Journal ArticleDOI
Scale effects in the response and failure of fiber reinforced composite laminates loaded in tension and in flexure
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The feasibility of using scale model testing for predicting the full-scale behavior of flat composite coupons loaded in tension and beam-columns loaded in flexure is examined in this article, where classical laws of similitude are applied to fabricate and test replica model specimens to identify scaling effects in the load response, strength, and mode of failure.Abstract:
The feasibility of using scale model testing for predicting the full-scale behavior of flat composite coupons loaded in tension and beam-columns loaded in flexure is examined. Classical laws of similitude are applied to fabricate and test replica model specimens to identify scaling effects in the load response, strength, and mode of failure. Experiments were performed on graphite-epoxy composite specimens having different laminate stacking sequences and a range of scaled sizes. From the experiments it was deduced that the elastic response of scaled composite specimens was independent of size. However, a significant scale effect in strength was observed. In addition, a transition in failure mode was observed among scaled specimens of certain laminate stacking sequences. A Weibull statistical model and a fracture mechanics based model were applied to predict the strength scale effect since standard failure criteria cannot account for the influence of absolute specimen size on strength.read more
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BookDOI
Mechanical testing of advanced fibre composites
TL;DR: In this paper, the authors present a method for testing organic matrix composites using tension compression shear, flexure through-thickness testing, fracture toughness, impact and damage tolerance.
Journal ArticleDOI
Scaling of Structural Failure
Zdenek P. Bazant,Er-Ping Chen +1 more
Abstract: This article attempts to review the progress achieved in the understanding of scaling and size ef fect in the failure of structures. Particular emphasis is placed on quasi brittle materials for which the size etTect is important and complicated. After reflections on the long history of size effect studies, attention is focused on three main types of size effects, namely the statistical size effect due to randomness of strength, the energy release size effect, and the possible size effect due to fractality of fracture or microcracks. Definitive conclusions on the applicability of these theories are drawn. Subsequently, the article discusses the application of the known size effect law for the measurement of material fracture properties, and the modeling of the size effect by the cohesive crack model, non local finite element models and discrete element models. Extensions to com pression failure and to the rate-dependent material behavior are also outlined. The damage con stitutive law needed for describing a microcracked material in the fracture process zone is dis cussed. Various applications to quasibrittle materials, including concrete, sea ice, fiber compos ites, rocks and ceramics are presented. There are 377 references included in this article.
Journal ArticleDOI
Size effects in the testing of fibre-composite materials
TL;DR: In this article, the effect of test specimen size on the unnotched strength of continuous fiber reinforced composites is considered, and different fundamental failure mechanisms of fibre direction tension, fibre direction compression, and matrix dominated transverse tension and shear are discussed in turn.
Journal ArticleDOI
Size effects in unnotched tensile strength of unidirectional and quasi-isotropic carbon/epoxy composites
TL;DR: In this paper, a series of fully scaled tests on unidirectional and quasi-isotropic carbon fiber-epoxy has been carried out, and it was shown that transverse cracking and edge delamination caused premature failure in all cases.
Journal ArticleDOI
Size Effect and Fracture Characteristics of Composite Laminates
TL;DR: In this paper, the size effect on the nominal strength of fiber composite laminates has been investigated and it has been shown that there is a significant effect on nominal strength on fiber composite notches.
References
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Journal ArticleDOI
A Statistical Distribution Function of Wide Applicability
TL;DR: In this article, the applicability of statistics to a wide field of problems is discussed, and examples of simple and complex distributions are given, as well as a discussion of the application of statistics in a wide range of problems.
Book
Dimensional analysis and theory of models
TL;DR: Dimensional analysis as discussed by the authors is a technique that involves the study of dimensions of physical quantities and is used primarily as a tool for obtaining information about physical systems too complicated for full mathematical solutions to be feasible.
Journal ArticleDOI
Constrained cracking in glass fibre-reinforced epoxy cross-ply laminates
TL;DR: In this paper, the authors tested 90° cross-ply glass-reinforced epoxy resins in tension parallel to the direction of reinforcement in the outer plies and found that at large inner-ply thicknesses the specimens showed uniform transverse cracking.
Journal ArticleDOI
Progressive Transverse Cracking In Composite Laminates
Norman Laws,George J. Dvorak +1 more
TL;DR: In this article, a satisfactory theory for cross-ply laminates which have been damaged by transverse matrix cracking under monotonic loading has attracted a substantial number of investigators.
Journal ArticleDOI
Experimental Determination of the In Situ Transverse Lamina Strength in Graphite/Epoxy Laminates
Donald L. Flaggs,Murat H. Kural +1 more
TL;DR: In this article, the uniaxial tensile load at which transverse cracking initiated in the 90 deg. laminates was determined experimentally using DIB enhanced x-radiography.