis of multiple limit states within the framework of performance-based design. A number of parameters which govern the selection of the intervention devices are investigated.

The present article provides a brief review of the open literature concerning applications of piezoelectric sen- sors and actuators for active and passive vibration control. Then, some recent advances on this subject are presented. In... more

The present article provides a brief review of the open literature concerning applications of piezoelectric sen- sors and actuators for active and passive vibration control. Then, some recent advances on this subject are presented. In particular, the following topics are discussed in detail: i) modeling of structures with piezoelectric sensors and actu- ators, ii) evaluation of the effective electromechanical cou-

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