[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

A review of the present and future utilisation of FRP composites in the civil infrastructure with reference to their important in-service properties

Composites science and technology

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

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Fatigue damage modeling of fibre-reinforced composite materials: Review

The review outlines modern trends in theoretical developments, novel designs and modern applications of sandwich structures. The most recent work published at the time of writing of this review is considered, older sources are listed only on as-needed basis. The review begins with the discussion on the analytical models and methods of analysis of sandwich structures as well as representative problems utilizing or comparing these models. Novel designs of sandwich structures is further elucidated concentrating on miscellaneous cores, introduction of nanotubes and smart materials in the elements of a sandwich structure as well as using functionally graded designs. Examples of problems experienced by developers and designers of sandwich structures, including typical damage, response under miscellaneous loads, environmental effects and fire are considered. Sample applications of sandwich structures included in the review concentrate on aerospace, civil and marine engineering, electronics and biomedical areas. Finally, the authors suggest a list of areas where they envision a pressing need in further research.

Review of current trends in research and applications of sandwich structures

The advantages of the use of glass fiber composites for grid shell are presented. The shape of grid shells results from a post-buckling state of tubes. To bypass the difficulty to predict the geometry of the final equilibrium state, the large rotations which occur during the erection process are modelled using the dynamic relaxation algorithm. This paper proposes an adaptation of this method for structures prestressed by bending through the development of a computer program. It includes the validation of this numerical tool through comparisons with a finite elements software. Then an application to the form-finding of a grid shell and the study of its stability under standard loading conditions will be presented. Finally the authors conclude on the technical and economic feasibility of this composite grid shell.

Form-finding of a grid shell in composite materials

The mechanical problem discussed in this paper focuses on the stress state estimation in a composite laminate in the vicinity of a free edge or microcracks. To calculate these stresses, we use two models called Multiparticle Models of Multilayered Materials (M4). The first one can be considered as a stacking sequence of Reissner-Mindlin plates (5 kinematic fields per layer), while the second is a membranar superposition (2 fields per layer plus a global one). These simplified models are able to provide finite values of interfacial stresses, even on the free edges of a structure. The current paper consists of validating the M4 by a finite element analysis through describing the stress fields in both a (0,90)s laminate in tension (free-edge problem) and a transversally microcracked (0,90)s laminate. A comparison of the various energy contributions helps yield a mechanical perspective: it appears possible to define an interply energy as well as a layer energy, these energies expressing the FE 3D reality.

Model of multilayered materials for interface stresses estimation and validation by finite element calculations

https://hal.archives-ouvertes.fr/hal-00401790/document

Jean-François Caron

Papers

Form-finding of a grid shell in composite materials

Model of multilayered materials for interface stresses estimation and validation by finite element calculations

Model of multilayered materials for interface stresses estimation and validation by finite element calculations

Multi-particle modelling for the prediction of delamination in multi-layered materials

Finite element analysis of free-edge stresses in composite laminates under mechanical an thermal loading